Progress in the genetics of the partial epilepsies.

The importance of genetic contributions to the partial epilepsies is now well established. Evidence for this genetic contribution has come from familial aggregation studies, twin studies, positional cloning of specific genes that raise risk, and clinical descriptions of families. Familial aggregation studies are consistent in showing an increased risk of epilepsy in the relatives of patients with partial epilepsies that occur in the absence of environmental insults to the central nervous system. Susceptibility genes have been localized in five syndromes: autosomal dominant nocturnal frontal lobe epilepsy (20q, 1q, and 15q), autosomal dominant partial epilepsy with auditory features (10q), familial partial epilepsy with variable foci (22q), benign epilepsy of childhood with centrotemporal spikes (15q), and benign familial infantile convulsions (19q). In nocturnal frontal lobe epilepsy, the genes on chromosome 20q and 1q have been identified as subunits of the neuronal nicotinic acetylcholine receptor.