With SOD1 and C9orf72 more than 20 mutated genes have now been found to be specifically associated with fALS (78) that include TARDBP (79–81) and FUS (82, 83), the fused in sarcoma gene on chromosome 16p11.2, that is involved with RNA processing, which together with SOD1 and C9orf72, are the four most common genes involved in causing ALS clinically. The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.