Association between ABCB1 C3435T polymorphism and drug-resistant epilepsy in Han Chinese.

There is accumulating evidence to suggest that overexpression of efflux drug transporters at the blood-brain barrier, by reducing antiepileptic drug (AED) accumulation in the seizure foci, contributes to drug resistance in epilepsy. P-glycoprotein, encoded by the ABCB1 gene, is the most studied drug transporter. There are conflicting data as to whether the CC genotype of the ABCB1 3435C>T polymorphism is associated with drug resistance in Caucasian patients with epilepsy. We investigated this association in ethnic Chinese. ABCB1 3435C>T was genotyped in 746 Han Chinese patients with epilepsy and 179 controls. Patients with drug-resistant epilepsy were more likely to have the TT genotype compared with those with drug-responsive epilepsy (16.7% vs 7.4%, odds ratio=2.5, 95% confidence interval=1.4-4.6, P=0.0009). Our results contrast with those of studies of Caucasians, and highlight the complexity of the possible role of this polymorphism in AED response in different ethnic populations.