To the Editor: Familial hypertrophic cardiomyopathy is a heterogeneous disease caused by mutations in eight different genes that encode cardiac sarcomeric proteins. Relatives of affected persons are at low risk for the disease in later life if the electrocardiographic and two-dimensional echocardiographic findings are normal in early adulthood. The only reported exceptions are patients with mutations in the gene for cardiac myosin-binding protein C, in whom the disease typically develops in middle age.¹,² We describe a 57-year-old man with hypertrophic cardiomyopathy caused by a mutation in the gene for troponin T.

The patient presented with a three-year history of . . .