【作者】 楚洁；

【导师】 董方田； 钟勇； 张美芬；

【作者基本信息】 中国协和医科大学 ， 眼科学， 2007， 博士

【摘要】 目的了解CFH、BF及HTRA1三种基因在中国汉族人群中的等位基因及基因型分布,探讨其单核苷酸多态性（Single Neucleotide Polymorphism,SNP）与渗出性年龄相关性黄斑变性（Age-related Macular Degeneration,AMD）易感性的关系,以及这三种基因与环境因素之间是否存在交互作用。方法采取年龄、性别和种族匹配的病例对照关联研究,选取有代表性的SNP位点:CFH基因（dbSNP:rs1061170和rs1410996）、BF基因（dbSNP:rs641153和rs4151667）、HTRA1基因（dbSNP:rs11200638）,通过PCR-RFLP法测定144例渗出性AMD患者和126例正常对照的各SNP基因型,探讨中国汉族人群中各SNP与渗出性AMD之间的关系,并采用非条件logistic回归模型进行环境因素的多因素分析以及基因与环境间交互作用的分析。结果病例对照组CFH Y402H危险等位基因C频率分别为12.5%和5.4%,显著低于高加索人群（P＜0.001）。Y402H多态性与AMD发病中等程度相关（OR=2.63,1.36-5.07）。与正常基因型个体相比,CT基因型与AMD患病显著相关（OR=3.23,1.36-5.07）,而CC基因型与AMD的关联无统计学显著性（OR=0.32,0.02-5.62）,C危险等位基因的人群归因危险（Population Attributable Risk,PAR）为3.3%（1.4-4.3%）。调整了CFH Y402H对疾病的影响后,rs1410996仍然与AMD发病显著相关:携带单拷贝危险等位基因的个体患病风险约增加2.24倍（1.04-4.79）,而携带双拷贝危险等位基因的个体约增加3.93倍（1.74-8.87）,PAR分别为28.3%（2.0-40.5%）和38.2%（21.8-45.4%）。BF rs641153与AMD发病无关联（OR=0.66,0.40-1.09）;BF rs4151667未发现多态性存在。HTRA1 rs11200638与AMD易感性显著相关（OR=2.24,1.57-3.20）。与携带正常基因型个体相比,杂合子基因型与AMD患病无关（OR=1.23,0.60-2.51）,而危险等位基因纯合子基因型与AMD患病显著相关（OR=3.98,1.88-8.43）,PAR为38.9%（24.3-45.8%）。多因素logistic回归分析结果发现3个变量最终进入模型,分别为吸烟情况、受教育程度和食用蛋类。曾经吸烟是AMD发病的强危险因素（OR=6.60,2.21-19.72）,高文化程度和经常食用蛋类是AMD的保护性因素,OR分别为0.17（0.08-0.37）和0.33（0.14-0.79）。基因与环境交互作用分析发现:在调整了其它环境因素及基因型后,吸烟与rs1410996存在交互作用,吸烟可使杂合子基因型个体患病风险大大增加(OR_交互=11.42,P_交互=0.029)。其它环境因素及基因型均独立与AMD相关。结论中国汉族人群中,CFH Y402H变异体与渗出性AMD易感性有关,但存在明显地种族差异,且CFH基因还可能存在其它的易感位点;HTRA1启动子多态性是较CFH Y402H更强危险性的遗传易感位点;BF基因R32Q、L9H变异体与渗出性AMD无关,提示存在种族差异。多种环境因素与AMD发病相关联,各基因与AMD发病独立相关,可修饰的环境因素如吸烟与易感基因间存在交互作用。更多还原

【Abstract】 Purpose:To assess the genotypic distribution of single neucleotide polymorphisms （SNPs） in CFH,BF and HTRA1 genes and their association with exudative AMD susceptibility in Han Chinese population.The interaction between environmental factors and genes were also evaluated.Methods:A case-control study with age,gender and ethnicity matched was conducted to genotype the representative SNPs loci including rs1061170 and rs1410996 in CFH,rs641153 and rs4151667 in BF and rs11200638 in HTRA1 gene in 144 exudative AMD patients and 126 normal controls using PCR-RFLP,and the relationships between SNPs and AMD were explored.The environmental factors for AMD and the interaction between environmental factors and CFH and HTRA1 genes were analyzed by multivariate unconditional logistic regression.Results:The C risk allele frequencies for CFH rs1061170（Y402H） in case and control groups were 12.5%and 5.4%respectively,which were much lower than those in Caucasian（P＜0.001）.Y402H polymorphism was moderately associated with AMD susceptibility（OR=2.63,1.36-5.07）.In contrast to homozygous genotype of non-risk allele,the heterozygous genotype of risk allele was positively associated with AMD with odds ratio of 3.23（1.36-5.07）.However,no association was found between the homozyous genotype of risk allele and exdutative AMD（probably because the frequency in Chinese population is too low to detect the association in our study）.The population attribute risk（PAR） of C risk allele was only 3.3%（1.4-4.3%）.Rs1410996 was also associated with AMD independent of Y402H.The ORs of exudative AMD for individuals carrying one copy risk allele and two copy risk alleles were 2.24 fold （1.04-4.79） and 3.93 fold（1.74-8.87） respectively,with correspondent PARs of 28.3% （2.0-40.5%） and 38.2%（21.8-45.4%）.Rs641153 in BF was not associated with AMD （OR 0.66（0.40-1.09））,and no polymorphism of Rs4151667 in BF was found in Han Chinese population.Rs11200638 in HTRA1 was a susceptible locus for AMD with odds ratio of 2.24（1.57-3.20）:although the heterozygous genotype was not associated with AMD,homozygotes of risk alleles were significantly susceptible for exedutie AMD（OR=3.98,1.88-8.43） with PAR of 38.9%（24.3-45.8%）.Three variables,namely smoking status,education status and egg intake were included in the final model using multiple logistic regression with stepwise backwards method.Ever smoking was a strong risk factor for AMD（OR=6.60,2.21-19.72）,while high education status and high egg intake were found to be protective factors for AMD with OR of 0.17 （0.08-0.37） and 0.33（0.14-0.79） respectively.The analysis of interaction between gene and environmental factors suggests:smoking synergisticly increased susceptibility of AMD for heterozygotes of intronic SNP rs1410996,with OR_interaction of 11.42(P_interaction =0.029).Other environmental factors and genotypes were all independent of AMD.Conclusion:In Han Chinese population,CFH Y402H variant is associated with exudative AMD,although the genotype distribution is significantly different from Caucasian.It is possible that other susceptibility loci in CFH are associated with AMD. The promoter polymorphism in HTRA1 gene is a stronger genetic susceptible locus of exudative AMD than CFH Y402H in Chinese population.R32Q and L9H variants in BF are not associated with AMD,which contradicts previous investigations in Caucasians.Various environmental factors are associated with AMD,and susceptible genes and environmental factors attribute independently to AMD.No interactions between selected genes are found,while sigarette smoking,a modifiable environmental factor,is interactive with genetic susceptible genes.更多还原