[Association of Crohn's disease with aryl hydrocarbon receptor gene polymorphisms and haplotypes].

Objective: To explore the relationship of Crohn's disease (CD) susceptibility to aryl hydrocarbon receptor (AhR) polymorphisms and haplotypes in Han population in Wenzhou city, China. Methods: A total of 310 CD patients and 573 age- and sex-matched healthy controls were enrolled in our study. Three single nucleotide polymorphisms (SNPs) of AhR(rs10249788,rs2158041,rs2066853) were determined by the improved multiple ligase detection reaction technique. Unconditional logistic regression analyses was applied to analyze the allelic and genotypic differences of each SNP between CD patients and controls, as well as their influence on the clinicopathologic characteristics in CD patients. Analyses of linkage disequilibrium and haplotype were performed by Haploview 4.2 software in all study subjects. Results: Compared with the controls, the variant allele (T) and genotype (CT+TT) of (rs2158041) were evidently decreased among CD patients (19.52% vs. 25.04%, P= 0.009; 34.19% vs. 44.68%, P= 0.003). According to "the Montreal Classification Standards" , CD patients were divided into different subgroups. The variant allele (T) and genotype (CT+TT) of (rs2158041) were significantly lower in patients with terminal ileum CD than in controls (16.79% vs. 25.04%, P= 0.005; 28.24% vs. 44.68%, P= 0.001). Similar conclusions were also drawn in patients with constricting disease when compared with the controls (15.20% vs. 25.04%, P= 0.003; 28.43% vs. 44.68%, P= 0.003). The three SNPs above were shown to be in a linkage disequilibrium. Compared with the controls respectively, the frequency of haplotype (CCG) was increased in CD patients (44.73% vs. 39.60%, P= 0.039), whereas that of haplotype (CTG) was decreased (18.02% vs. 22.78%, P= 0.047). Conclusions: AhR (rs2158041) variation might influence the risk as well as the location and behavior of CD. The haplotype (CCG) possibly increase the risk of CD development, whereas haplotype (CTG) might decrease it.