Genetics of childhood epilepsy.

The epilepsies are a heterogeneous group of disorders with many causes. However, a genetic aetiology may be present in up to 40% of patients, and this proportion is even higher in epilepsy of childhood onset. The past decade has seen spectacular advances in our understanding of the genetics of epilepsy at a molecular level, and several comprehensive reviews are available. 3 It is apparent that epilepsy genes fall into several quite distinct classes including those in which mutations cause abnormal brain development, progressive neurodegeneration, disturbed energy metabolism, or dysfunction of ion channels. The discovery that several idiopathic mendelian epilepsies are caused by mutations in ion channels, including voltage gated potassium and sodium channels, is the most exciting advance because this might provide a clue to the cause of the more common idiopathic familial epilepsies. In this short review, the focus is on those mendelian childhood epilepsies for which genes have recently been identified, and non-mendelian epilepsies for which mapping data are available.