Frequency of Specific Genes in Different Types of Epilepsy.

Objective: To determine the diagnostic importance of using an exome-based multigene panel in childhood epilepsy.

Study Design: Observational study.

Place And Duration Of Study: Department of Medical Genetics, Diskapi Yildirim Beyazid Training and Research Hospital, from January 2017 to May 2020.

Methodology: The phenotype-genotype relationship was investigated in 35 pediatric patients (aged 18 years or younger) with epilepsy, using a large gene panel comprising 464 epilepsy-related genes. The exome-based panel was used to analyse secondary findings.   Results: The diagnostic yield of the targeted multi-gene panel used was 20% (7/35). The causative genes identified in seven patients (5 boys, 2 girls) were CACNA1E, RELN, PRRT2, TSC1, GABRG2, SCN2A, and SHH. Four of the detected disease-related variants were defined as the novel. Secondary findings in various genes were detected in 19 of the patients. Seven patients with causal genes and the remaining 28 patients were compared in terms of parameters such as gender, mental retardation, developmental retardation, autism, hypotonia, seizure phenotype (only), seizure phenotype (plus), magnetic resonance imaging, degree of kinship of their parents and number of relatives with epilepsy. In addition, patients were evaluated statistically in terms of the same parameters by grouping them according to their gender. There was no statistically significant difference in either study (p >0.05).

Conclusion: Genetic testing is an important tool for clinicians in determining the diagnosis, management, and treatment strategies of epilepsy patients. Key Words: Epilepsy, Diagnostic yield, Exome-based multigene panel, Next-generation sequencing, Seconder findings.