An increased number of contiguous trinucleotide repeats in the DNA sequence from one generation to the next. The presence of these regions is associated with diseases such as FRAGILE X SYNDROME and MYOTONIC DYSTROPHY. Some CHROMOSOME FRAGILE SITES are composed of sequences where trinucleotide repeat expansion occurs.
Microsatellite repeats consisting of three nucleotides dispersed in the euchromatic arms of chromosomes.
An autosomal recessive disease, usually of childhood onset, characterized pathologically by degeneration of the spinocerebellar tracts, posterior columns, and to a lesser extent the corticospinal tracts. Clinical manifestations include GAIT ATAXIA, pes cavus, speech impairment, lateral curvature of spine, rhythmic head tremor, kyphoscoliosis, congestive heart failure (secondary to a cardiomyopathy), and lower extremity weakness. Most forms of this condition are associated with a mutation in a gene on chromosome 9, at band q13, which codes for the mitochondrial protein frataxin. (From Adams et al., Principles of Neurology, 6th ed, p1081; N Engl J Med 1996 Oct 17;335(16):1169-75) The severity of Friedreich ataxia associated with expansion of GAA repeats in the first intron of the frataxin gene correlates with the number of trinucleotide repeats. (From Durr et al, N Engl J Med 1996 Oct 17;335(16):1169-75)
An increase number of repeats of a genomic, tandemly repeated DNA sequence from one generation to the next.
A heterogenous group of degenerative syndromes marked by progressive cerebellar dysfunction either in isolation or combined with other neurologic manifestations. Sporadic and inherited subtypes occur. Inheritance patterns include autosomal dominant, autosomal recessive, and X-linked.
Neuromuscular disorder characterized by PROGRESSIVE MUSCULAR ATROPHY; MYOTONIA, and various multisystem atrophies. Mild INTELLECTUAL DISABILITY may also occur. Abnormal TRINUCLEOTIDE REPEAT EXPANSION in the 3' UNTRANSLATED REGIONS of DMPK PROTEIN gene is associated with Myotonic Dystrophy 1. DNA REPEAT EXPANSION of zinc finger protein-9 gene intron is associated with Myotonic Dystrophy 2.
A condition characterized genotypically by mutation of the distal end of the long arm of the X chromosome (at gene loci FRAXA or FRAXE) and phenotypically by cognitive impairment, hyperactivity, SEIZURES, language delay, and enlargement of the ears, head, and testes. INTELLECTUAL DISABILITY occurs in nearly all males and roughly 50% of females with the full mutation of FRAXA. (From Menkes, Textbook of Child Neurology, 5th ed, p226)
A familial disorder inherited as an autosomal dominant trait and characterized by the onset of progressive CHOREA and DEMENTIA in the fourth or fifth decade of life. Common initial manifestations include paranoia; poor impulse control; DEPRESSION; HALLUCINATIONS; and DELUSIONS. Eventually intellectual impairment; loss of fine motor control; ATHETOSIS; and diffuse chorea involving axial and limb musculature develops, leading to a vegetative state within 10-15 years of disease onset. The juvenile variant has a more fulminant course including SEIZURES; ATAXIA; dementia; and chorea. (From Adams et al., Principles of Neurology, 6th ed, pp1060-4)
A RNA-binding protein that is found predominately in the CYTOPLASM. It helps regulate GENETIC TRANSLATION in NEURONS and is absent or under-expressed in FRAGILE X SYNDROME.
Proteins that specifically bind to IRON.
Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).
A group of dominantly inherited, predominately late-onset, cerebellar ataxias which have been divided into multiple subtypes based on clinical features and genetic mapping. Progressive ataxia is a central feature of these conditions, and in certain subtypes POLYNEUROPATHY; DYSARTHRIA; visual loss; and other disorders may develop. (From Joynt, Clinical Neurology, 1997, Ch65, pp 12-17; J Neuropathol Exp Neurol 1998 Jun;57(6):531-43)
A dominantly-inherited ATAXIA first described in people of Azorean and Portuguese descent, and subsequently identified in Brazil, Japan, China, and Australia. This disorder is classified as one of the SPINOCEREBELLAR ATAXIAS (Type 3) and has been associated with a mutation of the MJD1 gene on chromosome 14. Clinical features include progressive ataxia, DYSARTHRIA, postural instability, nystagmus, eyelid retraction, and facial FASCICULATIONS. DYSTONIA is prominent in younger patients (referred to as Type I Machado-Joseph Disease). Type II features ataxia and ocular signs; Type III features MUSCULAR ATROPHY and a sensorimotor neuropathy; and Type IV features extrapyramidal signs combined with a sensorimotor neuropathy. (From Clin Neurosci 1995;3(1):17-22; Ann Neurol 1998 Mar;43(3):288-96)
Inherited disorders characterized by progressive atrophy and dysfunction of anatomically or physiologically related neurologic systems.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
'Nerve tissue proteins' are specialized proteins found within the nervous system's biological tissue, including neurofilaments, neuronal cytoskeletal proteins, and neural cell adhesion molecules, which facilitate structural support, intracellular communication, and synaptic connectivity essential for proper neurological function.
An increased tendency of the GENOME to acquire MUTATIONS when various processes involved in maintaining and replicating the genome are dysfunctional.
The most common clinical form of FRONTOTEMPORAL LOBAR DEGENERATION, this dementia presents with personality and behavioral changes often associated with disinhibition, apathy, and lack of insight.
Endonucleases that remove 5' DNA sequences from a DNA structure called a DNA flap. The DNA flap structure occurs in double-stranded DNA containing a single-stranded break where the 5' portion of the downstream strand is too long and overlaps the 3' end of the upstream strand. Flap endonucleases cleave the downstream strand of the overlap flap structure precisely after the first base-paired nucleotide, creating a ligatable nick.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The apparent tendency of certain diseases to appear at earlier AGE OF ONSET and with increasing severity in successive generations. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
A variety of simple repeat sequences that are distributed throughout the GENOME. They are characterized by a short repeat unit of 2-8 basepairs that is repeated up to 100 times. They are also known as short tandem repeats (STRs).
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
Copies of nucleic acid sequence that are arranged in opposing orientation. They may lie adjacent to each other (tandem) or be separated by some sequence that is not part of the repeat (hyphenated). They may be true palindromic repeats, i.e. read the same backwards as forward, or complementary which reads as the base complement in the opposite orientation. Complementary inverted repeats have the potential to form hairpin loop or stem-loop structures which results in cruciform structures (such as CRUCIFORM DNA) when the complementary inverted repeats occur in double stranded regions.
Tandem arrays of moderately repetitive, short (10-60 bases) DNA sequences which are found dispersed throughout the GENOME, at the ends of chromosomes (TELOMERES), and clustered near telomeres. Their degree of repetition is two to several hundred at each locus. Loci number in the thousands but each locus shows a distinctive repeat unit.
Copies of DNA sequences which lie adjacent to each other in the same orientation (direct tandem repeats) or in the opposite direction to each other (INVERTED TANDEM REPEATS).
The record of descent or ancestry, particularly of a particular condition or trait, indicating individual family members, their relationships, and their status with respect to the trait or condition.
Incoordination of voluntary movements that occur as a manifestation of CEREBELLAR DISEASES. Characteristic features include a tendency for limb movements to overshoot or undershoot a target (dysmetria), a tremor that occurs during attempted movements (intention TREMOR), impaired force and rhythm of diadochokinesis (rapidly alternating movements), and GAIT ATAXIA. (From Adams et al., Principles of Neurology, 6th ed, p90)
The age, developmental stage, or period of life at which a disease or the initial symptoms or manifestations of a disease appear in an individual.
Circumscribed masses of foreign or metabolically inactive materials, within the CELL NUCLEUS. Some are VIRAL INCLUSION BODIES.
Susceptibility of chromosomes to breakage leading to translocation; CHROMOSOME INVERSION; SEQUENCE DELETION; or other CHROMOSOME BREAKAGE related aberrations.
An autosomal dominant hereditary disease that presents in late in life and is characterized by DYSPHAGIA and progressive ptosis of the eyelids. Mutations in the gene for POLY(A)-BINDING PROTEIN II have been associated with oculopharyngeal muscular dystrophy.
Diseases that are caused by genetic mutations present during embryo or fetal development, although they may be observed later in life. The mutations may be inherited from a parent's genome or they may be acquired in utero.
Proteins that bind to RNA molecules. Included here are RIBONUCLEOPROTEINS and other proteins whose function is to bind specifically to RNA.
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
A degenerative disorder affecting upper MOTOR NEURONS in the brain and lower motor neurons in the brain stem and SPINAL CORD. Disease onset is usually after the age of 50 and the process is usually fatal within 3 to 6 years. Clinical manifestations include progressive weakness, atrophy, FASCICULATION, hyperreflexia, DYSARTHRIA, dysphagia, and eventual paralysis of respiratory function. Pathologic features include the replacement of motor neurons with fibrous ASTROCYTES and atrophy of anterior SPINAL NERVE ROOTS and corticospinal tracts. (From Adams et al., Principles of Neurology, 6th ed, pp1089-94)
The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.
Hereditary and sporadic conditions which are characterized by progressive nervous system dysfunction. These disorders are often associated with atrophy of the affected central or peripheral nervous system structures.
Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Proteins, generally found in the CYTOPLASM, that specifically bind ANDROGENS and mediate their cellular actions. The complex of the androgen and receptor migrates to the CELL NUCLEUS where it induces transcription of specific segments of DNA.
Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
Genes that influence the PHENOTYPE both in the homozygous and the heterozygous state.
A heterogeneous group of primarily familial disorders characterized by myoclonic seizures, tonic-clonic seizures, ataxia, progressive intellectual deterioration, and neuronal degeneration. These include LAFORA DISEASE; MERRF SYNDROME; NEURONAL CEROID-LIPOFUSCINOSIS; sialidosis (see MUCOLIPIDOSES), and UNVERRICHT-LUNDBORG SYNDROME.
The process by which a DNA molecule is duplicated.
The complete genetic complement contained in the DNA of a set of CHROMOSOMES in a HUMAN. The length of the human genome is about 3 billion base pairs.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
MutS homolog 2 protein is found throughout eukaryotes and is a homolog of the MUTS DNA MISMATCH-BINDING PROTEIN. It plays an essential role in meiotic RECOMBINATION and DNA REPAIR of mismatched NUCLEOTIDES.
A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.
A sequential pattern of amino acids occurring more than once in the same protein sequence.
An individual having different alleles at one or more loci regarding a specific character.
The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.
Double-stranded nucleic acid molecules (DNA-DNA or DNA-RNA) which contain regions of nucleotide mismatches (non-complementary). In vivo, these heteroduplexes can result from mutation or genetic recombination; in vitro, they are formed by nucleic acid hybridization. Electron microscopic analysis of the resulting heteroduplexes facilitates the mapping of regions of base sequence homology of nucleic acids.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.

