Epileptic encephalopathies are severe neurodevelopmental disorders in the pathogenesis of which genetic factors play a key role, in particular mutations in the genes of voltage-gated sodium channels. This paper discusses the functional aspects of loss - of - function (LOF) and gain - of - function (GOF) mutations in the SCN family of genes (SCN 1 A, SCN 2 A, SCN 3 A, SCN 8 A) and their contribution to the development of epileptic encephalopathies. An analysis of current literature data on the molecular mechanisms of neuronal excitability disorders and their clinical manifestations is conducted. Particular attention is paid to the genotype-function-phenotype relationship and its significance for personalized therapy. It is shown that the functional characterization of mutations is important for the selection of an effective treatment strategy and disease prognosis.

epileptic encephalopathies, sodium channels, SCN 1 A, SCN 2 A, SCN 8 A, loss - of - function, gain - of - function, neuronal excitability, genetics, personalized medicine.

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