Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Choline acetyltransferase activity was measured postmortem in five brain regions to determine if such activity provided biochemical support for clinical and pathological subgrouping of Alzheimer's disease. Seven patients with Alzheimer's disease were divided into groups based on age at onset, severity of neuropathological changes, history of myoclonus, family history of dementia, cerebellar amyloid plaques, and congophilic angiopathy. Thirty-two age-matched normal control subjects and 17 neurological control patients with Huntington's disease were also studied. Patients with early-onset and late-onset Alzheimer's disease did not differ in the clinical duration of their disease. Choline acetyltransferase activity was significantly lower in patients with early-onset Alzheimer's disease than in age-matched control subjects in frontal cortex, temporal cortex, hippocampus, and cerebellum. In contrast, choline acetyltransferase activity in patients with late-onset Alzheimer's disease was significantly lower than in age-matched control subjects only in hippocampus. There was a tendency for choline acetyltransferase activity to be lower in cortex from patients with early-onset Alzheimer's disease compared with cortex from the late-onset group, and this difference was significant in temporal cortex. Choline acetyltransferase activity was also measured in the substantia innominata from 9 patients with Alzheimer's disease and 5 age-matched control subjects. Subjects with early-onset Alzheimer's disease had significantly lower choline acetyltransferase activity in substantia innominata than did control subjects. Patients with Alzheimer's disease and a history of myoclonus had significantly lower choline acetyltransferase activity than did affected patients without myoclonus. Multivariate regression analysis showed myoclonus to be the single best predictor of low brain choline acetyltransferase activity. These results provide further evidence for clinical, pathological, and biochemical heterogeneity in Alzheimer's disease.
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PMID:Alzheimer's disease: choline acetyltransferase activity in brain tissue from clinical and pathological subgroups. 622 76

Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant neurodegenerative disorder characterized clinically by various combinations of myoclonus, epilepsy, cerebellar ataxia, choreoathetosis, dementia and psychiatric symptoms. Based on the phenomenon of anticipation, the gene for DRPLA was recently identified. DRPLA is caused by unstable expansion of a CAG repeat in the gene located on the short arm of chromosome 12. As have been observed in Huntington's disease and SCA1, there is a strong correlation between the age of onset and the size of CAG repeats. Furthermore, patients with larger repeats tend to show a PME (progressive myoclonus epilepsy) phenotype as well as earlier ages of onset. More prominent anticipation and larger intergenerational increase of CAG repeats in paternal transmission can be accounted for by the meiotic instability of CAG repeats in male gametogenesis. Comparison of size distributions of CAG repeats in Japanese, African-American and white populations revealed that 7.4% of the Japanese alleles had greater than 19 repeats, whereas none of the whites and 1% of the African-American alleles were of this size. The results may account for the ethnic predilection of DRPLA.
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PMID:Dentatorubral-pallidoluysian atrophy (DRPLA). Molecular basis for wide clinical features of DRPLA. 761 90

Dentatorubropallidoluysian atrophy is a neurodegenerative disorder with characteristic pathology, chiefly described in reports from Japan, and is associated with an unstable CAG trinucleotide repeat in a gene on chromosome 12. We describe four European families, three British and one Maltese, with this mutation. All exhibited autosomal dominant inheritance, and there was evidence for anticipation associated with an increase of the expansion with paternal transmission in two families. Affected chromosomes from patients with dentatorubropallidoluysian atrophy had CAG expansions of 58 to 74 repeats, compared to 7 to 26 in control chromosomes, and the size of repeat was significantly inversely correlated with age of onset. The clinical features were diverse, even within individual families, and comprised a combination of a movement disorder (chorea, myoclonus, dystonia, or parkinsonism), cerebellar ataxia, epilepsy, psychosis, and dementia. A clinical diagnosis of Huntington's disease had been made in affected individuals from all families. Neuropathological examination of 2 patients showed no specific abnormality in one and degenerative changes predominantly affecting the spinal cord in the other. Investigation of 55 patients who might represent sporadic examples of dentatorubropallidoluysian atrophy did not detect any expanded alleles. Dentatorubropallidoluysian atrophy is likely to be more common than previously recognized in non-Japanese populations, and should be considered in any patient with a dominantly inherited neurodegenerative disorder with the above-mentioned clinical features.
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PMID:A clinical and molecular genetic study of dentatorubropallidoluysian atrophy in four European families. 771 81

Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder affecting primarily dentatorubral as well as pallidoluysian atrophy. From a view point of clinical genetics, DRPLA is characterized by prominent anticipation and considerable heterogeneities in its clinical manifestations. Given the fact that unstable CAG repeat expansion is the causative genes for Huntington disease and spinocerebellar ataxia 1, in which anticipation and parental bias of transmission of the severest form are present, we hypothesized that DRPLA might be caused by unstable expansion of a gene containing a CAG repeat. By screening published genes containing CAG repeats, were able to identify the gene for DRPLA located on the chromosome 12. All the DRPLA patients had expanded CAG repeats, and furthermore, there is a good correlation between the degree of CAG repeat expansions and the ages of onset. There are also good correlation in the ages of onset of each of the neurological of manifestations including myoclonus, choreoathetosis, epilepsy, dementia, and psychiatric symptoms. We concluded that the unstable expansion of the CAG repeat in the DRPLA gene is intimately involved in the pathogenesis of DRPLA.
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PMID:[Molecular basis of heterogeneities of clinical presentation of dentatorubral pallidoluysian atrophy (DRPLA)]. 777 19

