Alternative titles and symbols : Myophosphorylase deficiency; Mcardle disease; Pygm deficiency; Gsd V; Muscle glycogen phosphorylase deficiency;
Description : McArdle disease is an autosomal recessive metabolic disorder characterized by onset
of exercise intolerance and muscle cramps in childhood or adolescence. Transient myoglobinuria
may occur after exercise, due to rhabdomyolysis. Severe myoglobinuria may lead to
acute renal failure. Patients may report muscle weakness, myalgia, and lack of endurance
since childhood or adolescence. Later in adult life, there is persistent and progressive
muscle weakness and atrophy with fatty replacement. McArdle disease is a relatively
benign disorder, except for possible renal failure as a complication of myoglobinuria
(summary by Chen, 2001).;
Inheritance : Autosomal recessive;
Molecular basis : Caused by mutation in the muscle glycogen phosphorylase gene (PYGM, 608455.0001);
Laboratory abnormalities : Muscle glycogen phosphorylase deficiency; Increased creatine kinase; Increased ammonia with exercise; Increased uric acid with exercise;