Expression of Bcl-2 protein is decreased in colorectal adenocarcinomas with microsatellite instability. (1/845)

Bcl-2 is known to inhibit apoptosis and is thought to play a role in colorectal tumour development. Studies of the promoter region of bcl-2 have indicated the presence of a p53 responsive element which downregulates bcl-2 expression. Since p53 is commonly mutated in colorectal cancers, but rarely in those tumours showing microsatellite instability (MSI), the aim of this study was to examine the relationship of bcl-2 protein expression to MSI, as well as to other clinicopathological and molecular variables, in colorectal adenocarcinomas. Expression of bcl-2 was analysed by immunohistochemistry in 71 colorectal cancers which had been previously assigned to three classes depending upon their levels of MSI. MSI-high tumours demonstrated instability in three or more of six microsatellite markers tested, MSI-low tumours in one or two of six, and MSI-null in none of six. Bcl-2 expression in tumours was quantified independently by two pathologists and assigned to one of five categories, with respect to the number of cells which showed positive staining: 0, up to 5%; 1, 6-25%; 2, 26-50%; 3, 51-75%; and 4, > or =76%. Bcl-2 negative tumours were defined as those with a score of 0. Bcl-2 protein expression was tested for association with clinicopathological stage, differentiation level, tumour site, age, sex, survival, evidence of p53 inactivation and MSI level. A significant association was found between bcl-2 expression and patient survival (P = 0.012, Gehan Wilcoxon test). Further, a significant reciprocal relationship was found between bcl-2 expression and the presence of MSI (P = 0.012, Wilcoxon rank sum test). We conclude that bcl-2 expressing colorectal cancers are more likely to be MSI-null, and to be associated with improved patient survival.  (+info)

Genetics of the SCA6 gene in a large family segregating an autosomal dominant "pure" cerebellar ataxia. (2/845)

Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominant cerebellar degeneration caused by the expansion of a CAG trinucleotide repeat in the CACNA1A gene. Mutations in patients are characterised by expanded alleles of between 21 and 30 repeat units and by extreme gonadal stability when transmitted from parents to children. We have investigated the SCA6 mutation in a large Spanish kindred in which previously reported spinocerebellar SCA genes and loci had been excluded. We observed a 23 CAG repeat expanded allele in the 13 clinically affected subjects and in three out of 10 presymptomatic at risk subjects. Transmission of the mutant allele was stable in six parent to child pairs and in 29 meioses through the pedigree. Linkage analysis with the SCA6-CAG polymorphism and marker D19S221 confirmed the location of SCA6 on chromosome 19p13. The molecular findings in this large family confirm the expansion of the CAG repeat in the CACNA1A gene as the cause of SCA6 and the high meiotic stability of the repeat.  (+info)

Linkage disequilibrium and haplotype analysis in German Friedreich ataxia families. (3/845)

The main mutation causing Friedreich ataxia (FRDA) is the expansion of a GAA repeat localized within the intron between exon 1 and exon 2 of the gene X25. This expansion has been observed in 98% of FRDA chromosomes. To analyze frequencies of markers tightly linked to the Friedreich ataxia gene and to investigate wheter a limited number of ancestral chromosomes are shared by German FRDA families, a detailed analysis employing nine polymorphic markers was performed. We found strong linkage disequilibria and association of FRDA expansions with a few haplotypes. FRDA haplotypes differ significantly from control haplotypes. Our results confirm that GAA repeat expansions in intron 1 of the frataxin gene are limited to a few chromosomes and indicate an obvious founder effect in German patients. Based on these analyses, we estimate a minimum age of the mutation of 107 generations.  (+info)

Intermediate expansions of a GAA repeat in the frataxin gene are not associated with type 2 diabetes or altered glucose-induced beta-cell function in Danish Caucasians. (4/845)

A variable expansion of a GAA repeat is present in the first intron of the frataxin gene, also termed FRDA1 or X25. Long repeat lengths (>66 repeats) are present in patients with Friedreich's ataxia, while an intermediate expansion (10-66 repeats) has recently been reported to be highly associated with type 2 diabetes. Using a polymerase chain reaction-based assay, we found that 32.4% (95%CI 29.9-34.9) of 636 Danish Caucasian type 2 diabetic patients were carriers of an intermediate expansion, whereas the frequency was 30.4% (26.4-34.4) among 224 matched glucose-tolerant control subjects (P = 0.6). In the control subjects, the values of serum insulin and C-peptide responses during an oral glucose tolerance test were similar between the 69 carriers and 155 noncarriers. Furthermore, we investigated a possible relationship between expansions of the FRDA1 gene and glucose-induced beta-cell function in 338 young Caucasians (33.7% [30.1-37.3] carriers) and in 215 glucose-tolerant subjects (31.0% [26.6-35.4] carriers) with a type 2 diabetic parent. In neither population did the carriers differ from noncarriers according to values of fasting plasma glucose, serum insulin, or C-peptide, acute serum insulin, or C-peptide responses after intravenous glucose. In conclusion, intermediate expansion of the frataxin trinucleotide repeat is not associated with type 2 diabetes or altered glucose-induced insulin secretion in Danish Caucasians.  (+info)

Altered beta-cell characteristics in impaired glucose tolerant carriers of a GAA trinucleotide repeat polymorphism in the frataxin gene. (5/845)

Friedreich's ataxia is associated with GAA trinucleotide repeat expansions in the frataxin gene. In the general population, these trinucleotide expansions are variable in length, and three types of expansions are seen: short, intermediate, and long repeats. Friedreich's ataxia patients are generally homozygous for the long repeats and exhibit diabetes as pronounced comorbidity. Ristow et al. recently reported an association between the intermediate-length normal allele in the frataxin gene and type 2 diabetes. We have investigated in 94 subjects with impaired glucose tolerance (IGT) as to whether the length of the GAA trinucleotide repeat polymorphism in the frataxin gene associates with parameters reflecting beta-cell function. A hyperglycemic clamp at 10 mmol/l glucose for 3 h was used to quantitate beta-cell characteristics. Carriers of one or two intermediate repeat alleles (n = 32) had a 50% higher median first- phase insulin response to glucose than the noncarriers. Furthermore, they needed less time to reach peak insulin. An analysis of the distribution of the various repeat lengths in elderly type 2 diabetic (n = 179) and control subjects (n = 183), with the same age and ethnic background, did not provide evidence for an association of the intermediate-length repeat allele with type 2 diabetes in Dutch Caucasians.  (+info)

Fate of unstable Bacillus subtilis subgenome: re-integration and amplification in the main genome. (6/845)

The plastic Bacillus subtilis genome was dissected into two physically separate genomes, the 3.9 Mb main genome and the 0.3 Mb subgenome. DNA replication of the main genome was initiated from the normal replication origin (oriC) and that of the subgenome was from a 7.2 kb oriN-containing fragment artificially inserted. When the 7.2 kb fragment was shortened to a 1.5 kb fragment that contains oriN but lacks the segregational function, the subgenome became unstable and was rapidly lost from the cell, producing inviable cells due to the loss of essential genes carried by the subgenome. Stable survivors were isolated in which the subgenome had re-integrated and multiplied in the main genome. These results suggest that a reduced genetic stability of the subgenome induces size variation of the B. subtilis genome.  (+info)

Increased instability of human CTG repeat tracts on yeast artificial chromosomes during gametogenesis. (7/845)

Expansion of trinucleotide repeat tracts has been shown to be associated with numerous human diseases. The mechanism and timing of the expansion events are poorly understood, however. We show that CTG repeats, associated with the human DMPK gene and implanted in two homologous yeast artificial chromosomes (YACs), are very unstable. The instability is 6 to 10 times more pronounced in meiosis than during mitotic division. The influence of meiosis on instability is 4.4 times greater when the second YAC with a repeat tract is not present. Most of the changes we observed in trinucleotide repeat tracts are large contractions of 21 to 50 repeats. The orientation of the insert with the repeats has no effect on the frequency and distribution of the contractions. In our experiments, expansions were found almost exclusively during gametogenesis. Genetic analysis of segregating markers among meiotic progeny excluded unequal crossover as the mechanism for instability. These unique patterns have novel implications for possible mechanisms of repeat instability.  (+info)

Adenovirus-mediated expression of mutant DRPLA proteins with expanded polyglutamine stretches in neuronally differentiated PC12 cells. Preferential intranuclear aggregate formation and apoptosis. (8/845)

To investigate the molecular mechanisms of neurodegeneration caused by expanded CAG repeats in dentatorubral-pallidoluysian atrophy (DRPLA), an autosomal dominant neuro degrees enerative disorder caused by unstable expansion of a CAG trinucleotide repeat in the DRPLA gene on 12p13.31, we established an efficient expression system for truncated and full-length DRPLA proteins with normal or expanded polyglutamine stretches in neuronally differentiated PC12 cells and fibroblasts using an adenovirus expression system. Although aggregate body formation was observed both in neuronally differentiated PC12 cells and in fibroblasts expressing truncated DRPLA proteins with Q82, >97% ( n = 3) of neuronally differentiated PC12 cells showed intra-nuclear inclusions, while only 31 21% ( n = 3) of fibro-blasts had intranuclear inclusions at 3 days after infection. The percentage of apoptotic cells was significantly higher in neuronally differentiated PC12 cells expressing the truncated DRPLA protein with Q82 than in fibroblasts, suggesting the possibility that intranuclear aggregate bodies are formed preferentially in neuronally differentiated PC12 cells and that these cells are more vulnerable than fibroblasts to the toxic effects of expanded polyglutamine stretches in the DRPLA protein. When the full-length DRPLA protein with Q82 was expressed, aggregate bodies were found exclusively in the nuclei of the neuronally differentiated PC12 cells, while they were found in the cytoplasm of fibroblasts. Despite the presence of aggregate bodies, apoptosis was not induced by expression of the full-length DRPLA protein with Q82 in either neuronally differentiated PC12 cells or fibroblasts, suggesting that the presence of intranuclear aggregate bodies is in itself not necessarily toxic to cells.  (+info)

Trinucleotide Repeat Expansion is a genetic mutation where a sequence of three DNA nucleotides is repeated more frequently than what is typically found in the general population. In this type of mutation, the number of repeats can expand or increase from one generation to the next, leading to an increased risk of developing certain genetic disorders.

These disorders are often neurological and include conditions such as Huntington's disease, myotonic dystrophy, fragile X syndrome, and Friedreich's ataxia. The severity of these diseases can be related to the number of repeats present in the affected gene, with a higher number of repeats leading to more severe symptoms or an earlier age of onset.

It is important to note that not all trinucleotide repeat expansions will result in disease, and some people may carry these mutations without ever developing any symptoms. However, if the number of repeats crosses a certain threshold, it can lead to genetic instability and an increased risk of disease development.

Trinucleotide repeats refer to a specific type of DNA sequence expansion where a particular trinucleotide (a sequence made up of three nucleotides) is repeated multiple times. In normal genomic DNA, these repeats are usually present in a relatively stable and consistent range. However, when the number of repeats exceeds a certain threshold, it can result in an unstable genetic variant known as a trinucleotide repeat expansion.

These expansions can occur in various genes and are associated with several neurogenetic disorders, such as Huntington's disease, myotonic dystrophy, fragile X syndrome, and Friedreich's ataxia. The length of the trinucleotide repeat tends to expand further in subsequent generations, which can lead to anticipation – an earlier age of onset and increased severity of symptoms in successive generations.

The most common trinucleotide repeats involve CAG (cytosine-adenine-guanine) or CTG (cytosine-thymine-guanine) repeats, although other combinations like CGG, GAA, and GCT can also be involved. These repeat expansions can result in altered gene function, protein misfolding, aggregation, and toxicity, ultimately leading to the development of neurodegenerative diseases and other clinical manifestations.

Friedreich Ataxia is a genetic disorder that affects the nervous system and causes issues with movement. It is characterized by progressive damage to the nerves (neurons) in the spinal cord and peripheral nerves, which can lead to problems with muscle coordination, gait, speech, and hearing. The condition is also associated with heart disorders, diabetes, and vision impairment.

Friedreich Ataxia is caused by a mutation in the FXN gene, which provides instructions for making a protein called frataxin. This protein plays a role in the production of energy within cells, particularly in the mitochondria. The mutation in the FXN gene leads to reduced levels of frataxin, which can cause nerve damage and other symptoms associated with Friedreich Ataxia.

The condition typically begins in childhood or early adulthood and progresses over time, often leading to significant disability. There is currently no cure for Friedreich Ataxia, but treatments are available to help manage the symptoms and improve quality of life.

DNA repeat expansion is a genetic alteration in which a particular sequence of DNA base pairs is repeated multiple times. In normal genes, these repeats are relatively short and stable, but in certain diseases, the number of repeats can expand beyond a threshold, leading to changes in the structure or function of the gene. This type of mutation is often associated with neurological and neuromuscular disorders, such as Huntington's disease, myotonic dystrophy, and fragile X syndrome. The expanded repeats can also be unstable and may increase in size over generations, leading to more severe symptoms or earlier age of onset.

