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)

Myoclonus occurs in a variety of pathological conditions, some inherited. We recently evaluated 3 members of a Louisiana-Texas family with an autosomal dominant disorder manifested by adult-onset, generalized, stimulus-sensitive myoclonus and slowly progressive distal muscle weakness and wasting. The analyses of cerebrospinal fluid homovanillic acid and 5-hydroxyindoleacetic acid before and after probenecid provided some evidence of impaired turnover of central dopamine and serotonin. Treatment with clonazepam resulted in complete and lasting improvement of the myoclonus. A postmortem examination in 1 member of the family revealed chiefly neuronal degeneration of the anterior horn cells, Clark's nucleus, and the lower cranial nerve nuclei. A similar syndrome has not previously been reported.
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PMID:Hereditary myoclonus and progressive distal muscular atrophy. 53 21

A patent, who suffered from nonprogressive athetotic-myoclonic hyperkinesia of the left arm and spastic paresis of the underdeveloped left leg since early childhood, experienced a febrile episode at the age of 23, after which a weakness and ataxia of the right limbs with frequent falling persisted; at the age of 28, he developed a right-sided rigidity, tremor at rest and mask-like face as sequelae of encephalitis disseminata exacerbations. The violent intention myoclonus of the left side of the body could be abolished by stereotactic coagulation in the V.o.p and V.o.a and zona incerta until death 11 days later. The athetotic myoclonic hyperkinesia is the consequence of a left-sided severe status marmoratus of the right putamen with extensive loss of nerve cells and shrinkage. The additional nerve cell loss in the right substantia nigra due to demyelinating encephalitic foci did not produce Parkinson symptoms, because these require a normal striatum. This loss did, however, exaggerate the original hyperkinesia to a violent intention myoclonus, which was abolished by interruption of denatatothalamic afferents to the V.o.p nucleus and of pallidothalamic afferents to the V.o.a nucleus. The Parkinson syndrome of the right side is due to demyelinating foci of different ages. The Parkinson symptoms were manifest on the right side, because the left status marmoratus did not severely reduce the striatal nerve cells. In this case, there is no indication that the introduction of the stereotactic electrode has precipitated new demyelinating foci.
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PMID:Stereotactic treatment of action myoclonus in a case of combined status marmoratus and multiple sclerosis. A contribution to the pathophysiology of basal ganglia with multiple lesions in both the striatum and the substantia nigra. 109 75

A 50-year-old woman was admitted to our hospital because of abnormal involuntary movement of upper abdomen. Three months before admission, she had suffered from left lateral chest pain without skin lesions for one week. The neurological examination on admission revealed myoclonus of upper abdomen, and hyperalgesia and thermohyperesthesia from T4 to T9. There was no weakness, the tendon reflexes were symmetrical and the plantar responses were flexor. The surface EMG disclosed the symmetrical, synchronous contractions of m. rectus abdominis and m. obliques externus abdominis. This spinal myoclonus reduced during sleep. The EEG, CT and MRI showed no abnormalities. Serum varicella-zoster virus (VZV) titers increased significantly on follow-up examinations. Clonazepam, 1.5 mg daily was effective in this patient. The myoclonus spontaneously disappeared without clonazepam in six weeks after onset, and at the same time the sensory disturbance also improved. From the neurological findings and clinical course, we consider this spinal myoclonus was probably elicited by involvement of the inhibitory interneurons of the dorsal horns, due to immune response to latent VZV infection but not to direct neuronal destruction by VZV. Spinal myoclonus should be recognized as the spectrum of neurological disease associated with VZV even in the absence of skin lesions.
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PMID:[Varicella-zoster virus-associated spinal myoclonus without skin lesions]. 139 36

