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Purine-Pyrimidine Metabolism, Inborn ErrorsMetabolism, Inborn Errors: Errors in metabolic processes resulting from inborn genetic mutations that are inherited or acquired in utero.Osmium Tetroxide: (T-4)-Osmium oxide (OsO4). A highly toxic and volatile oxide of osmium used in industry as an oxidizing agent. It is also used as a histological fixative and stain and as a synovectomy agent in arthritic joints. Its vapor can cause eye, skin, and lung damage.Amino Acid Metabolism, Inborn Errors: Disorders affecting amino acid metabolism. The majority of these disorders are inherited and present in the neonatal period with metabolic disturbances (e.g., ACIDOSIS) and neurologic manifestations. They are present at birth, although they may not become symptomatic until later in life.Polydeoxyribonucleotides: A group of 13 or more deoxyribonucleotides in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.Purines: A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Poly dA-dT: Polydeoxyribonucleotides made up of deoxyadenine nucleotides and thymine nucleotides. Present in DNA preparations isolated from crab species. Synthetic preparations have been used extensively in the study of DNA.DNA, Superhelical: Circular duplex DNA isolated from viruses, bacteria and mitochondria in supercoiled or supertwisted form. This superhelical DNA is endowed with free energy. During transcription, the magnitude of RNA initiation is proportional to the DNA superhelicity.DNA: 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).Single-Strand Specific DNA and RNA Endonucleases: Enzymes that catalyze the endonucleolytic cleavage of single-stranded regions of DNA or RNA molecules while leaving the double-stranded regions intact. They are particularly useful in the laboratory for producing "blunt-ended" DNA molecules from DNA with single-stranded ends and for sensitive GENETIC TECHNIQUES such as NUCLEASE PROTECTION ASSAYS that involve the detection of single-stranded DNA and RNA.Base Composition: The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.Repetitive Sequences, Nucleic Acid: 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).Lipid Metabolism, Inborn Errors: Errors in the metabolism of LIPIDS resulting from inborn genetic MUTATIONS that are heritable.Molecular Sequence Data: 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.Neonatal Screening: The identification of selected parameters in newborn infants by various tests, examinations, or other procedures. Screening may be performed by clinical or laboratory measures. A screening test is designed to sort out healthy neonates (INFANT, NEWBORN) from those not well, but the screening test is not intended as a diagnostic device, rather instead as epidemiologic.Pyrimidines: A family of 6-membered heterocyclic compounds occurring in nature in a wide variety of forms. They include several nucleic acid constituents (CYTOSINE; THYMINE; and URACIL) and form the basic structure of the barbiturates.Oligodeoxyribonucleotides: A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Steroid Metabolism, Inborn Errors: Errors in metabolic processing of STEROIDS resulting from inborn genetic mutations that are inherited or acquired in utero.Carbohydrate Metabolism, Inborn ErrorsUrea Cycle Disorders, Inborn: Rare congenital metabolism disorders of the urea cycle. The disorders are due to mutations that result in complete (neonatal onset) or partial (childhood or adult onset) inactivity of an enzyme, involved in the urea cycle. Neonatal onset results in clinical features that include irritability, vomiting, lethargy, seizures, NEONATAL HYPOTONIA; RESPIRATORY ALKALOSIS; HYPERAMMONEMIA; coma, and death. Survivors of the neonatal onset and childhood/adult onset disorders share common risks for ENCEPHALOPATHIES, METABOLIC, INBORN; and RESPIRATORY ALKALOSIS due to HYPERAMMONEMIA.Circular Dichroism: A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Brain Diseases, Metabolic, Inborn: Brain disorders resulting from inborn metabolic errors, primarily from enzymatic defects which lead to substrate accumulation, product reduction, or increase in toxic metabolites through alternate pathways. The majority of these conditions are familial, however spontaneous mutation may also occur in utero.Argininosuccinic Aciduria: Rare autosomal recessive disorder of the urea cycle which leads to the accumulation of argininosuccinic acid in body fluids and severe HYPERAMMONEMIA. Clinical features of the neonatal onset of the disorder include poor feeding, vomiting, lethargy, seizures, tachypnea, coma, and death. Later onset results in milder set of clinical features including vomiting, failure to thrive, irritability, behavioral problems, or psychomotor retardation. Mutations in the ARGININOSUCCINATE LYASE gene cause the disorder.Hyperammonemia: Elevated level of AMMONIA in the blood. It is a sign of defective CATABOLISM of AMINO ACIDS or ammonia to UREA.Energy Metabolism: The chemical reactions involved in the production and utilization of various forms of energy in cells.Lipid Metabolism: Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.Phenylketonurias: A group of autosomal recessive disorders marked by a deficiency of the hepatic enzyme PHENYLALANINE HYDROXYLASE or less frequently by reduced activity of DIHYDROPTERIDINE REDUCTASE (i.e., atypical phenylketonuria). Classical phenylketonuria is caused by a severe deficiency of phenylalanine hydroxylase and presents in infancy with developmental delay; SEIZURES; skin HYPOPIGMENTATION; ECZEMA; and demyelination in the central nervous system. (From Adams et al., Principles of Neurology, 6th ed, p952).Smith-Lemli-Opitz Syndrome: An autosomal recessive disorder of CHOLESTEROL metabolism. It is caused by a deficiency of 7-dehydrocholesterol reductase, the enzyme that converts 7-dehydrocholesterol to cholesterol, leading to an abnormally low plasma cholesterol. This syndrome is characterized by multiple CONGENITAL ABNORMALITIES, growth deficiency, and INTELLECTUAL DISABILITY.Refractive Errors: Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.Infant, Newborn: An infant during the first month after birth.