Spinocerebellar degenerations (SCDs) are a group of genetic disorders that primarily affect the cerebellum, the part of the brain responsible for coordinating muscle movements, and the spinal cord. These conditions are characterized by progressive degeneration or loss of nerve cells in the cerebellum and/or spinal cord, leading to various neurological symptoms.

SCDs are often inherited in an autosomal dominant manner, meaning that only one copy of the altered gene from either parent is enough to cause the disorder. The most common type of SCD is spinocerebellar ataxia (SCA), which includes several subtypes (SCA1, SCA2, SCA3, etc.) differentiated by their genetic causes and specific clinical features.

Symptoms of spinocerebellar degenerations may include:

1. Progressive ataxia (loss of coordination and balance)
2. Dysarthria (speech difficulty)
3. Nystagmus (involuntary eye movements)
4. Oculomotor abnormalities (problems with eye movement control)
5. Tremors or other involuntary muscle movements
6. Muscle weakness and spasticity
7. Sensory disturbances, such as numbness or tingling sensations
8. Dysphagia (difficulty swallowing)
9. Cognitive impairment in some cases

The age of onset, severity, and progression of symptoms can vary significantly among different SCD subtypes and individuals. Currently, there is no cure for spinocerebellar degenerations, but various supportive treatments and therapies can help manage symptoms and improve quality of life.

Myotonic dystrophy is a genetic disorder characterized by progressive muscle weakness, myotonia (delayed relaxation of muscles after contraction), and other symptoms. It is caused by an expansion of repetitive DNA sequences in the DMPK gene on chromosome 19 (type 1) or the ZNF9 gene on chromosome 3 (type 2). These expansions result in abnormal protein production and accumulation, which disrupt muscle function and can also affect other organs such as the heart, eyes, and endocrine system. Myotonic dystrophy is a progressive disease, meaning that symptoms tend to worsen over time. It is typically divided into two types: myotonic dystrophy type 1 (DM1), which is more common and severe, and myotonic dystrophy type 2 (DM2), which tends to be milder with a later onset of symptoms.

Fragile X syndrome is a genetic disorder caused by a mutation in the FMR1 gene, which provides instructions for making a protein called fragile X mental retardation protein (FMRP). This protein is essential for normal brain development.

In people with Fragile X syndrome, the FMR1 gene is missing a critical piece of DNA, leading to little or no production of FMRP. As a result, the brain's nerve cells cannot develop and function normally, which can cause a range of developmental problems, including learning disabilities, cognitive impairment, and behavioral and emotional difficulties.

Fragile X syndrome is the most common form of inherited intellectual disability, affecting about 1 in 4,000 males and 1 in 8,000 females. The symptoms and severity can vary widely, but most people with Fragile X syndrome have some degree of intellectual disability, ranging from mild to severe. They may also have physical features associated with the condition, such as a long face, large ears, flexible joints, and flat feet.

There is no cure for Fragile X syndrome, but early intervention and treatment can help improve outcomes. Treatment typically involves a combination of educational support, behavioral therapy, speech and language therapy, physical therapy, and medication to manage symptoms such as anxiety, hyperactivity, and aggression.

Huntington Disease (HD) is a genetic neurodegenerative disorder that affects both cognitive and motor functions. It is characterized by the progressive loss of neurons in various areas of the brain, particularly in the striatum and cortex. The disease is caused by an autosomal dominant mutation in the HTT gene, which codes for the huntingtin protein. The most common mutation is a CAG repeat expansion in this gene, leading to the production of an abnormal form of the huntingtin protein that is toxic to nerve cells.

The symptoms of HD typically appear between the ages of 30 and 50, but they can start earlier or later in life. The early signs of HD may include subtle changes in mood, cognition, and coordination. As the disease progresses, individuals with HD experience uncontrolled movements (chorea), emotional disturbances, cognitive decline, and difficulties with communication and swallowing. Eventually, they become dependent on others for their daily needs and lose their ability to walk, talk, and care for themselves.

There is currently no cure for HD, but medications and therapies can help manage the symptoms of the disease and improve quality of life. Genetic testing is available to confirm the diagnosis and provide information about the risk of passing the disease on to future generations.

Fragile X Mental Retardation Protein (FMRP) is a protein encoded by the FMR1 gene in humans. It is an RNA-binding protein that plays a critical role in regulating the translation and stability of mRNAs, particularly those involved in synaptic plasticity and neuronal development.

Mutations in the FMR1 gene, leading to the absence or reduction of FMRP, have been associated with Fragile X syndrome (FXS), which is the most common inherited form of intellectual disability and the leading genetic cause of autism spectrum disorder (ASD). In FXS, the lack of FMRP leads to an overproduction of proteins at synapses, resulting in altered neuronal connectivity and dysfunctional synaptic plasticity.

FMRP is widely expressed in various tissues, but it has a particularly high expression level in the brain, where it regulates the translation of mRNAs involved in learning, memory, and other cognitive functions. FMRP also interacts with several other proteins involved in neuronal development and function, such as ion channels, receptors, and signaling molecules.

Overall, Fragile X Mental Retardation Protein is a crucial regulator of synaptic plasticity and neuronal development, and its dysfunction has been linked to various neurodevelopmental disorders, including Fragile X syndrome, autism spectrum disorder, and intellectual disability.

Iron-binding proteins, also known as transferrins, are a type of protein responsible for the transport and storage of iron in the body. They play a crucial role in maintaining iron homeostasis by binding free iron ions and preventing them from participating in harmful chemical reactions that can produce reactive oxygen species (ROS) and cause cellular damage.

Transferrin is the primary iron-binding protein found in blood plasma, while lactoferrin is found in various exocrine secretions such as milk, tears, and saliva. Both transferrin and lactoferrin have a similar structure, consisting of two lobes that can bind one ferric ion (Fe3+) each. When iron is bound to these proteins, they are called holo-transferrin or holo-lactoferrin; when they are unbound, they are referred to as apo-transferrin or apo-lactoferrin.

Iron-binding proteins have a high affinity for iron and can regulate the amount of free iron available in the body. They help prevent iron overload, which can lead to oxidative stress and cellular damage, as well as iron deficiency, which can result in anemia and other health problems.

In summary, iron-binding proteins are essential for maintaining iron homeostasis by transporting and storing iron ions, preventing them from causing harm to the body's cells.

An allele is a variant form of a gene that is located at a specific position on a specific chromosome. Alleles are alternative forms of the same gene that arise by mutation and are found at the same locus or position on homologous chromosomes.

Each person typically inherits two copies of each gene, one from each parent. If the two alleles are identical, a person is said to be homozygous for that trait. If the alleles are different, the person is heterozygous.

For example, the ABO blood group system has three alleles, A, B, and O, which determine a person's blood type. If a person inherits two A alleles, they will have type A blood; if they inherit one A and one B allele, they will have type AB blood; if they inherit two B alleles, they will have type B blood; and if they inherit two O alleles, they will have type O blood.

Alleles can also influence traits such as eye color, hair color, height, and other physical characteristics. Some alleles are dominant, meaning that only one copy of the allele is needed to express the trait, while others are recessive, meaning that two copies of the allele are needed to express the trait.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Repetitive sequences in nucleic acid refer to repeated stretches of DNA or RNA nucleotide bases that are present in a genome. These sequences can vary in length and can be arranged in different patterns such as direct repeats, inverted repeats, or tandem repeats. In some cases, these repetitive sequences do not code for proteins and are often found in non-coding regions of the genome. They can play a role in genetic instability, regulation of gene expression, and evolutionary processes. However, certain types of repeat expansions have been associated with various neurodegenerative disorders and other human diseases.

Spinocerebellar ataxias (SCAs) are a group of genetic disorders that affect the cerebellum, which is the part of the brain responsible for coordinating muscle movements. SCAs are characterized by progressive problems with balance, speech, and coordination. They are caused by mutations in various genes that result in the production of abnormal proteins that accumulate in neurons, leading to their degeneration.

There are over 40 different types of SCAs, each caused by a different genetic mutation. Some of the more common types include SCA1, SCA2, SCA3, SCA6, and SCA7. The symptoms and age of onset can vary widely depending on the type of SCA.

In addition to problems with coordination and balance, people with SCAs may also experience muscle weakness, stiffness, tremors, spasticity, and difficulty swallowing or speaking. Some types of SCAs can also cause visual disturbances, hearing loss, and cognitive impairment. Currently, there is no cure for SCAs, but treatments such as physical therapy, speech therapy, and medications can help manage the symptoms.

Machado-Joseph Disease (MJD) is a genetic disorder that affects the part of the brain that controls movement. It is also known as spinocerebellar ataxia type 3 (SCA3). MJD is characterized by progressive problems with coordination, speech, and swallowing, along with muscle stiffness, tremors, and in some cases, eye movement abnormalities.

MJD is caused by a mutation in the ATXN3 gene, which results in an expanded CAG repeat sequence. This genetic defect leads to the production of an abnormal protein that accumulates in nerve cells, causing them to die. The severity and age of onset of MJD can vary widely, even within families, but symptoms typically begin between the ages of 10 and 60.

MJD is inherited in an autosomal dominant manner, meaning that a child has a 50% chance of inheriting the disease-causing mutation from an affected parent. Currently, there is no cure for MJD, but treatments can help manage symptoms and improve quality of life.

Heredodegenerative disorders of the nervous system are a group of inherited conditions that involve progressive degeneration of the nervous system over time. These disorders are caused by genetic mutations that affect the development and function of nerve cells in the brain and spinal cord. The symptoms and severity of these disorders can vary widely, depending on the specific condition and the location and extent of nerve cell damage.

Examples of heredodegenerative disorders of the nervous system include:

1. Huntington's disease: a genetic disorder that causes the progressive breakdown of nerve cells in the brain, leading to uncontrolled movements, emotional problems, and cognitive decline.
2. Friedreich's ataxia: an inherited disorder that affects the nerves and muscle coordination, causing symptoms such as difficulty walking, poor balance, and speech problems.
3. Spinal muscular atrophy: a genetic disorder that affects the motor neurons in the spinal cord, leading to muscle weakness and wasting.
4. Hereditary sensory and autonomic neuropathies: a group of inherited disorders that affect the nerves that control sensation and automatic functions such as heart rate and digestion.
5. Leukodystrophies: a group of genetic disorders that affect the white matter of the brain, leading to symptoms such as motor and cognitive decline, seizures, and vision loss.

Treatment for heredodegenerative disorders of the nervous system typically focuses on managing symptoms and improving quality of life. There is no cure for most of these conditions, but research is ongoing to develop new treatments and therapies that may help slow or stop the progression of nerve cell damage.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Nerve tissue proteins are specialized proteins found in the nervous system that provide structural and functional support to nerve cells, also known as neurons. These proteins include:

1. Neurofilaments: These are type IV intermediate filaments that provide structural support to neurons and help maintain their shape and size. They are composed of three subunits - NFL (light), NFM (medium), and NFH (heavy).

2. Neuronal Cytoskeletal Proteins: These include tubulins, actins, and spectrins that provide structural support to the neuronal cytoskeleton and help maintain its integrity.

3. Neurotransmitter Receptors: These are specialized proteins located on the postsynaptic membrane of neurons that bind neurotransmitters released by presynaptic neurons, triggering a response in the target cell.

4. Ion Channels: These are transmembrane proteins that regulate the flow of ions across the neuronal membrane and play a crucial role in generating and transmitting electrical signals in neurons.

5. Signaling Proteins: These include enzymes, receptors, and adaptor proteins that mediate intracellular signaling pathways involved in neuronal development, differentiation, survival, and death.

6. Adhesion Proteins: These are cell surface proteins that mediate cell-cell and cell-matrix interactions, playing a crucial role in the formation and maintenance of neural circuits.

7. Extracellular Matrix Proteins: These include proteoglycans, laminins, and collagens that provide structural support to nerve tissue and regulate neuronal migration, differentiation, and survival.

