Mild Malformation of Cortical Development With Oligodendroglial Hyperplasia and Epilepsy: A Systematic Review

Mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy (MOGHE) is a newly described rare entity of drug-resistant epilepsy, with a wide spectrum of presentations. We aim to describe the diagnostic features and prognosis of MOGHE in a large cohort.

We performed a systematic review preregistered on PROSPERO (CRD42023472978), in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We searched PubMed, Embase, Scopus, and ScienceDirect between database inception and November 30, 2023, for all published studies on MOGHE. Inclusion criteria were a histopathologic diagnosis of MOGHE. The risk of bias was analyzed with a standardized tool specifically for case reports and case series. The demographic, clinical, EEG, neuroimaging, genetic, and neuropathologic features; treatments; and prognosis were extracted and analyzed. Subgroup analysis was performed with the age at onset and SLC35A2 variant status.

A total of 163 patients with MOGHE from 18 studies were included in the analysis. The median age at seizure onset was 1.2 years, and 103 were male. Ninety-five patients presented with unilobed lesions. Ninety-nine had lesions in the frontal lobe. A total of 101 patients achieved a favorable surgical outcome. Patients with an onset before 10 years were more likely to present with epileptic spasms, the West syndrome, a circumscribed pattern of interictal EEG, intellectual disabilities, and a better seizure outcome, compared with those with an onset age 10 years and older. Forty-five patients (72.6%) were SLC35A2-positive. Patients harboring the SLC35A2 variants were more likely to present as Lennox-Gastaut syndrome, when compared with those who were SLC35A2-negative.

MOGHE is a distinct entity of drug-resistant epilepsy associated with SLC35A2 variants, characterized by age-dependent phenotypes. The study emphasizes the clinical pearls indicative of the rare disease, which may facilitate early recognition and appropriate selection of treatments. The included studies were case reports or series, which were mainly limited by selection and reporting biases.