Mosaicism
Sex Chromosome Aberrations
Turner Syndrome
Gonadal Dysgenesis, Mixed
Chromosome Disorders
Pigmentation Disorders
Uniparental Disomy
Cryopyrin-Associated Periodic Syndromes
Aneuploidy
Chromosome Aberrations
Chromosomes, Human, X
In Situ Hybridization, Fluorescence
Pedigree
Abnormalities, Multiple
Epidermolysis Bullosa
Neurofibromatosis 2
X Chromosome
Chorionic Villi Sampling
Klinefelter Syndrome
Genetic Counseling
Prenatal Diagnosis
Y Chromosome
Preimplantation Diagnosis
Chromosome Banding
Gonadal Dysgenesis
Germ-Line Mutation
Phenotype
Chromosomes, Human, 21-22 and Y
Intellectual Disability
Chromosomes, Human, 13-15
Chromosomes, Human, Y
Encyclopedias as Topic
Comparative analysis of cell distribution in the pigment epithelium and the visual cell layer of chimaeric mice. (1/1468)
In chimaeras of both rdrdCC in equilibrium ++ cc and rdrdcc in equilibrium ++CC combinations two types of distribution were observed. In a majority of the chimaeras both retinal layers were chimaeric; whereas in a few cases the pigment epithelium was chimaeric but the visual cell layer was made of ++ cells only. No spatial relation was observed in the distribution of the cells in the two layers. The two eyes of the individuals were nearly always identical with regard to occurrence of chimaerism in the two layers. The findings are discussed in the light of the possible site and mode of expression of the rd gene. (+info)Analysis of spinocerebellar ataxia type 2 gene and haplotype analysis: (CCG)1-2 polymorphism and contribution to founder effect. (2/1468)
Spinocerebellar ataxia type 2 is a familial spinocerebellar ataxia with autosomal dominant inheritance. The gene responsible was recently cloned and this disorder was found to be the result of a CAG expansion in its open reading frame. We analysed 13 SCA2 patients in seven unrelated families in Gunma Prefecture, Japan. In four of the seven families, we detected CCG or CCGCCG interruptions in only the expanded alleles. Cosegregation of these polymorphisms with SCA2 patients was established within each family. Together with the results of haplotype analyses, we considered that at least two founders were present in our area and that these (CCG)1-2 polymorphisms may make analysis of founder effects easier. By sequencing analysis we found that although the number of the long CAG repeat varied in each subclone of expanded alleles, these polymorphisms did not change their configuration. This finding suggests that CCG or CCGCCG sequences are stable when surrounded by the long CAG repeat and a single CAG. Moreover, the presence of these polymorphisms may lead to miscounting the repeat size by conventional estimation using a size marker such as an M13 sequencing ladder. Therefore we should consider these polymorphisms and accurately determine the repeat size by sequencing. (+info)Dual role of extramacrochaetae in cell proliferation and cell differentiation during wing morphogenesis in Drosophila. (3/1468)
The Extramacrochaetae (emc) gene encodes a transcription factor with an HLH domain without the basic region involved in interaction with DNA present in other proteins that have this domain. EMC forms heterodimers with bHLH proteins preventing their binding to DNA, acting as a negative regulator. The function of emc is required in many developmental processes during the development of Drosophila, including wing morphogenesis. Mitotic recombination clones of both null and gain-of-function alleles of emc, indicate that during wing morphogenesis, emc participates in cell proliferation within the intervein regions (vein patterning), as well as in vein differentiation. The study of relationships between emc and different genes involved in wing development reveal strong genetic interactions with genes of the Ras signalling pathway (torpedo, vein, veinlet and Gap), blistered, plexus and net, in both adult wing phenotypes and cell behaviour in genetic mosaics. These interactions are also analyzed as variations of emc expression patterns in mutant backgrounds for these genes. In addition, cell proliferation behaviour of emc mutant cells varies depending on the mutant background. The results show that genes of the Ras signalling pathway are co-operatively involved in the activity of emc during cell proliferation, and later antagonistically during cell differentiation, repressing EMC expression. (+info)Germ-line mosaicism in tuberous sclerosis: how common? (4/1468)
Two-thirds of cases of tuberous sclerosis complex (TSC) are sporadic and usually are attributed to new mutations, but unaffected parents sometimes have more than one affected child. We sought to determine how many of these cases represent germ-line mosaicism, as has been reported for other genetic diseases. In our sample of 120 families with TSC, 7 families had two affected children and clinically unaffected parents. These families were tested for mutations in the TSC1 and TSC2 genes, by Southern blotting and by single-strand conformational analysis. Unique variants were detected in six families. Each variant was present and identical in both affected children of a family but was absent in both parents and the unaffected siblings. Sequencing of the variants yielded two frameshift mutations, one missense mutation, and two nonsense mutations in TSC2 and one nonsense mutation in TSC1. To determine which parent contributed the affected gametes, the families were analyzed for linkage to TSC1 and TSC2, by construction of haplotypes with markers flanking the two genes. Linkage analysis and loss-of-heterozygosity studies indicated maternal origin in three families, paternal origin in one family, and either being possible in two families. To evaluate the possibility of low-level somatic mosaicism for TSC, DNA from lymphocytes of members of the six families were tested by allele-specific PCR. In all the families, the mutant allele was detected only in the known affected individuals. We conclude that germ-line mosaicism was present in five families with mutations in the TSC2 gene and in one family with the causative mutation in the TSC1 gene. The results have implications for genetic counseling of families with seemingly sporadic TSC. (+info)Recurrence of Marfan syndrome as a result of parental germ-line mosaicism for an FBN1 mutation. (5/1468)
Mutations in the FBN1 gene cause Marfan syndrome (MFS), a dominantly inherited connective tissue disease. Almost all the identified FBN1mutations have been family specific, and the rate of new mutations is high. We report here a de novo FBN1mutation that was identified in two sisters with MFS born to clinically unaffected parents. The paternity and maternity were unequivocally confirmed by genotyping. Although one of the parents had to be an obligatory carrier for the mutation, we could not detect the mutation in the leukocyte DNA of either parent. To identify which parent was a mosaic for the mutation we analyzed several tissues from both parents, with a quantitative and sensitive solid-phase minisequencing method. The mutation was not, however, detectable in any of the analyzed tissues. Although the mutation could not be identified in a sperm sample from the father or in samples of multiple tissue from the mother, we concluded that the mother was the likely mosaic parent and that the mutation must have occurred during the early development of her germ-line cells. Mosaicism confined to germ-line cells has rarely been reported, and this report of mosaicism for the FBN1 mutation in MFS represents an important case, in light of the evaluation of the recurrence risk in genetic counseling of families with MFS. (+info)Chromosome abnormalities in human embryos. (6/1468)
The presence of numerical chromosome abnormalities in human embryos was studied using fluorescence in-situ hybridization with four or more chromosome-specific probes. When most cells of an embryo are analysed, this technique allows differentiation to be made between aneuploidy, mosaicism, haploidy and polyploidy. Abnormal types of fertilization, such as unipronucleated, tripronucleated zygotes and zygotes with uneven pronuclei, were studied using this technique. We have found a strong correlation between some types of dysmorphism with chromosomal abnormalities. In addition, the more impaired the development of an embryo, the more chromosomal abnormalities were detected in those embryos. Maternal age and other factors were linked to an increase in chromosome abnormalities (hormonal regimes, temperature changes), but not to intracytoplasmic sperm injection. (+info)Identification of mutations that cause cell migration defects in mosaic clones. (7/1468)
