Association of rs12255372 in the TCF7L2 gene with type 2 diabetes mellitus: a meta-analysis

Association between Transcription Factor 7-like-2 Polymorphisms and Type 2 Diabetes Mellitus in a Ghanaian Population

Type 2 diabetes mellitus (T2DM) has been strongly associated with single nucleotide polymorphisms (SNPs) in the TCF7L2 gene. This study investigated the association between rs12255372, rs7903146 in the TCF7L2 gene and T2DM in a Ghanaian population. A case-control study design was used for this study. A total of 106 T2DM patients and 110 control participants were selected. Basic data collected included body mass index, blood pressure and socio-demographics. Fasting blood samples were collected and processed for: serum lipid analysis, plasma glucose estimation and plasma HbA1c estimation. Parts of the whole blood samples were used for DNA extraction using a modified salting-out method. Common and allele-specific primers were designed for genotyping using the Modified Tetra-Primer Amplification assay. Associations were evaluated using logistic regression models. The rs7903146 risk variant was significantly associated with 2.16 vs. 4.06 increased odds for T2DM in patients <60 years vs. ≥60 years. Both rs7903146 and rs12255372 were significantly associated with increased odds of T2DM in women, overweight/obese, T2DM negative family history (T2DM-NFH) and low-HDL-C. In a multivariate model, rs7903146 but not rs12255372 was significantly associated with 2.18, 5.01 and 2.25 increased odds of T2DM, under the codominant, recessive and additive model, respectively (p < 0.05). The association between rs7903146 and rs12255372 with T2DM is more highly associated in a subgroup—women and those with T2DM-NFH, yet who have cardiometabolic risk.

Mechanisms Underlying the Comorbidity of Schizophrenia and Type 2 Diabetes Mellitus

The mortality rate of patients with schizophrenia is high, and life expectancy is shorter by 10 to 20 years. Metabolic abnormalities including type 2 diabetes mellitus (T2DM) are among the main reasons. The prevalence of T2DM in patients with schizophrenia may be epidemiologically frequent because antipsychotics induce weight gain as a side effect and the cognitive dysfunction of patients with schizophrenia relates to a disordered lifestyle, poor diet, and low socioeconomic status. Apart from these common risk factors and risk factors unique to schizophrenia, accumulating evidence suggests the existence of common susceptibility genes between schizophrenia and T2DM. Functional proteins translated from common genetic susceptibility genes are known to regulate neuronal development in the brain and insulin in the pancreas through several common cascades. In this review, we discuss common susceptibility genes, functional cascades, and the relationship between schizophrenia and T2DM. Many genetic and epidemiological studies have reliably associated the comorbidity of schizophrenia and T2DM, and it is probably safe to think that common cascades and mechanisms suspected from common genes' functions are related to the onset of both schizophrenia and T2DM. On the other hand, even when genetic analyses are performed on a relatively large number of comorbid patients, the results are sometimes inconsistent, and susceptibility genes may carry only a low or moderate risk. We anticipate future directions in this field.

TCF7L2 polymorphisms, nut consumption, and the risk of metabolic syndrome: a prospective population based study

Background

The aim of this study was to investigate whether two variants of the TCF7L2 (rs7903146 and rs12255372) modify the association between nut consumption and the risk of metabolic syndrome (MetS). Additionally, the modifying effect of weight change during follow-up on these associations was investigated.

Material and methods

We prospectively studied 1423 participants of the Tehran Lipid and Glucose study aged 19–74 years who were followed-up for dietary assessment using a validated, semi-quantitative food frequency questionnaire. Multivariable-adjusted Cox regression was used to estimate hazard ratios (HRs) for MetS events. Genotyping was performed by Human Omni Express-24-v1-0 chip.

