Previous reports of patients with myelitis associated with rheumatologic disease may have had unrecognized aquaporin-4 (AQP4)-IgG seropositive neuromyelitis optica spectrum disorder (NMOSD) or myelin oligodendrocyte glycoprotein (MOG)-IgG–associated disease (MOGAD). Here, AQP4 is linked to neuromyelitis optica.