GFAP and neuromyelitis optica: While some antibodies are helpful for differential diagnosis, such as anti-aquaporin 4 (AQP4), primarily associated with neuromyelitis optica spectrum disorders (NMOSDs), glial fibrillary acidic protein (GFAP) antibodies are typically found in patients with autoimmune GFAP astrocytopathy [144,145,146,147].