MELAS Syndrome Confirmed by Mitochondrial DNA Analysis in Siblings

MELAS(mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) syndrome is a major subgroup of mitochondrial myopathy. Recent advances in molecular genetics revealed specific mutations in mitochondrial DNA which cause MELAS. We described here clinical and molecular genetic findings of sister and brother with MELAS syndrome. For molecular genetic studies, DNAs from peripheral blood nucleated cells were used. And the substitution of adenine to guanine at the nucleated position 3243 in the mitochondrial tRNALeu(UUR) gene was confirmed in the patients. Their mother was a heteroplasmic pattern which supports maternal transmission.