转录因子7样2与2型糖尿病

转录因子7样2(TCF7L2)基因是2型糖尿病最重要的易感基因之一,其基因变异体与2型糖尿病有强相关性,是目前2型糖尿病多因子遗传学领域中最引人注目的基因之一.这一结果在许多人种中都得以证实,而在我国关于该基因的研究刚刚起步.TCF7L2基因位于染色体10q25,共编码619个氨基酸,其产物是Wnt信号通路中一种转录因子.该因子通过对胰高血糖素样肽-1(GLP-1)水平调节,在糖代谢中起重要作用.另外,该信号通路与胰腺和胰岛的正常发育密切相关.     

Association of serine racemase gene variants with type 2 diabetes in the Chinese Han population

A genome‐wide association study in the Chinese Han population has identified several novel genetic variants of the serine racemase (SRR) gene in type 2 diabetes. Our purpose was to systematically evaluate the contribution of SRR variants in the Chinese Han population. rs391300 and rs4523957 in SRR were genotyped respectively in the two independent populations. A meta‐analysis was used to estimate the effects of SRR in 21,305 Chinese Han individuals. Associations between single‐nucleotide polymorphisms and diabetes‐related phenotypes were analyzed among 2,615 newly diagnosed type 2 diabetes patients and 5,029 controls. Neither rs391300 nor rs4523957 were associated with type 2 diabetes in populations. Furthermore, meta‐analysis did not confirm an association between type 2 diabetes and SRR. In the controls, rs391300‐A and rs4523957‐G were associated with higher 30‐min plasma glucose in an oral glucose tolerance test. The present study did not confirm that SRR was associated with type 2 diabetes.     

Association between a MIR499A polymorphism and diabetic neuropathy in type 2 diabetes

Aims

Diabetic polyneuropathy (DPN) and cardiovascular autonomic neuropathy (CAN) affect a large percentage of diabetic people and impact severely on quality of life. As it seems that miRNAs and their variations might play a role in these complications, we investigated whether the rs3746444 SNP in the MIR499A gene could be associated with susceptibility to DPN and/or CAN.

Agreement among type 2 diabetes linkage studies but a poor correlation with results from genome-wide association studies

Aims/hypothesis  Little of the genetic basis for type 2 diabetes has been explained, despite numerous genetic linkage studies and the discovery of multiple genes in genome-wide association (GWA) studies. To begin to resolve the genetic component of this disease, we searched for sites at which genetic results had been corroborated in different studies, in the expectation that replication among studies should direct us to the genomic locations of causative genes with more confidence than the results of individual studies. Methods  We have mapped the physical location of results from 83 linkage reports (for type 2 diabetes and diabetes precursor quantitative traits [QTs, e.g. plasma insulin levels]) and recent large GWA reports (for type 2 diabetes) onto the same human genome sequence to identify replicated results in diabetes genetic ‘hot spots’. Results  Genetic linkage has been found at least ten times at 18 different locations, and at least five times in 56 locations. All replication clusters contained study populations from more than one ethnic background and most contained results for both diabetes and QTs. There is no close relationship between the GWA results and linkage clusters, and the nine best replication clusters have no nearby GWA result. Conclusions/interpretation  Many of the genes for type 2 diabetes remain unidentified. This analysis identifies the broad location of yet to be identified genes on 6q, 1q, 18p, 2q, 20q, 17pq, 8p, 19q and 9q. The discrepancy between the linkage and GWA studies may be explained by the presence of multiple, uncommon, mildly deleterious polymorphisms scattered throughout the regulatory and coding regions of genes for type 2 diabetes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Association testing of common variants in the insulin receptor substrate-1 gene (IRS1) with type 2 diabetes

