MOG and myelitis: In group I (samples sent in for routine assessment of MOG-IgG), MOG-IgG was detected in 95/386 (24.6 %) samples from 50/300 (16.7 %) patients; if only patients with a diagnosis of ON and/or myelitis are considered, MOG-IgG was present in 95/281 (33.8 %) samples from 50/202 (24.8 %) patients.