66034T/C polymorphism of the human pregnane X receptor (hPXR) as potential risk factor for drug resistance in epilepsy - Preliminary study

Abstract

Introduction and objectives: Recent research has suggested that genetic factors may play an important role in the development of drug resistance in epilepsy. It is not clear which gene loci are responsible for the drug-resistant phenotype. Studying certain nuclear receptors may be helpful in predicting drug response, as they regulate drug transporting proteins and enzymes involved in their metabolism. This study focuses on one of these receptors, the human pregnane X receptor (hPXR). The objective was to examine the link between selected single nucleotide polymorphisms (SNPs) 69789A/G rs 7643645 and 66034T/C rs 13059232 hPXR and the lack of response to epilepsy treatment.

Materials and methods: 73 patients diagnosed with drug-resistant epilepsy were included in the study. The diagnoses were made according to the criteria published by The International League Against Epilepsy (ILAE) in 2010. The control group was comprised of a group of 122 healthy volunteers. Genetic material isolated from the peripheral blood of the participants was analyzed with TagMan Genotyping Assays in search of the selected hPXR polymorphisms.

Results: The distribution of genotypes of the 66034T/C rs 13059232 hPXR polymorphism was significantly different in the group with drug-resistant epilepsy and the control group. In the drug-resistant group the CC genotype was significantly more common compared to the control group (50.7% vs 35.2%) p=0.0339. The distribution of 69789 A/G rs 7643645 hPXR genotypes was comparable in both groups.

Conclusions: There is potential association between hPXR and drug resistance but its relevance for the development of drug-resistant phenotype remains to be studied.

Keywords: Antiepileptic drugs; Drug resistant epilepsy; Human pregnane X receptor; Single nucleotide polymorphism.