Interleukin-1 beta gene polymorphism associated with radiographic knee osteoarthritis in Chinese

Abstract

Recently, the involvement of genetic factors for severe osteoarthritis (OA) has been widely reported. However, a lack of biomarkers that identify patients at risk complicates development of disease-modifying OA drugs. The purpose of this study was to identify polymorphisms at particular risk of osteoarthritis of the knee Chinese people. 481 participants were recruited. All control subjects were over 60 years. Severity of knee OA was evaluated by radiography. Cases (n = 300) were defined if Kellgren & Lawrence grade was 3-4, and controls (n = 181) were those in grade 0-1. Genotyping of these individuals were carried out by Sequenom. Interleukin-1 beta (IL1B) polymorphism was found to be associated with radiographic OA (ROA). Two SNPs (rs1143627 and rs16944) in high linkage disequilibrium (LD) upstream of the IL1B gene were found to be associated with ROA (Chi-square P-values = 0.009294 and 0.01012 respectively). Odds ratio (OR) for A allele of rs1143627 was 1.866, 95% confidence interval (95%CI) 0.2411 - 2.994. OR for G allele of rs16944 was 1.841, 95% CI 1.153 - 2.939. P-values for haplotype test for the SNPs were similar to single SNP test (0.009221), reflecting the high LD between the SNPs. Our results confirm the association of two SNPs in IL1B with ROA. An allele of rs1143627 and G allele of rs16944 were found to have significantly higher allele frequency in ROA cases than controls. The results indicate there is a possible role for IL1B played in the etiology of ROA.