A boy, 5 years of age, with nemaline myopathy complicated by respiratory failure and hypertrophic cardiomyopathy is reported from the Albany Medical College, Albany, NY. He presented at 2 mos of age with failure-to-thrive, diminished suck, and hypotonia. CK was normal and EMG showed rare fibrillations and fasciculations. Muscle biopsy demonstrated variation in fiber size and electron-dense nemaline rods. He walked late at 3 yrs, fell frequently and required a walker outdoors. At 5 1/2 yrs, during an upper respiratory tract infection, respiratory distress necessitated intubation. Neurologic examination revealed hypotonia, proximal muscle weakness, mild facial weakness, absent deep tendon reflexes. Echocardiography disclosed a thickened ventricular septum consistent with hypertrophic cardiomyopathy. Because of chronic nocturnal hypoventilation, tracheostomy and assisted ventilation were required. The authors recommend routine cardiac and pulmonary function evaluations in patients with nemaline myopathy. [1]
COMMENT. Sleep hypoventilation, a rare complication of Nemaline myopathy, has been attributed to central nervous system CO2 unresponsiveness. Cardiomyopathy has not been reported previously in a child with nemaline myopathy and the authors found only 2 other references, both in adults. Neurologic conditions associated with hypertrophic cardiomyopathy include Leigh disease, Kearn-Sayre syndrome, Friedreich ataxia, neurofibromatosis, and Pompe disease.