Cell movement is an important feature of animal development, wound healing and tumor metastasis; however, the mechanisms underlying cell motility remain to be elucidated. To further our understanding, it would be useful to identify all of the proteins that are essential for a cell to migrate, yet such information is not currently available for any cell type. We have carried out a screen for mutations affecting border cell migration in Drosophila. Mutations that cause defects in mosaic clones were identified, so that genes that are also required for viability could be detected. From 6000 mutagenized lines, 20 mutations on chromosome 2R were isolated that cause defects in border cell position. One of the mutations was dominant while all of the recessive mutations appeared to be homozygous lethal. This lethality was used to place the mutations into 16 complementation groups. Many of the mutations failed to complement cytologically characterized deficiencies, allowing their rapid mapping. Mutations in three loci altered expression of a marker gene in the border cells, whereas the remaining mutations did not. One mutation, which caused production of supernumerary border cells, was found to disrupt the costal-2 locus, indicating a role for Hedgehog signaling in border cell development. This screen identified many new loci required for border cell migration and our results suggest that this is a useful approach for elucidating the mechanisms involved in cell motility. (+info)Dicentric X isochromosomes in man. (8/1468)
Four cases of Turner's syndrome are presented in which an apparent X isochromosome i(Xq) has been found to possess two regions of centromeric heterochromatin. It is suggested that these chromosomes were isodicentric structures capable of functioning as monocentric elements as a result of the inactivation of one centromere. The prevalence of mosaicism is believed to be a consequence of the dicentric nature of these chromosomes, and it is considered possible that a high proportion of X isochromosmes are structurally dicentric. Banding patterns showed that the exchange site involved in the formation of the dicentric chromosome was different in at least three of the cases. (+info)Mosaicism, in the context of genetics and medicine, refers to the presence of two or more cell lines with different genetic compositions in an individual who has developed from a single fertilized egg. This means that some cells have one genetic makeup, while others have a different genetic makeup. This condition can occur due to various reasons such as errors during cell division after fertilization.
Mosaicism can involve chromosomes (where whole or parts of chromosomes are present in some cells but not in others) or it can involve single genes (where a particular gene is present in one form in some cells and a different form in others). The symptoms and severity of mosaicism can vary widely, depending on the type and location of the genetic difference and the proportion of cells that are affected. Some individuals with mosaicism may not experience any noticeable effects, while others may have significant health problems.
Sex chromosome aberrations refer to structural and numerical abnormalities in the sex chromosomes, which are typically represented as X and Y chromosomes in humans. These aberrations can result in variations in the number of sex chromosomes, such as Klinefelter syndrome (47,XXY), Turner syndrome (45,X), and Jacobs/XYY syndrome (47,XYY). They can also include structural changes, such as deletions, duplications, or translocations of sex chromosome material.
Sex chromosome aberrations may lead to a range of phenotypic effects, including differences in physical characteristics, cognitive development, fertility, and susceptibility to certain health conditions. The manifestation and severity of these impacts can vary widely depending on the specific type and extent of the aberration, as well as individual genetic factors and environmental influences.
It is important to note that while sex chromosome aberrations may pose challenges and require medical management, they do not inherently define or limit a person's potential, identity, or worth. Comprehensive care, support, and education can help individuals with sex chromosome aberrations lead fulfilling lives and reach their full potential.
Trisomy is a genetic condition where there is an extra copy of a particular chromosome, resulting in 47 chromosomes instead of the typical 46 in a cell. This usually occurs due to an error in cell division during the development of the egg, sperm, or embryo.
Instead of the normal pair, there are three copies (trisomy) of that chromosome. The most common form of trisomy is Trisomy 21, also known as Down syndrome, where there is an extra copy of chromosome 21. Other forms include Trisomy 13 (Patau syndrome) and Trisomy 18 (Edwards syndrome), which are associated with more severe developmental issues and shorter lifespans.
Trisomy can also occur in a mosaic form, where some cells have the extra chromosome while others do not, leading to varying degrees of symptoms depending on the proportion of affected cells.
Turner Syndrome is a genetic disorder that affects females, caused by complete or partial absence of one X chromosome. The typical karyotype is 45,X0 instead of the normal 46,XX in women. This condition leads to distinctive physical features and medical issues in growth, development, and fertility. Characteristic features include short stature, webbed neck, low-set ears, and swelling of the hands and feet. Other potential symptoms can include heart defects, hearing and vision problems, skeletal abnormalities, kidney issues, and learning disabilities. Not all individuals with Turner Syndrome will have every symptom, but most will require medical interventions and monitoring throughout their lives to address various health concerns associated with the condition.
Gonadal dysgenesis, mixed is a medical condition that refers to the abnormal development and function of the gonads (ovaries or testes). In this form of gonadal dysgenesis, both ovarian and testicular tissues are present in the same individual, but they are not properly organized or functioning. This can lead to ambiguous genitalia, infertility, and an increased risk of developing gonadal tumors. The condition is often associated with genetic disorders such as Turner, Klinefelter, or other sex chromosome abnormalities.
Karyotyping is a medical laboratory test used to study the chromosomes in a cell. It involves obtaining a sample of cells from a patient, usually from blood or bone marrow, and then staining the chromosomes so they can be easily seen under a microscope. The chromosomes are then arranged in pairs based on their size, shape, and other features to create a karyotype. This visual representation allows for the identification and analysis of any chromosomal abnormalities, such as extra or missing chromosomes, or structural changes like translocations or inversions. These abnormalities can provide important information about genetic disorders, diseases, and developmental problems.
Chromosome disorders are a group of genetic conditions caused by abnormalities in the number or structure of chromosomes. Chromosomes are thread-like structures located in the nucleus of cells that contain most of the body's genetic material, which is composed of DNA and proteins. Normally, humans have 23 pairs of chromosomes, for a total of 46 chromosomes.
Chromosome disorders can result from changes in the number of chromosomes (aneuploidy) or structural abnormalities in one or more chromosomes. Some common examples of chromosome disorders include:
1. Down syndrome: a condition caused by an extra copy of chromosome 21, resulting in intellectual disability, developmental delays, and distinctive physical features.
2. Turner syndrome: a condition that affects only females and is caused by the absence of all or part of one X chromosome, resulting in short stature, lack of sexual development, and other symptoms.
3. Klinefelter syndrome: a condition that affects only males and is caused by an extra copy of the X chromosome, resulting in tall stature, infertility, and other symptoms.
4. Cri-du-chat syndrome: a condition caused by a deletion of part of the short arm of chromosome 5, resulting in intellectual disability, developmental delays, and a distinctive cat-like cry.
5. Fragile X syndrome: a condition caused by a mutation in the FMR1 gene on the X chromosome, resulting in intellectual disability, behavioral problems, and physical symptoms.
