The familial occurrence of epilepsy among 462 children with newly diagnosed multiple unprovoked seizures was studied at the Leiden University Medical Centre, and other hospitals in the Netherlands. Epilepsy was classified as generalized in 57% of the probands, localization-related in 42%, and undetermined in 1%. Compared to the total group, generalized epilepsies were more common (77%) and localization-related epilepsies less common (23%) in the 10% of cases found to be familial. Epilepsy occurred in 58 first-degree and 21 other relatives. The majority (83%) of first degree relatives with idiopathic or cryptogenic epilepsy had the same seizure type as the proband. 
COMMENT. Epilepsy is familial in 10% of newly diagnosed cases in childhood. Those with a positive family history are most likely to have generalized, idiopathic or cryptogenic seizures. The relatives of familial cases usually had the same seizure type as the newly diagnosed child. The role of genetic factors in the pathogenesis of idiopathic generalized childhood epilepsy is supported by this study.