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)

We describe the first Danish family with dentatorubral-pallidoluysian atrophy (DRPLA), containing 16 clinically affected individuals in five generations. Inheritance is autosomal dominant. The disorder was diagnosed as Huntington's disease (HD), but analysis of the IT15 gene for HD revealed normal alleles. The diagnosis of DRPLA was based on the finding of elongated CAG repeats in the B37 gene on chromosome 12 in affected individuals. The age at onset ranged from 13 to 60 years, with the most severe clinical picture being associated with onset in childhood. Clinical features included varying combinations of dementia, euphoria, visuomotor disturbances, speech problems, ataxia, tremor, epilepsy and involuntary movements presenting as chorea, athetosis, and dystonia. We discuss characteristics of DRPLA that may enable the differentiation from HD on a clinical basis. In conclusion, DRPLA should be considered and DNA analysis is recommended in patients manifesting varying combinations of extrapyramidal and cerebellar symptoms, especially when clinical features show pronounced intrafamilial variability, and dyscoordination, tremor, myoclonus, epilepsy, and euphoria are part of the syndrome.
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PMID:Dentatorubral-pallidoluysian atrophy. Clinical features of a five-generation Danish family. 886 94

Over the past 15 years we have treated 526 patients with severe hyperkinetic movement disorders with tetrabenazine (TBZ), a monoamine-depleting and a dopamine-receptor-blocking drug. We report here the results in 400 patients with adequate follow-up. The response was rated on a scale of 1 to 5 (1 = marked improvement, 4 = no response, 5 = worsening) and was assessed initially and at the last clinic visit. The average duration of TBZ treatment was 28.9 months (+/- 31.1; range, 0.25 to 180 months). The global response rating of 1 (marked improvement) was recorded in 89.2% of 93 patients with tardive stereotypy, 83.3% of 12 with myoclonus, 82.8% of 29 with Huntington's disease, 80.5% of 82 with tardive dystonia, 79.3% of 29 with other movement disorders, 62.9% of 108 with idiopathic dystonia, and in 57.4% of 47 with Tourette's syndrome. The most common side effects included drowsiness (36.5%), parkinsonism (28.5%), depression (15.0%), insomnia (11.0%), nervousness or anxiety (10.3%), and akathisia (9.5%). The side effects were controlled with reduction in the dosage. TBZ is an effective and safe drug for the treatment of a variety of hyperkinetic movement disorders. In contrast to typical neuroleptics, TBZ has not been demonstrated to cause tardive dyskinesia.
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PMID:Long-term effects of tetrabenazine in hyperkinetic movement disorders. 904 Jul 21

Dentatorubral and pallidoluysian atrophy (DRPLA) is an autosomal dominant disorder that clinically overlaps with Huntington's disease (HD) and manifests combinations of chorea, myoclonus, seizures, ataxia, and dementia. DRPLA is caused by a CAG triplet repeat (CTG-B37) expansion coding for polyglutamine on chromosome 12 and exhibits the genetic phenomenon of anticipation. This neurodegenerative disease has only rarely been reported in non-Japanese pedigrees, and there are only a few neuropathological studies in genetically confirmed patients. We report 10 cases of DRPLA from two North American and two British pedigrees in which CTG-B37 expansions have been demonstrated within each kindred (54-83 repeats), individually in 8 of the 10 cases, and describe the neuropathological findings in 4 cases. Members of DRPLA kindreds have a wide range of clinical phenotypes and markedly variable ages at onset. The neuropathological spectrum is centered around the cerebellifugal and pallidofugal systems, but neurodegenerative changes can be found in many nuclei, tracts, and systems. Evidence of CTG-B37 triplet repeat expansion should be sought in HD-like cases that are negative for expanded triplet repeats within the HD IT15 gene or in autopsy cases with degeneration of the dentatorubral or pallidoluysian systems.
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PMID:Dentatorubral and pallidoluysian atrophy (DRPLA). Clinical and neuropathological findings in genetically confirmed North American and European pedigrees. 975 63

Primary defects of mitochondrial DNA leading to respiratory chain dysfunction have been described in association with dystonia, chorea and parkinsonism. Myoclonus remains the commonest movement disorder associated with such defects. The genetic basis of Leigh's syndrome, which is frequently associated with movement disorders, may be mitochondrial or nuclear. Respiratory chain dysfunction has been identified in Huntington's disease in addition to Parkinson's disease, but the cause and relationship of this dysfunction to the pathogenesis of these common disorders is not yet determined.
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PMID:Movement disorders and mitochondrial dysfunction. 926 61

Juvenile Huntington disease (JHD) patients are distinguished from adult patients by an age at onset of less than 20 years. Investigating patients in our own database, we examined the proposition derived from studies in world literature that JHD should not be viewed as a separate clinical entity but rather as a manifestation of the rigid variant of the disease. Of 53 patients with JHD recorded in the Leiden Roster for Huntington Disease, relationships between sex, age at onset, duration of illness, maternal or paternal inheritance, motor symptom, first clinical features, and characteristics during the disease course, were obtained from the patients' files, and investigated. Although chorea is present in JHD, patients more often developed rigidity. Paternal inheritance, early dementia, epilepsy/myoclonus, and tremor during the disease course are confined for the most part to the rigid cases. A shorter duration of illness was evident in male patients with rigid JHD who inherited the disease from their father and developed their first disease feature at a younger age. The recognition of JHD as a distinct clinical entity does not appear to be warranted. Therefore, we propose, in accordance with other investigators, that rigid JHD be considered a clinical variant with special features.
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PMID:Juvenile Huntington disease in the Netherlands. 930 74

