In fALS, mutations have been identified in genes encoding several proteins: the copper/zinc superoxide dismutase 1 (SOD1), the transactive response DNA-binding protein (TARDBP), the fused in sarcoma/translocated in liposarcoma RNA-binding protein (FUS/TLS) and the chromosome 9 open reading frame 72 (C9orf72). The gene discussed is FUS; the disease is sarcoma.