SOD1 and amyotrophic lateral sclerosis: Most (90–95%) of ALS forms are sporadic (sALS), while about 10% of cases are familial (fALS) and are associated with mutations in specific genes, such as superoxide dismutase 1 (SOD1, 20% of fALS), TARDBP and FUS (5% of fALS) and C9ORF72 (40% of fALS)6–8.