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)

Posthypoxic action myoclonus is usually associated with impaired serotonin (5-HT) neurotransmission but in some patients 5-HT precursors aggravate and 5-HT blockers improve action myoclonus. We studied a 65-year-old man who presented with action myoclonus following a prolonged episode of moderate hypoxia and severe hypercarbia. The myoclonus increased with 5-hydroxytryptophan (5-HTP) 1,200 mg/day plus carbidopa 300 mg/day and sodium salt of valproic acid (SVA) 800 mg/day, and improved with 1 mg of clonazepam (CNZ) in an intravenous bolus. Biochemical analysis of the cerebrospinal fluid (CSF) prior to any drug therapy did not reveal abnormalities in the levels of homovanillic acid (HVA) and methoxyhydroxyphenylglycol (MHPG) but 5-hydroxyindoleacetic acid (5-HIAA) levels were elevated in comparison with controls (33 versus 21 ng/ml). SVA therapy produced a moderate increase and 5-HTP plus carbidopa a threefold elevation of 5-HIAA in CSF and marked aggravation of action myoclonus. Methysergide (3 mg/day) totally suppressed myoclonus and decreased CSF 5-HIAA to undetectable levels. Methysergide also reduced CSF tryptophan to 40% of baseline levels. Discontinuation of methysergide and substitution by placebo was followed by reappearance of myoclonus. A partial and incomplete spontaneous remission of symptoms took place 7 months after the asphyxic episode. Action myoclonus and enhanced 5-HT neurotransmission may be present in patients in which acidosis reverses the effects of hypoxia on 5-HT neurotransmission.
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PMID:Clinical, biochemical, and pharmacological observation in a patient with postasphyxic myoclonus: association to serotonin hyperactivity. 245 56

An eight-week-old infant, the fourth child of consanguineous parents presented with intractable neonatal seizures. The mother had two previous miscarriages. The infant initially presented on day one with multifocal myoclonus, complex partial and generalised tonic-clonic seizures. On examination, there were dysmorphic hands and feet, with absent nails and terminal phalanges of the fingers and toes, hepatomegaly, marked axial and peripheral hypotonia and severe global developmental delay. Ophthalmological assessment showed 'salt and pepper' pigmentary retinopathy. The urinary organic acid profile revealed a marked increase in tricarboxylic acid metabolites. Urinary phosphate reabsorption was reduced at 84%. Type I fibre atrophy was seen on muscle histology, and a cytochrome c oxidase deficiency was found only on enzymology of liver tissue. Limb malformations associated with respiratory chain defects have rarely been reported. To our knowledge, this child has the most severe limb anomaly associated with a tissue-specific complex IV respiratory chain defect.
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PMID:Neonatal seizures and limb malformations associated with liver-specific complex IV respiratory chain deficiency. 1502 75