Association Study Between Interleukin-1 Gene Cluster Single Nucleotide Polymorphism With As In Anhui Han Population

Objective The aim of our study is to investigate the association between the single nucleotide polymorphisms of IL-1F5–F10 genes, the relatively newly discovered genes of interleukin-1 gene cluster, and susceptibility to ankylosing spondylitis (AS). That may help exploring the genetic etiology of AS.Methods 161 B27-positive cases with ankylosing spondylitis were selected from the first affiliated hospital of Anhui Medical University during 2007 to 2009. 181 individuals of healthy blood donors and healthy people from physical examination were selected as controls during the same period. Seven functional single nucleotide polymorphism loci in different exon regions of IL-1F5–F10 genes were analyzed using a ligase detection reaction way based on high temperature ligase. The distribution of the SNPs'genotypes and allele frequencies were detected between the two groups.Results The rate of HLA-B27-positive individuals in cases is 92.5%. Five subtypes were found. They are B2702, B2704, B2705, B2710 and B2715, respectively. B2704 got the highest rate (51.55%), the next is B2705(43.48%). In cases, genotype AA, AG and GG frequencies of SNP rs3811047 in the IL-1F7 gene exon 2 were respectively 0, 24.1% and 75.9%, but 2.8%, 29.8% and 69.4% in controls. There was a significant difference in the distribution between the two groups (P < 0.05), and G allele frequency in case group were significantly higher (P < 0.05, OR = 1.57, 95% CI 1.02–2.42). The SNP rs28938777 is in IL-1F5 gene exon 4 and the genotype AA, AG, and GG frequencies in case group were respectively 88.4%, 11.6% and 0, in comparison of 89.7%, 10.3% and 0 in the control group. No significant differences of the distribution were found. The SNPs rs6743376 and rs6761276 are in IL-1F10 gene. In the case group and the control group, A allele frequency of rs6761376 locus were 74.2% and71.6%. C allele frequency were 25.8% and 28.4%.C Allele frequency of rs6761276 locus were 21.1% and 18.0%, and T allele frequency were 78.9% and 82.0%. There were no significant differences between the two groups either( both P > 0.05 ). The distribution of genotypes between the two groups also had no significant difference. SNPs rs895497, rs2723187, and rs6707930 in respectively F6, F7 and F9 gene were found no gene polymorphism. They all got the CC genotype.Conclusion The rate of HLA-B27-positive individuals in cases is 92.5%. Five subtypes were found. They are B2702, B2704, B2705, B2710 and B2715, respectively. The six relatively newly discovered genes of Interleukin-1 gene cluster has functional SNP loci that associated with susceptibility to ankylosing spondylitis in Anhui Han population. SNP rs3811047 of the IL-1F7 gene is associated with AS. Other detected SNPs were not associated with susceptibility to AS.