SCN1A and focal epilepsy: More recently, findings from a study of 1018 patients with mesial temporal lobe epilepsy with hippocampal sclerosis (a subtype of focal epilepsy) implicated the 2q24.3 region around the gene encoding the sodium channel SCN1A,14 and findings from an independent study of Han Chinese patients with known or suspected lesional focal epilepsy showed evidence for a risk allele at 1q32 on the basis of a discovery sample of 504 cases.15