Familial recurrence of atypical symptoms in an extended pedigree with the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS).

We report a clinically heterogeneous, multigenerational pedigree with the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) associated with a mutation at nucleotide 3243 in the mitochondrial DNA tRNA(Leu)(UUR) gene. Our findings suggest that the mutation at nucleotide 3243 is not always associated with the classic MELAS phenotype and that other symptoms (notably cardiac and gastrointestinal abnormalities) should raise the suspicion of a mitochondrial disorder.