Abstract: Objective To evaluate the clinical significance of myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) in chronic relapsing inflammatory optic neuropathy (CRION) by comparing the clinical characteristics and prognosis of MOG-IgG(+) CRION and MOG-IgG(-) CRION. Design Retrospective case control study. Participants From December 2015 to April 2018, the data of 40 in-patients with CRION who were treated in neuro-ophthalmology Department of General Hospital of Chinese PLA and Beijing Chaoyang Hospital were collected and followed up for at least one year. Methods According to the results of MOG IgG examination, the participants were divided into MOG IgG (+) CRION group and MOG IgG (-) CRION group. The database was established to compare the differences in demographic characteristics, symptoms, auxiliary examination and prognosis between the two groups. Main Outcome Measures Sex ratio, age of onset, monocular or binocular, visual prognosis, recurrence frequency, concomitant symptoms and MRI features. Results The average age of onset of MOG-IgG (+) CRION  group was 30.0±11.7 years, which was significantly younger than that of MOG-IgG (-) CRION  group (46.6±10.1 years old) (P<0.001). Six patients (23.1%) in MOG-IgG (+) CRION group suffered from simultaneous onset of both eyes for the first time, and all patients in MOG-IgG (-) CRION group onset in one eye for the first time. During the follow-up, 20 cases (76.9%) of MOG-IgG (+) CRION group had binocular involved, which was significantly higher than that of MOG-IgG (-) group (21.5%) (P<0.001). The average number of recurrences per year in MOG-IgG (+) group (3.36±0.90) was significantly higher than that in MOG-IgG (-) group (2.55±0.69) (P=0.015). In MOG-IgG(+) CRION group, 10 cases (38.5%) eventually complicated with craniocerebral and spinal cord symptoms, which was significantly higher than that in MOG-IgG(-) group (0 cases) (P=0.006). The MOG-IgG(+) CRION group was more likely to involve two or more sites (P=0.014). Conclusion MOG-IgG has important clinical significance in the diagnosis, treatment and prognosis of CRION patients. Specifically, MOG-IgG (+) CRION is younger in onset, easy to involve both eyes, and involves a longer segment of the optic nerve, easy to relapse. During follow-up, neurological symptoms such as craniocerebral and spinal cord were more likely to occur.

Key words: myelin oligodendrocyte glycoprotein immunoglobulin G; , chronic relapsing inflammatory optic neuropathy