AQP4 and atypical hemolytic-uremic syndrome: It is currently approved by the U.S. Food and Drug Administration (FDA) for the treatment of paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), generalized myasthenia gravis (gMG), and aquaporin-4 immunoglobulin G-positive optic neuromyelitis optica spectrum disorders (AQP4-IgG+NMOSD), which play important roles in the allopathic treatment of complement-associated immune disorders.