OPTN and amyotrophic lateral sclerosis: Thus far, more than 16 ALS causative genes including SOD1, ALS2, SETX, SPG11, FUS, VAPB, ANG, TARDBP, FIG4, OPTN, ATXN2, VCP, C9orf72, UBQLN2, SIGMAR1, and CHMP2B have been identified [1, 4] (http://neuromuscular.wustl.edu/index.html) (Table 1).