Summary: Progress in understanding the genetics of epilepsy is proceeding at a dizzying pace. Due in large part to rapid progress in molecular genetics, gene defects underlying many of the inherited epilepsies have been mapped, and several more are likely to be added each year. In this review, we summarize the available information on the genetic basis of human epilepsies and epilepsy syndromes, and correlate these advances with rapidly expanding information about the mechanisms of epilepsy gained from both spontaneous and transgenic animal models. We also provide practical suggestions for clinicians confronted with families in which multiple members are afflicted with epilepsy. Key Words: Epilepsy-GeneticsHuman-Pathophysiology-Animal models.Over the past few years, there has been an explosion of information about the genetic basis of epilepsy and epilepsy syndromes. Some of these advances have been documented in recent reviews (1-6). In parallei with advances in understanding the genetics of human epilepsies, several spontaneous and transgenic animal models of inherited epilepsy have been produced. These approaches will expand our ability to dissect cellular mechanisms of seizure generation and propagation and help us to move from serendipity to rationality in designing targeted therapies for seizure disorders (7,8). In this review we summarize the recent progress in mapping genes for human epilepsy, describe some relevant animal models of genetic epilepsy, and examine the relation between gene defects and the cellular mechanisms of epilepsy. Finally, we provide practical suggestions for clinicians caring for patients and families with inherited epilepsies. Clinical details of the various epilepsy syndromes, available elsewhere, are largely omitted here.Epilepsy, characterized by recurrent seizures, results from excessive synchronous firing of neurons in cortical networks. A number of intricately linked mechanisms at the network, cellular, subcellular, and molecular levels