Genomic instability is a term used in genetics and molecular biology to describe a state of increased susceptibility to genetic changes or mutations in the genome. It can be defined as a condition where the integrity and stability of the genome are compromised, leading to an increased rate of DNA alterations such as point mutations, insertions, deletions, and chromosomal rearrangements.

Genomic instability is a hallmark of cancer cells and can also be observed in various other diseases, including genetic disorders and aging. It can arise due to defects in the DNA repair mechanisms, telomere maintenance, epigenetic regulation, or chromosome segregation during cell division. These defects can result from inherited genetic mutations, acquired somatic mutations, exposure to environmental mutagens, or age-related degenerative changes.

Genomic instability is a significant factor in the development and progression of cancer as it promotes the accumulation of oncogenic mutations that contribute to tumor initiation, growth, and metastasis. Therefore, understanding the mechanisms underlying genomic instability is crucial for developing effective strategies for cancer prevention, diagnosis, and treatment.

Frontotemporal dementia (FTD) is a group of disorders caused by progressive degeneration of the frontal and temporal lobes of the brain. These areas of the brain are associated with personality, behavior, and language.

There are three main types of FTD:

1. Behavioral variant FTD (bvFTD): This type is characterized by changes in personality, behavior, and judgment. Individuals may become socially inappropriate, emotionally indifferent, or impulsive. They may lose interest in things they used to enjoy and have difficulty with tasks that require planning and organization.

2. Primary progressive aphasia (PPA): This type affects language abilities. There are two main subtypes of PPA: semantic dementia and progressive nonfluent aphasia. Semantic dementia is characterized by difficulty understanding words and objects, while progressive nonfluent aphasia is characterized by problems with speech production and articulation.

3. Motor neuron disease (MND) associated FTD: Some individuals with FTD may also develop motor neuron disease, which affects the nerves that control muscle movement. This can lead to weakness, stiffness, and wasting of muscles, as well as difficulty swallowing and speaking.

FTD is a degenerative disorder, meaning that symptoms get worse over time. There is no cure for FTD, but there are treatments available to help manage symptoms and improve quality of life. The exact cause of FTD is not known, but it is believed to be related to abnormalities in certain proteins in the brain. In some cases, FTD may run in families and be caused by genetic mutations.

Flap endonucleases are a type of enzyme that are involved in the repair of damaged DNA. They are named for their ability to cleave or cut the "flaps" of single-stranded DNA that extend beyond the ends of double-stranded DNA. These flaps can occur as a result of DNA damage, such as oxidation or exposure to UV light, or during the normal process of DNA replication.

Flap endonucleases play an important role in several DNA repair pathways, including base excision repair and nucleotide excision repair. In these pathways, the enzyme recognizes and cleaves the flaps, allowing for the damaged or incorrect nucleotides to be removed and replaced with correct ones.

Flap endonucleases are highly conserved across different species, indicating their important role in maintaining genomic stability. Defects in these enzymes have been linked to increased susceptibility to cancer and other diseases associated with DNA damage.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Genetic anticipation is a phenomenon observed in certain genetic disorders where the severity and/or age of onset of the disease tend to worsen in successive generations. This occurs due to an expansion of triplet repeat sequences (sequences of three consecutive DNA base pairs) in the affected gene, which can lead to an increased production of abnormal proteins associated with the disorder. The expanded repeats are more likely to be inherited when the parent who carries them is a female. Examples of genetic disorders that exhibit anticipation include Huntington's disease, myotonic dystrophy, and fragile X syndrome.

Microsatellite repeats, also known as short tandem repeats (STRs), are repetitive DNA sequences made up of units of 1-6 base pairs that are repeated in a head-to-tail manner. These repeats are spread throughout the human genome and are highly polymorphic, meaning they can have different numbers of repeat units in different individuals.

Microsatellites are useful as genetic markers because of their high degree of variability. They are commonly used in forensic science to identify individuals, in genealogy to trace ancestry, and in medical research to study genetic diseases and disorders. Mutations in microsatellite repeats have been associated with various neurological conditions, including Huntington's disease and fragile X syndrome.

Deoxyribonucleic acid (DNA) is the genetic material present in the cells of organisms where it is responsible for the storage and transmission of hereditary information. DNA is a long molecule that consists of two strands coiled together to form a double helix. Each strand is made up of a series of four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - that are linked together by phosphate and sugar groups. The sequence of these bases along the length of the molecule encodes genetic information, with A always pairing with T and C always pairing with G. This base-pairing allows for the replication and transcription of DNA, which are essential processes in the functioning and reproduction of all living organisms.

Nucleic acid conformation refers to the three-dimensional structure that nucleic acids (DNA and RNA) adopt as a result of the bonding patterns between the atoms within the molecule. The primary structure of nucleic acids is determined by the sequence of nucleotides, while the conformation is influenced by factors such as the sugar-phosphate backbone, base stacking, and hydrogen bonding.

Two common conformations of DNA are the B-form and the A-form. The B-form is a right-handed helix with a diameter of about 20 Å and a pitch of 34 Å, while the A-form has a smaller diameter (about 18 Å) and a shorter pitch (about 25 Å). RNA typically adopts an A-form conformation.

The conformation of nucleic acids can have significant implications for their function, as it can affect their ability to interact with other molecules such as proteins or drugs. Understanding the conformational properties of nucleic acids is therefore an important area of research in molecular biology and medicine.

Inverted repeat sequences in a genetic context refer to a pattern of nucleotides (the building blocks of DNA or RNA) where a specific sequence appears in the reverse complementary orientation in the same molecule. This means that if you read the sequence from one end, it will be identical to the sequence read from the other end, but in the opposite direction.

For example, if a DNA segment is 5'-ATGCAT-3', an inverted repeat sequence would be 5'-GTACTC-3' on the same strand or its complementary sequence 3'-CAGTA-5' on the other strand.

These sequences can play significant roles in genetic regulation and expression, as they are often involved in forming hairpin or cruciform structures in single-stranded DNA or RNA molecules. They also have implications in genome rearrangements and stability, including deletions, duplications, and translocations.

Minisatellites, also known as VNTRs (Variable Number Tandem Repeats), are repetitive DNA sequences that consist of a core repeat unit of 10-60 base pairs, arranged in a head-to-tail fashion. They are often found in non-coding regions of the genome and can vary in the number of times the repeat unit is present in an individual's DNA. This variation in repeat number can occur both within and between individuals, making minisatellites useful as genetic markers for identification and forensic applications. They are also associated with certain genetic disorders and play a role in genome instability.

Tandem Repeat Sequences (TRS) in genetics refer to repeating DNA sequences that are arranged directly after each other, hence the term "tandem." These sequences consist of a core repeat unit that is typically 2-6 base pairs long and is repeated multiple times in a head-to-tail fashion. The number of repetitions can vary between individuals and even between different cells within an individual, leading to genetic heterogeneity.

TRS can be classified into several types based on the number of repeat units and their stability. Short Tandem Repeats (STRs), also known as microsatellites, have fewer than 10 repeats, while Minisatellites have 10-60 repeats. Variations in the number of these repeats can lead to genetic instability and are associated with various genetic disorders and diseases, including neurological disorders, cancer, and forensic identification.

It's worth noting that TRS can also occur in protein-coding regions of genes, leading to the production of repetitive amino acid sequences. These can affect protein structure and function, contributing to disease phenotypes.

I must clarify that the term "pedigree" is not typically used in medical definitions. Instead, it is often employed in genetics and breeding, where it refers to the recorded ancestry of an individual or a family, tracing the inheritance of specific traits or diseases. In human genetics, a pedigree can help illustrate the pattern of genetic inheritance in families over multiple generations. However, it is not a medical term with a specific clinical definition.

Cerebellar ataxia is a type of ataxia, which refers to a group of disorders that cause difficulties with coordination and movement. Cerebellar ataxia specifically involves the cerebellum, which is the part of the brain responsible for maintaining balance, coordinating muscle movements, and regulating speech and eye movements.

The symptoms of cerebellar ataxia may include:

* Unsteady gait or difficulty walking
* Poor coordination of limb movements
* Tremors or shakiness, especially in the hands
* Slurred or irregular speech
* Abnormal eye movements, such as nystagmus (rapid, involuntary movement of the eyes)
* Difficulty with fine motor tasks, such as writing or buttoning a shirt

Cerebellar ataxia can be caused by a variety of underlying conditions, including:

* Genetic disorders, such as spinocerebellar ataxia or Friedreich's ataxia
* Brain injury or trauma
* Stroke or brain hemorrhage
* Infections, such as meningitis or encephalitis
* Exposure to toxins, such as alcohol or certain medications
* Tumors or other growths in the brain

Treatment for cerebellar ataxia depends on the underlying cause. In some cases, there may be no cure, and treatment is focused on managing symptoms and improving quality of life. Physical therapy, occupational therapy, and speech therapy can help improve coordination, balance, and communication skills. Medications may also be used to treat specific symptoms, such as tremors or muscle spasticity. In some cases, surgery may be recommended to remove tumors or repair damage to the brain.

The "age of onset" is a medical term that refers to the age at which an individual first develops or displays symptoms of a particular disease, disorder, or condition. It can be used to describe various medical conditions, including both physical and mental health disorders. The age of onset can have implications for prognosis, treatment approaches, and potential causes of the condition. In some cases, early onset may indicate a more severe or progressive course of the disease, while late-onset symptoms might be associated with different underlying factors or etiologies. It is essential to provide accurate and precise information regarding the age of onset when discussing a patient's medical history and treatment plan.

Intranuclear inclusion bodies are abnormal, rounded structures found within the nucleus of a cell. They are composed of aggregated proteins or other cellular components and can be associated with various viral infections and certain genetic disorders. These inclusion bodies can interfere with normal nuclear functions, leading to cell damage and contributing to the pathogenesis of diseases such as cytomegalovirus infection, rabies, and some forms of neurodegenerative disorders like polyglutamine diseases. The presence of intranuclear inclusion bodies is often used in diagnostic pathology to help identify specific underlying conditions.

Chromosome fragility refers to the susceptibility of specific regions on chromosomes to break or become unstable during cell division. These fragile sites are prone to forming gaps or breaks in the chromosome structure, which can lead to genetic rearrangements, including deletions, duplications, or translocations.

Chromosome fragility is often associated with certain genetic disorders and syndromes. For example, the most common fragile site in human chromosomes is FRAXA, located on the X chromosome, which is linked to Fragile X Syndrome, a leading cause of inherited intellectual disability and autism.

Environmental factors such as exposure to chemicals or radiation can also increase chromosome fragility, leading to an increased risk of genetic mutations and diseases.

Oculopharyngeal Muscular Dystrophy (OPMD) is a genetic disorder that affects the muscles, particularly those around the eyes and throat. The medical definition of OPMD, as per the National Organization for Rare Disorders (NORD), is:

"Oculopharyngeal Muscular Dystrophy (OPMD) is an inherited neuromuscular disorder characterized by progressive weakness of specific muscle groups, particularly those around the eyes (ocular) and throat (pharyngeal). The symptoms may include drooping of the eyelids (ptosis), difficulty swallowing (dysphagia), and, in some cases, proximal limb weakness. Onset of the disorder usually occurs in adulthood, typically after age 40, but earlier onsets have been reported."

The underlying cause of OPMD is a genetic mutation that leads to the production of an abnormal protein in muscle cells, ultimately resulting in muscle degeneration and weakness.

Inborn genetic diseases, also known as inherited genetic disorders, are conditions caused by abnormalities in an individual's DNA that are present at conception. These abnormalities can include mutations, deletions, or rearrangements of genes or chromosomes. In many cases, these genetic changes are inherited from one or both parents and may be passed down through families.

Inborn genetic diseases can affect any part of the body and can cause a wide range of symptoms, which can vary in severity depending on the specific disorder. Some genetic disorders are caused by mutations in a single gene, while others are caused by changes in multiple genes or chromosomes. In some cases, environmental factors may also contribute to the development of these conditions.

