Association between the polymorphisms in the ATP-binding cassette genes ABCB1 and ABCC2 and the risk of drug-resistant epilepsy in a Chinese Han population.

Epilepsy is a common disease of the nervous system; approximately 20-30% of all patients with epilepsy are reported resistant to antiepileptic drugs. ABCB1 and ABCC2 are members of ATP-binding cassette transporter (ABC) family that is involved in the excretion of antiepileptic drugs. In this case-control study, we have investigated the role of ABCB1 rs1045642 and rs2032582 and ABCC2 rs2273697 and rs717620 single nucleotide polymorphisms in antiepileptic drug-resistance in patients with epilepsy. A total of 254 patients with epilepsy (104 drug-resistant and 150 drug-responsive) were recruited from the People's Hospital of Wuhan University between March 2013 and April 2014. The correlation between the demographic, clinical, and genotypic characteristics of the patients and risk of drug resistance was statistically analyzed. Patients with drug-resistant epilepsy were more likely to present symptomatic epilepsy (χ(2) = 22.29, P < 0.001) compared to those with drug-responsive epilepsy. The TT genotype of the ABCB1 rs717620 polymorphism was associated with a higher risk of drug-resistant epilepsy compared to the CC genotype [odds ratio (OR) = 2.97, 95% confidence interval (CI) = 1.11-8.29]. The TT genotype of ABCB1 rs717620 was also related with an increased risk of drug-resistant epilepsy (OR = 2.64, 95%CI = 1.03-7.13) compared to the CC+CT genotype in the recessive model. Thus, our study suggests that the ABCC2 rs717620 polymorphism is associated with resistance to antiepileptic drugs in Chinese patients with epilepsy.