The remainder of cases are familial (FALS),3 which are predominantly associated with Mendelian-inherited mutations in genes encoding the Cu/Zn superoxide dismutase (SOD1), TAR-DNA binding protein 43 (TDP-43), fused in sarcoma/translocated in liposarcoma (FUS/TLS), and C9ORF72.4,5. The gene discussed is SOD1; the disease is liposarcoma.