Atypical presentation of MOG-related disease: Slowly progressive behavioral and personality changes following a seizure.

Myelin Oligodendrocyte Glycoprotein (MOG) antibodies-related disease is mainly presented with acute disseminated encephalomyelitis (ADEM), recurrent optic neuritis, and neuromyelitis optica spectrum disorders (NMOSDs), however the complete clinical spectrum has not yet been defined. We describe an unusual presentation of MOG- related disease. A previously well 10-year-old girl admitted with a focal onset seizure. Neurological examination, electroencephalography, and brain magnetic resonance imaging (MRI) were normal. Following seizure episode she developed gradually increased behavioral and personality changes during a period of 2.5 months. Neurological examination was unremarkable except for drowsiness and minimal ataxia on tandem walking. Repeated brain MRI revealed hazy and poorly demarcated lesions with gadolinium enhancement in the basal ganglia, supratentorial white matter, cerebral peduncles, cerebellum, and servical spinal cord. Cerebrospinal fluid analyses (CSF) revealed 10 lymphocytes /µL, normal protein concentration and IgG index, and negative oligoclonal bands. Auto-antibodies against N-methyl-d-aspartate receptor and CASPR2 in CSF, and antibodies against aquaporin 4 in serum were negative. Analysis with a cell-based assay identified high serum titer of MOG antibodies (1:320). Following IVIG therapy, the patient showed complete clinical recovery within a week with no further relaps for the following 6-month period.Slowly progressive behavioral and personality changes following a seizure may be a manifestation of MOG-related disease in children.