Myoclonus epilepsy with ragged-red fibers (MERRF) has been shown to be associated with a specific point mutation at the nucleotide 8344 in the tRNA(Lys) gene of mitochondrial DNA (mtDNA). We screened 6 patients with clinically diagnosed MERRF and 1 patient with ocular myopathy for point mutations in the tRNA(Lys) gene, using single strand conformation polymorphism (SSCP) analysis, which can detect even a 1-basepair difference between 2 DNA sequences. Using SSCP and consequent DNA sequencing, we identified the known MERRF mutation in 4 out of 6 MERRF patients, as well as in 1 patient with a new clinical phenotype associated with this mutation: progressive external ophthalmoplegia, muscle weakness and a lipoma, but no myoclonus or epilepsy. Two of the patients with clinical MERRF had neither the MERRF-mutation nor any other mutations in the tRNA(Lys) gene. Using SSCP analysis, we also detected a new polymorphism in 1 patient. Thus, SSCP analysis can be applied to search effectively and rapidly for point mutations or polymorphisms in mitochondrial DNA.
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PMID:Use of single strand conformation polymorphism analysis to detect point mutations in human mitochondrial DNA. 143 90

A 21-year-old woman, who had no particular familial history, was admitted to our hospital because of hand tremor and gait disturbance. On neurological examination, she showed muscle weakness in the proximal extremities. There was an ataxia on heel-to-shin testing. Action and postural myoclonus involving the extremities were also noted. In addition, with dorsiflexion of the hands, asterixis-like movement was manifested. Pyruvate was 1.0 mg/dl and lactate was 24.1 mg/dl in cerebrospinal fluid. Brain CT scan revealed mild cerebellar atrophy. EEG showed synchronous diffuse slow wave. Median nerve SEPs showed a large N20-P25 component (20 microV). Median nerve C-reflex was not evoked. With dorsiflexion of the hands, the asterixis-like movement was induced with brief cessation of surface EMG activity in the forearm muscles, as shown by the accelerometer trace. Biopsy specimens of the biceps brachii muscle revealed numerous ragged-red fibers. By PCR-RFLP method with use of a mismatched primer, we analyzed mitochondrial DNA extracted from peripheral leukocytes. The A to G mutation at nucleotide position 8,344 in a tRNA(Lys) gene of a mitochondrial genome was detected. In this patient, clonazepam was effective on the asterixis-like movements. From existence of positive myoclonus, giant SEPs and efficacy of clonazepam, we considered this movement to be negative myoclonus. Our study indicated the possibility that such an involuntary movement could be induced by certain posture in patients with MERRF.
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PMID:[Myoclonus epilepsy associated with ragged-red fibers--report of a patient with negative myoclonus]. 149 Mar 14

We describe a young man with a progressive neurological disorder including myoclonus, mental retardation, muscle weakness and a mitochondrial myopathy (myoclonus epilepsy and ragged red fibres--MERRF). Multiple abnormalities of the mitochondrial respiratory chain in skeletal muscle are shown by direct measurement of the flux through the individual complexes, low-temperature redox spectroscopy and decreased immunodetectable subunits of complexes I and IV by immunoblotting. No abnormality of mitochondrial DNA was found. This is the first report of combined defects of complexes I, III and IV as a cause of this clinical syndrome. However, we propose that the occurrence of multiple respiratory chain defects may be more common than previously recognised and that this particular combination of defects, involving complexes I, III and IV, may be the predominant biochemical abnormality in MERRF.
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PMID:Multiple defects of the mitochondrial respiratory chain in a mitochondrial encephalopathy (MERRF): a clinical, biochemical and molecular study. 164 12

Ten patients with involuntary leg movements due to myelopathy were studied clinically and polysomnographically. The clinical manifestation and polysomnographical findings of involuntary leg movements were identical to sleep-related periodic leg movement (PLM) (nocturnal myoclonus). Since 2 patients had complete transection of spinal cord due to injury or vascular accident, the spinal cord deprived of supraspinal influences was considered to generate the rhythm of PLM. Suppression of the leg movements during REM sleep was not obvious in the patients with complete transection of spinal cord. In addition, PLM alternated from one side to the other 1-4 times a night with intervals of 1-4 h in all patients. This alternation also seemed to be from the spinal cord. This PLM of spinal cord origin was different from spinal myoclonus in their clinical features although both were generated within the spinal cord. PLM of spinal cord origin showed a triple flexion of the ankle, knee and hip, and this was very similar to a flexor withdrawal reflex which all patients exhibited. Therefore, it was suggested that PLM of spinal cord origin has a common mechanisms with spinal automatism. Although all patients had extensor plantar responses, PLM preceded the paresis in three patients and the severity of paresis was variable. There was no laterality of left and right PLMs even in patients with weakness of the leg on one side. This suggested that PLM of spinal cord origin might be induced by the interruption of the tract which was separate from, but runs near the corticospinal tract.
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PMID:Sleep-related periodic leg movements (nocturnal myoclonus) due to spinal cord lesion. 191 96

