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.