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)

Three siblings presented with a progressive neurological disorder beginning in the third decade of life and characterised by palatal myoclonus, nystagmus, bulbar weakness and spastic tetraparesis. There was no evidence of intellectual deterioration or seizures. CT scan showed marked brainstem atrophy in two patients and basal ganglia calcification in one. MRI scan in one showed high signal in the brainstem and periventricular region and cerebral biopsy in this patient showed myelin loss and the presence of Rosenthal fibres. A similar disease affected the siblings' mother, maternal aunt and two of the aunt's daughters, suggesting an autosomal dominant mode of transmission of what appears to be a unique genetic disorder.
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PMID:A familial disorder associated with palatal myoclonus, other brainstem signs, tetraparesis, ataxia and Rosenthal fibre formation. 841 38

We report 18 patients (13 women, 5 men; age range, 22 to 75 years; mean, 42.5), whom we ultimately diagnosed as having "psychogenic myoclonus." The myoclonus was present for an average of 36 months (range, 1 to 110), and it was segmental in 10, generalized in seven, and focal in one. Stress precipitated or exacerbated the myoclonic movements in 15 patients; 14 had a definite increase in myoclonic activity during periods of anxiety. A combination of the following findings helped to establish the psychogenic nature of the myoclonus: (1) clinical features incongruous with "organic" myoclonus, (2) evidence of underlying psychopathology, (3) an improvement with distraction in 14 and with placebo in nine, and (4) the presence of incongruous sensory loss or false weakness in five. Over half of all patients with adequate follow-up improved after gaining insight into the psychogenic mechanisms of their movement disorder. This study attempts to characterize psychogenic myoclonus, the most common psychogenic movement disorder in our movement disorders clinic, and provides a guide to its diagnosis and treatment.
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PMID:Psychogenic myoclonus. 825 56

A 38-year-old woman had an episode of headache, fever and convulsion in October, 1993. She became alert in two weeks, though weakness and atrophy remained in the upper limb muscles. She was diagnosed as Russian spring summer encephalitis (RSSE) based on several serological studies. Three kinds of involuntary movements were noted after recovery. These were spontaneous muscle jerks in the left arm, action tremor in the right arm and pathological associated-movement in the right leg. The movements were studied physiologically by electroencephalogram (EEG)-electromyogram (EMG) polygraphic recordings, jerk-locked averaging (JLA), magnetencephalography (MEG), and sensory evoked potentials (SEPs). The jerky movements in her left arm were observed at rest and aggravated by emotional stress. EEG-EMG polygraph showed that the jerks were sometimes associated with small spikes thus were considered to be due to epilepsia partialis continua (EPC). JLA analysis revealed a pre-myoclonus spike on the right hemisphere which preceded the onset of the jerk in the left first dorsal interosseous muscle by 25.2ms, which was equal to the magnetic cortical latency of that muscle. Jerk-locked magnetic field, obtained by averaging neuromagnetic activities with respect to the onset of myoclonus, showed that the spike preceding the jerk, originated from the right motor cortex. The spontaneous spikes were localized mainly on the right motor cortex. Sensory evoked potentials (SEPs) were normal in both size and latency. No hyperexcitability of the sensory cortex was demonstrated even by using paired stimulation SEPs. Based on these results, we conclude that the jerky movements in this patient were produced by abnormal spontaneous discharges in the motor cortex. The action tremor had a frequency of 4-5 Hz and its clinical features were compatible with cerebellar tremor. This is thought to result from a lesion in the left thalamus, affecting the cerebellothalamic pathways. Her right leg unintentionally moved whenever she began to move the hands. This was considered to be a pathological associated-movement due to dysfunction of the pyramidal tracts.
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PMID:[Involuntary movements observed in a patient with Russian spring summer encephalitis]. 881 Aug 52

A 27-month-old girl presented with chest pain. Further evaluation confirmed posterior mediastinal neuroblastoma with bone marrow infiltration, which was treated with a combination of chemotherapy and surgery. Four months after completing treatment, she presented with myoclonus and weakness of her right arm. The myoclonus eventually subsided but her right arm weakness progressed to a right hemiplegia. High titers of antineuronal nuclear antibodies identified as anti-Hu were found in both serum and cerebrospinal fluid. One month later she presented with a relapse of her original tumor, from which she died. Identification of anti-Hu antineuronal nuclear antibodies in this neuroblastoma-associated paraneoplastic syndrome supports the hypothesis that the syndrome is due to autoimmune disease.
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PMID:Neuroblastoma-associated paraneoplastic syndrome with anti-Hu antineuronal antibodies presenting at the time of recurrence. 883 43

We describe a progressive neurologic disorder in three sisters characterized clinically by palatal myoclonus, spastic weakness, hyperreflexia, mild cerebellar dysfunction, and ocular motor abnormalities. Postmortem examination of one patient demonstrated widespread Rosenthal fiber deposition associated with demyelination. The father previously was reported to have similar pathologic findings and carried a clinical diagnosis of multiple sclerosis. These clinical and pathologic findings describe a rare familial leukodystrophy that corresponds most closely to cases reported as adult Alexander's disease. Although similar pathologically to the well-characterized infantile variant of Alexander's disease, it is not known whether this adult variant represents the same disease process.
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PMID:Hereditary adult-onset Alexander's disease with palatal myoclonus, spastic paraparesis, and cerebellar ataxia. 904 Jul 73

