β细胞素基因-226A>G多态性与糖耐量减低人群的相关性研究

Association of betacellulin gene -226A>G polymorphism with impaired glucose tolerance

目的探讨β细胞素基因(BTC)-226A>G多态性与云南省昆明地区糖耐量减低人群的相关性。方法根据口服75 g葡萄糖耐量试验(OGTT)将1 076例云南省昆明地区人群分为糖耐量减低组(IGT)、2型糖尿病组(T2DM)和健康对照组(NGT),用稳态模型法胰岛素抵抗指数(HOMA-IR)、稳态模型法β细胞功能指数(HOMA-β)、早期胰岛素分泌指数(ΔI30/ΔG30)等进行组间比较。同时采集血样后提取基因组DNA,应用高分辨率熔解曲线分析方法(HRM)检测BTC基因-226A>G基因型,观察3组人群中基因型和等位基因的分布情况,同时分析糖耐量减低人群中不同基因型相关临床变量的差异性。结果①BTC基因-226A>GGG基因型及A等位基因在T2DM组中的频率分别为0.133和0.657,在IGT组中为0.085和0.715,差异均无统计学意义(P>0.05);G等位基因在T2DM组中为0.343,在IGT组中为0.285,两组之间差异具有统计学意义(P=0.041)。②IGT组-226位点AA基因型和AG+GG基因型的表型间的空腹血糖(FBG)、空腹胰岛素(Fins)、OGTT 2 h血糖(PBG)、OGTT 2 h胰岛素(PINS)、HOMA-IR、HOMA-β和ΔI30/ΔG30比较差异无统计学意义(P>0.05)。结论 BTC基因-226A>G多态性可能与云南省昆明地区人群糖耐量减低相关,推测含有G等位基因的糖耐量减低人群更易进展为T2DM。

[Objective] To investigate the association of betacellulin （BTC） gene-226A〉G single nu- cleotide polymorphism with impaired glucose tolerance in Kunming, Yunnan province. [Methods] 200 people with impaired glucose tolerance （IGT）, 430 patients with type 2 diabetes mellitus （T2DM） and 446 normal volunteers （NGT） were recruited in the study. All subjects received oral glucose tolerance test. Insulin resistance index （HOMA- IR）, 13 cell function index （HOMA-β） of Homa model, and the ratio of the increment of insulin to that of glucose at 30 mix after the glucose load （△I30/△G30） were applied to assess the status of IR and β cell function in these groups. Their blood specimens were collected to extract the genomie DNA. BTC gene-226A〉G were identified by high resolution melting and DNA direct sequencing. The distribution of genotype and allele in three groups were investigated. We also observed the association of clinic phenotype with two subsets in impaired glucose tolerance group. [Results] This study indicated that GG genotype and A allele frequencies of BTC gene-226A〉G variant were 0.133, 0.657 in T2DM group and 0.085, 0.715 in IGT group respectively （P〉 0.05）. G allele frequencies of -226A〉G polymorphisms show significant difference between two groups respectively （P =0.041）. Among 200 people with impaired glucose tolerance, there were no significant difference between the clinic phenotype of FBG, PBG, FINS, PINS, HOMA-IR, HOMA-13, △I30/△G30 and the genotype （P 〉0.05）. [Conclusion] BTC gene-226A〉G single nucleotide polymorphism is associated with impaired glucose tolerance in Kunming, Yunnan province. These results further suggest people carried with G allele in IGT group maybe have a higher probability of T2DM.