Biological Bases of Symptomatic Generalized Epilepsies in Children

Symptomatic generalized epilepsies represent a group of challenging epilepsy syndromes, most often seen in children, which share the hallmark of a triad encompassing multiple seizure types, electroencephalographical (EEG) evidence of diffuse brain involvement, and dysfunction in the intellectual domain (global developmental delay or mental retardation). SGEs include the early myoclonic encephalopathy, early infantile epileptic encephalopathy (Ohtahara syndrome), West syndrome, epilepsy with myoclonic-astatic seizures, epilepsy with myoclonic absence, Lennox-Gastaut syndrome, and the progressive myoclonic epilepsies. SGEs may arise from various genetic, developmental, or acquired brain pathologies and also can be associated with other cerebral or systemic defects and thus being part of a broader epilepsy syndrome phenotype. SGEs are associated with significant mortality and morbidity and most patients with SGE grow up to have intractable epilepsy, mental retardation, and depend on parents and institutions for the activities of the daily living. The mechanisms of SGE are numerous and heterogeneous and the EEG findings usually reflect the age-related changes as the brain matures.