C9orf72 and amyotrophic lateral sclerosis: Mutations in SOD1 (Rosen et al., 1993), TAR DNA-binding protein-43 (TDP-43), fused in sarcoma/translocated in liposarcoma (FUS/TLS, FUS) (Zou et al., 2017), and open reading frame 72 on chromosome 9 (C9ORF72) genes (DeJesus-Hernandez et al., 2011) are common in major cases of ALS.