OPTN and amyotrophic lateral sclerosis: Three mutations in the gene encoding optineurin in Japanese familiar or sporadic ALS patients have also been reported (Maruyama et al. 2010) which include a homozygous deletion of exon 5, a homozygous nonsense Gln398 stop (Q398X) and a heterozygous missense Glu478Gly (E478G).