During the last two decades, the molecular revolution in medicine has had a strong impact in the field of epilepsies. The quest for epilepsy-genes has been focused mainly on large mendelian pedigrees. This approach has allowed the identification of new causative genes and has provided new information about the pathogenesis of many epilepsy syndromes. Neverthless, the clinical implication of this information still has a relatively little impact on the genetic counselling for most of the syndromes.