Aims/hypothesis Activation of the insulin receptor substrate-1 (IRS1) is a key initial step in the insulin signalling pathway. Despite several reports of association of the G972R polymorphism in its gene IRS1 with type 2 diabetes, we and others have not observed this association in well-powered samples. However, other nearby variants might account for the putative association signal. Subjects and methods We characterised the haplotype map of IRS1 and selected 20 markers designed to capture common variations in the region. We genotyped this comprehensive set of markers in several family-based and case-control samples of European descent totalling 12,129 subjects. Results In an initial sample of 2,235 North American and Polish case-control pairs, the minor allele of the rs934167 polymorphism showed nominal evidence of association with type 2 diabetes (odds ratio [OR] 1.25, 95% CI 1.03–1.51, p = 0.03). This association showed a trend in the same direction in 7,659 Scandinavian samples (OR 1.16, 95% CI 0.96–1.39, p = 0.059). The combined OR was 1.20 (p = 0.008), but statistical correction for the number of variants examined yielded a p value of 0.086. We detected no differences across rs934167 genotypes in insulin-related quantitative traits. Conclusions/interpretation Our data do not support an association of common variants in IRS1 with type 2 diabetes in populations of European descent. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users. D. Altshuler and L. Groop jointly supervised this project.     

转录因子7类似物2基因rs11196205多态性与安徽地区2型糖尿病及糖调节受损的相关性

目的 探讨转录因子7类似物2(TCF7L2)基因rs11196205位点多态性在安徽地区汉族人群中与2型糖尿病(T2DM)和糖调节受损(IGR)的相关性.方法 选取2009年1月至8月于安徽医科大学第一附属医院就诊的2型糖尿病患者300例、糖调节受损患者300例和糖耐量正常对照者(NGT)300名,收集临床资料和采集血样,测定生化指标并提取DNA;探针固定于芯片,PCR制备荧光标记靶基因与芯片杂交,扫描杂交结果;采用单因素方差分析及K-W检验统计分析rs11196205突变等位基因和基因型频率与T2DM及IGR发病的关系.结果 TCF7L2基因rs11196205位点等位基因频率[C在T2DM、IGR、NGT组频率分别为21%(126/600)、19%(114/600)、11%(68/600)]和基因型频率[GC+CC在T2DM、IGR、NGT组频率分别为41%(122/300)、37%(111/300)、22%(67/300)].T2DM与NGT、IGR与NGT、T2DM+IGR与NGT 3组比较差异均有统计学意义(P<0.05).携带突变等位基因C可增加罹患T2DM(OR=2.08,95%C1=1.51～2.86,X2=20.68,P<0.05)、IGR(OR=1.84,95%CI=1.33～2.54,X2=13.71,P<0.05)或任何一种(OR=1.96,95%CI=1.46～2.61,X2=21.18,P<0.05)的风险.与野生纯合基因型GG比较,体内携带一个以上突变基因C复本可增加罹患T2DM(OR:2.38,95%CI=1.67～3.40,X2=23.37,P<0.05)、IGR(OR=2.04,95%CI=1.43～2.92,X2=15.46,P<0.05)或任何一种(OR=2.21,95%CI=1.61～3.03,X2=24.50,P<0.05)的风险.结论 rs11196205位点G→C突变在安徽地区汉族人群中可能与T2DM和IGR关联,携带突变等位基因C可显著增加罹患T2DM和IGR的风险.     

A genetic variant of G6PC2 is associated with type 2 diabetes and fasting plasma glucose level in the Chinese population

