Syndrome of mitochondrial myopathy of the heart and skeletal muscle, congenital cataract and lactic acidosis.

The syndrome of hypertrophic cardiomyopathy, mitochondrial myopathy, congenital cataract, and lactic acidosis is a rare disease. It is now considered as an autosomal recessive inheritance. Two forms of the syndrome can be identified, the neonatal fatal and the benign adult variants. We report on 2 cases from a family and compared their clinical and histopathological features with 23 other patients previously reported in the literature. Detailed histochemical and ultrastructural findings of these two patients are outlined in the text. Histopathological features revealed abnormal mitochondrial proliferation in the heart and skeletal muscles. Tissue staining showed the activities of several enzymes of the mitochondrial respiratory chain to be within normal range. Despite severe lactic acidemia, no defect was found in the rate of pyruvate oxidation among these patients.