Epilepsy is a common, paroxysmal, and heterogeneous neurological disorder. Many factors, including complex genetic influences, contribute to the pathogenesis of epilepsy. However, several epilepsy syndromes are caused by mutations in single genes (Table 1). Most epilepsy-associated genes that have been identified within the past 5 years encode ion channels. This review illustrates the progress in defining the molecular basis of inherited epilepsies and highlights conditions caused by dysfunctional ion channels.
Ion channels may be broadly classified as voltage or ligand gated, depending on whether the primary stimulus for their activity is a change in local membrane potential or a chemical messenger (eg, neurotransmitter). The role of ion channels in neuronal excitability is well established, and the identification of mutations in neuronal ion channel genes linked to inherited epilepsy emphasizes the delicate balances that maintain electrical harmony in the central nervous system. These discoveries have also revealed new approaches to diagnosis and disease categorization, with the ultimate hope of new, gene-specific therapeutics.