SOD1 and amyotrophic lateral sclerosis: The 10–15% of remaining cases, referred to as familial ALS (fALS), are characterized by the frequent (20% of the cases) occurrence of mutations in superoxide dismutase 1 (SOD1) gene (Rosen et al., 1993), leading to the development of mouse models of ALS (Gurney et al., 1994).