Results

Over a median 8.9 years of follow-up, 415 new cases of MetS were documented. The median nut consumption was 20.0 g/week (Interquartile Range (IQR): 8.6–38.9 g/week). Regarding the rs7903146 genotype, in carriers of T allele (CT + TT), highest tertile of nut consumption was associated with a reduced risk of MetS after adjusting for confounders (HR: 0.67 (0.50–0.91)). Regarding the rs12255372 genotype, highest versus lowest tertile of nut consumption in participants with T allele (GT + TT) resulted in 34% reduction of MetS risk after adjustment for confounders (HR: 0.66 (0.49–0.69)). After stratification by weigh change (< 7% or ≥ 7% weight gain), in individuals with ≥ 7% weight gain, highest tertile of nut consumption was associated with reduced risk of MetS among the risk allele of rs7903146. In the risk allele of rs12255372, among individuals with < 7% weight gain, third tertile of nuts intake reduced the risk of MetS, after adjustment for confounders.

Conclusion

Higher consumption of nuts may reduces the risk of MetS in T-risk allele of the TCF7L2 rs7903146 and rs12255372 variants and weight change may modify this association.

Functionality of Cricket and Mealworm Hydrolysates Generated after Pretreatment of Meals with High Hydrostatic Pressures

The low consumer acceptance to entomophagy in Western society remains the strongest barrier of this practice, despite these numerous advantages. More positively, it was demonstrated that the attractiveness of edible insects can be enhanced by the use of insect ingredients. Currently, insect ingredients are mainly used as filler agents due to their poor functional properties. Nevertheless, new research on insect ingredient functionalities is emerging to overcome these issues. Recently, high hydrostatic pressure processing has been used to improve the functional properties of proteins. The study described here evaluates the functional properties of two commercial insect meals (Gryllodes sigillatus and Tenebrio molitor) and their respective hydrolysates generated by Alcalase®, conventionally and after pressurization pretreatment of the insect meals. Regardless of the insect species and treatments, water binding capacity, foaming and gelation properties did not improve after enzymatic hydrolysis. The low emulsion properties after enzymatic hydrolysis were due to rapid instability of emulsion. The pretreatment of mealworm meal with pressurization probably induced protein denaturation and aggregation phenomena which lowered the degree of hydrolysis. As expected, enzymatic digestion (with and without pressurization) increased the solubility, reaching values close to 100%. The pretreatment of mealworm meal with pressure further improved its solubility compared to control hydrolysate, while pressurization pretreatment decreased the solubility of cricket meal. These results may be related to the impact of pressurization on protein structure and therefore to the generation of different peptide compositions and profiles. The oil binding capacity also improved after enzymatic hydrolysis, but further for pressure-treated mealworm hydrolysate. Despite the moderate effect of pretreatment by high hydrostatic pressures, insect protein hydrolysates demonstrated interesting functional properties which could potentially facilitate their use in the food industry.

Association between type 2 diabetes mellitus & TCF7L2 gene variants in the Emirati population: Genetics of diabetes in the United Arab Emirates

OBJECTIVE

Type 2 diabetes mellitus (T2DM) has a multifactorial etiology involving a complex interplay between genes and the environment. The prevalence of T2DM among the countries of the Gulf Corporation Council (GCC), including the United Arab Emirates (UAE), ranks among the top 15 in the world. A number of studies have shown an increase in T2DM risk for the "TT" genotype at the rs4506565 and rs12255372 Single Nucleotide Polymorphisms (SNP) of the TCF7L2 gene. However, the association between TCF7L2 and T2DM still needs to be investigated in the UAE population. Therefore, this study analyzed the potential associations with rs4506565 and rs12255372 in UAE subjects.

METHODS

For this case-control study, T2DM patients (n = 890) and healthy subjects (n = 686) were genotyped using a Taqman Real-Time PCR assay. Statistical analysis was performed with the resulting data using the R (version 3.3.1) and STATA (version 13) software packages.

