The Association between Adenosine Triphosphate Binding Cassette B1 Cytosine 3435 Thymine Polymorphism and Pharmacoresistant Idiopathic Epilepsy: An Egyptian Study

Abstract

Background: P-glycoprotein (P-gp) is a drug efflux transporter present in the blood brain barrier whose function was suggested to be modified by a genetic polymorphism affecting ABCB1 C3435T gene at exon 26. Overexpression was related to homozygous C allele in some studies, however other studies in different ethnic populations showed relation to homozygous T allele, furthermore others failed to confirm any relation to resistance to therapeutic effects of AEDs. Aim of the study: Our aim is to find out the association between C3435T polymorphism and pharmacoresistance in idiopathic epilepsy in order to identify early the pharmacoresistant patients so we can select the proper AED and other proper therapeutic modalities. Patients and methods: Our case-control study was conducted on 44 idiopathic epileptic patients (22 drug-resistant and 22 drug-responsive epilepsy) and 44 healthy controls of comparable age and sex. Blood samples were obtained. Allele and genotype frequencies were evaluated between our study groups and their association with pharmacoresistance, some historical and semiology of epilepsy. Results: Our work revealed a lower risk of drug resistance in patients with the genotype CT (OR: 0.8) in comparison to genotypes CC and TT (OR: 1.2, 1 respectively) but the results were not statistically significant. However, significant association regarding daytime seizures was found with genotype CC in comparison to genotypes CT and TT. Conclusion: Daytime seizures were found to be more prevalent among those with CC genotype and this association was significant. The risk of drug resistant epilepsy was lower in patients with CT than those with CC and TT genotypes, but this association was not statistically significant in our study.