Examples of inborn genetic diseases include cystic fibrosis, sickle cell anemia, Huntington's disease, Duchenne muscular dystrophy, and Down syndrome. These conditions can have significant impacts on an individual's health and quality of life, and many require ongoing medical management and treatment. In some cases, genetic counseling and testing may be recommended for individuals with a family history of a particular genetic disorder to help them make informed decisions about their reproductive options.

RNA-binding proteins (RBPs) are a class of proteins that selectively interact with RNA molecules to form ribonucleoprotein complexes. These proteins play crucial roles in the post-transcriptional regulation of gene expression, including pre-mRNA processing, mRNA stability, transport, localization, and translation. RBPs recognize specific RNA sequences or structures through their modular RNA-binding domains, which can be highly degenerate and allow for the recognition of a wide range of RNA targets. The interaction between RBPs and RNA is often dynamic and can be regulated by various post-translational modifications of the proteins or by environmental stimuli, allowing for fine-tuning of gene expression in response to changing cellular needs. Dysregulation of RBP function has been implicated in various human diseases, including neurological disorders and cancer.

Polymerase Chain Reaction (PCR) is a laboratory technique used to amplify specific regions of DNA. It enables the production of thousands to millions of copies of a particular DNA sequence in a rapid and efficient manner, making it an essential tool in various fields such as molecular biology, medical diagnostics, forensic science, and research.

The PCR process involves repeated cycles of heating and cooling to separate the DNA strands, allow primers (short sequences of single-stranded DNA) to attach to the target regions, and extend these primers using an enzyme called Taq polymerase, resulting in the exponential amplification of the desired DNA segment.

In a medical context, PCR is often used for detecting and quantifying specific pathogens (viruses, bacteria, fungi, or parasites) in clinical samples, identifying genetic mutations or polymorphisms associated with diseases, monitoring disease progression, and evaluating treatment effectiveness.

Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disorder that affects nerve cells in the brain and spinal cord responsible for controlling voluntary muscle movements, such as speaking, walking, breathing, and swallowing. The condition is characterized by the degeneration of motor neurons in the brain (upper motor neurons) and spinal cord (lower motor neurons), leading to their death.

The term "amyotrophic" comes from the Greek words "a" meaning no or negative, "myo" referring to muscle, and "trophic" relating to nutrition. When a motor neuron degenerates and can no longer send impulses to the muscle, the muscle becomes weak and eventually atrophies due to lack of use.

The term "lateral sclerosis" refers to the hardening or scarring (sclerosis) of the lateral columns of the spinal cord, which are primarily composed of nerve fibers that carry information from the brain to the muscles.

ALS is often called Lou Gehrig's disease, named after the famous American baseball player who was diagnosed with the condition in 1939. The exact cause of ALS remains unknown, but it is believed to involve a combination of genetic and environmental factors. There is currently no cure for ALS, and treatment primarily focuses on managing symptoms and maintaining quality of life.

The progression of ALS varies from person to person, with some individuals experiencing rapid decline over just a few years, while others may have a more slow-progressing form of the disease that lasts several decades. The majority of people with ALS die from respiratory failure within 3 to 5 years after the onset of symptoms. However, approximately 10% of those affected live for 10 or more years following diagnosis.

Genetic polymorphism refers to the occurrence of multiple forms (called alleles) of a particular gene within a population. These variations in the DNA sequence do not generally affect the function or survival of the organism, but they can contribute to differences in traits among individuals. Genetic polymorphisms can be caused by single nucleotide changes (SNPs), insertions or deletions of DNA segments, or other types of genetic rearrangements. They are important for understanding genetic diversity and evolution, as well as for identifying genetic factors that may contribute to disease susceptibility in humans.

Neurodegenerative diseases are a group of disorders characterized by progressive and persistent loss of neuronal structure and function, often leading to cognitive decline, functional impairment, and ultimately death. These conditions are associated with the accumulation of abnormal protein aggregates, mitochondrial dysfunction, oxidative stress, chronic inflammation, and genetic mutations in the brain. Examples of neurodegenerative diseases include Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis (ALS), and Spinal Muscular Atrophy (SMA). The underlying causes and mechanisms of these diseases are not fully understood, and there is currently no cure for most neurodegenerative disorders. Treatment typically focuses on managing symptoms and slowing disease progression.

Nuclear proteins are a category of proteins that are primarily found in the nucleus of a eukaryotic cell. They play crucial roles in various nuclear functions, such as DNA replication, transcription, repair, and RNA processing. This group includes structural proteins like lamins, which form the nuclear lamina, and regulatory proteins, such as histones and transcription factors, that are involved in gene expression. Nuclear localization signals (NLS) often help target these proteins to the nucleus by interacting with importin proteins during active transport across the nuclear membrane.

A phenotype is the physical or biochemical expression of an organism's genes, or the observable traits and characteristics resulting from the interaction of its genetic constitution (genotype) with environmental factors. These characteristics can include appearance, development, behavior, and resistance to disease, among others. Phenotypes can vary widely, even among individuals with identical genotypes, due to differences in environmental influences, gene expression, and genetic interactions.

Peptides are short chains of amino acid residues linked by covalent bonds, known as peptide bonds. They are formed when two or more amino acids are joined together through a condensation reaction, which results in the elimination of a water molecule and the formation of an amide bond between the carboxyl group of one amino acid and the amino group of another.

Peptides can vary in length from two to about fifty amino acids, and they are often classified based on their size. For example, dipeptides contain two amino acids, tripeptides contain three, and so on. Oligopeptides typically contain up to ten amino acids, while polypeptides can contain dozens or even hundreds of amino acids.

Peptides play many important roles in the body, including serving as hormones, neurotransmitters, enzymes, and antibiotics. They are also used in medical research and therapeutic applications, such as drug delivery and tissue engineering.

Proteins are complex, large molecules that play critical roles in the body's functions. They are made up of amino acids, which are organic compounds that are the building blocks of proteins. Proteins are required for the structure, function, and regulation of the body's tissues and organs. They are essential for the growth, repair, and maintenance of body tissues, and they play a crucial role in many biological processes, including metabolism, immune response, and cellular signaling. Proteins can be classified into different types based on their structure and function, such as enzymes, hormones, antibodies, and structural proteins. They are found in various foods, especially animal-derived products like meat, dairy, and eggs, as well as plant-based sources like beans, nuts, and grains.

DNA repair is the process by which cells identify and correct damage to the DNA molecules that encode their genome. DNA can be damaged by a variety of internal and external factors, such as radiation, chemicals, and metabolic byproducts. If left unrepaired, this damage can lead to mutations, which may in turn lead to cancer and other diseases.

There are several different mechanisms for repairing DNA damage, including:

1. Base excision repair (BER): This process repairs damage to a single base in the DNA molecule. An enzyme called a glycosylase removes the damaged base, leaving a gap that is then filled in by other enzymes.
2. Nucleotide excision repair (NER): This process repairs more severe damage, such as bulky adducts or crosslinks between the two strands of the DNA molecule. An enzyme cuts out a section of the damaged DNA, and the gap is then filled in by other enzymes.
3. Mismatch repair (MMR): This process repairs errors that occur during DNA replication, such as mismatched bases or small insertions or deletions. Specialized enzymes recognize the error and remove a section of the newly synthesized strand, which is then replaced by new nucleotides.
4. Double-strand break repair (DSBR): This process repairs breaks in both strands of the DNA molecule. There are two main pathways for DSBR: non-homologous end joining (NHEJ) and homologous recombination (HR). NHEJ directly rejoins the broken ends, while HR uses a template from a sister chromatid to repair the break.

Overall, DNA repair is a crucial process that helps maintain genome stability and prevent the development of diseases caused by genetic mutations.

DNA Sequence Analysis is the systematic determination of the order of nucleotides in a DNA molecule. It is a critical component of modern molecular biology, genetics, and genetic engineering. The process involves determining the exact order of the four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - in a DNA molecule or fragment. This information is used in various applications such as identifying gene mutations, studying evolutionary relationships, developing molecular markers for breeding, and diagnosing genetic diseases.

The process of DNA Sequence Analysis typically involves several steps, including DNA extraction, PCR amplification (if necessary), purification, sequencing reaction, and electrophoresis. The resulting data is then analyzed using specialized software to determine the exact sequence of nucleotides.

In recent years, high-throughput DNA sequencing technologies have revolutionized the field of genomics, enabling the rapid and cost-effective sequencing of entire genomes. This has led to an explosion of genomic data and new insights into the genetic basis of many diseases and traits.

Androgen receptors (ARs) are a type of nuclear receptor protein that are expressed in various tissues throughout the body. They play a critical role in the development and maintenance of male sexual characteristics and reproductive function. ARs are activated by binding to androgens, which are steroid hormones such as testosterone and dihydrotestosterone (DHT). Once activated, ARs function as transcription factors that regulate gene expression, ultimately leading to various cellular responses.

In the context of medical definitions, androgen receptors can be defined as follows:

Androgen receptors are a type of nuclear receptor protein that bind to androgens, such as testosterone and dihydrotestosterone, and mediate their effects on gene expression in various tissues. They play critical roles in the development and maintenance of male sexual characteristics and reproductive function, and are involved in the pathogenesis of several medical conditions, including prostate cancer, benign prostatic hyperplasia, and androgen deficiency syndromes.

Genetic models are theoretical frameworks used in genetics to describe and explain the inheritance patterns and genetic architecture of traits, diseases, or phenomena. These models are based on mathematical equations and statistical methods that incorporate information about gene frequencies, modes of inheritance, and the effects of environmental factors. They can be used to predict the probability of certain genetic outcomes, to understand the genetic basis of complex traits, and to inform medical management and treatment decisions.

There are several types of genetic models, including:

1. Mendelian models: These models describe the inheritance patterns of simple genetic traits that follow Mendel's laws of segregation and independent assortment. Examples include autosomal dominant, autosomal recessive, and X-linked inheritance.
2. Complex trait models: These models describe the inheritance patterns of complex traits that are influenced by multiple genes and environmental factors. Examples include heart disease, diabetes, and cancer.
3. Population genetics models: These models describe the distribution and frequency of genetic variants within populations over time. They can be used to study evolutionary processes, such as natural selection and genetic drift.
4. Quantitative genetics models: These models describe the relationship between genetic variation and phenotypic variation in continuous traits, such as height or IQ. They can be used to estimate heritability and to identify quantitative trait loci (QTLs) that contribute to trait variation.
5. Statistical genetics models: These models use statistical methods to analyze genetic data and infer the presence of genetic associations or linkage. They can be used to identify genetic risk factors for diseases or traits.

Overall, genetic models are essential tools in genetics research and medical genetics, as they allow researchers to make predictions about genetic outcomes, test hypotheses about the genetic basis of traits and diseases, and develop strategies for prevention, diagnosis, and treatment.

Transgenic mice are genetically modified rodents that have incorporated foreign DNA (exogenous DNA) into their own genome. This is typically done through the use of recombinant DNA technology, where a specific gene or genetic sequence of interest is isolated and then introduced into the mouse embryo. The resulting transgenic mice can then express the protein encoded by the foreign gene, allowing researchers to study its function in a living organism.

The process of creating transgenic mice usually involves microinjecting the exogenous DNA into the pronucleus of a fertilized egg, which is then implanted into a surrogate mother. The offspring that result from this procedure are screened for the presence of the foreign DNA, and those that carry the desired genetic modification are used to establish a transgenic mouse line.

Transgenic mice have been widely used in biomedical research to model human diseases, study gene function, and test new therapies. They provide a valuable tool for understanding complex biological processes and developing new treatments for a variety of medical conditions.

Genotype, in genetics, refers to the complete heritable genetic makeup of an individual organism, including all of its genes. It is the set of instructions contained in an organism's DNA for the development and function of that organism. The genotype is the basis for an individual's inherited traits, and it can be contrasted with an individual's phenotype, which refers to the observable physical or biochemical characteristics of an organism that result from the expression of its genes in combination with environmental influences.

It is important to note that an individual's genotype is not necessarily identical to their genetic sequence. Some genes have multiple forms called alleles, and an individual may inherit different alleles for a given gene from each parent. The combination of alleles that an individual inherits for a particular gene is known as their genotype for that gene.

