More than 50% of fALS has been attributed to pathogenic mutations in four major ALS genes, SOD1, TARDBP, FUS and C9orf72. In European-based populations, more than 180 different mutations in SOD1 (MIM 105400; NM_000454) have been reported, and account for between 12% and 20% of ALS families TARDBP (MIM 612069; NM_007375) and FUS (MIM 608030; NM_004960) mutations each account for approximately 4% of fALS [21]. The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.