Among such genes, mutations in superoxide dismutase 1 (SOD1), transactive response DNA binding-43 kDa (TDP-43), fused in sarcoma/translocated in sarcoma (FUS/TLS), and the most frequent intronic hexanucleotide GGGGCC repeat expansion in the C9orf72 gene (accounting for the 40–50% of fALS and 7% of sALS) are responsible for approximately the 70% of all fALS monogenic cases [8,9]. The gene discussed is SOD1; the disease is sarcoma.