Chromosome disorders can be diagnosed through various genetic tests, such as karyotyping, chromosomal microarray analysis (CMA), or fluorescence in situ hybridization (FISH). Treatment for these conditions depends on the specific disorder and its associated symptoms and may include medical interventions, therapies, and educational support.
Pigmentation disorders are conditions that affect the production or distribution of melanin, the pigment responsible for the color of skin, hair, and eyes. These disorders can cause changes in the color of the skin, resulting in areas that are darker (hyperpigmentation) or lighter (hypopigmentation) than normal. Examples of pigmentation disorders include melasma, age spots, albinism, and vitiligo. The causes, symptoms, and treatments for these conditions can vary widely, so it is important to consult a healthcare provider for an accurate diagnosis and treatment plan.
Uniparental disomy (UPD) is a chromosomal abnormality where an individual receives two copies of a chromosome, or part of a chromosome, from one parent and no copies from the other parent. This occurs when there is an error in gamete formation, such as nondisjunction or segregation defects during meiosis, resulting in the production of gametes with abnormal numbers of chromosomes.
There are two types of UPD: heterodisomy and isodisomy. Heterodisomy occurs when an individual receives two different copies of a chromosome from one parent, while isodisomy occurs when an individual receives two identical copies of a chromosome from one parent.
UPD can have significant genetic consequences, particularly if the affected chromosome contains imprinted genes, which are genes that are expressed differently depending on whether they are inherited from the mother or father. UPD can lead to abnormal gene expression and may result in developmental disorders, growth abnormalities, and increased risk of certain diseases, such as Prader-Willi syndrome and Angelman syndrome.
It is important to note that UPD is a rare event and occurs in less than 1% of the population. However, it can have serious health consequences, and genetic counseling and testing may be recommended for individuals with a family history of chromosomal abnormalities or developmental disorders.
Cryopyrin-Associated Periodic Syndromes (CAPS) are a group of rare, hereditary autoinflammatory disorders caused by mutations in the NLRP3 gene, which encodes the cryopyrin protein. The mutation leads to overactivation of the inflammasome, an intracellular complex that regulates the activation of inflammatory cytokines, resulting in uncontrolled inflammation.
CAPS include three clinical subtypes:
1. Familial Cold Autoinflammatory Syndrome (FCAS): This is the mildest form of CAPS and typically presents in infancy or early childhood with recurrent episodes of fever, urticaria-like rash, and joint pain triggered by cold exposure.
2. Muckle-Wells Syndrome (MWS): This subtype is characterized by more severe symptoms than FCAS, including recurrent fever, urticaria-like rash, joint pain, and progressive hearing loss. Patients with MWS are also at risk for developing amyloidosis, a serious complication that can lead to kidney failure.
3. Neonatal-Onset Multisystem Inflammatory Disease (NOMID): Also known as chronic infantile neurological cutaneous and articular syndrome (CINCA), this is the most severe form of CAPS. It presents at birth or in early infancy with fever, urticaria-like rash, joint inflammation, and central nervous system involvement, including chronic meningitis, developmental delay, and hearing loss.
Treatment for CAPS typically involves targeted therapies that block the overactive inflammasome, such as IL-1 inhibitors. Early diagnosis and treatment can help prevent long-term complications and improve quality of life for patients with these disorders.
Aneuploidy is a medical term that refers to an abnormal number of chromosomes in a cell. Chromosomes are thread-like structures located inside the nucleus of cells that contain genetic information in the form of genes.
In humans, the normal number of chromosomes in a cell is 46, arranged in 23 pairs. Aneuploidy occurs when there is an extra or missing chromosome in one or more of these pairs. For example, Down syndrome is a condition that results from an extra copy of chromosome 21, also known as trisomy 21.
Aneuploidy can arise during the formation of gametes (sperm or egg cells) due to errors in the process of cell division called meiosis. These errors can result in eggs or sperm with an abnormal number of chromosomes, which can then lead to aneuploidy in the resulting embryo.
Aneuploidy is a significant cause of birth defects and miscarriages. The severity of the condition depends on which chromosomes are affected and the extent of the abnormality. In some cases, aneuploidy may have no noticeable effects, while in others it can lead to serious health problems or developmental delays.
Chromosome aberrations refer to structural and numerical changes in the chromosomes that can occur spontaneously or as a result of exposure to mutagenic agents. These changes can affect the genetic material encoded in the chromosomes, leading to various consequences such as developmental abnormalities, cancer, or infertility.
Structural aberrations include deletions, duplications, inversions, translocations, and rings, which result from breaks and rearrangements of chromosome segments. Numerical aberrations involve changes in the number of chromosomes, such as aneuploidy (extra or missing chromosomes) or polyploidy (multiples of a complete set of chromosomes).
Chromosome aberrations can be detected and analyzed using various cytogenetic techniques, including karyotyping, fluorescence in situ hybridization (FISH), and comparative genomic hybridization (CGH). These methods allow for the identification and characterization of chromosomal changes at the molecular level, providing valuable information for genetic counseling, diagnosis, and research.
A chromosome is a thread-like structure that contains genetic material, made up of DNA and proteins, in the nucleus of a cell. In humans, there are 23 pairs of chromosomes, for a total of 46 chromosomes, in each cell of the body, with the exception of the sperm and egg cells which contain only 23 chromosomes.
The X chromosome is one of the two sex-determining chromosomes in humans. Females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The X chromosome contains hundreds of genes that are responsible for various functions in the body, including some related to sexual development and reproduction.
Humans inherit one X chromosome from their mother and either an X or a Y chromosome from their father. In females, one of the two X chromosomes is randomly inactivated during embryonic development, resulting in each cell having only one active X chromosome. This process, known as X-inactivation, helps to ensure that females have roughly equal levels of gene expression from the X chromosome, despite having two copies.
Abnormalities in the number or structure of the X chromosome can lead to various genetic disorders, such as Turner syndrome (X0), Klinefelter syndrome (XXY), and fragile X syndrome (an X-linked disorder caused by a mutation in the FMR1 gene).
In situ hybridization, fluorescence (FISH) is a type of molecular cytogenetic technique used to detect and localize the presence or absence of specific DNA sequences on chromosomes through the use of fluorescent probes. This technique allows for the direct visualization of genetic material at a cellular level, making it possible to identify chromosomal abnormalities such as deletions, duplications, translocations, and other rearrangements.
The process involves denaturing the DNA in the sample to separate the double-stranded molecules into single strands, then adding fluorescently labeled probes that are complementary to the target DNA sequence. The probe hybridizes to the complementary sequence in the sample, and the location of the probe is detected by fluorescence microscopy.
FISH has a wide range of applications in both clinical and research settings, including prenatal diagnosis, cancer diagnosis and monitoring, and the study of gene expression and regulation. It is a powerful tool for identifying genetic abnormalities and understanding their role in human disease.
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.
'Abnormalities, Multiple' is a broad term that refers to the presence of two or more structural or functional anomalies in an individual. These abnormalities can be present at birth (congenital) or can develop later in life (acquired). They can affect various organs and systems of the body and can vary greatly in severity and impact on a person's health and well-being.
