SOD1 and amyotrophic lateral sclerosis: These data demonstrate that skeletal muscle is a primary target of SOD1(G93A)-mediated toxicity and disclose the molecular mechanism whereby oxidative stress triggers muscle atrophy, where human SOD1 has a causal role in ALS and motor neuron degeneration explaining their selective vulnerability (Dobrowolny et al., 2008; Wong and Martin, 2010).