MOG-Abs can be detected in NMOSD with AQP4-Ab seronegative, recurrent optic neuritis, transverse myelitis, multiphasic acute disseminated encephalomyelitis, and combined central and peripheral demyelination (CCPD) syndromes; [24–26] a proportion of these patients will develop a relapsing type of disease [23, 27]. Here, AQP4 is linked to optic neuritis.