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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report on a 13 years old girl with Rett syndrome (autism, dementia, ataxia and loss of purposeful hand use in girls). The Rett syndrome is unexpectedly frequent (1:15,000 in 1-14 years old girls). The diagnosis is based solely upon clinical development observation. Typical false diagnoses are: autism, some types of epilepsia, deprivation, cerebral palsy, degenerative encephalopathy, infantile psychosis and types of ataxia. The etiology is unknown, genetic factors, possibly an X-linked dominant new mutation, explain many, but not all findings. The empiric recurrence-risk is apparently low.
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PMID:[Rett syndrome--case report]. 365 39

A family is described with familial myoclonic epilepsy associated with mitochondrial myopathy. The disorder follows a maternal inheritance pattern consistent with a mitochondrial DNA (mtDNA) mutation. The large kindred permitted exclusion of autosomal dominant, recessive, and X-linked patterns of transmission. Several characteristics of the inheritance and variability of expression within the pedigree are consistent with recently acquired knowledge about the genetics of human mtDNA. The clinical spectrum of disease is compatible with a proportionality model of mutant and wild-type mtDNAs. Muscle biopsies of affected patients showed an increased number of abnormal muscle mitochondria. Serum levels of pyruvate or pyruvate and lactate were elevated. The most severely affected patient had constant myoclonic jerking, dementia, ataxia, spasticity, hearing loss, and hypoventilation. Cerebral dysfunction in patients with mild involvement was marked by prominent photic driving seen on electroencephalograms and high-amplitude visual and somatosensory evoked responses but no myoclonus, ataxia, or dementia. The individual clinical features of the disease worsen over time for all patients; however, mildly affected patients have not become moderately affected and moderately affected patients have not become severely affected.
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PMID:Maternally inherited mitochondrial myopathy and myoclonic epilepsy. 392 81

We reviewed the natural history and differential diagnosis of ornithine transcarbamylase deficiency (an X-linked inborn error of urea synthesis) in 13 symptomatic female heterozygotes. The patients presented as early as the first week of life or as late as the sixth year. The most common symptoms before diagnosis were nonspecific: episodic extreme irritability (100 percent), episodic vomiting and lethargy (100 percent), protein avoidance (92 percent), ataxia (77 percent), Stage II coma (46 percent), delayed physical growth (38 percent), developmental delay (38 percent), and seizures (23 percent). Including the proband, 42 percent of the female members of the 13 families studied had symptoms. The median interval between the onset of major symptoms (vomiting and lethargy, seizures, and coma) and diagnosis was 16 months (range, 1 to 142). Five patients had IQ scores below 70 at the time of diagnosis. We suggest that careful evaluation of the family history, the dietary history, the episodic nature of the nonspecific symptoms, the response of these symptoms to the withdrawal of protein, and their frequent onset at the time of weaning from breast milk will permit early diagnosis and might thereby reduce the risk of death or neurologic impairment in female patients with partial ornithine transcarbamylase deficiency.
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PMID:Natural history of symptomatic partial ornithine transcarbamylase deficiency. 394 92

Triplet-repeat mutations are a newly discovered class of mutations that have so far been described only in patients with neuropsychiatric disorders. The features of these so-called dynamic mutations are discussed with reference to the known examples (Huntington's chorea, fragile X syndrome, myotonic dystrophy, X-linked spinal and bulbar muscular atrophy, spinocerebellar ataxia type 1, and dentatorubral and pallidoluysian atrophy, DRPLA). These features not only explain a number of clinical-epidemiological facts that cannot be accounted for by Mendelian genetics, but also suggest that schizophrenia and major affective disorder may be the result of a similar mutation mechanism. The most important support for this suggestion can be derived from the observation that dynamic mutations cause anticipation-i.e., an increase in severity and/or an decrease in the age at onset of a disease in subsequent generations-which, in turn, has been discovered in schizophrenia and major affective disorder. From a systematic as well as from a historical perspective, we argue that in light of these findings, degeneration has been rediscovered in the disguise of a new name.
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PMID:[From degeneration to anticipation. Systematic and historical scientific aspects of the genetics of neuropsychiatric diseases]. 867 94

X-linked adrenomyeloneuropathy (AMN) is a phenotypic variant of adrenoleukodystrophy (ADL) presenting in early adult life with progressive ataxia and spasticity, and on occasion with adrenal insufficiency. We describe a 26-year-old Chinese man with a 2-year history of gait difficulty due to spasticity, absent pattern shift visual evoked (VER) responses and posterior white matter lesions on T2 weighted brain magnetic resonance images. His parents are clinically normal and his 24-year-old brother has hyperreflexia in the legs but normal VER latencies. The patient's ACTH levels were elevated and the serum cortisol did not rise with either Synacthen or corticotropin releasing hormone. Assay of his plasma confirmed elevation of very long chain fatty acids (VLCFA) consistent with a defect in peroxisomal VLCFA metabolism. This is the first local report of a patient with AMN.
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PMID:An index case of adrenomyeloneuropathy in a Chinese man. 776 96

