Early fatal nemaline myopathy: case report and review.

A newborn girl with atonia and arthrogryposis multiplex required mechanical ventilation; she died on the 14th day. Postmortem muscle histology disclosed nemaline myopathy with a lack of myofibrils. Peripheral nerves appeared to be normal. The parents are first cousins. The findings for 13 other patients who died from nemaline myopathy within the first year of life are reviewed. It is suggested that early fatal cases, in contrast to patients with the 'benign' childhood form, are homozygotic for the disease gene, and that the myopathy results from abnormal myosin synthesis.