The mutation in C9orf72 and mutations in three other genes – TDP-43 (TAR DNA-binding protein 43), SOD1 (superoxide dismutase) and FUS (fused in sarcoma) – account for approximately two-thirds of familial ALS cases (Hardiman et al., 2017). The gene discussed is TARDBP; the disease is amyotrophic lateral sclerosis.