SOD1 and amyotrophic lateral sclerosis: The identification of mutations in the SOD1 gene in 1993 marked a significant breakthrough in ALS research (Rosen et al., 1993), and 1 year later the first ALS mouse model was generated, carrying the SOD1 gene with a glycine-to-alanine substitution at position 93 (Gurney et al., 1994).