However, 5%–10% of ALS cases are familial, with more than 40 distinct genes currently associated and mutations in C9ORF72, superoxide dismutase 1 (SOD1), TAR-DNA-binding protein (TARDBP), and fused in sarcoma (FUS) recognized as major genetic causes of ALS (1, 2). The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.