Secondary hypertrophic cardiomyopathy in infancy and childhood.

In 12 infants and children with hypertrophic cardiomyopathy (HCM), seen during a 5-year period, the incidence of the idiopathic or primary form was similar to that secondary to systemic disease. Five of the six patients with secondary HCM are reported. Pompe's disease, Friedreich's ataxia, and Noonan's syndrome were seen in one each. There were two patients with lentiginosis. The diagnosis of HCM and of the metabolic disorder was made simultaneously in the patient with Pompe's disease. In two patients, one with Friedreich's ataxia and the other with lentiginosis, the diagnosis of HCM preceded the manifestations of the associated disorder. The other two patients were referred to rule out heart disease. The diagnosis of HCM in infancy and childhood should be considered with the possibility of being a secondary form, and patients with known associations with HCM should be referred for early diagnosis of heart conditions.