Serotonin syndrome, a condition with numerous clinical neurological manifestations, is the result of central serotonergic hyperstimulation. Features of the syndrome include mental status and behavioral changes (agitation, excitement, hypomania, obtundation), motor system involvement (myoclonus, hemiballismus, tremor, hyperreflexia, motor weakness, dysarthria, ataxia) and autonomic symptoms (fever, chills, diarrhea). Serotonin syndrome has been reported exclusively in patients on medications for psychiatric illness and Parkinsonism, despite the fact that the putative action of many antimigraine agents also involves the serotonin system. We herein report six patients with migraine who developed symptoms suggestive of the serotonin syndrome. Five were taking one or more serotomimetic agents for migraine prophylaxis (sertraline, paroxetine, lithium, imipramine, amitriptyline). In each case the symptoms and signs developed in close temporal proximity with use of a migraine abortive agent known to interact with serotonin receptors. In three instances the agent was subcutaneous sumatriptan and, in three, intravenous dihydroergotamine. In each instance the symptoms were transient and there was full recovery. With the ever increasing use of migraine medications active at serotonin receptor sites, cases of serotonin syndrome will likely occur more frequently. It is important that physicians treating migraine are aware of the serotonin syndrome and are able to recognize its varying presentations.
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PMID:Serotonin syndrome complicating migraine pharmacotherapy. 886 67

The appearance of involuntary movements in the clinical course of reflex sympathetic dystrophy (DSR) constitutes a rare clinical entity. In this context, the most frequent changes in movements are muscle spasms and focal dystonia, although postural tremor, muscle weakness and rhythmic myoclonus have also been described. The disorder is more frequent in young women and in the lower limbs. It may have a focal, segmental, multifocal, hemicorporal or symmetrical distribution. It is almost always secondary to local trauma. The pathogenesis and most effective treatment are unknown. We present the case of a 62 year old woman with muscle spasms of both legs and feet as a complication of spontaneously appearing DSR. The electromyogram showed continuous non-rhythmic discharges with morphologically normal motor unit potentials in both anterior tibial muscles. The clinical course and symptomatic improvement following treatment with benzodiazepine seems to suggest that the disorder is of central origin.
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PMID:[Muscular spasms associated with a reflex sympathetic dystrophy]. 898 30

MERRF (myoclonic epilepsy with ragged-red fibers) is a severe, multisystem disorder characterized by myoclonus, seizures, progressive cerebellar syndrome, muscle weakness, and the presence of ragged-red fibers in the muscle biopsy. MERRF is associated with heteroplasmic point mutations, either A8344G or T8356C, in the gene encoding the mitochondrial tRNA(Lys). The human rho degree cell system was utilized to examine the phenotypic consequences of these mutations, and to investigate their molecular genetic causes. Wild-type and mutant transmitochondrial cell lines harboring a pathogenic point mutation at either A8344G or T8356C in the human mitochondrial tRNA(Lys) gene were isolated and examined. Mitochondrial transformants containing 100% mutated mitochondrial DNAs (mtDNAs) exhibited severe defects in respiratory chain activity, in the rates of protein synthesis, and in the steady-state levels of mitochondrial translation products as compared with mitochondrial transformants containing 100% wild-type mtDNAs. In addition, both mutant cell lines exhibited the presence of aberrant mitochondrial translation products. These results demonstrate that two different mtDNA point mutations in tRNA(Lys) result in fundamentally identical defects at the cellular level, and that these specific protein synthesis abnormalities contribute to the pathogenesis of MERRF.
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PMID:Point mutations in the mitochondrial tRNA(Lys) gene: implications for pathogenesis and mechanism. 930 90

A 16-year-old boy with mitochondrial encephalomyopathy had seizures, short stature, muscle weakness, progressive hearing loss, mental retardation, and myoclonus. His cranial computed tomography showed progressive calcification in the basal ganglia and cerebral atrophy. Muscle biopsy revealed many ragged-red fibers with variable cytochrome c oxidase activity and some strongly succinate dehydrogenase-reactive blood vessels. Sequence analysis of the entire mitochondrial DNA revealed a novel point mutation in the tRNA-Thr gene at nucleotide pair 15915. Serum lactate levels were decreased by high-dose coenzyme Q10 (CoQ10) therapy. The spectral power density, a parameter of background activity on electroencephalography, was markedly improved after additional administration of idebenone. After initiation of combined CoQ10 and idebenone therapy, the clinical abnormalities did not progress for 16 months.
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PMID:Mitochondrial encephalomyopathy with 15915 mutation: clinical report. 936 99

The brainstem is said to be the generator of pathological startle responses due to reticular reflex myoclonus or hyperekplexia. A patient with facial weakness, nystagmus, and pyramidal tract signs had generalised reflex spasms in response to auditory, visual and tactile stimuli which clinically and neurophysiologically resembled hyperekplexia. The case is unusual because as well as hyperekplexia, the patient's initial presentation was with an equally rare manifestation of brainstem pathology-brainstem mediated trismus. The causes of brainstem trismus and exaggerated startle responses are discussed with respect to their underlying mechanisms.
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PMID:Hyperekplexia and trismus due to brainstem encephalopathy. 966 74


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