ABCB1 and epilepsy: Based on the hypothesis that ABCB1 genetic variants can modulate drug response phenotype in epilepsy, this study was carried out to assess the association of three SNPs of the ABCB1 gene, rs1128503 at exon 12, rs2032582 at exon 21, and rs1045642 at exon 26, and the drug response to ASMs in Saudi epileptic children.