However, tg mice expressing ALS-causing mutant hSOD1 in only skeletal muscle develop motor deficits and skeletal muscle disease involving myofiber atrophy and mitochondrial perturbations (49) and also oxidative stress and increased protein nitration and MN degeneration, even with low copy number of transgene (50). The gene discussed is SOD1; the disease is amyotrophic lateral sclerosis.