C9orf72 and amyotrophic lateral sclerosis: Approximately 5%–10% of ALS cases have a genetic link within the family, and several genes have been identified as responsible for familial ALS, including superoxide dismutase 1 (SOD1), C9orf72, fused in sarcoma (FUS), less commonly transactive response DNA binding protein (TARDBP), ubiquilin-2 (UBQLN2), VCP, and TBK1 [47, 48].