Phenotypic spectrum of the SCN1A mutation (from febrile seizures to Dravet syndrome).

with the Dravet's syndrome phenotype are associated with the detection of a sequence variant in the SCN1A gene (alpha 1 subunit of the voltage-gated sodium channel) (2). However, sequence variants in the SCN1A gene are associated with a very broad clinical spectrum, from asymptomatic carriers to the severe myoclonic epilepsy phenotype with severe disease (3).In the presented work, we retrospectively evaluated a group of 6 patients of the Department of Pediatric Neurology of the Medical Faculty of Masaryk University and the University Hospital in Brno with a proven missense mutation. Based on the specific pathogenic sequence variant, we correlated the patient's phenotype with the location of the sequence variant in the SCN1A gene. The aim of the analysis was to verify the extent, to which the storage of a pathogenic sequence variant in the SCN1A gene corresponds to the clinical picture of the patient (Tab. 2, Fig. 2, Ref. 10). Keywords: Dravet's syndrome, sodium channel, functional analysis, prognosis.

Next-generation sequencing in children with epilepsy: The importance of precise genotype-phenotype correlation.

AIM: The primary goal was to determine the yield of next-generation sequencing (NGS) epilepsy gene panels used for epilepsy etiology diagnosing using a multidisciplinary approach and to demonstrate the importance of genotype-phenotype correlations. The secondary goal was to evaluate the application of precision medicine in selected patients. METHODS: This single-center retrospective study included a total of 175 patients (95 males and 80 females) aged 0-19 years. They were examined between 2015 and 2020 using an NGS epilepsy gene panel (270 genes). A bioinformatic analysis was performed including copy number variation identification. Thorough genotype-phenotype correlation was performed. RESULTS: Out of 175 patients, described pathogenic variants or novel variants with clear pathogenic impact were identified in 30 patients (17.14%). Genotype-phenotype correlations and parental DNA analysis were performed, and genetic diagnosis was confirmed on the basis of the results in another 16 out of 175 patients (9.14%). The diagnostic yield of our study increased from 30 to 46 patients (by 53.33%) by the precise genotype-phenotype correlation. INTERPRETATION: We emphasize a complex genotype-phenotype correlation and a multidisciplinary approach in evaluating the results of the NGS epilepsy gene panel, which enables the most accurate genetic diagnosis and correct interpretation of results.