 These conditions can appear as Neuromyelitis optica (NMO), and its associated "spectrum of disorders" (NMOSD), currently considered a common syndrome for several separated diseases but with some still idiopathic subtypes.Some researchers think that there could exist an overlapping between Anti-NMDA receptor encephalitis cases and neuromyelitis optica or acute disseminated encephalomyelitis.Originally found in neuromyelitis optica, this autoantibody has been associated with other conditions.