Neuromyelitis optica spectrum disorder (NMOSD) includes conditions with autoimmune genesis, which are manifested by attacks of optic neuritis (ON) and transverse myelitis (TM), and also express aquaporin 4 (NMO-IgG) or myelin oligo-endocytic glycoprotein (MOGAb) antibodies. Here, AQP4 is linked to optic neuritis.