Variants of the human NR1I2 (PXR) locus in chronic periodontitis

Abstract

Background and Objective: Recent studies on genetic variants of the pregnane X receptor (PXR) revealed associations with the mucosal immune response. This study aimed to investigate the potential association of functional polymorphisms of the NR1I2 (PXR)-encoding gene (rs12721602, rs3814055, rs1523128, rs1523127, rs45610735, rs6785049, rs2276707 and rs3814057) with chronic periodontitis. Material and Methods: At total of 402 periodontitis patients and 793 healthy individuals were genotyped using PCR and melting-curve analysis. Results: Frequency distribution of genotypes for the eight single nucleotide polymorphisms showed no significant difference between patients with periodontitis and controls. Among the eight tested polymorphisms, two blocks were defined showing complete or almost complete linkage disequilibrium (linkage disequilibrium block 1: rs3814055 and rs1523127; and linkage disequilibrium block 2: rs6785049, rs2276707 and rs3814057). For one haplotype (GTGAG) composed of rs12721602, rs3814055, rs1523128, rs12721607 and rs6785049, a significant association with periodontitis was found [p-value after permutation with 100,000 iterations (p permut.)=0.011, odds ratio = 0.46, 95% confidence interval: 0.25-0.84) following adjustment for age, gender and smoking. Conclusion: A rare haplotype of the NR1I2 (PXR) locus was associated with the individual susceptibility for chronic periodontitis in a German cohort. As a result of the borderline significance and the small effect size the present results need further confirmation. © 2011 John Wiley & Sons A/S.