RESULTS

The rs12255372 SNP was significantly associated with T2DM (OR = 1.16, 95% CI = 1.00-1.34; P = .042). However, no significant association was found for the rs4506565 SNP (P = .120). After gender stratification, a significant association was found for both SNPs in males (P_rs4506565 = .009 and P_rs12255372 = .021). Interestingly, we found the interaction between the SNP rs4506565 with gender alone (P = .032) and in conjunction with BMI and age (P = .036) confers associations with T2DM.

CONCLUSIONS

These findings suggest that the genetic variants of the TCF7L2 gene are associated with an increased susceptibility to T2DM, especially in Emirati males. Our study also highlights the impact of biological and environmental risk factors including age, BMI, and gender on the genetic susceptibility to T2DM.

Lack of association between TCF7L2 gene variants and type 2 diabetes mellitus in a Brazilian sample of patients with the risk for cardiovascular disease

OBJECTIVE

Genetic variants in the transcription factor 7-like 2 (TCF7L2) gene have been described as the most noteworthy ones regarding the type 2 diabetes mellitus (T2DM) liability. This work is aimed to evaluate the association between rs12255372 and rs7903146 polymorphisms and T2DM in patients with cardiovascular disease (CAD) risk.

METHODS

A sample of six hundred and forty-seven patients that underwent the coronary angiography in a Cardiac Catheterization Lab was evaluated. The patients were investigated for the presence of T2DM and coronary stenosis. The TCF7L2 polymorphisms were genotyped by real-time PCR and the haplotype analysis was performed with the MLOCUS software. All genetic tests were carried out by considering the haplotype combinations in patients divided into three groups: 0 - carrying none disease risk allele, 1 - carrying one or two risk alleles and 2 - carrying three or four risk alleles.

RESULTS

No significant associations between TCF7L2 risk haplotypes and the presence of T2DM or CAD were detected.

CONCLUSIONS

Our results indicate that the TCF7L2 rs12255372 and rs7903146 polymorphisms do not influence T2DM in Brazilian patients with the high risk for CAD. Therefore, we assume that these variants may only be relevant for a specific subgroup of T2DM patients or some particular human population.

Relationship of lactation, BMI, and rs12255372 TCF7L2 polymorphism on the conversion to type 2 diabetes mellitus in women with previous gestational diabetes

Women with previous gestational diabetes mellitus (pGDM) have a high risk of developing postpartum type 2 diabetes mellitus (T2DM). This study aimed to analyze the relationship between lactation, BMI, and TCF7L2 polymorphisms in the conversion to T2DM in women with pGDM. One hundred and fifty-three women con pGDM were recruited from public hospitals of León Guanajuato México. Three groups: normal glucose tolerance (NGT), impaired glucose intolerance (IGT), and T2DM after the oral glucose tolerance test were formed. Metabolic and hormone variables were measured, and genotyping was made by PCR-RFLP. The questionnaire included data on lactation (yes/no), duration of lactation, and full lactation. After 35 (21-49) months from the last partum, 54% of women had an NGT, 30.7% IGT, and 15% T2DM. BMI and rs12255372 are associated with the risk of conversion to IGT and T2DM [OR = 1.07 (95% IC 1.0-1.14, p = .041; OR =2.14, 95% IC 1.01-4.55, p = .04 respectively), while the lactation shows a strong protective effects OR = 0.15 (95% IC 0.062-0.39, p = .00007), and an apparent interaction with rs12255372T decreasing the risk in carriers (OR =2.15; 95% IC 0.97-4.7, p = .05). BMI is an independent risk factor of IGT/T2DM development. The lactation shows a strong protective effect and a possible interaction with rs12255372 polymorphism.

Targeted deletion of Tcf7l2 in adipocytes promotes adipocyte hypertrophy and impaired glucose metabolism

OBJECTIVE

Activation of the Wnt-signaling pathway is known to inhibit differentiation in adipocytes. However, there is a gap in our understanding of the transcriptional network regulated by components of the Wnt-signaling pathway during adipogenesis and in adipocytes during postnatal life. The key intracellular effectors of the Wnt-signaling pathway occur through TCF transcription factors such as TCF7L2 (transcription factor-7-like 2). Several genetic variants in proximity to TCF7L2 have been linked to type 2 diabetes through genome-wide association studies in various human populations. Our work aims to functionally characterize the adipocyte specific gene program regulated by TCF7L2 and understand how this program regulates metabolism.

