Although the vast majority of ALS is sporadic (without a family history), ∼10% is familial; mutations in the gene FUS (fused-in-sarcoma) account for ∼5% of familial and ∼1% sporadic ALS (Kwiatkowski et al., 2009; Vance et al., 2009; Rademakers et al., 2010; Nolan et al., 2016). The gene discussed is FUS; the disease is amyotrophic lateral sclerosis.