The startling morphological abnormalities of sideroblastic anaemia contrasts our uncertainty about its cause. Studies are hampered by the fact that the abnormality resides in the dividing and differentiating erythroblast which is difficult to obtain pure and in large numbers, and in which many levels of metabolic control must coexist. Recent molecular biology approaches have confirmed abnormalities of erythroid delta-aminolaevulinic acid synthase as the cause of X-linked, pyridoxine-responsive sideroblastic anaemia and mitochondrial DNA deletions as the most common cause of congenital macrocytic sideroblastic anaemia. They have also identified a second X-linked sideroblastic anaemia locus linked to phosphoglycerate kinase and associated with ataxia. An association between sideroblastic anaemia and the use of an oral copper chelating agent has highlighted unexplained links between erythroid copper and iron metabolism. Management decisions in relation to pyridoxine treatment, iron reduction, family studies, genetic counselling and antenatal diagnosis have in recent years become of practical relevance to families with known cases of congenital sideroblastic anaemia and careful documentation of the clinical outcome of these cases and of other family members is invaluable. Parallel and integrated studies on the molecular biology of erythroid differentiation are revealing the range of possible controlling influences on erythroblasts and defining the circumstances for each, allowing studies on the cause of the most prevalent form of sideroblastic anaemia (the idiopathic acquired form) and those inherited forms that are not X-linked to be approached with a much clearer perspective.
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PMID:Sideroblastic anaemia. 788 Nov 57

Over the past few years, molecular neurogenetics has developed into one of the most promising and active research fields. The new discipline applies modern molecular genetic techniques to the investigation of classical neurological disorders. In the following article, a definition of neurogenetic disease is introduced, the molecular basis of four groups of neurogenetic disorders is described and recent diagnostic developments are presented. The first group of diseases is caused by trinucleotide expansions. "Expanding" trinucleotide repeats were not known to occur in any species until about three years ago. Today, disorders such as Huntington's disease, spinocerebellar ataxia type 1, fragile X mental retardation, spinobulbar muscular atrophy and myotonic dystrophy are all known to be caused by the expansion of trinucleotides. The second group is characterized by chromosomal deletions or uniparental disomies. Lissencephaly and the Miller-Dieker syndrome, Prader-Willi and Angelman syndromes and Duchenne and Becker muscular dystrophies belong to this category. The third group includes those neurogenetic disorders that are mainly caused by point mutations such as the X-linked leukodystrophies, including Pelizaeus-Merzbacher disease and adrenoleukodystrophy, Charcot-Marie-Tooth syndrome type 1, familial forms of amyotrophic lateral sclerosis, several types of craniosynostoses and some CNS tumor syndromes. Finally, Alzheimer's and Parkinson's disease are discussed as representatives of group four, i.e. genetically heterogeneous neurological disorders.
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PMID:Molecular basis and diagnosis of neurogenetic disorders. 796 63

Expansion of trinucleotide repeats is now recognized as a major cause of neurological disease. At least seven disorders result from trinucleotide repeat expansion: X-linked spinal and bulbar muscular atrophy (SBMA), two fragile X syndromes of mental retardation (FRAXA and FRAXE), myotonic dystrophy, Huntington's disease, spinocerebellar ataxia type 1 (SCA1), and dentatorubral-pallidoluysian atrophy (DRPLA). The expanded trinucleotide repeats are unstable, and the phenomenon of anticipation, i.e., worsening of disease phenotype over successive generations, correlates with increasing expansion size. In this review, we compare the clinical and molecular features of the trinucleotide repeat diseases, which may be classified into two types. Fragile X and myotonic dystrophy are multisystem disorders usually associated with large expansions of untranslated repeats, while the four neurodegenerative disorders, SBMA, Huntington's disease, SCA1, and DRPLA, are caused by smaller expansions of CAG repeats within the protein coding portion of the gene. CAG repeats encode polyglutamine tracts. Polyglutamine tract expansion thus appears to be a common mechanism of inherited neurodegenerative disease. Although polyglutamine tract lengthening presumably has a toxic gain of function effect in the CAG trinucleotide repeat disorders, the basis of this neuronal toxicity remains unknown.
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PMID:Trinucleotide repeat expansion in neurological disease. 799 66

Some transcription factors contain stretches of polyglutamine encoded by repeats of the trinucleotide CAG. Expansion of the CAG repeat in the androgen receptor (AR) has been correlated with the incidence and severity of X-linked spinal and bulbar muscular atrophy (Kennedy's disease). In order to understand the relationship of this mutation to AR function, we constructed ARs that varied in the position and size of the polyglutamine tract, and assayed for the abilities of these mutant receptors to bind androgen and to activate transcription of several different AR-responsive reporter genes. Elimination of the tract in both human and rat AR resulted in elevated transcriptional activation activity, strongly suggesting that the presence of the polyglutamine tract is inhibitory to transactivation. Progressive expansion of the CAG repeat in human AR caused a linear decrease of transactivation function. Importantly, expansion of the tract did not completely eliminate AR activity. We postulate that this residual AR activity may be sufficient for development of male primary and secondary sex characteristics, but may fall below a threshold level of activity necessary for normal maintenance of motor neuron function. This functional abnormality may be representative of other genetic diseases that are associated with CAG expansion mutations in open reading frames, such as spinocerebellar ataxia type I and Huntington's disease.
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PMID:The length and location of CAG trinucleotide repeats in the androgen receptor N-terminal domain affect transactivation function. 806 34

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


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