IL-23R gene confers susceptibility to Behcet's disease in a Chinese Han population

Purpose IL-23 has been shown to be involved in the pathogenesis of Behcet's disease (BD) through promoting IL-17 production. This study examined whether IL-23R polymorphisms were associated with susceptibility to this disease in a Chinese Han population. Methods Four single-nucleotide polymorphisms (SNP), rs7517847, rs11209032, rs 1343151 and rs17375018 were genotyped in 338 BD patients and 407 age, sex and ethnically matched healthy controls using a PCR restriction fragment length polymorphism assay. Results A significantly increased prevalence of the homozygous rs17375018 GG genotype and G allele was found in BD patients compared with controls (corrected p (p(c)) <0.001, odds ratio (OR) 1.86, 95% CI 1.39 to 2.49; p(c)<0.001, OR 1.57, 95% CI 1.25 to 1.98, respectively). The frequencies of the AA genotype and A allele of the SNP rs11209032 were significantly higher in BD patients compared with controls (p(c) = 0.024, OR 1.69, 95% CI 1.21 to 2.35; p(c) < 0.001, OR 1.48, 95% CI 1.21 to 1.82, respectively). In addition, the results showed a significantly decreased frequency of the AGCG haplotype in BD patients compared with controls (p(c) = 0.0016, OR 0.59, 95% CI 0.45 to 0.77). Conclusions This study, for the first time, identified a strong association of an SNP of IL-23R, rs17375018, with BD. The results also suggested that both rs11209032 AA and rs17375018 GG of IL-23R are predisposing genotypes for BD and that the AGCG haplotype may provide protection against BD.