GFAP and encephalomyelitis: Glial fibrillary acidic protein (GFAP) astrocytopathy, which was first described in 2016, is an immune-mediated, inflammatory disease of the central nervous system (CNS) characterized by the presence of IgG autoantibodies against the intermediate filament protein GFAP (especially GFAPα isoform) in the cerebrospinal fluid (CSF) [1].