title: Dominant inheritance of McArdle syndrome.
abstract: Myophosphorylase deficiency (McArdle syndrome) is an uncommon condition characterized by exercise intolerance, muscle cramping, and myoglobinuria. Although the original report by McArdle dealt with a sporadic case, subsequent cases reported in the literature show high familial incidence and consanguinity, implying that the defect is transmitted as a rare recessive gene or a possible sex-limited mode of inheritance. The present report describes the clinical, histoenzymatic, and biochemical findings in a 40-year-old woman with myophosphorylase deficiency. The family history reveals that four other members are also affected: an older sister, a younger brother, a 10-year-old son, and her 75-year-old mother, and possibly her maternal grandmother. Because of this particular pattern of direct transmission in this family, a dominant inheritance is postulated.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D005799:Genes, Dominant; D006008:Glycogen Storage Disease / Q000235:genetics*; D006012:Glycogen Storage Disease Type V / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000473:pathology; D010375:Pedigree; D005082:Physical Exertion
chemical_list: D007773:Lactates