Retrospective analysis of patients with epilepsy or seizure free EEG anomaly evaluated by WES analysis in Gazi University Faculty of Medicine, Department of Medical Genetics between 2017-2020.

Epilepsy is a chronic neurological disease characterized by epileptic seizures due to abnormal electrical activity in brain cells, while genetic factors play a predominant role in its etiology. NGS technologies are powerful diagnostic tools in elucidating the genetic etiology of epilepsy. Thanks to the widespread use of NGS, hundreds of epilepsy genes have been identified; however, the number of cases defined for many of these genes is quite low. Due to the small number of cases, there is limited data on the diversity of manifestations of diseases associated with these genes, and therefore each case to be defined is expected to contribute significantly to the spectrum of manifestations of the disease. In this study, 102 patients with epilepsy or seizure-free EEG anomalies in the WES archive of Gazi University Faculty of Medicine, Department of Medical Genetics between 2017-2020 were divided into different phenotypic subgroups according to their clinical findings and epilepsy types; and evaluated together with their demographic, clinical and molecular genetic results. It was found that 37% of the patients in the study had parental consanguinity, and about a quarter of patients had a history of affected relatives. Although 45% of the patients were diagnosed with WES analysis, it was determined that the diagnosis rates varied in phenotypic subgroups. The results show that the heritability of epilepsy-related diseases is high and, WES analysis is a powerful diagnostic tool in the genetic diagnosis of epilepsy. Different diagnosis rates were found among the study subgroups, suggesting that alternative genetic mechanisms that cannot be detected by WES may role at different rates in their etiologies. In many patients, molecular diagnoses provided genetic counseling information such as treatment options, prognosis, risk of recurrence, as well as diagnosis of affected family members, and offered prenatal diagnosis in cases with a high risk of recurrence. This indicates that WES analysis should be an important part of epilepsy patients' management with suspected genetic etiology. Key Words: Epilepsy, WES, Archival Study