Detection rate of causal variants in severe childhood epilepsy is highest in patients with seizure onset within the first four weeks of life

BACKGROUND: Epilepsy is a heterogeneous disease with a broad phenotypic spectrum and diverse genotypes. A significant proportion of epilepsies has a genetic aetiology. In our study, a custom designed gene panel with 112 genes known to be associated with epilepsies was used. In total, one hundred and fifty-one patients were tested (86 males / 65 females). RESULTS: In our cohort, the highest probability for the identification of the cause of the disease was for patients with a seizure onset within the first four weeks of life (61.9% clarification rate) – about two times more than other groups. The level of statistical significance was determined using a chi-square analysis. From 112 genes included in the panel, suspicious and rare variants were found in 53 genes (47.3%). Among the 151 probands included in the study we identified pathogenic variants in 39 patients (25.8%), likely pathogenic variants in three patients (2%), variants of uncertain significance in 40 patients (26.5%) and likely benign variants in 69 patients (45.7%). CONCLUSION: Our report shows the utility of diagnostic genetic testing of severe childhood epilepsies in a large cohort of patients with a diagnostic rate of 25.8%. A gene panel can be considered as a method of choice for the detection of pathogenic variants within patients with unknown origin of early onset severe epilepsy. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13023-018-0812-8) contains supplementary material, which is available to authorized users.