Intriguingly, despite the identification of over 40 genes linked to ALS pathogenesis, mutations in just four genes–superoxide dismutase 1 (SOD1), TARDBP (which encodes the TAR DNA-binding protein-43 [TDP-43]), fused in sarcoma (FUS), and chromosome 9 open reading frame 72 (C9ORF72)–are responsible for approximately 70% of familial ALS cases (Al-Chalabi et al., 2017; Roggenbuck et al., 2017). This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.