Multiple abnormalities can occur due to genetic factors, environmental influences, or a combination of both. Chromosomal abnormalities, gene mutations, exposure to teratogens (substances that cause birth defects), and maternal infections during pregnancy are some of the common causes of multiple congenital abnormalities.
Examples of multiple congenital abnormalities include Down syndrome, Turner syndrome, and VATER/VACTERL association. Acquired multiple abnormalities can result from conditions such as trauma, infection, degenerative diseases, or cancer.
The medical evaluation and management of individuals with multiple abnormalities depend on the specific abnormalities present and their impact on the individual's health and functioning. A multidisciplinary team of healthcare professionals is often involved in the care of these individuals to address their complex needs.
Epidermolysis Bullosa (EB) is a group of rare inherited skin disorders that are characterized by the development of blisters, erosions, and scarring following minor trauma or friction. The condition results from a genetic defect that affects the structural proteins responsible for anchoring the epidermis (outer layer of the skin) to the dermis (inner layer of the skin).
There are several types of EB, which vary in severity and clinical presentation. These include:
1. Epidermolysis Bullosa Simplex (EBS): This is the most common form of EB, and it typically affects the skin's superficial layers. Blistering tends to occur after minor trauma or friction, and healing usually occurs without scarring. There are several subtypes of EBS, which vary in severity.
2. Junctional Epidermolysis Bullosa (JEB): This form of EB affects the deeper layers of the skin, and blistering can occur spontaneously or following minor trauma. Healing often results in scarring, and affected individuals may also experience nail loss, dental abnormalities, and fragile mucous membranes.
3. Dystrophic Epidermolysis Bullosa (DEB): DEB affects the deeper layers of the skin, and blistering can lead to significant scarring, contractures, and fusion of fingers and toes. There are two main subtypes of DEB: recessive DEB (RDEB), which is more severe and associated with a higher risk of skin cancer, and dominant DEB (DDEB), which tends to be milder.
4. Kindler Syndrome: This is a rare form of EB that affects both the epidermis and dermis. Blistering can occur spontaneously or following minor trauma, and affected individuals may experience photosensitivity, poikiloderma (a mottled skin appearance), and oral and gastrointestinal abnormalities.
Treatment for EB typically focuses on managing symptoms, preventing blister formation and infection, and promoting wound healing. There is currently no cure for EB, but research is ongoing to develop new therapies and treatments.
Neurofibromatosis 2 (NF2) is a genetic disorder characterized by the development of non-cancerous tumors in the nervous system, particularly on the nerves related to hearing and balance. It's also known as central neurofibromatosis or bilateral acoustic neuroma syndrome.
The primary feature of NF2 is the growth of schwannomas, which are tumors that develop from the cells surrounding nerve fibers. These typically grow on the vestibular nerve, leading to hearing loss, ringing in the ears (tinnitus), and balance problems. Bilateral acoustic neuromas (schwannomas affecting both vestibular nerves) are a hallmark of this condition.
Other common features include:
1. Meningiomas: These are tumors that grow in the meninges, the protective layers surrounding the brain and spinal cord.
2. Ependymomas: These are tumors that develop from the ependymal cells lining the ventricles (fluid-filled spaces) in the brain or the spinal cord canal.
3. Neurofibromas: Unlike in Neurofibromatosis type 1, these are less common and typically don't become cancerous.
4. Skin changes: While not as prevalent as in NF1, some people with NF2 may have skin freckles, café-au-lait spots, or skin tumors.
5. Eye problems: Some individuals may experience cataracts, retinal abnormalities, or optic nerve tumors (optic gliomas).
6. Other potential symptoms: Headaches, facial weakness or numbness, and difficulty swallowing or speaking.
NF2 is an autosomal dominant disorder, meaning that a person has a 50% chance of inheriting the condition if one of their parents has it. However, about half of all NF2 cases result from spontaneous genetic mutations with no family history of the disorder.
The X chromosome is one of the two types of sex-determining chromosomes in humans (the other being the Y chromosome). It's one of the 23 pairs of chromosomes that make up a person's genetic material. Females typically have two copies of the X chromosome (XX), while males usually have one X and one Y chromosome (XY).
The X chromosome contains hundreds of genes that are responsible for the production of various proteins, many of which are essential for normal bodily functions. Some of the critical roles of the X chromosome include:
1. Sex Determination: The presence or absence of the Y chromosome determines whether an individual is male or female. If there is no Y chromosome, the individual will typically develop as a female.
2. Genetic Disorders: Since females have two copies of the X chromosome, they are less likely to be affected by X-linked genetic disorders than males. Males, having only one X chromosome, will express any recessive X-linked traits they inherit.
3. Dosage Compensation: To compensate for the difference in gene dosage between males and females, a process called X-inactivation occurs during female embryonic development. One of the two X chromosomes is randomly inactivated in each cell, resulting in a single functional copy per cell.
The X chromosome plays a crucial role in human genetics and development, contributing to various traits and characteristics, including sex determination and dosage compensation.
A ring chromosome is a structurally abnormal chromosome that has formed a circle or ring shape. This occurs when both ends of the chromosome break off and the resulting fragments join together to form a circular structure. Ring chromosomes can vary in size, and the loss of genetic material during the formation of the ring can lead to genetic disorders and developmental delays. The effects of a ring chromosome depend on the location of the breakpoints and the amount of genetic material lost. Some individuals with ring chromosomes may have mild symptoms, while others may have severe disabilities or health problems.
Chorionic villi sampling (CVS) is a prenatal testing procedure that involves taking a small sample of the chorionic villi, which are finger-like projections of the placenta that contain fetal cells. The sample is then tested for genetic disorders and chromosomal abnormalities, such as Down syndrome.
CVS is typically performed between the 10th and 12th weeks of pregnancy and carries a small risk of miscarriage (about 1 in 100 to 1 in 200 procedures). The results of CVS can provide important information about the health of the fetus, allowing parents to make informed decisions about their pregnancy. However, it is important to note that CVS does not detect all genetic disorders and may produce false positive or false negative results in some cases. Therefore, follow-up testing may be necessary.
Klinefelter Syndrome: A genetic disorder in males, caused by the presence of one or more extra X chromosomes, typically resulting in XXY karyotype. It is characterized by small testes, infertility, gynecomastia (breast enlargement), tall stature, and often mild to moderate intellectual disability. The symptoms can vary greatly among individuals with Klinefelter Syndrome. Some men may not experience any significant health problems and may never be diagnosed, while others may have serious medical or developmental issues that require treatment. It is one of the most common chromosomal disorders, affecting about 1 in every 500-1,000 newborn males.
Genetic counseling is a process of communication and education between a healthcare professional and an individual or family, aimed at understanding, adapting to, and managing the medical, psychological, and familial implications of genetic contributions to disease. This includes providing information about the risk of inherited conditions, explaining the implications of test results, discussing reproductive options, and offering support and resources for coping with a genetic condition. Genetic counselors are trained healthcare professionals who specialize in helping people understand genetic information and its impact on their health and lives.
