Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An 18-year-old male patient presented with clinical and radiological evidence of Leigh's syndrome (LS), having developed progressive myoclonic epilepsy and ataxia 11 years previously. Muscle biopsy showed cytochrome oxidase deficiency but no ragged red fibres. Autopsy confirmed the diagnosis of LS; there was additional degenerative change in the cerebellum and dentate and olivary nuclei, and an axonal peripheral neuropathy. Biochemical studies showed reduced activity of complexes I and IV of the respiratory chain in mitochondria from heart, liver and kidney. The mutation of mitochondrial DNA (mtDNA) at position 8344, commonly associated with the syndrome of myoclonic epilepsy and ragged red fibres, was detected in the patient's blood and was present in muscle, brain, liver, heart, and kidney in uniformly high amounts. It is clear that LS is genetically heterogeneous and represents one of the most severe phenotypes of a number of different mtDNA defects.
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PMID:Mitochondrial DNA mutation underlying Leigh's syndrome: clinical, pathological, biochemical, and genetic studies of a patient presenting with progressive myoclonic epilepsy. 813 13

Three adult patients with acid beta-galactosidase deficiency/GM1 gangliosidosis who were from two unrelated families of Scandinavian descent were found to share a common point mutation in the coding region of the corresponding gene. The patients share common clinical features, including early dysarthria, mild ataxia, and bone abnormalities. When cDNA from the two patients in family 1 was PCR amplified and sequenced, most (39/41) of the clones showed a C-to-T transition (C-->T) at nucleotide 245 (counting from the initiation codon). This mutation changes the codon for Thr(ACG) to Met(ATG). Mutant and normal sequences were also found in that position in genomic DNA, indicating the presence of another mutant allele. Genomic DNA from the patient in family 2 revealed the same point mutation in one allele. It was determined that in each family only the father carried the C-->T mutation. Expression studies showed that this mutation produced 3%-4% of beta-galactosidase activity, confirming its deleterious effects. The cDNA clones from the patients in family 1 that did not contain the C-->T revealed a 20-bp insertion of intronic sequence between nucleotides 75 and 76, the location of the first intron. Further analysis showed the insertion of a T near the 5' splice donor site which led to the use of a cryptic splice site. It appears that the C-->T mutation results in enough functional enzyme to produce a mild adult form of the disease, even in the presence of a second mutation that likely produces nonfunctional enzyme.
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PMID:Mutations in the lysosomal beta-galactosidase gene that cause the adult form of GM1 gangliosidosis. 819 23

We performed a 5-year clinical and electrophysiologic follow-up study on two sibling cases with myoclonus epilepsy with ragged-red fibers. Both had myoclonus, intention tremor, slight muscle weakness, slight mental disturbance, hearing impairment, and optic atrophy. Neither had epileptic attacks or truncal or gait ataxia. Biochemical activity of cytochrome c oxidase was at the lower limit of the normal range of values, and an adenine to guanine transition mutation at nucleotide 8344 in the transfer RNA specific for lysine of mitochondrial DNA was detected in both cases. The electroencephalograms showed slowing of basic patterns, diffuse spike-and-wave complexes, occipital dominant wave-and-spike phantoms, 6- and 14-Hz positive spikes, and photosensitivity. No definite deterioration of basic patterns was seen, and diffuse spike-and-wave complexes and photosensitivity gradually disappeared during the slowly progressive clinical course. P2 latencies of pattern-reversal visual evoked potentials throughout the clinical course and III through V interpeak latencies of auditory brainstem responses at follow-up were prolonged without giant sensory evoked potentials in both cases.
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PMID:Myoclonus epilepsy with ragged-red fibers: a clinical and electrophysiologic follow-up study on two sibling cases. 822 33

