Myelin oligodendrocyte glycoprotein antibody-associated isolated seizures in children: a retrospective single-center case series

Background and purpose Isolated seizures represent a distinct, rare, and underrecognized phenotype of myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD). In recent years, documentation of this phenotype has been limited to sporadic reports, with dedicated case series being extremely scarce. This study aimed to describe the clinical characteristics of isolated seizures in pediatric patients with MOGAD. Methods We retrospectively reviewed the medical records of pediatric patients diagnosed with MOG antibody-associated isolated seizures between January 2019 and January 2026. Clinical manifestations, brain magnetic resonance imaging (MRI) findings, laboratory data, treatment regimens, and clinical outcomes were systematically analyzed. Results Among the cohort of 172 pediatric patients with seropositive MOG antibodies, 6 (3.4%) met the inclusion criteria for isolated seizures. The median age at onset was 7.5 years (range, 5–9 years), with a male-to-female ratio of 1:2. Clinically, 4 patients presented solely with epileptic seizures, while the other 2 patients had additional transient limb weakness or headache, respectively. Focal seizures were observed in 5 patients, including 3 with focal motor seizures; additionally, 2 cases experienced status epilepticus. No patients exhibited encephalopathy or focal neurological deficits. Four patients had peripheral blood leukocytosis (range, 11.9–26 × 10 9 /L), and five had elevated erythrocyte sedimentation rates (ESR; range, 22–43 mm/h). All six patients showed cerebrospinal fluid (CSF) pleocytosis (41.1 ± 20.4/μL; range, 15–69/μL) without detectable infectious pathogens. Abnormal electroencephalogram (EEG) findings, including abnormal background activity and focal slow waves, were identified in 3 patients. No cranial MRI abnormalities were detected in any patient. All patients received immunotherapy, with one patient additionally receiving anti-seizure medications (ASMs). At final follow-up, all patients had favorable outcomes, with no recurrence of seizures or subsequent demyelinating events. Conclusion Myelin oligodendrocyte glycoprotein antibody-associated isolated seizures is a rare and frequently underrecognized phenotype within the spectrum of MOGAD. For school-age children presenting with epileptic seizures, particularly focal motor seizures, along with elevated ESR and CSF pleocytosis, early testing for MOG antibody is recommended in the absence of clinical or radiological evidence of encephalitis or focal neurological deficits. Most patients achieve favorable clinical outcomes, which may be partially attributed to immunotherapy. However, the efficacy of immunotherapy in preventing seizure recurrence, subsequent demyelinating events, and subclinical radiological disease remains indeterminate.