Aims/hypothesis  Single nucleotide polymorphisms (SNPs) in G6PC2 have been reported to be associated with fasting plasma glucose level in several populations of European descent. However, whether G6PC2 variants have a similar effect in other ethnic groups is unknown. The aim of this study was to investigate the effect of common variants of G6PC2 on type 2 diabetes and related clinical features in a Chinese population. Methods  We selected four SNPs, rs13387347, rs2232316, rs492594 and rs16856187, tagging all the common variants spanning the G6PC2 gene (r ² ≥ 0.8) based on HapMap Chinese data, and genotyped them in a group of 3,676 Shanghai Chinese individuals, comprising 1,876 cases and 1,800 controls. Results  Three SNPs were nominally associated with type 2 diabetes, with rs16856187 showing the strongest evidence for association (p = 0.0009, empirical p = 0.0047). Further conditional analysis revealed that the association signal arose from an individual SNP, rs16856187. This SNP was also associated with fasting plasma glucose level in participants with normal glucose regulation (p = 0.0002), with the fasting plasma glucose level observed to increase by 0.067 mmol/l with each copy of the rare C allele. Conclusions/interpretation  In this study we identified a novel risk-conferring G6PC2 SNP for type 2 diabetes in a Chinese population and confirmed the previous finding that G6PC2 variants are associated with fasting plasma glucose concentration. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users. An erratum to this article can be found at     

Contribution of common variants of ENPP1, IGF2BP2, KCNJ11, MLXIPL,PPARγ, SLC30A8 and TCF7L2 to the risk of type 2 diabetes in Lebanese and Tunisian Arabs

BackgroundWhile several type 2 diabetes mellitus (T2DM) susceptibility loci identified through genome-wide association studies (GWAS) have been replicated in many populations, their association in Arabs has not been reported. For this reason, the present study looked at the contribution of ENNP1 (rs1044498), IGF2BP2 (rs1470579), KCNJ11 (rs5219), MLXIPL (rs7800944), PPARγ (rs1801282), SLC30A8 (rs13266634) and TCF7L2 (rs7903146) SNPs to the risk of T2DM in Lebanese and Tunisian Arabs.MethodsStudy subjects (case/controls) were Lebanese (751/918) and Tunisians (1470/838). Genotyping was carried out by the allelic discrimination method.ResultsIn Lebanese and Tunisians, neither ENNP1 nor MLXIPL was associated with T2DM, whereas TCF7L2 was significantly associated with an increased risk of T2DM in both the Lebanese [P < 0.001; OR (95% CI): 1.38 (1.20–1.59)] and Tunisians [P < 0.001; OR (95% CI): 1.36 (1.18–1.56)]. Differential associations of IGF2BP2, KCNJ11, PPARγ and SLC30A8 with T2DM were noted in the two populations. IGF2BP2 [P = 1.3 × 10^?5; OR (95% CI): 1.66 (1.42–1.94)] and PPARγ [P = 0.005; OR (95% CI): 1.41 (1.10–1.80)] were associated with T2DM in the Lebanese, but not Tunisians, while KCNJ11 [P = 8.0 × 10^?4; OR (95% CI): 1.27 (1.09–1.47)] and SLC30A8 [P = 1.6 × 10^?5; OR (95% CI): 1.37 (1.15–1.62)] were associated with T2DM in the Tunisians, but not Lebanese, after adjusting for gender and body mass index.ConclusionT2DM susceptibility loci SNPs identified through GWAS showed differential associations with T2DM in two Arab populations, thus further confirming the ethnic contributions of these variants to T2DM susceptibility.     

Heterogeneity in effects of genetically determined adiposity on insulin resistance and type 2 diabetes: The atherosclerosis risk in communities study

Background

A recent genome-wide association study has identified 12 genetic variants robustly associated with body fat percentage (BF%) with diverse cardiometabolic consequences. We developed three genetic risk scores (GRSs) according to the associations of the 12 individual variants with type 2 diabetes (T2D) and test the GRSs' associations with insulin resistance and T2D in the Atherosclerosis Risk in Communities Study.

