Recurrent optic neuritis associated with MOG antibody seropositivity

Introduction Optic neuritis (ON) can be the first manifestation of autoimmune central nervous system diseases such as multiple sclerosis and neuromyelitis optica, but it can also occur as an isolated monophasic or relapsing disease. A proportion of these patients have antibodies against myelin oligodendrocyte glycoprotein (MOG). We report a case of recurrent ON with MOG antibodies in a South Asian patient. Case Report A 50-year-old Sri Lankan female with a previous history of 2 episodes of steroid-responsive ON presented with a 20/120 visual impairment of her right eye. On examination on admission, visual acuity was noted to be 20/30 on the left and visual evoked potentials were prolonged bilaterally, but all other neurological investigations including screening tests for infections and vasculitis were unremarkable. AQP4 antibodies were negative but MOG antibodies were positive. She responded to intravenous and long-term steroids combined with mycophenolate mofetil, but relapsed when steroids were discontinued. She has been relapse free on low-dose steroids and mycophenolate for 2 years. Conclusions Recurrent ON occurs in association with MOG antibodies distinct from neuromyelitis optica and multiple sclerosis, and may require steroid-based immunosuppression to maintain remission. This case report from South Asia adds to map the worldwide occurrence of MOG antibody disease.