Myelin Oligodendrocyte Glycoprotein (MOG)-IgG Associated Demyelinating Disease: Our Experience with this Distinct Syndrome

BACKGROUND: Discovery of serum myelin oligodendrocyte glycoprotein (MOG) antibody testing in demyelination segregated MOG-IgG disease from AQ-4-IgG positive NMOSD. AIMS: To study clinico-radiological manifestations, pattern of laboratory and electrophysiological investigations and response to treatment through follow up in MOG-IgG positive patients. METHOD: Retrospective data of MOG-IgG positive patients was collected. Demographics, clinical manifestations at onset and at follow up and relapses, anti AQ-4-IgG status, imaging and all investigations were performed, treatment of relapses and further immunomodulatory therapy were captured. RESULTS: In our 30 patients, F: M ratio was 2.75:1 and adult: child ratio 4:1. Relapses at presentation were optic neuritis {ON}(60%), longitudinally extensive transverse myelitis {LETM}(20%), acute disseminated encephalomyelitis {ADEM}(13.4%), simultaneous ON with myelitis (3.3%) and diencephalic Syndrome (3.3%). Salient MRI features were ADEM-like lesions, middle cerebellar peduncle fluffy infiltrates, thalamic and pontine lesions and longitudinally extensive ON {LEON} as well as non-LEON. Totally, 50% patients had a relapsing course. Plasma exchange and intravenous immunoglobulin worked in patients who showed a poor response to intravenous methylprednisolone. Prednisolone, Azathioprine, Mycophenolate and Rituximab were effective attack preventing agents. CONCLUSIONS: MOG-IgG related manifestations in our cohort were monophasic/recurrent/simultaneous ON, myelitis, recurrent ADEM, brainstem encephalitis and diencephalic Syndrome. MRI features suggestive of MOG-IgG disease were confluent ADEM-like lesions, middle cerebellar peduncle fluffy lesions, LETM, LEON and non-LEON. Where indicated, patients need to go on immunomodulation as it has a relapsing course and can accumulate significant disability. Because of its unique manifestations, it needs to be considered as a distinct entity. To the best of our knowledge, this is the largest series of MOG-IgG disease reported from India.