Most cases of ALS are sporadic, but 10% are caused by mutations in different genes, mainly TDP-43, FUS (fused in sarcoma), optineurin, SOD1 and C9orf72 (hexanucleotide repeat expansion of the non-coding region of reading frame 72 on chromosome 9) [126,127]. This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.