OPTN and amyotrophic lateral sclerosis: Pathogenic mutations of the genes TAR DNA BINDING PROTEIN (TARDBP), FUSED IN SARCOMA/TRANLOCATED IN LIPOSARCOMA (FUS), OPTINEURIN (OPTN), TANK-BINDING KINASE 1 (TBK1), as well as intronic expansions in the gene C9ORF72, are among the most frequent familial ALS mutations (previously reviewed by Cook and Petrucelli, 2019; Mejzini et al., 2019; Kim et al., 2020; McAlary et al., 2020; Ustyantseva et al., 2020).