葡萄糖激酶基因6个标签单核苷酸多态性位点与2型糖尿病的相关性研究

Relationship between glucokinase gene 6 tag single nucleotide polymorphism sites and type 2 diabetes mellitns

目的探讨葡萄糖激酶（glucokinase，GCK）基因6个标签单核苷酸多态性（tagsingle—nucleotidepolymorphisms，tagSNPs）位点rs2971672、rs12702070、rs2268569、rs2268573、rs2300587、rsl476891与2型糖尿病（type2diabetes，T2D）的关系。方法病例对照研究。选取2013年8月至2014年12月在中山大学附属中山医院住院的中国南方汉族T2D患者499例（T2D组），同时选择在该院康体保健中心体检的汉族健康人499名作为对照组，对GCK基因的6个tagSNPs位点采用改良多重高温连接酶检测反应技术（improved multiple ligase detection reaction，iMLDR）进行基因分型，应用Hardy—Weinberg平衡规律检测样本代表性，采用x2检验、logistic回归分析比较T2D组和对照组基因型和等位基因频率的差异，并在加性、显性和隐性3种遗传模型下对各SNP位点进行相关性分析。应用Haploview软件构建GCK基因6个tagSNPs位点的单体型，分析是否存在连锁不平衡（linkage disequilibrium，LD）及不同的GCK单体型与T2D易感性的关系。结果rs2268573、rs2300587、rs2268569、rsl476891的基因型（x2值分别为3．361、2．076、0．582、0．918，P均〉0．05）和等位基因频率（x。值分别为0．222、1．980、0．590、0．851，P均〉0．05）在T2D组和对照组之间差异均无统计学意义。rs2971672和rs12702070的基因型（x。值分别为6．896、7．990，P均〈0．01）和等位基因分布（x。值分别为4．708、5．979，P〈0．05、P〈0．01）在D2M组和对照组之间差异有统计学意义。在显性遗传模式下（rs2971672：OR=1．74，95％C／=1．17—2．57，P〈0．01；rs12702070：OR=1．54，95％CI=1．17～2．04，P〈0．01）以及在加性遗传模式下（rs2971672：OR=1．51，95％C／=1．06～2．14，P〈0．05；rs12702070：OR=1．26，95％CI=1．04—1．52，P〈0．05）2个SNP位点的基因型分布在D2M组和对照组之间差异有统计学意义。GCK基因6个位点中的5个位点有两个LD域，rs2971672和rs2300587共存在TC、TA、CA三种主要单体型，单体型TA和CA均降低个体患T2D的风险，OR值分别为0．81（95％CI：0．66～1．00，P〈0．05）和0．78（95％CI：0．62～0．98，P〈0．05）。rs2268569、rs12702070和rs1476891共存在TAG、TGG、TAT、CGG四种主要单体型，均与个体患T2D的风险无相关性（X2=2．718，P〉0．05）。结论在汉族人群中，GCK基因区域的rs2971672和rs12702070位点与糖尿病遗传易感性密切相关，而rs2268573、rs2300587、rs2268569、rs1476891位点与糖尿病遗传易感性无明确相关性。rs2971672和rs2300587LD域单体型11A和CA均降低个体患T2D的风险；rs2268569、rs12702070、rs1476891LD域四种主要单体型均与个体患T2D的风险无相关性。

Objective To investigate the relationships between Glucokinase （GCK） gene 6 （tag single-nucleotide polymorphisms, tagSNPs ）sites which named rs12702070, rs2971672, rs2268569, rs2268573, rs2300587 and rs1476891 polymorphisms and type 2 diabetes in Chinese Southern Han Population. Methods This study was designed as a case-control. 499 type 2 diabetes patients and 499 healthy controls were chosen. All subjects were from August 2013 to December 2014 in Zhongshan Affiliated Hospital of Sun Yat-sen University. 6 GCK tagSNPs sites were analyzed by improved multiple ligase detection reaction （iMLDR） , and genotype and allele frequency between T2D group and healthy controls could be determined by chi-square test, logistic regression analysis, and tagSNPs were further analyzed under three genetic modes（dominant, recessive and additive）. What＇s more, Haploview software was used to construct the haplotype of 6 GCK tagSNPs and the linkage disequilibrium（LD） and relationship between various GCK haplotype and T2D susceptibility could be analyzed. Results Genotype distribution of rs2268573, rs2300587 ,rs2268569 and rs1476891 （Xz were 3. 361,2. 076,0. 582 and 0. 918 respectively, all P 〉0. 05 ） and allele frequency （ X2 were 0. 222,1. 980,0. 590 and 0. 851 respectively, all P 〉 0. 05 ） in T2D group were no significant differenees with health controls. Significant differences in genotype distribution of rs2971672 and rs12702070 （X2 were 6. 896 and 7. 990 respectively, all P 〈0. 01 ） and allele frequency （ X2 were 4. 708 and 5. 979, P 〈 0. 05 and P 〈 0. 01 respectively） were observed between T2D group and health controls. Under dominant model （ rs2971672： OR = 1.74, 95% CI = 1.17 - 2. 57, P 〈 0. 01 ; rs12702070 ： OR = 1.54,95 % CI = 1.17 - 2. 04, P 〈 0. 01 ） and additive model （ rs2971672 ： OR = 1.51,95 % CI=1.06 -2.14,P 〈0.05;rs12702070：OR = 1.26,95% CI = 1.04 - 1.52,P 〈0.05）, Genotype distribution of rs2971672 and rs2971672 in T2D were significantly different from health controls. There are two LD domains in 5 tagSNPs among those 6 sites of GCK gene. There are three main haplotypes（TC, TA, CA）in rs2971672 and rs2300587, and four main haplotypes （TAG, TGG, TAT, CGG）in Rs2268569, rs12702070 and rs1476891. Although TAG,TGG,TAT and CGG have no relevance to the individual risk of T2D（P 〉 0. 05 ）, haplotype TA and CA reduce the individual risk of T2D with OR O. 81 （95% CI： O. 66 - 1.00, P〈0.05） and 0.78 （95% CI： 0.62 -0.98, P〈0.01）respectively. Conelusions The results indicated that GCK gene 2 tagSNPs sites included rs2971672 and rs12702070 imparts susceptibility to T2D in Han Chinese, but not rs2268573, rs2300587, rs2268569 and rs1476891. Haplotype TA and CA in rs2971672 and rs2300587 reduce the individual risk of T2D and four main haplotypes （TAG, TGG, TAT, CGG） in rs2268569, rs12702070 and rs1476891 have no relevance to T2D.