Creatine Therapy in Myophosphorylase Deficiency (McArdle Disease)

Abstract

MCARDLE DISEASE is a rare autosomal recessive metabolic myopathy caused by a defect of the muscle-specific isozyme of glycogen phosphorylase that leads to a blockade of adenosine triphosphate (ATP) formation from glycogen in skeletal muscle. The defect in the glycogen breakdown pathway leads to deprivation of an important energy source, particularly during the early stages of exercise when the availability of fatty acids for oxidation is limited. Typically, patients with McArdle disease have exercise intolerance with premature fatigue, exercise-induced muscle pain in working muscles, and recurrent myoglobinuria, which usually start in childhood. Treatments for McArdle disease have been unsatisfactory.¹