AQP4 and neuromyelitis optica: <h4>Rationale</h4>Neuromyelitis optica spectrum disorders (NMOSD) is an autoimmune-mediated central nervous system (CNS) inflammatory demyelinating disease characterized by 6 major clinical syndromes, including myelitis, optic neuritis, area postrema syndrome, symptomatic cerebral syndrome, brainstem syndromes, and acute diencephalic clinical syndrome.<h4>Patient concerns</h4>A 32-year-old female, complaining of numbness in her right limb for 1 month, was diagnosed with aquaporin-4 antibody (AQP4-IgG)-positive NMOSD.