MOG and neuromyelitis optica: It is discussed whether MOG-IgG define a separate disease entity tentatively called MOG-IgG-associated diseases, MOG-IgG autoimmunity or MOG-IgG seropositive encephalomyelitis rather than being part of several autoimmune disorders, especially neuromyelitis optica spectrum disorders (NMOSD) [1, 3, 8, 9].