Association analysis of a polymorphism of MDR1 Gene and refractory temporal lobe epilepsy in a Chinese population

Background and Objective: Although pharmacoresistance is almost certainly due to several factors, the family of multidrug transporter proteins are likely to play a prominent role in this phenomenon given the often observed broad resistance to all antiepileptic drugs despite their different modes of action. Evidence suggests that the homozygous C-variant, which is associated with higher expression and increased activity of P-gp, is more common in patients with pharmocoresistent epilepsy.1 In addition, recent studies showed high-degree linkage disequilibrium among C1236T-G2677T-C3435T, homozygous carriers of the CGC haplotype in exons 12, 21 and 26 were found to exhibit higher pharmacoresistance in patients with epilepsy.2 We investigated the prevalence of those polymorphisms in a population of China, and the association with pharmacoresistance in temporal lobe epilepsy (TLE). Methods: The study consisted of 154 outpatients diagnosed with TLE who visited the Hakuai Epilepsy Center in Peking Union Medical College Hospital from December 2000 to Jan 2006. All patients had used several suitable AEDs over 12 consecutive months. We stratified patients for whom average seizure frequencies could be reliably assessed into “Drug-resistant group ” (n = 80, mean age at the time of the study was 32.6 ± 8.7 years, mean duration of epilepsy was 15.3 ± 7.5 years) and “Drug-responsive group ” (n = 74, mean age at the time of the study was 32.2 ± 9.7 years, mean duration o