An atypical phenotype of myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD)

Case presentation: A previously healthy boy, aged 3 years and 2 months, with no relevant perinatal or personal history and with normal neuropsychomotor development, started with monoparesis of the right lower limb that evolved in 4 days to hemiparesis without change in level of consciousness or behavior. Neurological examination showing hemiparetic gait. Hyperreflexia, more evident in right hemibody members. Absence of Babinski sign. Screening laboratory tests were normal. Brain MRI showed diffuse hyperintensity on T2/FLAIR white matter, extending through the temporal, occipital and bilateral parietal regions, more markedly on the left, with bilateral punctate areas of contrast medium uptake. In view of the initial condition, corticosteroid therapy was initiated with complete remission of hemiparesis in 3 days. It was then decided to maintain corticosteroid therapy and complement the investigation with an anti-MOG antibody test whose result was positive. He maintained a normal neurological exam in the outpatient visits and control MRI showed improvement in the lesions.

Discussion: Myelin Oligodendrocyte Glycoprotein Antibody Associated Disease (MOGAD) represents 34% of pediatric acquired demyelinating disease cases. The phenotypes vary according to the age of presentation, with optic neuritis (in all age), ADEM (in children) and myelitis (in adolescents) being more common. Other less frequent phenotypes were described, including a phenotype supported by bilateral and relatively symmetrical white matter commonly described as Leucodystrophy-like phenotype. Although the imaging exam and the patient's age corroborate the picture of this type, the dystrophy-like phenotype is a recurrent condition characterized by encephalopathy, ataxia, optic neuritis and seizures, with long-term behavioral impairment and intellectual deficit. About 50% of children with MOGAD will have a recurrence, so do not rule out the possibility of developing this phenotype in the future.

Final comments: The phenotypic description of MOGAD cases is important to the determination of patient's prognosis. A better understanding and prediction of outcome is essential to guide treatment decisions.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
18 September 2023