Genetic causes of epilepsy

Background: The contribution of genetic factors to the origin of different epilepsies is a fact established by epidemiological, clinical, and molecular studies. These studies have made it possible to identify numerous mutations in different genes that cause or predispose to the development of certain types of epilepsy. Review Summary: The study of single-gene epilepsies has contributed relevant data regarding the pathophysiology of epilepsy. Most of these genes encode voltage- or ligand-gated ion channels. Other single-gene epilepsies are related to mutations that provoke alterations in neuronal maturation and migration during embryonic development. Nevertheless, the most common forms of epilepsy are not caused by single mutations but by a combination of polymorphisms, most of which are unknown, that generate an alteration in neuronal excitability. In some syndromes, genetic alterations and their consequences have made it possible to explain the therapeutic response to different drugs. Therefore, the progress being made in genetics is changing the classification and diagnosis of epilepsy; moreover, it can sometimes influence the choice of treatment. Conclusion: The advances made in genetic knowledge of epilepsy have led to the description of new epilepsy syndromes and to a better characterization of known ones. However, the genes responsible for the most common forms of idiopathic epilepsy remain mostly unknown. This means that for the time being, in clinical practice, genetic diagnosis is limited to uncommon syndromes and to cases in which treatment decisions or genetic counseling can be derived from the diagnosis.