Screening of OPTN in French familial amyotrophic lateral sclerosis

Mutations in OPTN gene encoding optineurin have recently been identified at the homozygote and heterozygote state in Japanese families with slowly progressive amyotrophic lateral sclerosis (ALS). OPTN had previously been involved in adult primary open angle glaucoma (POAG). We sequenced the coding exons of OPTN in 126 French patients with familial ALS (FALS). We identified, at the heterozygote state, the nonsense c.382_383insAG variant (also called 691_692insAG), alternatively reported as a causative mutation for primary open angle glaucoma (POAG) or a rare polymorphism and the new p.Arg96Leu variant in a family with dominant ALS. Western blot experiments on the patients' lymphoblasts showed that the former variant led to a loss of function and the latter did not cause protein accumulation. Our results do not confirm the contribution of OPTN in ALS.