Lack of association between ABCB1 gene polymorphisms and pharmacoresistant epilepsy: an analysis in a western Chinese pediatric population

Objective: The genetic polymorphisms of the ABCB1 (ATP-binding cassette B1) gene encoding P-glycoprotein have been proposed to be associated with pharmacoresistance phenotype in epilepsy patients. P-glycoprotein, a transmembrane transporter, works as an efflux pump by limiting antiepileptic drugs across the blood brain barrier, with correspondingly lowering drug concentrations in epileptogenic loci. In this study, we analyzed whether the three single nucleotide polymorphisms (C1236T, G2677T/A, and C3435T) in the ABCB1 gene were associated with pharmacoresistant epilepsy in a western Chinese pediatric population.

Methods: A total of 350 children with epilepsy who had been prescribed antiepileptic drugs for at least 1year were included. Of this patient group 193 were drug responsive and 157 were drug resistant according to the presence of seizures. Genotypes of the three loci of ABCB1 gene were detected in 368 age- and sex-matched normal children and 350 epileptic children using the polymerase chain reaction (PCR)-restriction fragment length polymorphism technique. Normal population sample populace from the same ethnicity and territory was genotyped to check for population stratification. The allele, genotype, haplotype, and diplotype frequencies of ABCB1 polymorphisms were compared between drug-resistant and drug-responsive subjects.

Results: No significant differences were observed in the frequencies of genotype, allele, haplotype, or diplotype of ABCB1 polymorphisms between patients with drug-resistant and drug-responsive epilepsy (p>0.05).

Conclusion: The above three polymorphisms in the ABCB1 gene were not found to be significantly associated with drug resistant epilepsy in a western Chinese pediatric population.