title: Muscle phosphorylase deficiency in childhood.
abstract: Myophosphorylase deficiency (McArdle's syndrome) is an uncommon condition characterized by exercise intolerance, muscle cramps and myoglobinuria. The present report describes the clinical, histochemical, electronmicroscopic and biochemical findings in a 12-year-old boy with myophosphorylase deficiency. The diagnosis should have been suspected when the boy was 6 years old. Most index cases have not been diagnosed until adult life, but this syndrome has to be considered in the differential diagnosis of exercise intolerance in childhood.
mesh_terms: D002648:Child; D006008:Glycogen Storage Disease / Q000175:diagnosis*; D006012:Glycogen Storage Disease Type V / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D009132:Muscles / Q000648:ultrastructure; D005082:Physical Exertion