Variations in KCNQ1 are associated with type 2 diabetes and beta cell function in a Chinese population

Aims/hypothesis  Recent genome-wide association studies in East Asian populations reported that single nucleotide polymorphisms (SNPs) in KCNQ1 are associated with type 2 diabetes. The aim of this study was to validate this finding in a Chinese population. Methods  We genotyped four SNPs, rs2074196, rs2237892, rs2237895 and rs2237897, in a group of 3,503 Shanghai Chinese individuals, comprising 1,769 type 2 diabetic patients and 1,734 normoglycaemic controls. Both the cases and the controls were extensively phenotyped for anthropometric and biochemical traits related to glucose metabolism. Arginine stimulation tests under fasting conditions were performed in a subgroup of 466 cases. Results  All four of the SNPs were associated with type 2 diabetes, with rs2237892 showing strongest evidence for association (OR 1.532, 95% CI 1.381–1.698, p = 5.0 × 10⁻¹⁶). The SNP rs2237897 was associated with both acute insulin and C-peptide response after arginine stimulation in a subgroup of cases (p = 0.0471 and p = 0.0156, respectively). The SNP rs2237895 was associated with both first- and second-phase insulin secretion in the controls (p = 0.0334 and p = 0.0002, respectively). Conclusions/interpretation  In this study we found that KCNQ1 was associated with type 2 diabetes susceptibility in a Chinese population, possibly through its effect on beta cell function. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Combined effects of single-nucleotide polymorphisms in GCK, GCKR, G6PC2 and MTNR1B on fasting plasma glucose and type 2 diabetes risk

Aims/hypothesis  Variation in fasting plasma glucose (FPG) within the normal range is a known risk factor for the development of type 2 diabetes. Several reports have shown that genetic variation in the genes for glucokinase (GCK), glucokinase regulatory protein (GCKR), islet-specific glucose 6 phosphatase catalytic subunit-related protein (G6PC2) and melatonin receptor type 1B (MTNR1B) is associated with FPG. In this study we examined whether these loci also contribute to type 2 diabetes susceptibility. Methods  A random selection from the Dutch New Hoorn Study was used for replication of the association with FGP (2,361 non-diabetic participants). For the genetic association study we extended the study sample with 2,628 participants with type 2 diabetes. Risk allele counting was used to calculate a four-gene risk allele score for each individual. Results  Variants of the GCK, G6PC2 and MTNR1B genes but not GCKR were associated with FPG (all, p ≤ 0.001; GCKR, p = 0.23). Combining these four genes in a risk allele score resulted in an increase of 0.05 mmol/l (0.04–0.07) per additional risk allele (p = 2 × 10⁻¹³). Furthermore, participants with less than three or more than five risk alleles showed significantly different type 2 diabetes susceptibility compared with the most common group with four risk alleles (OR 0.77 [0.65–0.93], p = 0.005 and OR 2.05 [1.50–2.80], p = 4 × 10⁻⁶ respectively). The age at diagnosis was also significantly associated with the number of risk alleles (p = 0.009). Conclusions  A combined risk allele score for single-nucleotide polymorphisms in four known FPG loci is significantly associated with FPG and HbA_1c in a Dutch population-based sample of non-diabetic participants. Carriers of low or high numbers of risk alleles show significantly different risks for type 2 diabetes compared with the reference group. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Association between rs13266634 C/T polymorphisms of solute carrier family 30 member 8 (SLC30A8) and type 2 diabetes, impaired glucose tolerance, type 1 diabetes--a meta-analysis

Aims

To investigate the association of solute carrier family 30 member 8 (SLC30A8) rs13266634 C/T polymorphism with type 2 diabetes (T2DM), impaired glucose tolerance (IGT), and type 1 diabetes (T1DM).

Methods

We searched all the publications about the association between SLC30A8 and diabetes from PubMed, and evaluated the association between SLC30A8 rs13266634 C/T polymorphism and T2DM, IGT and T1DM, respectively, by meta-analysis of all the validated studies. Allelic and genotypic comparisons between cases and controls were evaluated.

