Fatal infantile muscle phosphorylase deficiency.

A premature female infant born of a consanguineous union exhibited joint contractures and signs and symptoms of perinatal asphyxia. A muscle biopsy examined by light microscopic, histochemical, and electron microscopic techniques exhibited changes of muscle phosphorylase deficiency and glycogenosis, identical to those of McArdle's disease. Postmortem ultrastructural examination of liver and heart did not reveal lysosomal storage. This case and one previously reported example of fatal infantile phosphorylase deficiency suggest that the clinical spectrum of McArdle's disease may be broader than previously recognized.