C9orf72 and amyotrophic lateral sclerosis: Mutations in ~30 genes have already been identified in patients with ALS to date; among them, major pathological mechanisms of the known ALS genes have been identified, including SOD1, TDP43, FUS and C9orf72. Recently discovered ALS-related candidates and risk genes include SPTLC1, KANK1, CAV1, HTT, and WDR7 (Brenner and Freischmidt, 2022).