Hypertrophic Cardiomyopathy Associated with Nemaline Myopathy Due to ACTA1 Mutation

Abstract

Nemaline myopathy, a common type of congenital myopathy, rarely presents with cardiac involvement. We report a female patient with atypical hypertrophic cardiomyopathy and nemaline myopathy associated with ACTA1 mutation. She presented with an abnormal gait at the age of 18 months. Slowly progressive muscle hypotonia and weakness were recognized at the age of 2 years. A cardiovascular assessment performed at the age of 7 years showed atypical hypertrophic cardiomyopathy. The diagnosis of nemaline myopathy was confirmed by a skeletal muscle biopsy, and an ACTA1 mutation was identified at the age of 8 years. Echocardiography and cardiac catheterization revealed severe diastolic dysfunction and atypical concentric left ventricular hypertrophy between the base and the apex of the heart. A β-blocker was administered without effect, and the patient died of ventricular fibrillation accompanied by heart failure at the age of 9 years. Some of the clinical features of this case resembled the recently reported hypertrophic cardiomyopathy associated with thin-filament gene mutations. Nemaline myopathy may result in fatal cardiomyopathy; therefore, careful assessment and appropriate manage-ment for cardiovascular involvement are essential.