Fatal nemaline myopathy in infancy.

The clinical and neuropathological findings in two infants with congenital nemaline myopathy are described. One patient presented at birth with severe hypotonia, respiratory failure and contractures and died shortly after the neonatal period. The other presented at age two months with hypotonia and, following a period of clinical stability, died at age seven months from respiratory failure. Pathological findings in the fatal neonatal case revealed numerous rod bodies in lingual, pharyngeal, diaphragm and limb muscles, correlating with clinical findings. Significant, but less rod body involvement was found in the diaphragm and limb muscles of the second patient. Although a neural basis has been suggested for this disorder, no abnormalities were found in the central nervous system or in the peripheral nerves of these two severely affected patients.