Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0162671 (MELAS)
 587 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A T-to-C transition mutation at nucleotide position 3,250 in the mitochondrial tRNA(Leu)(UUR) gene was present in a family with mitochondrial myopathy. Two of three muscle biopsies examined had complex I (NADH-ubiquinone oxidoreductase) deficiency. Heteroplasmy of wild and mutant mitochondrial DNA was detected by Nae I digestion of the polymerase chain reaction products with a modified primer. This was found in blood or muscle samples or both from all seven members examined. Similar to the 3,243 mutation in most patients with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes), the new mutation site was located in the dihydrouridine loop and embedded in the binding region of mitochondrial transcription termination factor. Elucidation of the effects of this mutation may help clarify the role of mitochondrial tRNAs and transcription termination.
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PMID:A novel point mutation in the mitochondrial tRNA(Leu)(UUR) gene in a family with mitochondrial myopathy. 151 79

A 29-year-old man with mitochondrial encephalomyopathy caused by partial deficiency of mitochondrial NADH-ubiquinone oxidoreductase (Complex I) is described. Clinical manifestations were characterized by generalized convulsion, dementia and stroke-like episodes consisting of hemianopsia, Gerstmann's syndrome and visual hallucination. Blood and cerebrospinal fluid lactate and pyruvate levels were elevated. Biochemical studies on a muscle biopsy specimen revealed partial deficiency of Complex I activity, and decreases in the 75-kDa and the 20-kDa subunits of Complex I by immunoblotting analysis. Serial brain CT scans revealed multiple low-density areas with fluctuating densities. Single photon emission tomographic study revealed preservation of blood circulation where CT scans showed diminished density in acute stage, suggesting the presence of abnormal cellular metabolism rather than vascular occlusion as the basic mechanism of his stroke-like episodes. Pathogenesis of neurological manifestations in MELAS is discussed with reference to the possible involvement of free radicals in inducing brain damage.
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PMID:Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes with special reference to the mechanism of cerebral manifestations. 251 13