MELAS syndrome: peripheral neuropathy and cytochrome C-oxidase deficiency: a case report and review of the literature.

A 4-year-old boy presented with developmental delay, aggressive behavior, and incoordination. His EEG showed a diffuse encephalopathy. At age 10 he developed convulsions and severe migraine-like headaches. Muscle wasting, arreflexia, and lactic acidemia following exercise were noted. Electromyography was myopathic and nerve conduction studies revealed a peripheral neuropathy. Muscle biopsy demonstrated variation in fiber size and an excess of lipid droplets. He than had several stroke-like episodes and periods of unconsciousness, associated with severe metabolic acidosis. Muscle cytochrome C oxidase was abnormally low. This boy displayed the classical clinical and biochemical features of MELAS syndrome, namely Mitochondrial myopathy, Encephalopathy, Lactic Acidosis, and Stroke-like episodes. Treatment included carnitine, vitamin C, vitamin K, riboflavin, coenzyme Q10, and corticosteroids. He died at the age of 14 years following an episode of seizures, coma, and gastrointestinal hemorrhage. This is the first reported case of MELAS syndrome in Israel.