Seizures and myelin oligodendrocyte glycoprotein (MOG) antibodies: Two paradigmatic cases and a review of the literature

Background: Myelin oligodendrocyte glycoprotein (MOG) antibodies (Abs) have been associated with a heterogeneous range of acquired CNS demyelinating disorders. More recently, increasing evidence correlates the presence of such Abs with seizures, occurring in concomitance with CNS demyelinating events, or even as isolated phenomena. In this scenario, the full clinical spectrum of MOG Ab-associated seizures and the contribution of such Abs to epileptogenesis are unclear.

Methods: We report on two paradigmatic cases of MOG Ab-associated seizures, one showing isolated seizures, without evidence of encephalopathy or MRI changes, followed by a demyelinating event one month later, and the other presenting with seizures as the main manifestation of an acute disseminated encephalomyelitis (ADEM) event. To better frame this topic, we performed a literature review, identifying 49 patients with MOG Ab-associated disorders presenting seizures at any stage of their disease, and analysed the clinico-therapeutic, brain MRI, cerebrospinal fluid, and EEG features.

Results: MOG Ab-associated seizures occurred mostly during encephalitis, including: a) "cortical encephalitis", a clinically poorly defined syndrome characterised by gray matter lesions on brain MRI, with or without subcortical white matter involvement; b) ADEM; c) NMDAR encephalitis with demyelinating features. Seizures can also occur in isolation, often in clusters of focal motor seizures, in patients with normal brain MRI, heralding the more typical MOG Ab-associated demyelinating syndrome by days to months.

Conclusion: Testing for MOG Abs should be considered in children with isolated and unexplained seizures, and in adults with suspected encephalitis and/or seizures. In these cases, MOG Abs detection is highly relevant for patients' clinical management.