Many other less-frequent genetic mutations have also been associated with ALS, including mutations in UBQLN2 (ubiquilin 2), OPTN (optineurin), VCP (valosin-containing protein) and TBK1 (TANK-binding kinase 1) (Al-Chalabi et al., 2017; Renton et al., 2014). This evidence concerns the gene OPTN and amyotrophic lateral sclerosis.