NMOSD is clinically characterized by attacks of uni- or bilateral optic neuritis (ON), acute myelitis and/or brain/brainstem encephalitis (8) and is associated with specific autoantibodies (aAbs) such as anti-aquaporin-4 (AQP4), targeting an astrocytic water channel (9), or anti-myelin oligodendrocyte glycoprotein (MOG)-IgG (5, 10). The gene discussed is AQP4; the disease is optic neuritis.