SOD1 and amyotrophic lateral sclerosis: To date, hundreds of mutations in more than 20 genes have been implicated in the pathology of ALS, such as mutations in superoxide dismutase (SOD1), TAR DNA-binding protein 43 (TARDBP), fusion (FUS), and a hexanucleotide expansion on chromosome 9 in open reading frame 72 (C9ORF72).