Developmental and epileptic encephalopathies (DEE/EEs) are characterized by early onset of seizures, therapy resistance, neurodevelopmental delay, for example, as seen in channelopathies (e.g., GRIN2A-, SCN2A-, SCN1A-, and SCN8A-related epilepsies) or in metabolic conditions (e.g., SLC2A1). The gene discussed is SCN1A; the disease is epilepsy.