Consumption of large amounts of ethanol (EtOH) in a single drinking episode is common, but very little is known about the immunological effects of such occurrences. Exposure to EtOH for several days is immunosuppressive in rodent models, and a single dose of EtOH causes substantial increases in endogenous glucocorticoid levels which might have immunosuppressive effects. In the present study, the effects of a single dose of EtOH on the thymus and the role of endogenous glucocorticoids in these effects were examined in B6C3F1 female mice. A single dose of EtOH decreased thymus weight and cellularity, predominantly by elimination of CD4+CD8+ (immature) thymocytes. This occurred over a broad range of EtOH doses and was associated with behavioral effects (ranging from mild ataxia to unresponsiveness) similar to those noted in human binge drinkers. Several lines of evidence indicate that the effects of EtOH on the thymus are mediated by endogenous glucocorticoids: (1) corticosterone levels in EtOH-treated mice increased more than 10-fold and remained significantly elevated for up to 12 hr; (2) the most glucocorticoid-sensitive thymocytes (CD4+CD8+ cells) were preferentially depleted by EtOH; (3) before thymocyte depletion was evident, substantial DNA fragmentation occurred in the thymus as would be expected in the case of glucocorticoid-induced apoptosis; (4) the glucocorticoid antagonist, RU 486, blocked thymic atrophy and DNA fragmentation in EtOH-treated mice; (5) EtOH and its major metabolites at concentrations comparable to or greater than expected in vivo did not decrease thymocyte viability in 20-hr cultures, indicating that direct action of EtOH or its metabolites on thymocytes does not play an important role in EtOH-induced thymic atrophy. These results suggest that a single dose of EtOH induces thymic atrophy which is predominantly mediated by increased levels of endogenous glucocorticoids. The mouse model described here should be useful in evaluating other effects of binge drinking on the immune system, and the experimental strategy described should be applicable in investigating the role of endogenous glucocorticoids in thymic atrophy induced by other chemicals and drugs.
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PMID:Thymic atrophy caused by ethanol in a mouse model for binge drinking: involvement of endogenous glucocorticoids. 823 55

From spring 1990 to summer 1991 we investigated 21 horses with clinical symptoms of EHV-infection by means of serological and virological methods including DNA-hybridization to identify the causative agents. The results indicated that, as already reported by us, EHV4 may also cause the paralytic form of the infection. The possibility of double infection with EHV4 and EHV1 cannot be excluded. In 3 out of 21 affected horses we could investigate brain tissue and/or spinal fluid by Dotblot hybridization with EHV1 and EHV4-DNA. The investigated samples of all three horses showed hybridization with EHV4-DNA, without or with less pronounced reaction with EHV1-DNA. The results were confirmed by serological investigation. Brain tissue and cerebrospinal fluid from two horses with paretic or paralytic disorders (1979 and 1980) was also investigated by DNA hybridization. In the liquor of one horse--a 5-month-old foal with neonatal ataxia--we detected EHV1-DNA. The other horse showed a strong reaction with EHV1 and a weaker reaction with EHV4 in its brain material and no hybridisation in the cerebrospinal fluid. The results are discussed.
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PMID:[Recent information about the etiopathogenesis of paretic-paralytic forms of herpesvirus infection in horses]. 824 5

We report myoclonic epilepsy with ragged-red fibers (MERRF) syndrome in a Chinese family with confirmed mitochondrial DNA point mutation. Six members of the family including the grandmother, two siblings, and three grandchildren were affected. Among them, action myoclonus was seen in five; short stature, muscle weakness, and mental retardation in four; lactic acidosis, hearing impairment, and ataxia in two; and seizures in one. Muscle biopsy from two affected siblings revealed ragged-red fibers and abundant subsarcolemmal mitochondria with paracrystalline inclusions. Pedigree analysis suggests a maternal transmission. Analysis of mitochondrial DNA showed a point mutation from A to G at the 8344th nucleotide position located in the tRNA(Lys) gene. To our knowledge, this is the first report of MERRF syndrome with such genetic defect from a Chinese family. The present and previous reports support the notion that mitochondrial DNA point mutation at the 8344th nucleotide position is the most common cause of MERRF syndrome.
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PMID:Myoclonic epilepsy with ragged-red fibers (MERRF) syndrome: report of a Chinese family with mitochondrial DNA point mutation in tRNA(Lys) gene. 793 36

