AQP4 and systemic lupus erythematosus: Neuromyelitis optica spectrum disorder (NMOSD), formerly known as neuromyelitis optica (NMO), is a rare, autoimmune inflammatory CNS syndrome with a variety of symptoms that has been shown to be associated with serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG) [1-3]. In this report, we discuss a patient with systemic lupus erythematosus (SLE) who presented with area postrema syndrome that was ultimately diagnosed with NMOSD.