Treatment of McArdle Disease

Abstract

WE ARE approaching the 50th anniversary of the classical description by Brian McArdle¹ of the metabolic myopathy that bears his name. It was recognized 40 years ago that the symptoms of McArdle disease—exertional muscle fatigue, pain, cramps (contractures), and myoglobinuria—were due to deficiency of the muscle form of glycogen phosphorylase, and thus were related specifically to the unavailability of muscle glycogen as a source of energy for muscle contraction.^2,3 In the last few years, understanding of the molecular pathogenesis of McArdle disease has advanced with the description of approximately 20 different mutations in the phosphorylase gene on chromosome 11.⁴ However, treatment of McArdle disease has lagged and remains an important clinical challenge.