PILOT STUDY OF ACE INHIBITOR IN MCARDLE’S DISEASE

Myophosphorylase deficiency (McArdle’s disease, MCA) is a muscle glycogenosis characterized by exercise intolerance, recurrent myoglobinuria and, in some patients, fixed muscle weakness. The severity of symptoms may vary from case to case, with some being severely disabled and other minimally impaired in their activities. Recent studies have demonstrated that a polymorphic variant of the ACE gene associated with lower ACE activity correlates with milder clinical presentation of MCA. The pharmacologically induced inhibition of ACE improves muscle performance in cardiopathy or hypertensive patients. It is therefore conceivable that ACE inhibition may prove beneficial in patients with MCA. We propose a trial using the ACE inhibitor Ramipril in a small group of MCA patients. The study will follow a double blind, randomized, placebo-controlled, cross-over design. The treatment will be carried over for 12 weeks in each arm of the study. Exercise testing and muscle magnetic resonance spectroscopy will be used to explore muscle performance at baseline and after the completion of each of the treatment periods. Quality of life changes related to the treatment will also be explored. The results of the study will be important in view of a larger multicenter trial.