SOD1 and amyotrophic lateral sclerosis: However, the mechanism of MN degeneration still remains unresolved despite the discovery that mutations in the superoxide-dismutase (SOD1) caused the disease in 1–2% of ALS patients, and the development of transgenic mice overexpressing the mutated protein (SOD1G93A and SOD1G37R mice) and recapitulating the disease symptoms2, 3.