Developmental and epileptic encephalopathies: from genetic heterogeneity to phenotypic continuum

International audienceDevelopmental and epileptic encephalopathies are a heterogeneous group of disorders characterized by early-onset, often severe epileptic seizures, EEG abnormalities, on a background of developmental impairment that tends to worsen as a consequence of epilepsy. DEEs may result from both non-genetic and genetic etiologies. Genetic DEEs have been associated with mutations in many genes involved in different functions including cell migration, proliferation, and organization, neuronal excitability, and synapse transmission and plasticity. Functional studies performed in different animal models and clinical trials on patients have contributed to elucidate pathophysiological mechanisms underlying many DEEs and explored the efficacy of different treatments. Here, we provide an extensive review of the phenotypic spectrum included in the DEEs, of the genetic determinants and pathophysiological mechanisms underlying these conditions. We also provide a brief overview of the most effective treatment now available and of the emerging therapeutic approaches