Genetic considerations in movement disorders are described. 1) Familial parkinsonisms are heterogeneous; genes for two of them, 'Lubag' and Waisman syndrome have been mapped to X chromosome, though genes for others do not have been mapped. 2) The responsible gene for Huntington's disease has been cloned recently and named huntingtin. A (CAG)n repeat longer than the normal range was observed in huntingtin gene. The (CAG)n repeat appears to be located within the coding sequence of a predicted approximately 348 kD protein that is widely expressed but unrelated to any known gene. The expansion of an unstable trinucleotide CAG repeat are also the causes of hereditary neurodegenerative diseases such as X-linked bular and spinal muscular atrophy and spinocerebellar ataxia type 1. 3) There are various forms in hereditary dystonia. Although the responsible gene for idiopathic torsion dystonia, inherited as an autosomal dominant pattern, has been mapped to 9q 32-34, genes for others do not have been mapped. 4) The Gilles des la Tourette syndrome (GTS) is a hereditary, neuropsychiatric-neurobehavioral disorder with childhood onset that is characterized by motor and vocal tics. About 80% of the human genome could be excluded as possible site for the GTS gene by studies with over 600 DNA markers in an international collaborative effort, but actual localization has not yet been accomplished.
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PMID:[Genetics in movement disorders]. 827 74

We report a Canadian kindred with a novel mutation in the apolipoprotein (apo) A-I gene causing analphalipoproteinemia. The 34-yr-old proband, product of a consanguineous marriage, had bilateral retinopathy, bilateral cataracts, spinocerebellar ataxia, and tendon xanthomata. High density lipoprotein cholesterol (HDL-C) was < 0.1 mM and apoA-I was undetectable. Genomic DNA sequencing of the proband's apoA-I gene identified a nonsense mutation at codon [-2], which we designate as Q[-2]X. This mutation causes a loss of endonuclease digestion sites for both BbvI and Fnu4HI. Genotyping identified four additional homozygotes, four heterozygotes, and two unaffected subjects among the first-degree relatives. Q[-2]X homozygosity causes a selective failure to produce any portion of mature apoA-I, resulting in very low plasma level of HDL. Heterozygosity results in approximately half-normal apoA-I and HDL. Gradient gel electrophoresis and differential electroimmunodiffusion assay revealed that the HDL particles of the homozygotes had peak Stokes diameter of 7.9 nm and contained apoA-II without apoA-I (Lp-AII). Heterozygotes had an additional fraction of HDL3-like particles. Two of the proband's affected sisters had documented premature coronary heart disease. This kindred, the third reported apoA-I gene mutation causing isolated complete apoA-I deficiency, appears to be at significantly increased risk for atherosclerosis.
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PMID:Apolipoprotein A-I Q[-2]X causing isolated apolipoprotein A-I deficiency in a family with analphalipoproteinemia. 828 91