Results

Thirty six studies were included in the meta-analysis: 31 studies were analysed for rs13266634 C/T polymorphism with T2DM, 3 studies with IGT and 4 studies with T1DM. The pooled odds ratios (ORs) for allelic and genotypic comparisons (including additive model, co-dominant model, dominant model and recessive model) showed that rs13266634 C/T polymorphism was significantly associated with increased T2DM risk: OR = 1.15, 95% confidence interval (CI) = 1.13-1.17, P < 0.001, P_{heterogeneity} = 0.041, OR = 1.34, 95% CI = 1.26-1.41, P < 0.001, P_{heterogeneity} = 0.908, OR = 1.20, 95% CI = 1.16-1.24, P < 0.001, P_{heterogeneity} = 0.699, and OR = 1.23, 95% CI = 1.17-1.30, P < 0.001, P_{heterogeneity} = 0.801, respectively. In subgroup analyses, we found that rs13266634 C/T polymorphism was associated with T2DM risk both in Asian and European subgroup (P < 0.001), but not in African (P > 0.05). And the pooled odds ratio (OR) for allelic frequency comparison showed that rs13266634 C/T polymorphism was also significantly associated with IGT: OR = 1.15, 95% CI = 1.06-1.26, P < 0.001, P_{heterogeneity} = 0.364. Meanwhile, our meta-analysis did not suggest that rs13266634 C/T polymorphism was associated with T1DM risk (P > 0.05): OR = 1.02, 95% CI = 0.98-1.06, P = 0.328, P_{heterogeneity} = 0.488 for allelic frequency comparison.

Conclusions

Our meta-analysis results revealed the significant association between rs13266634 C/T polymorphism and T2DM and IGT, but did not support the association between this polymorphism and T1DM.     

Replication of the association between variants in WFS1 and risk of type 2 diabetes in European populations

Aims/hypothesis Mutations at the gene encoding wolframin (WFS1) cause Wolfram syndrome, a rare neurological condition. Associations between single nucleotide polymorphisms (SNPs) at WFS1 and type 2 diabetes have recently been reported. Thus, our aim was to replicate those associations in a northern Swedish case–control study of type 2 diabetes. We also performed a meta-analysis of published and previously unpublished data from Sweden, Finland and France, to obtain updated summary effect estimates. Methods Four WFS1 SNPs (rs10010131, rs6446482, rs752854 and rs734312 [H611R]) were genotyped in a type 2 diabetes case–control study (n = 1,296/1,412) of Swedish adults. Logistic regression was used to assess the association between each WFS1 SNP and type 2 diabetes, following adjustment for age, sex and BMI. We then performed a meta-analysis of 11 studies of type 2 diabetes, comprising up to 14,139 patients and 16,109 controls, to obtain a summary effect estimate for the WFS1 variants. Results In the northern Swedish study, the minor allele at rs752854 was associated with reduced type 2 diabetes risk [odds ratio (OR) 0.85, 95% CI 0.75–0.96, p = 0.010]. Borderline statistical associations were observed for the remaining SNPs. The meta-analysis of the four independent replication studies for SNP rs10010131 and correlated variants showed evidence for statistical association (OR 0.87, 95% CI 0.82–0.93, p = 4.5 × 10⁻⁵). In an updated meta-analysis of all 11 studies, strong evidence of statistical association was also observed (OR 0.89, 95% CI 0.86–0.92; p = 4.9 × 10⁻¹¹). Conclusions/interpretation In this study of WFS1 variants and type 2 diabetes risk, we have replicated the previously reported associations between SNPs at this locus and the risk of type 2 diabetes. An erratum to this article can be found at     

Common variants in the CLDN2-MORC4 and PRSS1-PRSS2 loci confer susceptibility to acute pancreatitis

Background/Objectives

Acute pancreatitis (AP) is one of the most common gastrointestinal disorders often requiring hospitalization. Frequent aetiologies are gallstones and alcohol abuse. In contrast to chronic pancreatitis (CP) few robust genetic associations have been described. Here we analysed whether common variants in the CLDN2-MORC4 and the PRSS1-PRSS2 locus that increase recurrent AP and CP risk associate with AP.

