[Mitochondrial diabetes complicated by or associated with "MELAS" syndrome?].

We report the case of fifty-two year-old mentally deficient female who presented with diabetes mellitus, deafness, stroke-like episodes, cardiomyopathy, and macular pattern dystrophy of the retina. Her brain exhibited calcification within basal ganglia, lactacidaemia was not increased. Although her skeletal muscles had never been clinically impaired, a quadriceps biopsy led to the diagnosis of mitochondrial disease because it exhibited ragged red fibers and heteroplasmic point-mutation at position 3243 of the mitochondrial DNA, although not any detectable respiratory chain complex deficiency was found. The mutant percentage in muscle was 70 p.100 and 5 to 10 p.100 in leukocytes. The question of whether a diabetic microangiopathy may be responsible stroke-like episodes is discussed. We suggest it was rather a complicated form of diabetes-deafness than a incomplete MELAS syndrome associated with mitochondrial diabetes.