Prenatal diagnosis is the medical testing of fetuses, embryos, or pregnant women to detect the presence or absence of certain genetic disorders or birth defects. These tests can be performed through various methods such as chorionic villus sampling (CVS), amniocentesis, or ultrasound. The goal of prenatal diagnosis is to provide early information about the health of the fetus so that parents and healthcare providers can make informed decisions about pregnancy management and newborn care. It allows for early intervention, treatment, or planning for the child's needs after birth.
The Y chromosome is one of the two sex-determining chromosomes in humans and many other animals, along with the X chromosome. The Y chromosome contains the genetic information that helps to determine an individual's sex as male. It is significantly smaller than the X chromosome and contains fewer genes.
The Y chromosome is present in males, who inherit it from their father. Females, on the other hand, have two X chromosomes, one inherited from each parent. The Y chromosome includes a gene called SRY (sex-determining region Y), which initiates the development of male sexual characteristics during embryonic development.
It is worth noting that the Y chromosome has a relatively high rate of genetic mutation and degeneration compared to other chromosomes, leading to concerns about its long-term viability in human evolution. However, current evidence suggests that the Y chromosome has been stable for at least the past 25 million years.
Preimplantation Diagnosis (PID) is a genetic testing procedure performed on embryos created through in vitro fertilization (IVF), before they are implanted in the uterus. The purpose of PID is to identify genetic disorders or chromosomal abnormalities in the embryos, allowing only those free of such issues to be transferred to the uterus, thereby reducing the risk of passing on genetic diseases to offspring. It involves biopsying one or more cells from an embryo and analyzing its DNA for specific genetic disorders or chromosomal abnormalities. PID is often recommended for couples with a known history of genetic disorders or those who have experienced multiple miscarriages or failed IVF cycles.
Chromosome banding is a technique used in cytogenetics to identify and describe the physical structure and organization of chromosomes. This method involves staining the chromosomes with specific dyes that bind differently to the DNA and proteins in various regions of the chromosome, resulting in a distinct pattern of light and dark bands when viewed under a microscope.
The most commonly used banding techniques are G-banding (Giemsa banding) and R-banding (reverse banding). In G-banding, the chromosomes are stained with Giemsa dye, which preferentially binds to the AT-rich regions, creating a characteristic banding pattern. The bands are numbered from the centromere (the constriction point where the chromatids join) outwards, with the darker bands (rich in A-T base pairs and histone proteins) labeled as "q" arms and the lighter bands (rich in G-C base pairs and arginine-rich proteins) labeled as "p" arms.
R-banding, on the other hand, uses a different staining procedure that results in a reversed banding pattern compared to G-banding. The darker R-bands correspond to the lighter G-bands, and vice versa. This technique is particularly useful for identifying and analyzing specific regions of chromosomes that may be difficult to visualize with G-banding alone.
Chromosome banding plays a crucial role in diagnosing genetic disorders, identifying chromosomal abnormalities, and studying the structure and function of chromosomes in both clinical and research settings.
Gonadal dysgenesis is a condition characterized by the abnormal development of the gonads, which are the reproductive organs that produce sex hormones and gametes (sperm or eggs). In individuals with gonadal dysgenesis, the gonads may be underdeveloped, structurally abnormal, or completely absent. This condition can affect people of any gender and is often associated with other genetic disorders, such as Turner or Klinefelter syndromes.
The clinical presentation of gonadal dysgenesis varies widely depending on the severity of the disorder and the presence of other associated conditions. Some individuals may have normal sexual development and fertility, while others may experience delayed puberty, infertility, or ambiguous genitalia. Gonadal dysgenesis can also increase the risk of developing gonadal tumors, particularly in individuals with complete or partial absence of the gonads.
The diagnosis of gonadal dysgenesis is typically made through a combination of clinical evaluation, imaging studies, and genetic testing. Treatment may include hormone replacement therapy to support sexual development and prevent complications associated with hormonal imbalances. In some cases, surgical removal of the gonads may be recommended to reduce the risk of tumor development.
A germ-line mutation is a genetic change that occurs in the egg or sperm cells (gametes), and thus can be passed down from parents to their offspring. These mutations are present throughout the entire body of the offspring, as they are incorporated into the DNA of every cell during embryonic development.
Germ-line mutations differ from somatic mutations, which occur in other cells of the body that are not involved in reproduction. While somatic mutations can contribute to the development of cancer and other diseases within an individual, they are not passed down to future generations.
It's important to note that germ-line mutations can have significant implications for medical genetics and inherited diseases. For example, if a parent has a germ-line mutation in a gene associated with a particular disease, their offspring may have an increased risk of developing that disease as well.
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.
Human chromosomes are thread-like structures that contain genetic material, composed of DNA and proteins, present in the nucleus of human cells. Each chromosome is a single, long DNA molecule that carries hundreds to thousands of genes.
Chromosomes 21, 22, and Y are three of the 23 pairs of human chromosomes. Here's what you need to know about each:
* Chromosome 21 is the smallest human autosomal chromosome, with a total length of about 47 million base pairs. It contains an estimated 200-300 genes and is associated with several genetic disorders, most notably Down syndrome, which occurs when there is an extra copy of this chromosome (trisomy 21).
* Chromosome 22 is the second smallest human autosomal chromosome, with a total length of about 50 million base pairs. It contains an estimated 500-600 genes and is associated with several genetic disorders, including DiGeorge syndrome and cat-eye syndrome.
* The Y chromosome is one of the two sex chromosomes (the other being the X chromosome) and is found only in males. It is much smaller than the X chromosome, with a total length of about 59 million base pairs and an estimated 70-200 genes. The Y chromosome determines maleness by carrying the gene for the testis-determining factor (TDF), which triggers male development in the embryo.
It's worth noting that while we have a standard set of 23 pairs of chromosomes, there can be variations and abnormalities in the number or structure of these chromosomes that can lead to genetic disorders.
Intellectual disability (ID) is a term used when there are significant limitations in both intellectual functioning and adaptive behavior, which covers many everyday social and practical skills. This disability originates before the age of 18.
Intellectual functioning, also known as intelligence, refers to general mental capacity, such as learning, reasoning, problem-solving, and other cognitive skills. Adaptive behavior includes skills needed for day-to-day life, such as communication, self-care, social skills, safety judgement, and basic academic skills.
Intellectual disability is characterized by below-average intelligence or mental ability and a lack of skills necessary for day-to-day living. It can be mild, moderate, severe, or profound, depending on the degree of limitation in intellectual functioning and adaptive behavior.
It's important to note that people with intellectual disabilities have unique strengths and limitations, just like everyone else. With appropriate support and education, they can lead fulfilling lives and contribute to their communities in many ways.
A syndrome, in medical terms, is a set of symptoms that collectively indicate or characterize a disease, disorder, or underlying pathological process. It's essentially a collection of signs and/or symptoms that frequently occur together and can suggest a particular cause or condition, even though the exact physiological mechanisms might not be fully understood.
For example, Down syndrome is characterized by specific physical features, cognitive delays, and other developmental issues resulting from an extra copy of chromosome 21. Similarly, metabolic syndromes like diabetes mellitus type 2 involve a group of risk factors such as obesity, high blood pressure, high blood sugar, and abnormal cholesterol or triglyceride levels that collectively increase the risk of heart disease, stroke, and diabetes.
