Individuals with anti-aquaporin-4 (AQP4) antibodies and anti-myelin oligodendrocyte glycoprotein (MOG) antibodies were previously grouped under the umbrella term neuromyelitis optica spectrum disorder (NMOSD), as they shared two cardinal clinical manifestations, optic neuritis and longitudinally extensive transverse myelitis. The gene discussed is MOG; the disease is optic neuritis.