METHODS

We generated Tcf7l2^F/F mice and assessed TCF7L2 function in isolated adipocytes and adipose specific knockout mice. ChIP-sequencing and RNA-sequencing was performed on the isolated adipocytes with control and TCF7L2 knockout cells. Adipose specific TCF7L2 knockout mice were challenged with high fat diet and assessed for body weight, glucose tolerance, and lipolysis.

RESULTS

Here we report that TCF7L2 regulates adipocyte size, endocrine function, and glucose metabolism. Tcf7l2 is highly expressed in white adipose tissue, and its expression is suppressed in genetic and diet-induced models of obesity. Genome-wide distribution of TCF7L2 binding and gene expression analysis in adipocytes suggests that TCF7L2 directly regulates genes implicated in cellular metabolism and cell cycle control. When challenged with a high-fat diet, conditional deletion of TCF7L2 in adipocytes led to impaired glucose tolerance, impaired insulin sensitivity, promoted weight gain, and increased adipose tissue mass. This was accompanied by reduced expression of triglyceride hydrolase, reduced fasting-induced free fatty acid release, and adipocyte hypertrophy in subcutaneous adipose tissue.

CONCLUSIONS

Together our studies support that TCF7L2 is a central transcriptional regulator of the adipocyte metabolic program by directly regulating the expression of genes involved in lipid and glucose metabolism.

Type 2 Diabetes-Associated Genetic Polymorphisms as Potential Disease Predictors

Diabetes is a major cause of mortality worldwide. There are several types of diabetes, with type 2 diabetes mellitus (T2DM) being the most common. Many factors, including environmental and genetic factors, are involved in the etiology of the disease. Numerous studies have reported the role of genetic polymorphisms in the initiation and development of T2DM. While genome-wide association studies have identified around more than 200 susceptibility loci, it remains unclear whether these loci are correlated with the pathophysiology of the disease. The present review aimed to elucidate the potential genetic mechanisms underlying T2DM. We found that some genetic polymorphisms were related to T2DM, either in the form of single-nucleotide polymorphisms or direct amino acid changes in proteins. These polymorphisms are potential predictors for the management of T2DM.

Association of TCF7L2 mutation and atypical diabetes in a Uruguayan population

AIM

To investigate if mutations in TCF7L2 are associated with “atypical diabetes” in the Uruguayan population.

METHODS

Healthy, nondiabetic controls (n = 133) and patients with type 2 diabetes (n = 177) were selected from among the presenting population at level-3 referral healthcare centers in Uruguay. Patients with type 2 diabetes were subgrouped according to “atypical diabetes” (n = 92) and “classical diabetes” (n = 85). Genotyping for the rs12255372 and rs7903146 single nucleotide polymorphisms (SNPs) in the TCFTL2 gene was carried out with TaqMan^® probes. Random samples were sequenced by Macrogen Ltd. (South Korea). Statistical analysis of the SNP data was carried out with the SNPStats online tool (http://bioinfo.iconcologia.net/SNPstats). The best inheritance model was chosen according to the lowest values of Akaike’s information criterion and Bayesian information criterion. Differences between groups were determined by unpaired t-tests after checking the normal distribution or were converted to normalize the data. The association of SNPs was tested for matched case-control samples by using χ² analysis and calculation of odds ratios (ORs) with 95% confidence intervals (CIs). All statistical tests were performed using SPSS v10.0 and EpiInfo7 statistical packages. Significant statistical differences were assumed in all cases showing adjusted P < 0.05.

