Genetic features of oligodendrogliomas and presence of seizures. The relationship of seizures and genetics in LGOs.

Low grade oligodendrogliomas (LGO) are diffusely infiltrating World Health Organization (WHO) grade II gliomas, 20 - 30% of which show contrast enhancement. Seizures are a common presenting feature. It has been suggested that 1p19q co-deletion is associated with occurrence of seizures in adults, however, to date, the relationship of tumor genetics and seizure activity has not been extensively investigated. We sought to assess the influence of 1p19q co-deletion, IDH1-R132H positivity, and radiological variables on seizure activity in LGO patients. Specifically, we examined whether these characteristics were associated with seizure at initial presentation, or if they could predict outcome in terms of seizure free survival. In 62 LGOs, neither tumor location nor tumor enhancement were associated with seizures. 1p19q co-deletion status did not predict seizures when controlled for mutant IDH1-R132H expression, tumor location, or enhancement status (odds ratio (OR) 0.9, 95% confidence interval (CI) 0.1 - 4.3). This study, although of limited statistical power, did not demonstrate an association between 1p19q status and seizure occurrence in LGO's. Replication in a larger cohort would further support our hypothesis that 1p19q status alone cannot be used as a reliable predictor of seizure occurrence in LGO's.