Neuromyelitis optica (NMO) is an inflammatory autoimmune disease that is associated with severe optic neuritis (ON) and/or longitudinally extensive transverse myelitis (LETM).[1] The discovery of immunoglobulin G (NMO-IgG)[2]/anti-aquaporin 4 (AQP4)[3] antibody has broadened the spectrum of NMO to neuromyelitis optica spectrum disorders (NMOSD).[4]. This evidence concerns the gene AQP4 and optic neuritis.