RESULTS

We genotyped two TCF7L2 SNPs (rs7903146 and rs12255372) in a population-based sample of 310 Uruguayan subjects, including 133 healthy control subjects and 177 clinical diagnosed with type 2 diabetes. For both SNPs analyzed, the best model was the dominant type: rs12255372 = G/G vs G/T+T/T, OR = 0.63, 95%CI: 0.40-0.98, P < 0.05 and rs7903146 = C/C vs C/T+T/T, OR = 0.79, 95%CI: 0.41-1.55, P = 0.3. The rs12255372 SNP showed high association with the type 2 diabetes cases (OR = 1.60, 95%CI: 1.20-2.51, P < 0.05). However, when the type 2 diabetics group was analyzed according to the atypical and classical subgroupings, the association with diabetes existed only for rs12255372 and the classical subgroup (vs controls: OR = 2.1, 95%CI: 1.21-3.75, P < 0.05); no significant differences were found for either SNP or atypical diabetes.

CONCLUSION

This is the first time SNPs_TCF7L2 were genotyped in a diabetic population stratified by genotype instead of phenotype. Classical and atypical patients showed statistical differences.

Associations of common variants in the SLC16A11, TCF7L2, and ABCA1 genes with pediatric-onset type 2 diabetes and related glycemic traits in families: A case-control and case-parent trio study

BACKGROUND

There is evidence of associations of single-nucleotide polymorphisms (SNPs) with type 2 diabetes (T2D) and related glycemic traits in adults, but there is a little information about such associations in youths.

OBJECTIVE

The aim of this study was to evaluate the associations of SNPs in the TCF7L2, SLC16A11, and ABCA1 genes with T2D and related glycemic traits in Mexican children and adolescents.

SUBJECTS

A total of 99 families with children with T2D (n = 327) and 83 families with children without the disease (n = 212).

METHODS

The associations between SNPs of TCF7L2 (rs7903146 and rs12255372), SLC16A11 (rs13342232), and ABCA1 (rs9282541) with T2D were analyzed. We also evaluated the effects of SNPs on quantitatively related glycemic traits after adjusting for age, sex, and the presence of overweight or obesity.

RESULTS

The G allele of SLC16A1 /rs13342232 was associated with T2D in adults (adjusted odds ratio [ORadj] = 1.89; 95% confidence interval [CI]: 1.18; 3.06) and children (ORadj = 1.94; 95% CI: 1.25; 3.00). In addition, the combined analysis of case-control and case-parent trio was also significant (OR = 1.43; 95% CI: 1.12; 1.74). After adjusting for known confounding factors, we found a significant association between TCF7L2/rs122555372 and C-peptide (β = -0.76, P = .005) in patients with diabetes and between fasting glucose (β = 2.05, P = .039) and homeostatic model assessment of β-cell function (β = -32.14, P = .025) levels in individuals without diabetes.

CONCLUSIONS

The results suggest that SLC16A1 /rs13342232 might be involved in the risk of pediatric-onset T2D in Mexican families. Moreover, TCF7L2/rs122555372 was associated with pancreatic reserve in patients with T2D and with fasting glucose and β-cell function in individuals without diabetes.

Genetic variants in KCNJ11, TCF7L2 and HNF4A are associated with type 2 diabetes, BMI and dyslipidemia in families of Northeastern Mexico: A pilot study

The aim of the present study was to investigate whether genetic markers considered risk factors for metabolic syndromes, including dyslipidemia, obesity and type 2 diabetes mellitus (T2DM), can be applied to a Northeastern Mexican population. A total of 37 families were analyzed for 63 single nucleotide polymorphisms (SNPs), and the age, body mass index (BMI), glucose tolerance values and blood lipid levels, including those of cholesterol, low-density lipoprotein (LDL), very LDL (VLDL), high-density lipoprotein (HDL) and triglycerides were evaluated. Three genetic markers previously associated with metabolic syndromes were identified in the sample population, including KCNJ11, TCF7L2 and HNF4A. The KCNJ11 SNP rs5210 was associated with T2DM, the TCF7L2 SNP rs11196175 was associated with BMI and cholesterol and LDL levels, the TCF7L2 SNP rs12255372 was associated with BMI and HDL, VLDL and triglyceride levels, and the HNF4A SNP rs1885088 was associated with LDL levels (P<0.05).