Understanding an individual's genotype can provide important information about their susceptibility to certain diseases, their response to drugs and other treatments, and their risk of passing on inherited genetic disorders to their offspring.

DNA primers are short single-stranded DNA molecules that serve as a starting point for DNA synthesis. They are typically used in laboratory techniques such as the polymerase chain reaction (PCR) and DNA sequencing. The primer binds to a complementary sequence on the DNA template through base pairing, providing a free 3'-hydroxyl group for the DNA polymerase enzyme to add nucleotides and synthesize a new strand of DNA. This allows for specific and targeted amplification or analysis of a particular region of interest within a larger DNA molecule.

Dominant genes refer to the alleles (versions of a gene) that are fully expressed in an individual's phenotype, even if only one copy of the gene is present. In dominant inheritance patterns, an individual needs only to receive one dominant allele from either parent to express the associated trait. This is in contrast to recessive genes, where both copies of the gene must be the recessive allele for the trait to be expressed. Dominant genes are represented by uppercase letters (e.g., 'A') and recessive genes by lowercase letters (e.g., 'a'). If an individual inherits one dominant allele (A) from either parent, they will express the dominant trait (A).

Progressive Myoclonic Epilepsies (PME) is a group of rare, genetic disorders characterized by myoclonus (rapid, involuntary muscle jerks), tonic-clonic seizures (also known as grand mal seizures), and progressive neurological deterioration. The term "progressive" refers to the worsening of symptoms over time.

The myoclonic epilepsies are classified as progressive due to the underlying neurodegenerative process that affects the brain, leading to a decline in cognitive abilities, motor skills, and overall functioning. These disorders usually begin in childhood or adolescence and tend to worsen with age.

Examples of PMEs include:

1. Lafora disease: A genetic disorder caused by mutations in the EPM2A or NHLRC1 genes, leading to the accumulation of abnormal protein aggregates called Lafora bodies in neurons. Symptoms typically start between ages 6 and 16 and include myoclonus, seizures, and progressive neurological decline.
2. Unverricht-Lundborg disease: Also known as Baltic myoclonus, this is an autosomal recessive disorder caused by mutations in the CSTB gene. It is characterized by progressive myoclonic epilepsy, ataxia (loss of coordination), and cognitive decline. Symptoms usually begin between ages 6 and 18.
3. Neuronal Ceroid Lipofuscinoses (NCLs): A group of inherited neurodegenerative disorders characterized by the accumulation of lipopigments in neurons. Several types of NCLs can present with progressive myoclonic epilepsy, including CLN2 (late-infantile NCL), CLN3 (juvenile NCL), and CLN6 (early juvenile NCL).
4. Myoclonus Epilepsy Associated with Ragged Red Fibers (MERRF): A mitochondrial disorder caused by mutations in the MT-TK gene, leading to myoclonic epilepsy, ataxia, and ragged red fibers on muscle biopsy.
5. Dentatorubral-Pallidoluysian Atrophy (DRPLA): An autosomal dominant disorder caused by mutations in the ATN1 gene, characterized by myoclonic epilepsy, ataxia, chorea (involuntary movements), and dementia.

These are just a few examples of disorders that can present with progressive myoclonic epilepsy. It is essential to consult a neurologist or epileptologist for proper diagnosis and management.

DNA replication is the biological process by which DNA makes an identical copy of itself during cell division. It is a fundamental mechanism that allows genetic information to be passed down from one generation of cells to the next. During DNA replication, each strand of the double helix serves as a template for the synthesis of a new complementary strand. This results in the creation of two identical DNA molecules. The enzymes responsible for DNA replication include helicase, which unwinds the double helix, and polymerase, which adds nucleotides to the growing strands.

A human genome is the complete set of genetic information contained within the 23 pairs of chromosomes found in the nucleus of most human cells. It includes all of the genes, which are segments of DNA that contain the instructions for making proteins, as well as non-coding regions of DNA that regulate gene expression and provide structural support to the chromosomes.

The human genome contains approximately 3 billion base pairs of DNA and is estimated to contain around 20,000-25,000 protein-coding genes. The sequencing of the human genome was completed in 2003 as part of the Human Genome Project, which has had a profound impact on our understanding of human biology, disease, and evolution.

Genetic transcription is the process by which the information in a strand of DNA is used to create a complementary RNA molecule. This process is the first step in gene expression, where the genetic code in DNA is converted into a form that can be used to produce proteins or functional RNAs.

During transcription, an enzyme called RNA polymerase binds to the DNA template strand and reads the sequence of nucleotide bases. As it moves along the template, it adds complementary RNA nucleotides to the growing RNA chain, creating a single-stranded RNA molecule that is complementary to the DNA template strand. Once transcription is complete, the RNA molecule may undergo further processing before it can be translated into protein or perform its functional role in the cell.

Transcription can be either "constitutive" or "regulated." Constitutive transcription occurs at a relatively constant rate and produces essential proteins that are required for basic cellular functions. Regulated transcription, on the other hand, is subject to control by various intracellular and extracellular signals, allowing cells to respond to changing environmental conditions or developmental cues.

MutS Homolog 2 (MSH2) Protein is a type of protein involved in the DNA repair process in cells. It is a member of the MutS family of proteins, which are responsible for identifying and correcting mistakes that occur during DNA replication. MSH2 forms a complex with another MutS homolog, MSH6, and this complex plays a crucial role in recognizing and binding to mismatched base pairs in the DNA. Once bound, the complex recruits other proteins to repair the damage and restore the integrity of the DNA. Defects in the MSH2 gene have been linked to an increased risk of certain types of cancer, including hereditary non-polyposis colorectal cancer (HNPCC) and uterine cancer.

Genetic markers are specific segments of DNA that are used in genetic mapping and genotyping to identify specific genetic locations, diseases, or traits. They can be composed of short tandem repeats (STRs), single nucleotide polymorphisms (SNPs), restriction fragment length polymorphisms (RFLPs), or variable number tandem repeats (VNTRs). These markers are useful in various fields such as genetic research, medical diagnostics, forensic science, and breeding programs. They can help to track inheritance patterns, identify genetic predispositions to diseases, and solve crimes by linking biological evidence to suspects or victims.

Amino acid repetitive sequences refer to patterns of amino acids that are repeated in a polypeptide chain. These repetitions can vary in length and can be composed of a single type of amino acid or a combination of different types. In some cases, expansions of these repetitive sequences can lead to the production of abnormal proteins that are associated with certain genetic disorders. The expansion of trinucleotide repeats that code for particular amino acids is one example of this phenomenon. These expansions can result in protein misfolding and aggregation, leading to neurodegenerative diseases such as Huntington's disease and spinocerebellar ataxias.

A heterozygote is an individual who has inherited two different alleles (versions) of a particular gene, one from each parent. This means that the individual's genotype for that gene contains both a dominant and a recessive allele. The dominant allele will be expressed phenotypically (outwardly visible), while the recessive allele may or may not have any effect on the individual's observable traits, depending on the specific gene and its function. Heterozygotes are often represented as 'Aa', where 'A' is the dominant allele and 'a' is the recessive allele.

Exons are the coding regions of DNA that remain in the mature, processed mRNA after the removal of non-coding intronic sequences during RNA splicing. These exons contain the information necessary to encode proteins, as they specify the sequence of amino acids within a polypeptide chain. The arrangement and order of exons can vary between different genes and even between different versions of the same gene (alternative splicing), allowing for the generation of multiple protein isoforms from a single gene. This complexity in exon structure and usage significantly contributes to the diversity and functionality of the proteome.

A nucleic acid heteroduplex is a double-stranded structure formed by the pairing of two complementary single strands of nucleic acids (DNA or RNA) that are derived from different sources. The term "hetero" refers to the fact that the two strands are not identical and come from different parents, genes, or organisms.

Heteroduplexes can form spontaneously during processes like genetic recombination, where DNA repair mechanisms may mistakenly pair complementary regions between two different double-stranded DNA molecules. They can also be generated intentionally in laboratory settings for various purposes, such as analyzing the similarity of DNA sequences or detecting mutations.

Heteroduplexes are often used in molecular biology techniques like polymerase chain reaction (PCR) and DNA sequencing, where they can help identify mismatches, insertions, deletions, or other sequence variations between the two parental strands. These variations can provide valuable information about genetic diversity, evolutionary relationships, and disease-causing mutations.

"Saccharomyces cerevisiae" is not typically considered a medical term, but it is a scientific name used in the field of microbiology. It refers to a species of yeast that is commonly used in various industrial processes, such as baking and brewing. It's also widely used in scientific research due to its genetic tractability and eukaryotic cellular organization.

However, it does have some relevance to medical fields like medicine and nutrition. For example, certain strains of S. cerevisiae are used as probiotics, which can provide health benefits when consumed. They may help support gut health, enhance the immune system, and even assist in the digestion of certain nutrients.

In summary, "Saccharomyces cerevisiae" is a species of yeast with various industrial and potential medical applications.

DNA-binding proteins are a type of protein that have the ability to bind to DNA (deoxyribonucleic acid), the genetic material of organisms. These proteins play crucial roles in various biological processes, such as regulation of gene expression, DNA replication, repair and recombination.

The binding of DNA-binding proteins to specific DNA sequences is mediated by non-covalent interactions, including electrostatic, hydrogen bonding, and van der Waals forces. The specificity of binding is determined by the recognition of particular nucleotide sequences or structural features of the DNA molecule.

DNA-binding proteins can be classified into several categories based on their structure and function, such as transcription factors, histones, and restriction enzymes. Transcription factors are a major class of DNA-binding proteins that regulate gene expression by binding to specific DNA sequences in the promoter region of genes and recruiting other proteins to modulate transcription. Histones are DNA-binding proteins that package DNA into nucleosomes, the basic unit of chromatin structure. Restriction enzymes are DNA-binding proteins that recognize and cleave specific DNA sequences, and are widely used in molecular biology research and biotechnology applications.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.

The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.

Examples of animal disease models include:

1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.

Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.

