Kunchok A, et al. - Researchers intended to define the frequency, sex ratio, and coexistence of glial antibodies (AQP4-IgG and MOG-IgG) in adults and children undergoing evaluation for the suspected central nervous system–demyelinating diseases. Myelin oligodendrocyte glycoprotein (MOG)–IgG is a biomarker correlated with central nervous system–demyelinating disorders termed MOG-IgG–associated disorders. It is indicated that these disorders have overlapping clinical features, involving optic neuritis and myelitis, with aquaporin-4 (AQP4)–IgG–positive neuromyelitis optica spectrum disorders. Whereas MOG-IgG–associated disorders are postulated to be autoimmune oligodendrocytopathies, these disorders are assumed to be biologically distinct; AQP4-IgG–positive neuromyelitis optica spectrum disorders are autoimmune astrocytopathies. Notwithstanding their immunopathogenic variations, there are rare records of individuals with dual positivity of MOG-IgG and AQP4-IgG.