C9orf72 and amyotrophic lateral sclerosis: Although mutations in TDP-43, C9orf72, SOD1, TARDBP, FUS, NEK1, TBK1, and KIF5A have been identified in familial ALS population3, importantly, a significant number of non-familial ALS, i.e., the majority of ALS cases, i.e., the sporadic ALS, lack clear causative genetics.