It's important to note that a syndrome is not a specific diagnosis; rather, it's a pattern of symptoms that can help guide further diagnostic evaluation and management.
Human chromosomes 13-15 are part of a set of 23 pairs of chromosomes found in the cells of the human body. Chromosomes are thread-like structures that contain genetic material, or DNA, that is inherited from each parent. They are responsible for the development and function of all the body's organs and systems.
Chromosome 13 is a medium-sized chromosome and contains an estimated 114 million base pairs of DNA. It is associated with several genetic disorders, including cri du chat syndrome, which is caused by a deletion on the short arm of the chromosome. Chromosome 13 also contains several important genes, such as those involved in the production of enzymes and proteins that help regulate growth and development.
Chromosome 14 is a medium-sized chromosome and contains an estimated 107 million base pairs of DNA. It is known to contain many genes that are important for the normal functioning of the brain and nervous system, as well as genes involved in the production of immune system proteins. Chromosome 14 is also associated with a number of genetic disorders, including Wolf-Hirschhorn syndrome, which is caused by a deletion on the short arm of the chromosome.
Chromosome 15 is a medium-sized chromosome and contains an estimated 102 million base pairs of DNA. It is associated with several genetic disorders, including Prader-Willi syndrome and Angelman syndrome, which are caused by abnormalities in the expression of genes on the chromosome. Chromosome 15 also contains important genes involved in the regulation of growth and development, as well as genes that play a role in the production of neurotransmitters, the chemical messengers of the brain.
It is worth noting that while chromosomes 13-15 are important for normal human development and function, abnormalities in these chromosomes can lead to a variety of genetic disorders and developmental issues.
Human Y chromosomes are one of the two sex-determining chromosomes in humans (the other being the X chromosome). They are found in the 23rd pair of human chromosomes and are significantly smaller than the X chromosome.
The Y chromosome is passed down from father to son through the paternal line, and it plays a crucial role in male sex determination. The SRY gene (sex-determining region Y) on the Y chromosome initiates the development of male sexual characteristics during embryonic development.
In addition to the SRY gene, the human Y chromosome contains several other genes that are essential for sperm production and male fertility. However, the Y chromosome has a much lower gene density compared to other chromosomes, with only about 80 protein-coding genes, making it one of the most gene-poor chromosomes in the human genome.
Because of its small size and low gene density, the Y chromosome is particularly susceptible to genetic mutations and deletions, which can lead to various genetic disorders and male infertility. Nonetheless, the Y chromosome remains a critical component of human genetics and evolution, providing valuable insights into sex determination, inheritance patterns, and human diversity.
An encyclopedia is a comprehensive reference work containing articles on various topics, usually arranged in alphabetical order. In the context of medicine, a medical encyclopedia is a collection of articles that provide information about a wide range of medical topics, including diseases and conditions, treatments, tests, procedures, and anatomy and physiology. Medical encyclopedias may be published in print or electronic formats and are often used as a starting point for researching medical topics. They can provide reliable and accurate information on medical subjects, making them useful resources for healthcare professionals, students, and patients alike. Some well-known examples of medical encyclopedias include the Merck Manual and the Stedman's Medical Dictionary.
Germ cells are the reproductive cells, also known as sex cells, that combine to form offspring in sexual reproduction. In females, germ cells are called ova or egg cells, and in males, they are called spermatozoa or sperm cells. These cells are unique because they carry half the genetic material necessary for creating new life. They are produced through a process called meiosis, which reduces their chromosome number by half, ensuring that when two germ cells combine during fertilization, the normal diploid number of chromosomes is restored.
Germline mosaicism
Confined placental mosaicism
Calico cat
Non-Mendelian inheritance
Diploid triploid mosaic
Angelo Maffucci
Blaschko's lines
Ring chromosome 20 syndrome
Anophthalmia
Cell-free fetal DNA
Osteogenesis imperfecta
PHACE syndrome
Most recent common ancestor
Eukaryote hybrid genome
Neuron derived neurotrophic factor
RPS6KA3
Turner syndrome
Blastomere
Waardenburg Syndrome Type 1
Malva vein clearing virus
Myotubularin 1
Trisomy 8
Vanishing twin
Glossary of genetics (0-L)
MYH9
Glossary of genetics (M-Z)
Trisomy X
SOX11
Postzygotic mutation
Trisomy 16
Germline mosaicism - Wikipedia
Mosaicism: MedlinePlus Medical Encyclopedia
Mosaicism in human skin. Understanding the patterns and mechanisms
mosaicism News Research Articles
Somatic Mosaicism across Human Tissues (SMaHT) | NIH Common Fund
Mechanisms of mosaicism, chimerism and uniparental disomy identified by single nucleotide polymorphism array analysis
somatic mosaicism - Washington University School of Medicine in St. Louis
A patient with 45XO-48XYYY mosaicism. | Journal of Medical Genetics
Placental mosaicism in the era of chromosomal microarrays - Aalborg Universitets forskningsportal
Trisomy 15 mosaicism in an IVF fetus. | Journal of Medical Genetics
Genetic Mosaicism: How Mutations That Arise in the Embryo May Cause Cancer Later in Life - American Association for Cancer...
RFA-RM-22-009: Somatic Mosaicism across Human Tissues (SMaHT) Program: Organizational Center (U24 Clinical Trial Not Allowed)
Mosaicism, somatic mutation... - Researchers - ANU
45,X/46,XY mosaicism: report on 14 patients from a Brazilian hospital. A retrospective study
Transferring Mosaic Embryos - Embryo Mosaicism - Austin Fertility Center
First description of late-onset autoinflammatory disease due to somatic NLRC4 mosaicism
Mosaicism of de novo pathogenic SCN1A variants in epilepsy is a frequent phenomenon that correlates with variable phenotypes
Revertant Mosaicism in Epidermolysis Bullosa<...
Neurocutaneous Manifestations of Genetic Mosaicism. | Read by QxMD
Revertant Mosaicism in Epidermolysis Bullosa - Fingerprint - Experts@Minnesota
Trisomy 12 mosaicism
Preimplantation Genetic Diagnosis: Overview, Indications and Conditions, Process
Adelaide Research & Scholarship: Mosaicism of a missense SCN1A mutation and Dravet syndrome in a Roma/Gypsy family
Paediatric IBD Mosaicism - EGA European Genome-Phenome Archive
Vista de Clinical patterns of pigmentary mosaicism - our experience
Coarse mosaicism - Cervical screening results - Jo's Cervical Cancer Trust Forum
Integrated CNV-seq, karyotyping and SNP-array analyses for effective prenatal diagnosis of chromosomal mosaicism | BMC Medical...
