C9orf72 and amyotrophic lateral sclerosis: Most cases of ALS are sporadic (sALS), but in 10–15%, there is a clear family history (fALS) and a cause can be detected in the mutations of several genes, including superoxide dismutase 1 (SOD1), Tar DNA binding protein 43 (TDP-43), Chromosome 9 open frame 72 (C9ORF72), and Fused in Sarcoma (FUS) [18].