A trinucleotide repeat expansion, also known as a triplet repeat expansion, is the DNA mutation responsible for causing any ... of trinucleotide repeat expansion transmission in many predicted models due to the difficulty of Trinucleotide Repeat Expansion ... trinucleotide repeat expansion can also occur during DNA repair. When a DNA trinucleotide repeat sequence is damaged, it may be ... In trinucleotide repeat expansion there is a certain threshold or maximum amount of repeats that can occur before a sequence ...
The process of DNA mismatch repair plays a prominent role in the formation of direct trinucleotide repeat expansions. Such ... ISBN 978-1-84800-254-8. Richard, G. F. (2021). "The Startling Role of Mismatch Repair in Trinucleotide Repeat Expansions". ... Tandem repeats (tandem repeat sequences) are repeated copies which lie adjacent to each other. These can also be direct or ... Flanking (or terminal) repeats (terminal repeat sequences) are sequences that are repeated on both ends of a sequence, for ...
The expansion of intronic trinucleotide repeat GAA results in Friedreich's ataxia. This expanded repeat causes R-loop formation ... 96% of FRDA patients have a GAA trinucleotide repeat expansion in intron 1 of both alleles of their FXN gene. Overall, this ... Baralle M, Pastor T, Bussani E, Pagani F (Jul 2008). "Influence of Friedreich ataxia GAA noncoding repeat expansions on pre- ... These mice are called YG22R (one GAA sequence of 190 repeats) and YG22R (two GAA sequences of 90 and 190 repeats). These mice ...
They determined that the disease was caused by an expansion of the glutamine-encoding CAG trinucleotide repeat in this gene, ... "Expansion of an unstable trinucleotide CAG repeat in spinocerebellar ataxia type 1". Nature Genetics. 4 (3): 221-226. doi: ... and that the younger the age of onset, the longer the CAG repeat. Further work by Zoghbi, Orr and their teams demonstrated that ...
July 1993). "Expansion of an unstable trinucleotide CAG repeat in spinocerebellar ataxia type 1". Nature Genetics. 4 (3): 221- ... This expansion results in a larger than normal number of repeats of the nucleotide sequence cytosine, adenine, guanine, or CAG ... It is caused by an expanded number of trinucleotide repeats in the polyglutamine tract of the ATXN1 gene, which encodes the ... Kraus-Perrotta C, Lagalwar S (November 22, 2016). "Expansion, mosaicism and interruption: mechanisms of the CAG repeat mutation ...
SCA1 is a trinucleotide repeat disorder caused by expansion of the CAG repeat in ATXN1; this leads to an expanded polyglutamine ... "Expansion of an unstable trinucleotide CAG repeat in spinocerebellar ataxia type 1". Nature Genetics. 4 (3): 221-6. doi:10.1038 ... Repeats of 39 or more uninterrupted CAG triplets cause disease, and longer repeat tracts are correlated with earlier age of ... There is a CAG repeat in the coding sequence which is longer in humans than other species (6-38 uninterrupted CAG repeats in ...
"Linkage between male infertility and trinucleotide repeat expansion in the androgen-receptor gene". Lancet. 354 (9179): 640-3. ... Yeh SH, Chiu CM, Chen CL, Lu SF, Hsu HC, Chen DS, Chen PJ (April 2007). "Somatic mutations at the trinucleotide repeats of ... Choong CS, Wilson EM (December 1998). "Trinucleotide repeats in the human androgen receptor: a molecular basis for disease". J ... is associated with a particular mutation of the androgen receptor's polyglutamine tract called a trinucleotide repeat expansion ...
"Moderate expansion of a normally biallelic trinucleotide repeat in spinocerebellar ataxia type 2". Nature Genetics. 14 (3): 269 ... Normal alleles usually have 22 or 23 repeats, but can contain up to 31 repeats. Longer expansions can cause spinocerebellar ... "cDNAs with long CAG trinucleotide repeats from human brain". Human Genetics. 100 (1): 114-22. doi:10.1007/s004390050476. PMID ... "Identification of the spinocerebellar ataxia type 2 gene using a direct identification of repeat expansion and cloning ...
Trinucleotide repeat expansion located in the non-coding region of the NOTCH2NLC gene. (CGG) 4. Trinucleotide repeat expansion ... Trinucleotide repeat expansion located in the 5-prime untranslated region of the LRP12 gene. (CGG) 2. Trinucleotide repeat ... discovered a heterozygous trinucleotide repeat expansion in the 5-prime untranslated region of the LRP12 gene in 5 patients ... discovered heterozygous trinucleotide repeat expansions in the non-coding region of the NOTCH2NLC gene of seven un-related ...
The trinucleotide repeat expansion of the polyglutamine tract of the AR gene that is associated with SBMA results in the ... "Linkage between male infertility and trinucleotide repeat expansion in the androgen-receptor gene". Lancet. 354 (9179): 640-3. ... Yeh SH, Chiu CM, Chen CL, Lu SF, Hsu HC, Chen DS, Chen PJ (April 2007). "Somatic mutations at the trinucleotide repeats of ... Choong CS, Wilson EM (December 1998). "Trinucleotide repeats in the human androgen receptor: a molecular basis for disease". J ...
The majority of diseases caused by expansions of simple DNA repeats involve trinucleotide repeats, but tetra-, penta- and ... are a set of over 50 genetic disorders caused by trinucleotide repeat expansion, a kind of mutation in which repeats of three ... has trinucleotide repeats that occur in the exons of the affected genes. Some of the problems in trinucleotide repeat syndromes ... Trinucleotide+Repeat+Expansion at the U.S. National Library of Medicine Medical Subject Headings (MeSH) GeneReviews/NCBI/NIH/UW ...
The disorder is related to the expansion of a trinucleotide repeat within this gene. In patients with DRPLA, truncated ATN1 has ... The number of CAG repeats in the ATN1 gene in a healthy person will range from six to thirty-five repeats. CAG repeats that ... The ATN1 gene has a segment of DNA called the CAG trinucleotide repeat. It is made up of cytosine, adenine, and guanine. ... Mutations in ATN1 are associated with a form of trinucleotide repeat disorder known as "dentatorubral-pallidoluysian atrophy" ...
Expansion of trinucleotide repeats also occurs in humans, in general leading to many diseases. Learning how D. discoideum cells ... The repeats correspond to repeated sequences of amino acids and are thought to be expanded by nucleotide expansion. ... Tandem repeats of trinucleotides are very abundant in this genome; one class of the genome is clustered, leading researchers to ... endure these amino acid repeats may provide insight to allow humans to tolerate them. Every genome sequenced plays an important ...
1996). "Moderate expansion of a normally biallelic trinucleotide repeat in spinocerebellar ataxia type 2". Nat. Genet. 14 (3): ... 1996). "Moderate expansion of a normally biallelic trinucleotide repeat in spinocerebellar ataxia type 2". Nat. Genet. 14 (3): ... 2004). "The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)". Genome ...
... may refer to: Insertion (genetics) Trinucleotide repeat, sometimes classified as a subgroup of insertions. This ... disambiguation page lists articles associated with the title Gene expansion. If an internal link led you here, you may wish to ...
FA is an autosomal recessive disorder caused by pathological GAA trinucleotide repeat expansions in the FXN gene. The encoded ... Autosomal Recessive Disease Caused by an Intronic GAA Triplet Repeat Expansion". Science. 271 (5254): 1423-7. Bibcode:1996Sci ...
This is an example of a Trinucleotide repeat disorder. Trinucleotide repeat expansion is likely a consequence of strand ... Minor expansions of CGG repeats that do not cause fragile X syndrome are associated with an increased risk for premature ... to base pair 146,738,156 Almost all cases of fragile X syndrome are caused by expansion of the CGG trinucleotide repeat in the ... The FMR1 gene is located on the X chromosome and contains a repeated CGG trinucleotide. In most people, the CGG segment is ...
These trinucleotide repeat expansions may occur through strand slippage during DNA replication or during DNA repair synthesis. ... Trinucleotide repeat expansions in the germline over successive generations can lead to increasingly severe manifestations of ... Huntington's disease is a neurodegenerative disorder which is due to the expansion of repeated trinucleotide sequence CAG in ... "Tandem Repeat". Genome.gov. Retrieved 2022-09-30. Sznajder ŁJ, Swanson MS (July 2019). "Short Tandem Repeat Expansions and RNA- ...
"Expansion of a novel CAG trinucleotide repeat in the 5' region of PPP2R2B is associated with SCA12". Nat Genet. 23 (4): 391-2. ... Schalling M, Hudson TJ, Buetow KH, Housman DE (1993). "Direct detection of novel expanded trinucleotide repeats in the human ...
SBMA is caused by a trinucleotide repeat expansion in the first exon of the androgen receptor (AR) gene. The AR gene, located ... Diagnosis of SBMA is established by genetic testing that identifies a CAG trinucleotide repeat expansion in the AR gene. If ... X-linked recessive lower motor neuron disease caused by trinucleotide CAG repeat expansions in exon 1 of the androgen receptor ... The repeat expansion likely causes a toxic gain of function in the receptor protein, since loss of receptor function in ...
Presumably the expansion interferes with normal antisense function of this transcript. RAN translation Trinucleotide repeat ... A cytidine, thymidine, guanosine (CTG) trinucleotide repeat expansion that is incorporated into the SCA8 but not the KLHL1 ... expansions of trinucleotide repeats in SCA8 and SCA17 are associated with typical Parkinson's disease". Clinical Genetics. 65 ( ... Sułek A, Hoffman-Zacharska D, Bednarska-Makaruk M, Szirkowiec W, Zaremba J (2004). "Polymorphism of trinucleotide repeats in ...
... the mutant FXN gene has 90-1,300 GAA trinucleotide repeat expansions in intron 1 of both alleles. This expansion causes ... FRDA was first linked to a GAA repeat expansion on chromosome 9 in 1996. Currently there is no cure for Friedreich's ataxia, ... March 1996). "Friedreich's ataxia: autosomal recessive disease caused by an intronic GAA triplet repeat expansion". Science. ... In about 4% of cases, the disease is caused by a (missense, nonsense, or intronic) point mutation, with an expansion in one ...
Trinucleotide repeat expansion occurring in a parental germline cell can lead to children that are more affected or display an ... Trinucleotide repeat expansion is considered to be a consequence of slipped strand mispairing either during DNA replication or ... In general, several neurodegenerative disorders were found to involve nucleotide repeat expansions in protein coding sequences ... Rice C, Beekman D, Liu L, Erives A (2015). "The Nature, Extent, and Consequences of Genetic Variation in the opa Repeats of ...
The key sequence which is found in Huntington's disease is a trinucleotide repeat expansion of glutamine residues beginning at ... This region is called a trinucleotide repeat. The usual CAG repeat count is between seven and 35 repeats. The HTT gene is ... As the altered gene is passed from one generation to the next, the size of the CAG repeat expansion can change; it often ... Nance MA, Mathias-Hagen V, Breningstall G, Wick MJ, McGlennen RC (Jan 1999). "Analysis of a very large trinucleotide repeat in ...
If the disease is caused by a polyglutamine trinucleotide repeat CAG expansion, a longer expansion may lead to an earlier onset ... Several types of SCA are characterized by repeat expansion of the trinucleotide sequence CAG in DNA that encodes a ... contains a large number of repeats of glutamine residues, termed a polyQ sequence or a "CAG trinucleotide repeat" disease for ... The expansion of CAG repeats over successive generations appears to be due to slipped strand mispairing during DNA replication ...
The 3' untranslated region of this gene contains 5-37 copies of a CTG trinucleotide repeat. Expansion of this unstable motif to ... As the DMPK repeat is replicated, the hairpin loop that is formed leads to repeat expansion (a) or contractions (b). Myotonic ... expansion of a trinucleotide (CTG) repeat at the 3' end of a transcript encoding a protein kinase family member". Cell. 68 (4 ... Repeat expansion is associated with condensation of local chromatin structure that disrupts the expression of genes in this ...
... triplet repeats, termed trinucleotide repeat expansion and classifying DM1 as a one of several trinucleotide repeat disorders. ... as the degree of repeat expansion beyond 75 repeats does not affect the age of onset or disease severity. The repeat expansion ... This expansion occurs in the first intron CNBP gene on chromosome 3. The repeat expansion for DM2 is much larger than for DM1, ... double-strand break repair or during other DNA repair processes likely contribute to trinucleotide repeat expansions in DM1. ...
... and Erasmus University Rotterdam identified a massive expansion of CGG repeat (Trinucleotide repeat disorder) in FMR1. This was ... sequences and was a co-discoverer of the mutation that causes Fragile X syndrome as an expansion of a trinucleotide repeat in ... Nelson's research group has used flies and mice to identify and characterize modifiers that showed that the CGG repeat is ... By studying humans, mice, flies and yeast Nelson's research group has characterized the origins of instability in the repeat, ...
