Associations Of FOXF2 Gene Polymorphisms With Ischemic Stroke In Chinese Han Population

Background and Purpose:Stroke has become the leading neurological cause of death and long-term disability worldwide.Recent studies have shown that genetic background is an important cause for the discrepancy in stroke susceptibility in populations with different ethnic and geographical backgrounds.Single nucleotide polymorphism mainly refers to the DNA sequence polymorphism caused by the variation of a single nucleotide at the genome level,which is the most common one among human heritable mutations.Ischemic stroke is an ischemic cerebrovascular disease caused by a complex interaction of environmental factors and genetic factors.In recent years,the number of the studies related to single nucleotide polymorphisms of ischemic stroke susceptibility has increased greatly.Recent Genome-wide Association Studies have suggested that the polymorphism of rs12204590,the SNP locus of the FOXF2gene,is associated with the risk of stroke in European populations.Furthermore,this gene encodes a forkhead transcription factor 2 and the functional defects are associated with the abnormalities of cerebral vascular pericyte differentiation,white matter hyperintensity,cerebral infarction and microbleed.Therefore,this case-control study intends to verify whether the above-mentioned site,rs12204590,is also associated with risk of ischemic stroke in Chinese Han population,and further search for novel loci of FOXF2 gene that might be associated with the increased risk of ischemic stroke and its major subtypes,and then raise our awareness of genetic risk factors for ischemic stroke and provide a basis for more comprehensive and accurate prevention.Methods:This study is a case-control study based on the ischemic stroke database of the Department of Neurology at the First Affiliated Hospital of Zhengzhou University.We extracted Chinese Han patients with ischemic stroke from July 2011 to March2016 as a case group,according to TOAST?Trial of Org 10172 In Acute Stroke Treatment?classification standard,the 803 patients in the case group were divided into LAA?large-artery atherosclerosis?subgroup and SAO?small-artery occlusion?subgroup.803 healthy adults matched with gender and age were selected as control group.Based on the International Genome Project?1000 Genomes Project,http://www.internationalgenome.org/?,screening conditions are set to determine the single nucleotide polymorphism?SNP?to be genotyped.The loci are:rs12204590,rs1711972,rs41300825,rs732835 and rs910023,they were genotyped by improved multiple Ligase Detection Reaction?iMLDR?technique and analyzed by SPSS 22.0software.The Goodness-of-fit?² test was used to verify whether the distribution of these genotypes in the sampling population was consistent with the Hardy-Weinberg?H-W?equilibrium.The quantitative and qualitative baseline data were compared between case and control groups by the Student t test and the Pearson?² test.Multivariate logistic regression was conducted to exclude traditional confounding factors and to explore whether the polymorphisms of these loci were related to the risk of ischemic stroke and its subtypes in Chinese Han population.Results:1.There was no significant difference in age,gender,the prevalences of dyslipidemia and smoking history between the case group and the control group?P>0.05?,but the proportions of hypertension and diabetes in the case group were significantly higher than those in the control group?P<0.001?.2.The genotypes of these loci in the control group conformed to Hardy-Weinberg equilibrium?P>0.05?,indicating that the genotype distribution was even and the subjects were representative.3.Genotyping was performed using iMLDR technology and verified by Sanger sequencing.The consistency rate of the two methods was 100%.4.The allele frequency of locus rs1711972?A>C?was significantly different between case and control group?P=0.014;OR=1.22;95%CI,1.04 to 1.42?.In the dominant-effect model,the polymorphism was associated with increased risk of ischemic stroke?CC/CA vs.AA,P=0.011;OR=1.34;95%CI,1.07 to 1.67?,carriers of CC/CA genotype were more likely to have a higher risk than those carrying AA.In the additive model,CA genotype is associated with increased risk of ischemic stroke?OR=1.35;95%CI,1.07 to 1.70?,but the results of Bonferroni corrections indicated that difference was not statistically significant(P^corr=0.019).5.In LAA subgroup analysis,the allele frequencies of rs1711972 are significantly different between case and control group?P=0.010;OR=1.34;95%CI,1.07 to 1.62?.The above differences were also found in locus rs41300825?P=0.033;OR=0.72;95%CI,0.53 to 0.98?.Genotype frequencies of rs1711972 are significantly different between case and control group?P=0.020?,CA genotype is related to an increased risk of LAA stroke?OR=1.50;95%CI,1.09 to 2.07?,and the result was still significant after Bonferroni correction(P^corr=0.008).In the dominant-effect model,the loci rs1711972?CC/CA vs.AA,P=0.010;OR=1.47;95%CI,1.09to 1.99?and rs41300825?CC/CG vs.GG,P=0.038;OR=0.68;95%CI,0.47 to0.98?are associated with LAA stroke susceptibility.6.Polymorphisms of loci rs1711972 and rs41300825 are not associated with the risk of SAO stroke?P>0.05?.The polymorphisms of rs12204590,rs732835,and rs910023 are not associated with the risk of ischemic stroke,LAA stroke and SAO stroke?P>0.05?.7.Linkage disequilibrium?LD?analysis revealed a block of LD,including three SNPs,rs41300825,rs732835,and rs910023?R²=0.831?.However,after adjusting for confounding factors,haplotype analysis showed no haplotype was associated with the risk of stroke.Conclusion:The rs1711972 polymorphism in FOXF2 gene is associated with the risk of ischemic stroke and LAA stroke in Chinese Han population.The rs41300825polymorphism is associated with the risk of LAA stroke,and there was no correlation between the remaining loci polymorphisms and susceptibilities to ischemic stroke.