The article is devoted to the urgent problem of neonatology and pediatric neurology — seizures in newborns and young children. In the work, a short review of the clinical and genetic characteristics of monogenic epilepsy is presented, in particular, the main attention is paid to the variants that begin in neonatal and early childhood. It has been shown that a significant number of epileptic encephalopathies are caused by mutations in genes whose protein products form voltage-dependent (sodium and potassium), ligan(dependent (γ-aminobutyric acid — GABA) channels, the functioning of which ensures the passage of a nerve impulse in neurons of the cerebral cortex. The necessity of including the molecular genetic methods into the algorithm for examining a child with epilepsy, in particular with epileptic encephalopathy, is emphasized. It is noted that congenital metabolic disorders are one of the etiological reasons for the development of epileptic seizures in children, in particular in newborns and young children. It was shown that congenital metabolic disorders have phenotypic manifestations of epileptic encephalopathy. Some curable metabolic defects that are accompanied by seizures, their diagnosis and timely treatment are described. No conflict of interest was declared by the authors. Key words: newborn, epilepsy, epileptic encephalopathy, diagnosis, genetic examination, metabolic defects, review.