Although more than 100 potentially causative or disease-modifying genes have been identified, the most common mutations are found in C9orf72 (chromosome 9 open reading frame 72), SOD1 (superoxide dismutase 1), FUS (fused in sarcoma/translocated in liposarcoma or heterogeneous nuclear ribonucleoprotein P2) and TARDBP (transactive response DNA binding protein 43) (60–70% of all FALS cases) [9]. The gene discussed is FUS; the disease is sarcoma.