Aquaporin-4 (AQP4) IgG-positive and myelin oligodendrocyte glycoprotein (MOG)-IgG–associated disorder (MOGAD) are CNS demyelinating diseases that present with optic neuritis, and transverse myelitis; some MOGAD patients may also have in combination acute disseminating encephalomyelitis or brainstem encephalitis. The gene discussed is AQP4; the disease is transverse myelitis.