SLC30A8和PTPRD基因多态性与南京地区中老年人群2型糖尿病的相关性研究

目的 探讨溶质载体家族30/锌转运体,成员8(SLC30A8)基因(rs13266634和rs3802177)和蛋白酪氨酸磷酸酶受体D(PTPRD)基因(rs17584499)单核苷酸多态性与南京地区中老年人群2型糖尿病的相关性.方法 对南京地区40岁以上人群行75 g口服葡萄糖耐量试验及问卷调查,选取2型糖尿病1 758例(糖尿病组),正常对照1 970名(对照组),提取外周血基因组DNA,对其SLC30A8和PTPRD基因3个目标位点的基因型进行检测,分析与2型糖尿病的关系.结果 SLC30A8基因位点rs13266634在糖尿病组的基因型频率(CC、CT和TT)分别为35.9％、48.2％和15.9％,对照组为33.3％、48.8％和17.9％,糖尿病组C等位基因频率高于对照组(x2=3.986,P=0.046),C等位基因携带者患2型糖尿病的风险是T等位基因的1.158倍[优势比(OR)=1.158,P=0.005].位点rs3802177在糖尿病组的基因型频率(CC、CT和TT)分别为35.3％、48.2％和16.5％,对照组为32.1％、49.9％和18.0％,糖尿病组C等位基因频率高于对照组(x2=4.085,P =0.043),C等位基因携带者患2型糖尿病的风险是T等位基因的1.162倍(OR =1.162,P=0.004).PTPRD基因位点rs17584499在糖尿病组的基因型频率(CC、CT和TT)分别为81.9％、16.9％和1.2％,对照组为82.4％、16.5％和1.1％,两组基因频率分布无统计学差异(x2=0.274,P=0.600).结论 SLC30A8基因位点rs13266634和rs3802177的C等位基因可能是2型糖尿病的风险基因,与南京地区中老年人群2型糖尿病相关,未发现PTPRD基因(rs17584499)与本地区2型糖尿病相关.     

Strong association of common variants in the <Emphasis Type="Italic">CDKN2A/CDKN2B</Emphasis> region with type 2 diabetes in French Europids

Aims/hypothesis Genome-wide association studies (GWASs) recently identified common variants in the CDKN2A/CDKN2B region on chromosome 9p as being strongly associated with type 2 diabetes. Since these association signals were not picked up by the French-Canadian GWAS, we sought to replicate these findings in the French Europid population and to further characterise the susceptibility variants at this novel locus. Methods We genotyped 20 single nucleotide polymorphisms (SNPs) spanning the CDKN2A/CDKN2B locus in our type 2 diabetes case-control cohort. The association between CDKN2A/CDKN2B SNPs and quantitative metabolic traits was also examined in the normoglycaemic participants comprising the control cohort. Results We report replication of the strong association of rs10811661 with type 2 diabetes found in the GWASs (; OR 1.43 [95% CI 1.24–1.64]). The other CDKN2A/CDKN2B susceptibility variant, rs564398, did not attain statistical significance (p = 0.053; OR 1.11 [95% CI 1.00–1.24]) in the present study. We also obtained several additional nominal association signals (p < 0.05) at the CDKN2A/CDKN2B locus; however, only the rs3218018 result (p = 0.002) survived Bonferroni correction for multiple testing (adjusted p = 0.04). Conclusions/interpretation Our comprehensive association study of common variation spanning the CDKN2A/CDKN2B locus confirms the strong association between the distal susceptibility variant rs10811661 and type 2 diabetes in the French population. Further genetic and functional studies are required to identify the aetiological variants at this locus and determine the cellular and physiological mechanisms by which they act to modulate type 2 diabetes susceptibility. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users. K. Duesing and G. Fatemifar contributed equally to this work.