Recent studies indicate a role of neuronal nitric oxide synthase (nNOS), nitric oxide, reactive oxygen species (ROS), and reactive nitrogen species in the pathology of DMD and BMD.18 The nNOS is a signal transduction protein associated with the dystrophin complex producing nitric oxide, which regulates local vascular perfusion, calcium mobilization, glucose metabolism, and contractile function.8, 12, 18 In DMD patients, reduced nNOS activity results in ischaemia and Ca++ overload. Here, NOS1 is linked to Becker muscular dystrophy.