Optic neuritis has been recently considered as an immune-mediated diseases with speculated autoimmune pathogenesis, as evidenced by studies providing that seropositive autoantibodies subtypes including myelin oligodendrocyte glycoprotein antibody (MOG-Ab) and seropositive aquaporin-4 antibody (AQP4-Ab) (26) typically present in patients with optic neuritis. The gene discussed is AQP4; the disease is optic neuritis.