[Association between single nucleotide polymorphisms in Wnk1 gene and ischemic stroke in Chinese Han population]

To investigate the association between single nucleotide polymorphisms (SNPs) in Wnk1 gene and ischemic stroke in Chinese Han population.

A hospital-based case-control study was carried out. The ischemic stroke group included 294 Chinese Han subjects, who were admitted with non-fatal ischemic stroke in departments of neurology of 5 hospitals in Xinjiang during January 2008 through December 2009. Control group included 314 age and sex-matched Han subjects without an inquired history of stroke, hospitalized in departments of surgery of these 5 hospitals. Ten tagging SNPs (tSNPs) of the Wnk1 gene were genotyped, and the association between these tSNPs and ischemic stroke were evaluated. The tSNPs (rs3858703, rs11611246, rs7305065, rs1990021, rs34408667, rs12309274, rs1012729, rs956868, rs12828016 and rs953361) were determined by the Multiplex SNaPshot platform. The data were analyzed by using t-test, Ξ2-test and logistic regression. Linkage disequilibrium and haplotype were analyzed by Haploview software.

The rates of alcohol drinking, hypertension ,diabetes and hyperlipidemia in ischemic stroke group were higher than those in control group (37.1% vs 21.0%, 62.9% vs 36.6%, 18.0% vs 6.1% and 36.4% vs 17.5%, respectively, all P<0.01). No significant difference in smoking rate was found between two groups. The genotyping loss rates of all sites were less than 1%. All the tSNPs were examined by Hardy-Weinberg equilibrium test except rs34408667. tSNP rs11611246 in the 4th intron of the Wnk1 gene was significantly associated with ischemic stroke. The distribution frequency of T allele in cases was significantly lower than that in male controls (30.3% vs 35.7%, P =0.046). When the samples were further stratified according to gender, rs11611246 was found to be associated with a reduced risk of ischemic stroke in male cases than in controls. GT and TT genotype frequencies were 43.3% and 7.2% in male cases, 43.1% and 15.2% in male controls, respectively (P=0.038). The T allele was associated with a reduced risk of ischemic stroke, with a per-allele OR of 0.702(95%CI:0.517-0.953, P=0.023) in male cases than in male controls. The significance remained after adjusting the covariates of age (P=0.022), or the covariates of age, BMI, cigarette smoking, alcohol drinking, hypertension, diabetes and hyperlipidemia (P=0.008). No association between other 9 tSNPs and ischemic stroke was noted in Chinese Han subjects.

The polymorphism of rs11611246 on the 4th intron of Wnk1 gene is associated with a reduced risk of ischemic stroke in Chinese Han population and the T allele might be a protective factor for ischemic stroke in male Chinese Hans.