Role of GNB3, NET, KCNJ11, TCF7L2 and GRL genes single nucleotide polymorphism in the risk prediction of type 2 diabetes mellitus

Type 2 diabetes (T2DM) is a polygenic metabolic disorder characterized by hyperglycemia occurring as a result of impaired insulin secretion or insulin resistance. Various environmental and genetic factors interact and increase the risk of T2DM and its complications. Among the various genetic factors associated with T2DM, single nucleotide polymorphism in different candidate genes have been studied intensively and the resulting genetic variants have been found to have either positive or negative association with T2DM thereby increasing or decreasing the risk of T2DM, respectively. In this review, we will focus on Guanine nucleotide-binding protein subunit beta 3 (GNB3), Norepinephrine Transporter (NET), Potassium Channel gene (KCNJ11), Transcription Factor 7-Like 2 (TCF7L2) and Glucocorticoid receptor (GRL) genes and their association with T2DM studied in different ethnic groups. The products of these genes are involved in the biochemical pathway leading to T2DM. Polymorphisms in these genes have been intensively studied in individuals of different ethnic origins. Results show that genetic variants of TCF7L2 and KCNJ11 genes have potential to emerge as a risk biomarker for T2DM whereas results of GNB3, GRL and NET genes have been controversial when studied in individuals of different ethnicities. We have tried to summarize the results generated globally in context to the selected genes which could possibly help researchers working in this field and would eventually help in understanding the mechanistic pathways of T2DM leading early diagnosis and prevention.

Association of polymorphism rs7903146 gene TCF7L2 with low concentrations of autoantibodies in latent autoimmune diabetes of adults (LADA)

Aim. To determine the frequencies of alleles and genotypes of polymorphic marker rs7903146 of the TCF7L2 gene in latent autoimmune diabetes in adults (LADA) and healthy individuals. The aims of the study were also to compare the distribution of alleles and genotypes and to explore the association with the development of LADA.Materials and methods. A total of 96 patients (46 females and 50 males) with LADA and 201 healthy individuals were examined. A quantitative determination of autoantibodies GADA, ICA, IA-2A and ZnT8 in the serum of LADA patients was performed. All patients underwent genotyping of rs7903146 of the TCF7L2 genes.Results. There was an increased frequency of the T allele and genotype T+ of marker rs7903146 of the TCF7L2 gene in patients with LADA with low concentrations of autoantibodies compared to a group of patients with high concentrations and with controls. We observed significant associations of the T allele and genotype T+ with LADA in patients with low concentrations of autoantibodies [p = 0.02; odds ratio (OR) = 1.85; 95% confidence interval (CI) = 1.10–3.13 and p = 0.04; OR = 2.14; 95% CI = 1.01–4.53 for the T allele and genotype T+, respectively).Conclusion. The results of the study suggest that LADA patients with low concentrations of autoantibodies have a genetically pre-determined similarity with patients with type 2 diabetes.

Association between the rs12255372 variant of the TCF7L2 gene and obesity in a Cameroonian population

BACKGROUND

The transcription factor 7-like 2 (TCF7L2) is one of the genes that have been identified as possible determinants of diabetes which is associated with obesity. Data on the genetic causes of obesity in sub-Saharan African populations are very scares. The aim of this study was to assess the association between the transcription factor 7-like 2 (TCF7L2) gene polymorphism (rs12255372 G/T) and obesity and weight-related traits in a Cameroonian population.

METHODS

A case-control study was conducted on 35 obese and 30 non-obese Cameroonian adults. TCF7L2 rs12255372 genotypes were determined using PCR-RFLP and correlated with BMI and weight-related traits.

