C9orf72 and amyotrophic lateral sclerosis: However, most mutations are found in only four of them (i.e. C9orf72, TARDBP, FUS and SOD1), which account for almost 75% familial amyotrophic lateral sclerosis and 20% sporadic amyotrophic lateral sclerosis cases.1,4,5 Despite being the most common form of MN disease (MND) in adults, effective treatments for amyotrophic lateral sclerosis, particularly for sporadic forms, remain elusive.