We describe three patients with Huntington's disease, from two families, in whom myoclonus was the predominant clinical feature. The diagnosis was confirmed at autopsy in two cases and by DNA analysis in all three. These patients all presented before the age of 30 years and were the offspring of affected fathers. Neurophysiological studies documented generalised and multifocal action myoclonus of cortical origin that was strikingly stimulus sensitive, without enlargement of the cortical somatosensory evoked potential. The myoclonus improved with piracetam therapy in one patient and a combination of sodium valproate and clonazepam in the other two. Cortical reflex myoclonus is a rare but disabling component of the complex movement disorder of Huntington's disease, which may lead to substantial diagnostic difficulties.
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PMID:Cortical myoclonus in Huntington's disease. 784 4

It is known that EEG findings reveal various abnormalities in patients with involuntary movement. But these findings are not specific. It has been reported to be related to myoclonus and spike. The other involuntary movement is unknown to the relation to EEG findings. The involuntary movement usually disappears during sleep, but a certain involuntary movement appears only during sleep. In the patient with Huntington's chorea and dystonia musculorum deformans, PSG reveals an increase in interspersed wakefulness, decrease of deep sleep and prolongation of REM latency. Periodic limb movement and nocturnal paroxysmal dystonia appear only during sleep. Nocturnal sleep studies are important for exploring the pathophysiology in involuntary movement.
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PMID:[EEG and polysomnography findings in patients with dyskinesia]. 827 65

As a clinical diagnostic approach, the evoked potential has been used to differentiate movement disorders, especially myoclonic movements, Giant somatosensory evoked potentials (SEPs) and long-loop reflex to electrical stimulation of the peripheral nerve are commonly employed in the evaluation of patients with myoclonus. Recently, abnormality in a specific component of SEP frontal N30 has been reported in focal dystonia. Jerk locked back averaging has been applied to cortical reflex myoclonus, minipolymyoclonus, cortical tremor, simple tics, chorea-acanthocytosis, Huntington's chorea, etc. Silent period locked averaging is also used for asterixis. With these new electrophysiological techniques, evaluation of functional mechanisms in movement disorders may be expected, with fruitful results.
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PMID:[Clinical diagnosis of movement disorders--evoked potentials]. 827 66

A patient with adult onset Huntington's disease (HD) and prominent action myoclonus is described. Neither epileptiform activity nor electroencephalography (EEG) correlates of the movements was found. Unlike the case with most (nonmyoclonic) HD patients, centro-parietal components of somatosensory evoked potentials (SEPs) were well defined and a clear V2 response was found. Treatment with valproic acid greatly reduced myoclonus suggesting that the gamma-aminobutyric acid (GABA) system might be involved in the pathophysiology of myoclonus in HD.
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PMID:Adult onset myoclonic Huntington's disease. 847 90

Developments in the field of Huntington's disease have focused on the potential benefits of predictive testing. Markers have been described for autosomal dominant cerebellar ataxia and for certain subtypes of Friedrich's ataxia. Argentophilic neuronal and glial inclusions appear to be the first specific pathologic hallmark of multiple system atrophy. "Pure" hereditary spastic paraplegia is not a multisystem disorder of the central nervous system, but a monomorphic and stereotyped disease. Advances in Tourette's syndrome are limited because the presumed gene eludes identification. A new type of myoclonus, propiospinal myoclonus, has been described. Clinical and electrophysiologic criteria for defining primary orthostatic tremor have been proposed. Understanding of the neurophysiologic substrate of essential tremor and myoclonus is improving. New neurologic disorders presenting clinically with prominent movement disorder continue to be described.
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PMID:Choreas, hereditary and other ataxias, tics, myoclonus, and other movement disorders. 850 6

Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder characterized by a degeneration of cerebellar and pallidal efferents, more frequent in Japan. Isolated cases are also encountered. Patients present with variable combination of signs including myoclonus, ataxia, epilepsy, choreoathetosis and dementia, with onset from childhood to the seventh decade. Clinically, DRPLA may be undistinguishable from other genetic disorders, in particular Huntington's disease or the spinocerebellar ataxias. The genetic basis of the inherited form of DRPLA is an expansion to more than 49 repeats of an unstable trinucleotide (CAG) in the DRPLA gene on the short arm of chromosome 12. We determined the frequency of this mutation in patients with the DRPLA phenotype. One hundred and seventeen patients with cerebellar ataxia, from 94 families and 23 isolated cases, as well as 3 patients from families with undiagnosed autosomal dominant neurodegenerative disorders were investigated for the presence of the expanded sequence. None of the patients carried this mutation. This finding suggests that DRPLA is rare in the French population. The search for the DRPLA mutation is justified in patients with the DRPLA phenotype, however, since genetic counselling is often requested and neither clinical, nor neuropathological examinations permit a definite diagnosis of the underlying disease.
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PMID:[Does the ataxo-choreic form of DRPLA exist in Europe? Search of mutation in 120 families]. 874 29


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