RESULTS

No significant association was observed between the rs12255372 T allele (χ(2) = 0.0684, p = 0.79) or the TT genotype (χ(2) = 0.372, p = 0.54) of the TCF7L2 gene and obesity in the Cameroonian population. However, amongst the weight-related traits, triglycerides were significantly associated with the T risk allele of the TCF7L2 gene (p = 0.012).

CONCLUSION

This study on Cameroonian subjects replicates the absence of association between the TCF7L2 rs12255372 variant and obesity as observed in European and American populations.

Association between Genetic Variants and Diabetes Mellitus in Iranian Populations: A Systematic Review of Observational Studies

INTRODUCTION

Diabetes mellitus as the most prevalent metabolic disease is a multifactorial disease which is influenced by environmental and genetic factors. In this systematic review, we assessed the association between genetic variants and diabetes/its complications in studies with Iranian populations.

METHODS

Google Scholar, PubMed, Scopus, and Persian web databases were systematically searched up to January 2014. The search terms were "gene," "polymorphism," "diabetes," and "diabetic complications"; nephropathy, retinopathy, neuropathy, foot ulcer, and CAD (coronary artery diseases); and Persian equivalents. Animal studies, letters to editor, and in vitro studies were excluded.

RESULTS

Out of overall 3029 eligible articles, 88 articles were included. We found significant association between CTLA-4, IL-18, VDR, TAP2, IL-12, and CD4 genes and T1DM, HNFα and MODY, haptoglobin, paraoxonase, leptin, TCF7L2, calreticulin, ERα, PPAR-γ2, CXCL5, calpain-10, IRS-1 and 2, GSTM1, KCNJ11, eNOS, VDR, INSR, ACE, apoA-I, apo E, adiponectin, PTPN1, CETP, AT1R, resistin, MMP-3, BChE K, AT2R, SUMO4, IL-10, VEGF, MTHFR, and GSTM1 with T2DM or its complications.

DISCUSSION

We found some controversial results due to heterogeneity in ethnicity and genetic background. We thought genome wide association studies on large number of samples will be helpful in identifying diabetes susceptible genes as an alternative to studying individual candidate genes in Iranian populations.

Design of an allele-specific PCR assay to genotype the rs12255372 SNP in a pilot study of association between common TCF7L2 polymorphisms and type 2 diabetes in Venezuelans

OBJECTIVE

The global burden of diabetes mellitus will impact strongly American countries in the coming decades. Type 2 diabetes mellitus (T2DM) is a multifactorial disease and the basis for its genetic susceptibility remains not fully understood. Different population studies have demonstrated that variants of the TCF7L2 gene are strongly associated with an increased risk of T2DM. Moreover, institutions or countries with limited budget to conduct genetic research need cost effective methods for detecting DNA variants.

SUBJECTS AND METHODS

We standardized a rapid and simple allele-specific PCR method for genotyping the rs12255372 single nucleotide polymorphism (SNP) in a pilot study exploring the association of three TCF7L2 polymorphisms (rs7903146, rs12255372 and DG10S478) with T2DM in 70 patients and 73 controls from Venezuela.

RESULTS

The performance of the designed allele-specific PCR reaction for rs12255372 genotyping was reliable and accurate. Patients carrying the TCF7L2 rs7903146 T allele (CT + TT genotypes) and heterozygous CT genotype had a significantly higher risk for T2DM (OR = 2.9 and 2.3, respectively). Although rs12255372 and DG10S478 risk alleles predominated in T2DM group no statistical significance was found.

CONCLUSIONS

We developed a novel allele-specific PCR method for easier and rapid detection of rs12255372 polymorphism without the use of expensive instrumentation and reagents. Our study in a relatively small sample of the Venezuelan population replicated the association of the rs7903146 SNP with T2DM. Further studies with larger sample size and more biochemical data should be conducted to explore the genetic basis of T2DM susceptibility in Venezuela.