Ceftazidime, a beta-lactamase-stable, third-generation cephalosporin, is widely used for the treatment of serious gram-negative infections. Neurotoxicity has rarely been associated with the drug; however, two of our patients developed ceftazidime-induced neurotoxicity that produced confusion, disorientation, agitation, generalized weakness, and myoclonus. In both patients these symptoms cleared with either discontinuation or reduction of the dosage of ceftazidime. This emphasizes the importance of adjusting the dosage of ceftazidime in patients with renal insufficiency.
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PMID:Neurotoxicity associated with ceftazidime therapy in geriatric patients with renal dysfunction. 192 20

The authors compare the clinical, neurophysiological and evolutive features of progressive myoclonus epilepsy (PME) associated with mitochondrial encephalomyopathy with ragged-red fibers (MERRF), based on 49 cases from the literature, and the two well-described types of degenerative PME: Baltic myoclonus (BM), of which over 100 cases have been reported from Finland, and Mediterranean myoclonus (MM), based on a personal series of 43 patients. Degenerative PMEs are age-dependent, recessively inherited conditions with homogeneous clinical signs and course; there are no major clinical symptoms beside the cardinal symptoms: generalized epileptic seizures, predominantly action myoclonus and cerebellar dysfunction; mental deterioration when present, is slight and progresses very slowly; associated neurological symptoms are uncommon and limited to mild spino-cerebellar involvement. In MERRF, the transmission is maternal, the age of onset is variable, the evolution is not stereotyped and associated symptoms are many (deafness, muscle weakness, optic atrophy, short stature, sensory disturbances, spasticity, clinical or neurophysiological signs of peripheral neuropathy, absence of motor reflexes); muscle biopsy generally shows ragged-red fibers. The differential diagnosis between these conditions is usually easy, although pathological examination (i.e. muscle biopsy) should be performed.
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PMID:[The role of mitochondrial encephalopathies in progressive myoclonus epilepsy]. 196 55

A case of mitochondrial encephalomyopathy with a partial cytochrome c oxidase deficiency was reported with special reference to electrophysiological studies. A 56-year-old man was readmitted to Himeji Central Hospital due to mental deterioration and character change. At the age of 44 when he was attacked by his first epileptic seizure, he was admitted to Himeji Central Hospital, where EEG abnormalities and cerebral atrophy were found. Anticonvulsants helped to relieve his generalized convulsions but the EEG abnormalities persisted. At age 46, he had the second generalized seizure, so he quit his job as a crane operator. His family began to notice deterioration of his intellectual function and hyperaggressive behavior. His daily activities, intellectual performance and mental condition gradually deteriorated (WAIS FIQ less than 60). Other clinical and laboratory findings are as follows: bilateral impaired hearing, no optic nerve atrophy, no disturbance of extra ocular muscle movements, mild wasting and weakness of his extremities, normal coordination and sensation, no myoclonus or other involuntary movements, normal laboratory data of serum creatinine kinase, lactate dehydrogenase and aldolase, and increased amount of lactate and pyruvate in serum and cerebrospinal fluid (CSF), no abnormal amino acids in urine. A biopsy specimen of right biceps brachii muscle revealed numerous ragged-red fibers in frozen sections stained by the Gomori trichrome method. These fibers did not react to a cytochrome c oxidase staining. An ATPase staining demonstrated an atrophy of type-2 fibers. An electron micrograph showed many mitochondria in the sarcoplasm but few paracrystalline inclusions. A biochemical analysis of the muscle biopsy also revealed a significant decrease in the cytochrome c oxidase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[A mitochondrial encephalomyopathy due to partial cytochrome c oxidase deficiency with giant evoked potentials--a case report]. 217 89


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