Abstracts

There is conflicting data whether CC genotype of the C3435T single nucleotide polymorphism (SNP) of the ABCB1 gene is associated with multi-drug resistance in Caucasian epilepsy patients. There is wide ethnic variation in the genotype frequencies of this SNP. We investigated whether the association might be observed in ethnic Chinese., [italic]ABCB1[/italic] 3435 was genotyped in 518 Chinese patients with epilepsy, classified as drug resistant in 221 and drug responsive in 279, and 179 control subjects without epilepsy. Phenotypic definitions were similar to previous studies in Caucasian subjects. Drug resistance was defined as at least 1 seizure per month despite treatment with 2 or more antiepileptic drugs, and drug responsive as seizure free for at least 1 year on treatment. Genotype was carried out by polymerase chain reaction-restriction fragment length polymorphism assays., As compared with patients with drug responsive epilepsy, patients with drug resistant epilepsy were more likely to have the TT genotype at [italic]ABCB1[/italic] 3435 than CT or CC genotypes (odds ratio 2.2, 95% confidence interval 1.2 [ndash] 4.1, p=0.004). The frequency of CC genotype was similar between patients with drug resistant and drug responsive epilepsy. There was no difference in genotype frequencies between the control subjects and the two patient groups., In Chinese patients with epilepsy, ABCB1 3435TT was found to be associated with drug resistance. The results contradict those reported in Caucasian subjects, and highlight the complexity of the potential role of ABCB1 3435 SNP in the pathogenesis of drug resistant epilepsy., (Supported by: Partially supported by the HKU Small Project Funding.)