Hypomelanosis of Ito with a trisomy 2 mosaicism: a case report
No genomic mosaicism in a putative hybrid butterfly species - Kronforst Lab
Chromosomal mosaicism3
- Two cases of trisomy 12 were reported in a large study of chromosomal mosaicism detected on CVS. (bcchr.ca)
- Chromosomal mosaicism is defined as the presence of two or more different cell lines in an organism that originate from the same embryo. (thieme-connect.com)
- Ontogenetic and pathogenetic views on somatic chromosomal mosaicism. (thieme-connect.com)
Somatic Mosaicism across Human Tissues3
- The Somatic Mosaicism across Human Tissues (SMaHT) Network aims to transform our understanding of how somatic mosaicism in human cells influences biology and disease. (nih.gov)
- This Funding Opportunity Announcement (FOA) invites applications to establish the Organizational Center for the Somatic Mosaicism across Human Tissues (SMaHT) Network. (nih.gov)
- The purpose of the Somatic Mosaicism across Human Tissues (SMaHT) Network is to propel discovery of new biological processes in human health and disease that are mediated by genomic variation in somatic tissues. (nih.gov)
Mosaic9
- In the paper Germline and somatic mosaicism in transgenic mice published in 1986, Thomas M.Wilkie, Ralph L.Brinster, and Richard D.Palmiter analyzed a germline mosaicism experiment done on 262 transgenic mice and concluded that 30% of founder transgenic mice are mosaic in the germline. (wikipedia.org)
- They may not discover that they have mosaicism until they give birth to a child who has the non-mosaic form of the disease. (medlineplus.gov)
- Sometimes a child born with the non-mosaic form will not survive, but a child born with mosaicism will. (medlineplus.gov)
- Notably, the authors found that among patients carrying mosaic variants who underwent previous germline genetic testing, most had been reported as not carrying germline mutations, and only half of those who had an evaluable medical history met the criteria for germline genetic testing, suggesting that in certain cases when a germline mutation is ruled out, mosaicism may be the culprit. (aacr.org)
- If you learn that some of your embryos have mosaicism, you might have questions about transferring mosaic embryos. (txfertility.com)
- Mosaicism at prenatal level constitutes a challenge in genetic counseling, particularly in the case of mosaic trisomy 5, due to its low incidence. (thieme-connect.com)
- Confirmation of mosaicism and uniparental disomy in amniocytes, after detection of mosaic chromosome abnormalities in chorionic villi. (thieme-connect.com)
- Rapid diagnosis of pseudomosaicism in a case of Level II mosaicism for trisomy 5 in a single colony from an in situ culture of amniocytes and a review of mosaic trisomy 5 at amniocentesis. (thieme-connect.com)
- Mosaicism (or mosaic Down syndrome) is diagnosed when there is a mixture of two types of cells, some with the usual 46 chromosomes and some with 47 chromosomes. (downsyndrome-singapore.org)
Mutation causing m1
- The concept of cutaneous mosaicism is important for gene mapping because here we have the opportunity to study two populations of cells differing only with regard to the mutation causing mosaicism. (nih.gov)
Trisomy 12 mosaicism5
- 1997) summarized findings in 23 cases of trisomy 12 mosaicism detected in amniotic fluid--20 of which were female and only three were male. (bcchr.ca)
- 2000) reported a case of trisomy 12 diagnosed in a newborn and summarized results for 4 other cases of trisomy 12 mosaicism diagnosed postnatally. (bcchr.ca)
- Brosens JJ, Overton C, Lavery SA, Thornton S. (1996) Trisomy 12 mosaicism diagnosed by amniocentesis. (bcchr.ca)
- 2000) Trisomy 12 mosaicism confirmed in multiple organs from a liveborn child. (bcchr.ca)
- English CJ, Goodship JA, Jackson A, Lowry M, Wolstenholme J. (1994) Trisomy 12 mosaicism in a 7 year old girl with dysmorphic features and normal mental development. (bcchr.ca)
Phenotype3
- That said, diverging from Mendelian gene inheritance patterns, a parent with a recessive allele can produce offspring expressing the phenotype as dominant through germline mosaicism. (wikipedia.org)
- Regarding cytogenetics, we did not observe any direct correlation between percentages of cell lines and phenotype.CONCLUSIONS: 45,X/46,XY mosaicism can present with a wide variety of phenotypes resulting from the involvement of different aspects of the individual. (figshare.com)
- Variations in the degree of mosaicism between tissues explained the phenotype. (lu.se)
Genomic mosaicism1
- Similarly, autosomal mutations resulting in genomic mosaicism may be either lethal or nonlethal. (nih.gov)
Germline16
- Germline mosaicism can be present at the same time as somatic mosaicism or individually, depending on when the conditions occur. (wikipedia.org)
- Pure germline mosaicism refers to mosaicism found exclusively in the gametes and not in any somatic cells. (wikipedia.org)
- Germline mosaicism can be caused either by a mutation that occurs after conception, or by epigenetic regulation, alterations to DNA such as methylation that do not involve changes in the DNA coding sequence. (wikipedia.org)
- With such mutation within the gamete cells, a pair of medically typical individuals may have repeated succession of children who suffer from certain genetic disorders such as Duchenne muscular dystrophy and osteogenesis imperfecta because of germline mosaicism. (wikipedia.org)
- however, if these parents produce more than one child with an AD disorder, germline mosaicism is more likely the cause than a sporadic mutation. (wikipedia.org)
- Germline mosaicism disorders are usually inherited in a pattern that suggests that the condition is dominant in either or both of the parents. (wikipedia.org)
- Diseases caused by germline mosaicism can be difficult to diagnose as genetically-inherited because the mutant alleles are not likely to be present in the somatic cells. (wikipedia.org)
- If the disease is a result of pure germline mosaicism, then the disease causing mutant allele would never be present in the somatic cells. (wikipedia.org)
- Germline mosaicism may contribute to the inheritance of many genetic conditions. (wikipedia.org)
- Conditions that are inherited by means of germline mosaicism are often mistaken as being the result of de novo mutations. (wikipedia.org)
- The frequency of germline mosaicism is not known due to the sporadic nature of the mutations causing it and the difficulty in obtaining the gametes that must be tested to diagnose it. (wikipedia.org)
- Autosomal dominant or X-linked familial disorders often prompt prenatal testing for germline mosaicism. (wikipedia.org)
- The recurrence rate of conditions caused by germline mosaicism varies greatly between subjects. (wikipedia.org)
- NGS analyses did not detect germline variants in any of the known autoinflammatory disease-associated genes, but they identified the p.Ser171Phe NLRC4 variant in unfractionated blood, with an allele fraction (2-4%) compatible with gene mosaicism. (upf.edu)
- Germline and somatic mosaicism for FGFR2 mutation in the mother of a child with Crouzon syndrome: Implications for genetic testing in "paternal age-effect" syndromes. (ox.ac.uk)
- However, even if this is the major mode of origin of mutations in paternal age-effect disorders, germline mosaicism may also occur. (ox.ac.uk)
Prenatal3
- These findings highlight the complexity of mosaicism for structural chromosomal aberrations in prenatal samples in the chromosomal microarray era. (aau.dk)
