Six of these studies, genotyping either ABCB1 3435 or the common haplotype combination, ABCB1 3435C>T-2677G>T-1236C>T, confirmed the association between the 3435 SNP or the three-SNP haplotype (containing the 3435 SNP) and AED-resistant epilepsy. Here, ABCB1 is linked to epilepsy.