A case of mitochondrial diabetes associated with cardiomyopathy

Maternally inherited diabetes and deafness (MIDD) is related to a point mutation at position 3243 of mitochondrial DNA and the same mutation has been identified in MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) syndrome. Although cardiomyopathy is known to be common in mitochondrial diabetes, cardiac involvement in MIDD has not been reported in Korea. Hear, we present a case of MIDD with clinical features of hypertrophic cardiomyopathy. A 32-year-old man was admitted with three months of dyspnea. He had been diagnosed with diabetes at the age of 26 and sensorineural hearing loss at the age of 29. He had no previous history of neurologic disorders suggesting MELAS syndrome. His parents and brother had diabetes and his sister had diabetes and deafness. Echocardiography revealed markedly reduced left ventricular ejection fraction (LVEF) and thickened left ventricular wall. His symptoms and LVEF were improved with medications including angiotensin converting enzyme (ACE) inhibitor and diuretics. Genetic analysis showed mitochondrial tRNA Leu(UUR) mutation at position 3243.(Korean J Med 73:S946-S950, 2007)