The mitochondrion is the only extranuclear organelle containing DNA (mtDNA). As such, genetically determined mitochondrial diseases may result from a molecular defect involving the mitochondrial or the nuclear genome. The first is characterized by maternal inheritance and the second by Mendelian inheritance. Ragged-red fibers (RRF) are commonly seen with primary lesions of mtDNA, but this association is not invariant. Conversely, RRF are seldom associated with primary lesions of nuclear DNA. Large-scale rearrangements (deletions and insertions) and point mutations of mtDNA are commonly associated with RRF and lactic acidosis, e.g. Kearns-Sayre syndrome (KSS) (major large-scale rearrangements), Pearson syndrome (large-scale rearrangements), myoclonus epilepsy with RRF (MERRF) (point mutation affecting tRNA(lys) gene), mitochondrial myopathy, lactic acidosis, and stroke-like episodes (MELAS) (two point mutations affecting tRNA(leu)(UUR) gene) and a maternally-inherited myopathy with cardiac involvement (MIMyCa) (point mutation affecting tRNA(leu)(UUR) gene). However, RRF and lactic acidosis are absent in Leber hereditary optic neuropathy (LHON) (one point mutation affecting ND4 gene, two point mutations affecting ND1 gene, and one point mutation affecting the apocytochrome b subunit of complex III), and the condition associated with maternally inherited sensory neuropathy (N), ataxia (A), retinitis pigmentosa (RP), developmental delay, dementia, seizures, and limb weakness (NARP) (point mutation affecting ATPase subunit 6 gene). The point mutations in MELAS, MIMyCa, and MERRF, and the large-scale mtDNA rearrangements in KSS and Pearson syndrome have a broader biochemical impact since these molecular defects involve the translational sequence of mitochondrial protein synthesis. The nuclear defects involving mitochondrial function generally are not associated with RRF. The biochemical classification of mitochondrial diseases principally catalogues these nuclear defects. This classification divides mitochondrial diseases into five categories. Primary and secondary deficiencies of carnitine are examples of a substrate transport defect. A lipid storage myopathy is often present. Disturbances of pyruvate or fatty acid metabolism are examples of substrate utilization defects. Only four defects of the Krebs cycle are known: fumarase deficiency, dihydrolipoyl dehydrogenase deficiency, alpha-ketoglutarate dehydrogenase deficiency, and combined defects of muscle succinate dehydrogenase and aconitase. Luft disease is the singular example of a defect in oxidation-phosphorylation coupling. Defects of respiratory chain function are manifold. Two clinical syndromes predominate, one involving limb weakness, and the other primarily affecting brain function. Leigh syndrome may result from different enzyme defects, most notably pyruvate dehydrogenase complex deficiency, cytochrome c oxidase deficiency, complex I deficiency, and complex V deficiency associated with the recently described NARP point mutation. A new group of mitochondrial diseases has emerged.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The expanding clinical spectrum of mitochondrial diseases. 833 7

Acrylamide (2-propenamide) monomer produces central-peripheral distal axonopathy in humans and some animal species. Its neurotoxicity is characterized by abnormal sensation, decreased motor strength, and ataxia. Acrylamide forms adducts with glutathione, proteins, and DNA. Recent studies demonstrated that acrylamide is metabolized to its epoxide, glycidamide (2,3-epoxy-1-propanamide). We studied the neurotoxicity potential of glycidamide in male Sprague-Dawley rats. Animals (groups of 6) were injected ip daily with either aqueous acrylamide or glycidamide at an acrylamide-equivalent dose of 50 mg/kg (0.70 mmol/kg). Both treatments resulted initially in the rats circling, which was followed by the onset of ataxia at 7-9 d and hindlimb paralysis at 12-14 d. Treated animals showed muscle wasting. At termination, acrylamide- and glycidamide-treated rats weighed 105% and 86% of initial weight, respectively, compared to 145% for controls. Animals were anesthetized and perfused with 10% neutral phosphate-buffered formalin 12 or 14 d after beginning of treatment. Both treatment groups exhibited similar neuropathologic changes in the central and peripheral nervous systems. More severe lesions were produced by glycidamide. A marked increase in the number of affected Purkinje cells in the cerebellum, which exhibited changes ranging from pyknosis to cell death, were present. The brainstem exhibited axonal degeneration with chromatolytic necrosis in midbrain medial and lateral reticular nuclei. The spinal cord was characterized by spongy form changes with vacuoles of different sizes in various levels. These results suggest that glycidamide is an active neurotoxic metabolite of acrylamide.
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PMID:Neurotoxicity of glycidamide, an acrylamide metabolite, following intraperitoneal injections in rats. 834 32


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