AQP4 and neuromyelitis optica: The existence of autoantibodies against glial cell proteins, namely aquaporin-4 (αAQP4) and myelin oligodendrocyte glycoprotein (αMOG) is an important pathobiological feature of certain central nervous system (CNS) autoimmune demyelinating diseases, such as neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) [1–3].