Treatment of glycogenosis type V (McArdle disease) with creatine and ketogenic diet with clinical scores and with ³¹P-MRS on working leg muscle

Abstract

McArdle’s disease is caused by genetic defects of the musclespecific isozyme of glycogen phosphorylase, which block ATP formation from glycogen in skeletal muscle. Creatine supplementation and ketogenic diet have been tested as potential supplements for muscle energy metabolism which may improve muscle symptomatic. Outcome measures were clinical scores describing muscle symptomatic and parameters derived from ³¹P-MRS examinations on working muscle. In two placebo controlled cross-over studies low dose creatine showed benefi cial effects on muscle symptoms and performance whereas high dose creatine distinctly worsened muscle symptomatic in patients. In both studies, however, the absence of an elevation in phosphocreatine indicated the absence of a creatine uptake by the muscle fibre. The effects of creatine on muscle symptomatic may be independent from energy metabolism in muscle. In a case study, ketogenic diet improved muscle symptomatic and performance. However, these effects again did not result in ³¹P-MRS visible changes in muscle energy metabolism.