Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), aquaporin-4 immunoglobulin G (AQP4-IgG) positive, neuromyelitis optica spectrum disorder (NMOSD), and multiple sclerosis (MS) are distinct inflammatory demyelinating diseases of the central nervous system (CNS), Although the overlap of anti-NMDAR encephalitis with MS is rare, reported cases confirm that MS can co-occur with NMDAR antibody positivity. This evidence concerns the gene AQP4 and viral encephalitis.