Mitochondrial myopathy MELAS

The condition known as fatal infantile mitochondrial myopathy and renal dysfunction involves severe diminution or absence of most oxidoreductases of the respiratory chain. MELAS (mitochondrial encephalopathy, lactic acidosis, and stroke) is an inherited condition due to NADHiubiquinone oxidoreductase (complex I) or cytochrome oxidase deficiency. It is caused by a muta-... 

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke like episodes (MELAS) Mitochondrial tRNA (leu)... 

Al. Abe, K., Fujimura, H., Nishikawa, Y., Yorifuji, S., Mezaki, T., Hirono, N., Nishitani, N., and Kameyama, M., Marked reduction in CSF lactate and pyruvate levels after CoQ therapy in a patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). Acta Neurol. Scand. 83, 356-359 (1991). 

Fourteen mtDNA tRNA mutations have been associated with maternally inherited disease. Such mutations are typically associated with severe mitochondrial myopathies, characterized by ragged red skeletal muscle fibers upon Gomori trichrome staining and the accumulation of structurally abnormal mitochondria in muscle. Mutations in tRNAs exemplify the threshold effect whereby (due to replicative segragation) individuals may not exhibit clinical signs until the proportion of mutant mtDNA exceeds 80-90%. Myoclonic epilepsy and ragged red fiber (MERRF) disease, mitochondrial encephalomyo-pathy tactic acidosis (MELAS), as well as maternally inherited myopathy and cardiomyopathy (MMC) are well-characterized mitochondrial diseases. 

MELAS (mitochondrial myopathy, encephalo-myopathy, lactic acidosis, and stroke-like episodes) Progressive neurodengenerative disease characterized by stoke-like episodes first occurring between 5 and 15 years of age and a mitochondrial myopathy 80-90% mutations in tRNA "... 

MELAS (mitochondrial myopathy. Finger nails (see nails) 580, i... 

Patients with mitochondrial disorders may present at any age and show variation in both the severity and kind of symptoms associated with a single genetic abnormality. For example, the tRNA mutation is predominantly associated with the neurological syndrome MELAS but may also be manifested as CPEO, myopathy, diabetes, and deafness. 

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