Nemaline Myopathy Appearing in Adults as Cardiomyopathy

We examined a 29-year-old woman with nemaline myopathy that appeared as cardiomyopathy. Clinical examination showed dilated cardiomyopathy, but no neuromuscular abnormalities of the skeletal muscles. Electromyography showed neither neurogenic nor myopathic abnormalities. A biopsy specimen from the quadripecs muscle showed typical nemaline bodies in about 50% of the muscle fibers. The patient died six months later of biventricular heart insufficiency. Autopsy revealed nemaline bodies in the working and conducting tissues of the myocardium. Earlier, the patient's mother and one of her sisters died unexplained, sudden deaths at the ages of 47 and 37 years, respectively. Sections of the myocardium taken from the sister at autopsy were available, and also disclosed nemaline bodies after restaining with trichrome.