C9orf72 and amyotrophic lateral sclerosis: Over the past two decades, several mutations in more than two-dozen genes have been discovered to in ALS, including TARDBP (transactive response to DNA binding protein 43kDa), FUS (fused in sarcoma) [7,8,9] and C9orf72 (C9orf72-SMCR8 complex subunit) [10,11].