There, she studied the trinucleotide repeat sequence expansions, the mutations responsible for the Fragile-X Syndrome, and ... The gene contains a polymorphic CGG trinucleotide repeat in their DNA sequence; the repeat ranged from 6 to 54 in individuals ... based on the hypothesis that genetic anticipation in Myotonic dystrophy is also caused by trinucleotide repeat expansion on ... Macdonald, M (Mar 26, 1993). "A novel gene containing a trinucleotide repeat that is expanded and unstable on Huntington's ...
Although trinucleotide contraction is possible, trinucleotide expansion occurs more frequently. Tandem repeats (the main ... trinucleotide expansion in the SCA3 gene), myotonic dystrophy ( trinucleotide expansion in the DMPK gene), and Friedreich's ... trinucleotide expansion in the DRPLA gene), spinocerebellar ataxia type 1 ( trinucleotide expansion in the SCA1gene), Machado- ... Trinucleotide repeat expansion is a cause of a number of human diseases including fragile X syndrome, Huntington's disease, ...
A trinucleotide repeat expansion, also known as a triplet repeat expansion, is the DNA mutation responsible for causing any ... of trinucleotide repeat expansion transmission in many predicted models due to the difficulty of Trinucleotide Repeat Expansion ... trinucleotide repeat expansion can also occur during DNA repair. When a DNA trinucleotide repeat sequence is damaged, it may be ... In trinucleotide repeat expansion there is a certain threshold or maximum amount of repeats that can occur before a sequence ...
... Muscle Nerve. 1995 Jul;18(7):782-3. doi: ...
David C. Rubinsztein on Microsatellite and trinucleotide repeat expansion diseases, part of a collection of multimedia lectures ... Microsatellite and trinucleotide repeat expansion diseases. *Prof. David C. Rubinsztein - University of Cambridge, UK ... Rubinsztein, D.C. (2020, June 30). Microsatellite and trinucleotide repeat expansion diseases [Video file]. In The Biomedical ... and trinucleotide repeat expansions diseases. The focus of my talk is going to be on the genetics of these diseases, and Ill ...
Molecular genetic analyses of trinucleotide repeat expansions. *Balasubramanian, Sureshkumar (Primary Chief Investigator (PCI)) ... A polynucleotide repeat expansion causing temperature-sensitivity persists in wild Irish accessions of Arabidopsis thaliana. ... RNA-Dependent Epigenetic Silencing Directs Transcriptional Downregulation Caused by Intronic Repeat Expansions. Eimer, H., ...
Exonic trinucleotide repeat expansions in ZFHX3 cause spinocerebellar ataxia type 4 : A poly-glycine disease. *Mark ... Here, we report the discovery of exonic GGC trinucleotide repeat expansions, encoding poly-glycine, in zinc finger homeobox 3 ( ... Here, we report the discovery of exonic GGC trinucleotide repeat expansions, encoding poly-glycine, in zinc finger homeobox 3 ( ... Here, we report the discovery of exonic GGC trinucleotide repeat expansions, encoding poly-glycine, in zinc finger homeobox 3 ( ...
A novel trinucleotide repeat expansion at chromosome 3q26.2 identified by a CAG/CTG repeat expansion detection array ... A novel trinucleotide repeat expansion at chromosome 3q26.2 identified by a CAG/CTG repeat expansion detection array. ... Home » A novel trinucleotide repeat expansion at chromosome 3q26.2 identified by a CAG/CTG repeat expansion detection array ...
... is a neurodegenerative disorder caused by an unstable and progressive expansion of a CAG trinucleotide repeat tract in the HD ... is a neurodegenerative disorder caused by an unstable and progressive expansion of a CAG trinucleotide repeat tract in the HD ... The knock-in mice carrying a 72-80 CAG repeat mutation is an accurate genetic model of early stage HD, displaying a more subtle ... To relate full-length HD gene expression and differential polyglutamine expansion with possible pathophysiological changes in ...
... is a progressive and fatal neurodegenerative disorder caused by an expanded CAG repeat in the huntingtin gene. Although HD is ... Relationship between trinucleotide repeat expansion and phenotypic variation in Huntingtons disease. Nat Genet 4, 393-397 ( ... Huntingtons disease is an inherited neurodegenerative disorder that results from a trinucleotide (CAG) repeat expansion (,35) ... A novel gene containing a trinucleotide repeat that is expanded and unstable on Huntingtons disease chromosomes. Cell 72, 971- ...
The normal CAG repeat range is 5-36, whereas 38 or more repeats are found in the diseased state; the severity of disease is ... 9) or an expanded repeat inserted into the endogenous mouse gene Hdh (ref. 10). With increasing repeat number, the protein ... For longer repeat lengths, somatic instability of the repeat size has been observed both in human cases at autopsy7,8 and in ... suggesting important functional correlations between repeat length and pathology. Because dinucleotide repeat instability is ...
TCF4 trinucleotide repeat expansion in Swedish cases with Fuchs endothelial corneal dystrophy. Title: TCF4 trinucleotide ... The TCF4 Trinucleotide Repeat Expansion of Fuchs Endothelial Corneal Dystrophy: Implications for the Anterior Segment of the ... The TCF4 Trinucleotide Repeat Expansion of Fuchs Endothelial Corneal Dystrophy: Implications for the Anterior Segment of the ... Title: The TCF4 Trinucleotide Repeat Expansion of Fuchs Endothelial Corneal Dystrophy: Implications for the Anterior Segment ...
Relationship between trinucleotide repeat expansion and phenotypic variation in Huntingtons disease. Nat. Genet. 1993. 4:393- ... Exon 1 contains a CAG trinucleotide repeat that encodes the amino acid glutamine, followed by another repeat that encodes ... Men occasionally have expanded repeats in their sperm (6). The expansion is thought to occur via slippage during the DNA ... In those affected by HD, there are more than 40 repeats. In those with 35-39 repeats, the disease is variably penetrant (3-5). ...
If the number of repeats increases, it is known as a trinucleotide repeat expansion. In some cases, the trinucleotide repeat ... called a trinucleotide repeat expansion. A trinucleotide repeat is a sequence of three DNA building blocks (nucleotides) that ... is repeated a number of times in a row. DNA segments with an abnormal number of these repeats are unstable and prone to errors ... This expansion causes the features of some disorders to become more severe with each successive generation. ...
Expansion of a novel CAG trinucleotide repeat in the 5 region of PPP2R2B is associated with SCA12. Nat Genet. 1999 Dec. 23(4): ... Expansion of an unstable trinucleotide CAG repeat in spinocerebellar ataxia type 1. Nat Genet. 1993 Jul. 4(3):221-6. [QxMD ... Many of the abnormal genes are of the expansion repeat variety. For example, in OPCA-I (or SCA-1), the SCA1 gene is on ... Unstable expansion of CAG repeat in hereditary dentatorubral-pallidoluysian atrophy (DRPLA). Nat Genet. 1994 Jan. 6(1):9-13. [ ...
Expansion of a novel CAG trinucleotide repeat in the 5 region of PPP2R2B is associated with SCA12. Nat Genet. 1999 Dec. 23(4): ... Expansion of an unstable trinucleotide CAG repeat in spinocerebellar ataxia type 1. Nat Genet. 1993 Jul. 4(3):221-6. [QxMD ... Unstable expansion of CAG repeat in hereditary dentatorubral-pallidoluysian atrophy (DRPLA). Nat Genet. 1994 Jan. 6(1):9-13. [ ... Cloning of the SCA7 gene reveals a highly unstable CAG repeat expansion. Nat Genet. 1997 Sep. 17(1):65-70. [QxMD MEDLINE Link] ...
Pearson, C.E. Slipping while sleeping? Trinucleotide repeat expansions in germ cells. Trends Mol. Med., 2003, 9(11), 490-495. ... Huntingtons disease is a genetic neurological disorder caused by a repeated expansion of the CAG trinucleotide, causing ... Huntingtons disease is a genetic neurological disorder caused by a repeated expansion of the CAG trinucleotide, causing ... A novel gene containing a trinucleotide repeat that is expanded and unstable on Huntingtons disease chromosomes. Cell, 1993, ...
... and trinucleotide repeat expansion disorders, such as Huntingtons disease and Fragile X Syndrome. ...
TTC repeats. Moreover, inhibitors must have a long residence time on their target enzymes for this activity. By interrogating ... Histone post-translational modifications near the expanded repeats are consistent with heterochromatin formation and consequent ... Histone posttranslational modifications near the expanded repeats are consistent with heterochromatin formation and consequent ... Evolution of the Friedreichs ataxia trinucleotide repeat expansion: founder effect and premutations. Proc Natl Acad Sci U S A ...
Trinucleotide repeat expansion disordersd. Not detected. Not detected. Not detected. Aberrant methylation. Not detected. Not ... triplet repeat expansions (as in fragile X syndrome), copy number variations (CNVs) outside of probe coverage, heterodisomy ( ... Apparently spontaneous cases with negative family history arise due to the expansion of premutations in female carriers. The ...
Trinucleotide Repeat Expansion 10% * Y-STR 9% * Development 8% * DNA Analysis 8% ...
HD is caused by a trinucleotide (CAG) repeat expansion in HTT that causes an elongated polyglutamine repeat in the Huntington ...
ATXN2 trinucleotide repeat length correlates with risk of ALS. Sproviero, W., Shatunov, A., Stahl, D., Shoai, M., van Rheenen, ... Detection of long repeat expansions from PCR-free whole-genome sequence data. Dolzhenko, E., Van Vugt, J. J. F. A., Shaw, R. J ... C9orf72 intermediate expansions of 24-30 repeats are associated with ALS. Alzheimers Disease Neuroimaging Initiative, ... Analysis of the hexanucleotide repeat expansion and founder haplotype at C9ORF72 in an Irish psychosis case-control sample. ...
Feng Y, Zhang F, Lokey LK, Chastain JL, Lakkis L, et al: Translational suppression by trinucleotide repeat expansion at FMR1. ... 31/79 repeats; POF1M: 29/72 repeats). FMR1 repeat expansion was excluded in the other control daughter-mother pairs. We ... It is caused most often by CGG trinucleotide repeat expansions, and less frequently by point mutations and partial or full ... Full-length CGG repeat expansions cause hypermethylation of the FMR1 promoter and the loss of both FMR1 mRNA and protein ...
Huntingtons disease (HD) is an inherited neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the HTT ... The UHDRS assesses relevant clinical features of HD and appears to be appropriate for repeated administration during clinical ...
Expansions of certain trinucleotide repeats cause neurodegenerative disorders of which Huntingtons disease constitutes the ... Our study demonstrates that a certain trinucleotide repeat influences normal brain structure in humans. This result may have ... We found an increase of GM with increasing long CAG repeat and its interaction with age within the pallidum, which is involved ... In 278 normal subjects, we determined CAG repeat length within the IT15 gene on chromosome 4 and analyzed high-resolution T1- ...
A trinucleotide repeat expansion in the FMR1 gene increases a womans risk of developing a condition called fragile X- ... Almost all cases of fragile X syndrome are caused by an expansion of the CGG trinucleotide repeat in the FMR1 gene. In these ... the CGG trinucleotide repeat in the FMR1 gene is repeated about 55 to 200 times, which is referred to as a premutation. Women ... One region of the FMR1 gene contains a particular DNA segment known as a CGG trinucleotide repeat, so called because this ...
Huntingtons disease (HD) is caused by trinucleotide repeat (CAG) expansions in the HTT gene, encoding huntingtin (Htt) protein ... Juvenile HD patients with ,60 repeats display early age of onset in children compared to adult HD patients with ~38-55 repeats ... while normal patients have 10-35 repeats. The tremendous difference in age of onset of juvenile and adult HD predicts ...
Trinucleotide repeat expansion in the FMR1 gene is caused by instability in early development and during germ cell production ... Fragile X syndrome (FXS) is caused by expansion of the CGG trinucleotide repeat in the Fragile X Mental Retardation gene, FMR1 ... This is the first study to examine FXS and trinucleotide repeat expansion in human embryonic stem cells. This work was ... thereby causing the DNA polymerase to slip and resulting in expansion of the CGG repeats. ...
Trinucleotide repeat expansion. Please click here after selecting answer. #image-caption p{ font-size: 12px; max-width: 525px; ... Spinocerebellar Ataxia type 3, also known as Machado-Joseph disease, is caused by the expansion of a repeated DNA sequence ...
The disorder is caused by expansion of a repeated trinucleotide segment of DNA, cytosine-guanine-guanine that leads to altered ... 5-44 repeats), 2) intermediate (45-54 repeats), 3) premutation (55-200 repeats), and 4) full mutation (greater than 200 repeats ... The larger the size of the premutation repeat, the more likely that there will be expansion to a full mutation Table 5. Women ... Clinical significance of tri-nucleotide repeats in Fragile X testing: a clarification of American College of Medical Genetics ...
Due to trinucleotide repeat expansions ranging from approximately 44-1700 "GAA" triplet sequences, affected individuals ...

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