MOG and neuromyelitis optica: MOG-IgG-seropositive patients had the following diagnosis: recurrent ON (N = 7), MOG-IgG-seropositive NMOSD (N = 12) meeting the 2015 IPND (International Panel for Neuromyelitis Optica Diagnosis) criteria for seronegative NMOSD [26], MOG-IgG-seropositive MS (N = 3) and MOG-IgG-seropositive meningoencephalomyelitis (N = 2).