[Mitochondrial gene mutation].

Mitochondrial DNA(mtDNA) anomaly was emerging as a cause of idiopathic cardiomyopathy in addition to sarcomeric gene mutation. Meanwhile, several point mutations and deletions in mtDNA initially recognized as major causes of mitochondrial encephalomyopathies are now clarified to share 1% cause of diabetes mellitus. These results indicate that mtDNA mutations will be a significant candidate for cardiomyopathies. Screening of cardiomyopathic patients with mtDNA point mutations revealed that there were at least several % of mtDNA anomaly (MELAS type) among them. They also showed specific findings in ultrastructures of the cardiac muscle.