We report the electrophysiologic findings of myoclonus in a patient with Huntington's disease (HD). This patient was studied postoperatively after a bilateral fetal cell transplant in his striatum. Incomplete transient improvement was seen in the myoclonus, followed by gradual deterioration. The myoclonus itself had a cortical correlate and was associated with an enlarged somatosensory evoked potential (SEP), consistent with the presence of cortical reflex myoclonus. An enlarged SEP has not been previously reported in myoclonus associated with HD. The postulated mechanisms for myoclonus, when it occurs in HD, have differed in the literature. The reason for the transient improvement of the myoclonus following transplantation is unclear, but this case raises the possibility that basal ganglia circuits may modulate cortical myoclonic activity.
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PMID:Cortical Myoclonus in Huntington's disease associated with an enlarged somatosensory evoked potential. 939 35

The author reviews the applications of transcranial magnetic stimulation (TMS) in a series of movement disorders--namely, Parkinson's disease, corticobasal degeneration, multiple system atrophy, progressive supranuclear palsy, essential tremor, dystonia, Huntington's chorea, myoclonus, the ataxias, Tourette's syndrome, restless legs syndrome, Wilson's disease, Rett syndrome, and stiff-person syndrome. Single- and paired-pulse TMS studies have been done mainly for pathophysiologic purposes. Repetitive TMS has been used largely for therapy. Many TMS abnormalities are seen in the different diseases. They concur to show that motor cortical areas and their projections are the main target of the basal ganglia dysfunction typical of movement disorders. Interpretation has not always been clear, and sometimes there were discrepancies and contradictions. Largely, this may be the result of the extreme heterogeneity of the methods used and of the patients studied. It is premature to give repetitive TMS a role in treatment. Overall, however, TMS gives rise to a new, outstanding enthusiasm in the neurophysiology of movement disorders. There is reason to predict that TMS, with its continuous technical refinement, will prove even more helpful in the near future. Then, research achievements are reasonably expected to spill over into clinical practice.
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PMID:Applications of transcranial magnetic stimulation in movement disorders. 1243 85

Myoclonus is a clinical symptom (or sign) defined as sudden, brief, shock-like, involuntary movements caused by muscular contractions or inhibitions. It may be classified by examination findings, etiology, or physiological characteristics. The main physiological categories for myocolonus are cortical, cortical-subcortical, subcortical, segmental, and peripheral. Neurodegenerative syndromes are potential causes of symptomatic myoclonus. Such syndromes include multiple system atrophy, corticobasal degeneration, progressive supranuclear palsy, frontotemporal dementia and parkinsonism linked to chromosome 17, Huntington's disease, dentato-rubro-pallido-luysian atrophy, Alzheimer's disease, and Parkinson's disease, and other Lewy body disorders. Each neurodegenerative syndrome can have overlapping as well as distinctive clinical neurophysiological properties. However, claims of differentiating between neurodegenerative disorders by using the presence or absence of small amplitude distal action myclonus appear unwarranted. When the myoclonus is small and repetitive, it may not be possible to distinguish it from tremor by phenotypic appearance alone. In this case, clinical neurophysiological offers an opportunity to provide greater differentiation of the phenomenon. More study of the myoclonus in neurodegenerative disease will lead to a better understanding of the processes that cause phenotypic variability among these disorders.
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PMID:Myoclonus and neurodegenerative disease--what's in a name? 1261 52

The clinical features of Juvenile Huntington's Disease (J-HD) differ from those of the more common adult-onset form, and include cognitive decline, parkinsonism, myoclonus and seizures. A paucity of literature is available describing the electroencephalographic (EEG) findings. We describe the clinical and EEG characteristics of a patient with genetically confirmed J-HD. A review of previously published cases yielded EEG descriptions in only 23 patients whose disease onset was prior to the age of 32, and only 14 of these were prior to the age of 20. Epileptiform abnormalities were noted in 17 (74%), which was considerably more common than in the adult form. Generalized discharges were noted in nine, with six having polyspike and wave. The remainder had focal or multifocal epileptiform discharges. With genetic testing now available, refinement of the EEG data will be possible.
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PMID:EEG characteristics in juvenile Huntington's disease: a case report and review of the literature. 1468 49

We report a case of cortical reflex myoclonus in adult onset Huntington's disease (HD). The patient is a 51-year-old woman. Chorea and myoclonus were observed on her face and extremities. Neurophysiological tests showed C reflex and abnormal waves preceding myoclonus by jerk-locked back averaging method but no giant somatosensory evoked potential. Gene analysis revealed the prolongation of CAG repeats (13/44) in IT15 gene. Oral administration of clonazepam was transiently effective for myoclonus. We should inscribe that the cortical reflex myoclonus may exceptionally manifest in HD.
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PMID:[Cortical reflex myoclonus in adult onset Huntington's disease]. 1551 12


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