Neonatal developmental and epileptic encephalopathies. English version

Abstract The International League Against Epilepsy (ILAE) distinguishes three main groups of neonatal epilepsy syndromes: (1) self-limiting neonatal, neonatal-infantile and infantile (familial or not familial) epilepsies, (2) developmental and epileptic encephalopathies (DEE) and (3) etiology-specific epilepsies. The DEEs are characterized by a combination of severe developmental disorders, neurological abnormalities and treatment-resistant seizures. This article focuses on early infantile DEEs, which manifest within the first 3 months of life. The underlying causes are mostly genetic, structural, and/or metabolic factors, with expanded diagnostic tools enabling identification in up to 80% of cases. Clinically, affected infants present with drug-resistant seizures of various semiologies, abnormal movement patterns and pathological interictal EEG patterns, such as a burst-suppression pattern or others. Epilepsy with migrating focal seizures in infancy is a rare form of DEE. It is characterized by focal motor, tonic-clonic seizures, which appear in EEG recordings as migrating onset epileptic activity. Among the etiology-specific DEEs, KCNQ2-related DEE, pyridoxine-dependent (ALDH7A1) and pyridoxamine-5-phosphate (PNPO)-dependent DEE as well as CDKL5-related DEE, are particularly associated with an onset in the neonatal and early infantile period. The treatment options for neonatal DEEs have improved due to advances in precision medicine. Specific genetic variants (e.g., KCNQ2, SCN2A and KCNT1 mutations) can be targeted with sodium channel blockers or other specific medications.; however, the prognosis remains poor, especially in severe treatment-resistant forms. Early genetic, structural, and metabolic diagnostics are crucial for initiating optimal treatment and improving long-term outcomes.