Myelin oligodendrocyte glycoprotein (MOG) antibody positive disease presenting as acute disseminated encephalomyelitis and unilateral optic neuritis

Abstract

The autoantibody against myelin oligodendrocyte glycoprotein (MOG-abs) is a recognized biomarker in acquired demyelinating syndromes. The diversity in clinical and neuroimaging phenotypes is still being understood in the paediatric population. The presenting clinical phenotype strongly depends on the age at onset. Acute disseminated encephalomyelitis (ADEM) and ADEM-like phenotypes are common in younger children, but optic neuritis (ON), often bilateral, is predominantly seen in females and older children and or adults.We present a 6.5-year-old boy with a rapid onset encephalopathy due to ADEM and a unilateral longitudinally affected optic neuritis detected on neuroimaging. His serum was positive for MOG-abs but negative for Aquaporin-4 antibodies. His cerebrospinal fluid was negative for oligoclonal bands. He gradually improved following treatment with intravenous high-dose methylprednisolone and five cycles of plasma exchange. Complete clinical recovery was achieved within twelve weeks of admission.Conclusion: Contrary to the usual older age of MOG-ON, and the bilateral involvement, this case illustrates a unilateral ON in a six-year-old boy occurring in conjunction with a MOG-ab positive encephalomyelitis.