Polymorphism of IL6 receptor gene is associated with ischaemic stroke in patients with metabolic syndrome

Abstract The interleukin 6 receptor (IL6R) gene has been shown to locate in the chromosome 1q21 associated with metabolic syndrome (MetS), a condition related to the augmented risk of ischaemic stroke (IS), cardiovascular diseases and all-cause mortality. The aim of this study was to assess the relationship between IL6R gene polymorphisms and IS in patients with MetS in the Chinese Han population. We designed a case-control study enrolling 447 patients with MetS plus IS and 438 patients with MetS alone. Tag single nucleotide polymorphisms (SNPs) of the IL6R gene were determined by a fine-mapping strategy and genotyped using SNPscan technology. A logistic regression model was used to analzse the associations between the genetic variations in IL6R and the risk of IS in MetS patients. The linkage disequilibrium (LD) analysis was performed and four gamete rules were used to define the block. The haplotypes was reconstructed by the SNPstats software. Two SNPs were significantly related to the risk of IS in MetS patients after adjusting for potential confounders as follows: regarding rs12083537, the GG genotype and the GA genotype decreased the risk of IS in the MetS patients compared with the IS risk in the patients with the AA genotype (multivariate-adjusted, P = 0.005); and regarding rs8192284, the CC genotype and the AC genotype decreased the risk of IS compared with the IS risk in the patients with the AA genotype (multivariate-adjusted, P = 0.004). Strong LD was existed in block 2 and the haplotype analysis showed that compared with the ACCG haplotype, the ATCT haplotype (adjusted OR 1.700; 95% CI 1.246–2.319; P = 0.001) increased the risk of IS in the MetS patients. The analysis of the SNP-SNP interactions showed that rs8192284 was the most influential contributor to the risk of IS in the MetS patients. Our results indicate that rs12083537 and rs8192284 in the IL6R gene might be related to the risk of IS in MetS patients.