Safety, Tolerability and Effects of L-Arginine in Boys With Dystrophinopathy on Corticosteroids

Dystrophinopathy is a muscular dystrophy (includes Duchenne or Becker's Muscular Dystrophy) that can be a lethal muscle disorder resulting from defects in the gene for dystrophin, a structural protein required to maintain muscle integrity. Absence of functional dystrophin leaves the muscle membrane vulnerable to damage during contraction. This damage can be exacerbated by an inflammatory response leading to myofiber necrosis. L-arginine is a widely available dietary supplement amino acid postulated to affect dystrophinopathy in several favorable ways: upregulation of utrophin, vasodilation in muscle via nitric oxide, enhanced synthesis of creatine, increase levels of growth hormone. We hypothesize that administration of L-arginine may increase levels of creatine and growth hormone and in turn reduce the extent of myofiber damage in our patients with dystrophinopathy