[Infantile cataract, hypertrophic cardiomyopathy and lactic acidosis following minor muscular exertion--a little known metabolic disease].

Three children from two unrelated families were found to be suffering from a hitherto little-known disorder. Infantile cataract was the primary symptom at the age of 3 months, progressed quickly and necessitated surgery. At the same age, muscular hypotonia was prominent and delayed gross motor development. At preschool and school ages muscle strength and exercise tolerance were reduced, and slight muscular exercise caused marked lactic acidemia. Subsequently, hypertrophic cardiomyopathy was discovered by echocardiography, though with no signs of cardiac obstruction at that time. There were no neurological symptoms. Intellectual development was normal. The disorder is inherited as an autosomal recessive. It can be recognized from the combination of infantile cataract, muscular hypotonia, cardiomyopathy, and lactic acidosis, which, however, must be looked for carefully. Early diagnosis is mandatory for genetic counseling. The ophthalmologist holds the key to diagnosis.