To determine utility of epilepsy gene panel in epilepsy surgery decision making.

Genetic diagnostics are still not routinely performed during pre-surgical evaluation of epilepsy patients, and reports on utility of genetics tests in epilepsy surgery are limited.

We included all adult patients with positive epilepsy gene panel test results who were discussed for epilepsy surgery in our institution during three years from 2018 to 2020.

After screening, 6 patients were identified. Average age at time of genetic testing was 35.5 years (range 21-48). Genetic findings included SCN1A (2 patients), GABRA1, PCDH19, UBE3A, TSC1. Two patients had genetic testing before the first epilepsy surgery conference discussion: TSC1 and SCN1A positive patients who had tuberous sclerosis and Dravet syndrome respectively. All patients except of one with Dravet syndrome phenotype had presumable focal epilepsy. After discussion, the Dravet syndrome patient had Deep Brain Stimulator (DBS) leads placement to the bilateral anterior nuclei of thalamus, and stereoelectroencephalography (SEEG) evaluation was recommended to the tuberous sclerosis patient to localize the seizure onset zone(s). The other four patients were approved for SEEG, but after the re-discussion with the genetic tests results, two patients (SCN1A and GABRA1 positive) continued treatment with medications. Two patients (UBE3A and PCDH19 positive) underwent SEEG evaluation which showed independent broad bilateral temporal neocortical ictal onsets in UBE3A patient, and broad left temporo-parietal ictal onset in PCDH19 patient, therefore DBS leads placement to the bilateral anterior nuclei of thalamus was recommended to both patients.

We propose that epilepsy surgery candidates would benefit from genetic testing to optimize surgical decision making, cost-effectiveness and ultimately to improve quality of life. Studies on a larger patient cohort are needed to identify the role of genetic testing in selection of epilepsy surgery candidates.