- The pre- and postnatal genetic tests (noninvasive prenatal testing, array comparative genomic hybridization, karyotype in amniotic fluid cells, karyotype in peripheral blood, and uniparental disomy analysis) revealed the fetal chromosomal status and indicated etiology giving rise to the mosaicism, suggesting a prezygotic meiotic error corrected through late trisomic rescue in the zygote. (thieme-connect.com)
- Prenatal detection of trisomy 5 mosaicism with normal outcome. (thieme-connect.com)
Chromosome2
- We used a genome-wide single nucleotide polymorphism (SNP) array to study patients with chromosome aneuploidy mosaicism, UPD and one individual with XX/XY chimerism to gain insight into the developmental mechanism and timing of these events. (nih.gov)
- Objective: Placental mosaicism for a subset of a chromosome, a structural chromosomal aberration, is thought to be a very rare finding in chorionic villus samples. (aau.dk)
Mutations2
Fetal4
- By cataloging the extent of somatic mosaicism in different cell types, disease states, and life stages, the SMaHT Network will lead to new understandings of how much somatic mosaicism influences fetal development, disease processes, and aging. (nih.gov)
- This kind of mosaicism may be more frequent than previously anticipated, and the fetal involvement seems difficult to predict. (aau.dk)
- 1997) European collaborative research on mosaicism in CVS (EUCROMIC)--fetal and extrafetal cell lineages in 192 gestations with CVS mosaicism involving single autosomal trisomy. (bcchr.ca)
- Fetal trisomy 5 mosaicism: case report and literature review. (thieme-connect.com)
SCN1A4
- We evaluated 128 participants with de novo, pathogenic SCN1A variants to investigate whether mosaicism, caused by postzygotic mutation, is a major modifier in SCN1A-related epilepsy. (uu.nl)
- Methods: Mosaicism was investigated by reanalysis of the pathogenic SCN1A variants using single molecule molecular inversion probes and next generation sequencing with high coverage. (uu.nl)
- Results: Mosaicism was present for 7.5% of de novo pathogenic SCN1A variants in symptomatic patients. (uu.nl)
- Participants with mosaicism have on average milder phenotypes, suggesting that mosaicism can be a major modifier of SCN1A-related diseases. (uu.nl)
Mechanisms2
- In this review, the various genetic mechanisms leading to mosaicism and the resulting cutaneous patterns are considered. (nih.gov)
- Variants occur widely throughout the genome and across the lifespan via a variety of genomic and biological mechanisms, creating stochastic, clonal, and dynamic somatic mosaicism. (nih.gov)
Clinical5
- Here, we present clinical and laboratory data on five cases with such mosaicism for structural chromosomal aberrations. (aau.dk)
- The aim of our study was to investigate the clinical and cytogenetic characteristics of patients with this mosaicism.DESIGN AND SETTING: A retrospective study in a referral hospital in southern Brazil.METHODS: Our sample consisted of patients diagnosed at the clinical genetics service of a referral hospital in southern Brazil, from 1975 to 2012. (figshare.com)
- The clinical picture was complicated by the co-existent diagnosis of confined placental mosaicism (CPM) for tetrasomy 9p. (ox.ac.uk)
- Mosaicism and clinical genetics. (thieme-connect.com)
- The clinical picture and exclude the presence of any mosaicism. (who.int)
Diagnosis1
- A diagnosis of mosaicism may cause confusion and uncertainty. (medlineplus.gov)
SMaHT1
- The goal of the SMaHT Network is to determine how somatic mosaicism impacts human biology and health. (nih.gov)
Developmental2
- We need additional research to fully understand the effect of mosaicism on embryo developmental potential. (txfertility.com)
- Genetic mosaicism is only detected occasionally when there are no obvious health or developmental issues. (biomedcentral.com)
Gene1
- The development of new genetic, cellular, and recombinant protein therapies has shown promise, and this review summarizes a unique gene and cell therapy phenomenon termed revertant mosaicism (RM). (umn.edu)
Kalousek DK1
- 14 Kalousek DK, Vekemans M. Confined placental mosaicism. (thieme-connect.com)
Biopsy1
- A day-5 biopsy is affected by lower-level mosaicism and provides more cells for testing. (medscape.com)
Structural2
Disorders2
- Ever more disorders are found to be manifestations of mosaicism and together constitute a significant proportion of the morbidity confronting pediatric specialists. (qxmd.com)
- We have developed a method (MAD) to detect genetic mosaicisms using SNP array data that has been used to assess association between mosaicisms and aging, cancer, and other disorders. (isglobal.org)
Embryos2
- Detecting mosaicism in embryos is an evolving science. (txfertility.com)
- On day 3, one or two cells are removed, and around one third of the embryos are affected by mosaicism, influencing the diagnostic accuracy of the test. (medscape.com)
Lymphocyte1
- Whereas both blood karyotypes obtained from peripheral lymphocyte cultures were normal, a 16% trisomy 2 mosaicism was found in cultured skinfibroblasts derived from a hypopigmented skin area of her father. (unimore.it)
Cells4
- conversely, somatic mosaicism is a type of genetic mosaicism found in somatic cells. (wikipedia.org)
- Mosaicism is a condition in which cells within the same person have a different genetic makeup. (medlineplus.gov)
- Somatic mosaicism refers to the post-conception changes to our DNA that lead to genetic variation among cells within an individual. (nih.gov)
- The effects of mosaicism depend on many factors, including where abnormal cells are located in the embryo and the proportion of cells that are abnormal. (txfertility.com)
Diseases1
- We know that over time, somatic mosaicism can lead to diseases like cancer, but we don't know how much somatic mosaicism there is in our personal genomes or how much it influences human biology. (nih.gov)
Genetically3
- Borrowing the term from art, genetic mosaicism describes the presence of two or more genetically diverse cell populations in an organism. (aacr.org)
- Genetic mosaicism is defined as the presence of two or more genetically distinct cell populations in a single individual. (qxmd.com)
- The clinico-pathological characterisation of focal cortical dysplasia type IIb genetically defined by MTOR mosaicism. (bvsalud.org)
Research1
- Research has indicated that mosaicism affecting CSGs can be associated with hereditary predisposition syndromes. (aacr.org)
Syndrome1
- 1. Subject has Fragile X syndrome with a molecular genetic confirmation of the full FMR1 mutation or mosaicism. (who.int)
Detect1
- Somatic mosaicism is challenging to study because low frequency variants are hard to detect, and repetitive regions of DNA are difficult to sequence reliably. (nih.gov)
Microarray1
- The accuracy of chromosomal microarray testing for identification of embryonic mosaicism in human blastocysts. (thieme-connect.com)
Diagnose1
- Genetic testing can diagnose mosaicism. (medlineplus.gov)
Variants1
- Allelic ratios of pathogenic variants were used to determine whether mosaicism was likely. (uu.nl)
Patterns1
- Mosaicism may produce different cutaneous patterns such as the lines of Blaschko, the checkerboard pattern, the phylloid pattern, and a patchy pattern without midline separation. (nih.gov)
Objective1
- CONTEXT AND OBJECTIVE: 45,X/46,XY mosaicism, or mixed gonadal dysgenesis, is considered to be a rare disorder of sex development. (figshare.com)
Mosaics1
- A bias towards females has been noted in other cases of trisomy mosaicism (e.g. trisomy 16) and suggests either preferential survival of female mosaics or a greater tendency to mosaicism in females. (bcchr.ca)
Cell1
- Mosaicism is caused by an error in cell division very early in the development of the unborn baby. (medlineplus.gov)