Non-Association between rs7903146 and rs12255372 Polymorphisms in Transcription Factor 7-Like 2 Gene and Type 2 Diabetes Mellitus in Jahrom City, Iran

Genetic Predisposition to Prediabetes in the Kazakh Population

The aim of this study was to conduct a comparative analysis of the population frequencies of the minor allele of polymorphic variants in the genes TCF7L2 (rs7903146) and PPARG (rs1801282), based on the genome-wide association studies analysis data associated with the risk of developing prediabetes, in an ethnically homogeneous Kazakh population compared to previously studied populations worldwide. This study utilized a genomic database consisting of 1800 ethnically Kazakh individuals who were considered in healthy condition. Whole-genome genotyping was performed using Illumina OmniChip 2.5-8 arrays, which interrogated approximately 2.5 million single nucleotide polymorphisms. The distribution of genotypes for the TCF7L2 (rs7903146) and PPARG (rs1801282) polymorphisms in the Kazakh sample was found to be in Hardy-Weinberg equilibrium (p > 0.05). The minor G allele of the "Asian" protective polymorphism rs1801282 in the PPARG gene was observed at a frequency of 13.8% in the Kazakh population. This suggests a potentially more significant protective effect of this polymorphism in reducing the risk of prediabetes among Kazakhs. The frequency of the unfavorable T allele of the insulin secretion-disrupting gene TCF7L2 (rs7903146) in Kazakhs was 15.2%. Studying the associations of genetic markers for prediabetes enables the timely identification of "high-risk groups" and facilitates the implementation of effective preventive measures. Further results from replicative genomic research will help identify significant polymorphic variants of genes underlying the alteration of prediabetes status.

Association between OX40L polymorphism and type 2 diabetes mellitus in Iranians

INTRODUCTION

Diabetes mellitus (DM) is one of the leading causes of morbidity and mortality worldwide. It is a multifactorial disease that genetic and environmental factors contribute to its development. The aim of the study was to investigate the association of OX40L promoter gene polymorphisms with type 2 diabetes mellitus (T2DM) in Iranians.

MATERIALS AND METHODS

Three hundred and sixty-eight subjects including 184 healthy subjects and 184 T2DM patients were enrolled in our study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was applied to detect genotype and allele frequencies of rs3850641, rs1234313 and rs10912580. In addition, SNPStats web tool was applied to estimate haplotype frequency and linkage disequilibrium (LD).

RESULTS

The distribution of tested polymorphisms was statistically different between the T2DM patients and healthy subjects (P < 0.01). rs1234313 AG (OR = 0.375, 95% CI = 0.193-0.727, P = 0.004) and rs10912580 AG (OR = 0.351, 95% CI = 0.162-0.758, P = 0.008) genotypes were associated with the decreased risk of T2DM in Iranians. Moreover, our prediction revealed that AAG (OR = 0.46, 95% CI= (0.28-0.76), P = 0.0028) and GAG (OR = 0.24, 95% CI= (0.13-0.45), P < 0.0001) haplotypes were related to the reduced risk of the disease. However, the tested polymorphisms had no effect on biochemical parameters and body mass index (BMI) in the patient group (P > 0.05).

CONCLUSION

Our findings revealed that OX40L promoter gene polymorphisms are associated with T2DM. Moreover, genotype and allelic variations were related to the decreased risk of T2DM in Iranians. Further studies are recommended to show whether these polymorphic variations could affect OX40/OX40L interaction or OX40L phenotype.

Metabolic and genetic risk factors associated with pre-diabetes and type 2 diabetes in Thai healthcare employees: A long-term study from the Siriraj Health (SIH) cohort study

BACKGROUND

The study of non-communicable diseases (NCDs) in a developing country like Thailand has rarely been conducted in long-term cohorts, especially among the working-age population. We aim to assess the prevalence and incidence of risk factors and their associations underlying NCDs, especially type-2 diabetes mellitus (T2DM) among healthcare workers enrolled in the Siriraj Health (SIH) study cohort.

METHODS

The SIH study was designed as a longitudinal cohort and conducted at Siriraj hospital, Thailand. A total of 5,011 participants (77% women) were recruited and follow-up. Physical examinations, blood biochemical analyses, family history assessments, behavior evaluations, and genetics factors were assessed.

RESULTS

The average age was 35.44±8.24 years and 51% of participants were overweight and obese. We observed that men were more likely to have a prevalence of T2DM and dyslipidemia (DLP) compared to women. Aging was significantly associated with pre-diabetes and T2DM (P<0.001). Additionally, aging, metabolic syndrome, and elevated triglycerides were associated with the development of pre-diabetes and T2DM. The minor T allele of the rs7903146(C/T) and rs4506565 (A/T) were associated with a high risk of developing pre-diabetes with odds ratios of 2.74 (95% confidence interval [CI]: 0.32-23.3) and 2.71 (95% CI: 0.32-23.07), respectively; however, these associations were statistically insignificant (P>0.05).

CONCLUSION

The findings of the SIH study provide a comprehensive understanding of the health status, risk factors, and genetic factors related to T2DM in a specific working population and highlight areas for further research and intervention to address the growing burden of T2DM and NCDs.

Association between TCF7L2 polymorphism and type 2 diabetes mellitus susceptibility: a case-control study among the Bangladeshi population

BACKGROUND

Diabetes is a severe health burden for Bangladesh. Genetic polymorphism has been reported to be one of the major risk factors for diabetes in various studies. TCF7L2 (transcription factor 7 like 2) transcripts in the human β-cell have effects on β-cell survival, function, and Wnt signaling activation. This study aimed to evaluate the frequency and association of various polymorphisms namely TCF7L2 rs12255372 and rs7903146 among Bangladeshi patients with T2DM (Type 2 Diabetes Mellitus).

METHODS

This case-control study included 300 patients with T2DM and 234 healthy individuals from two health facilities in the Chattogram Division of Bangladesh. Anthropometric measurements were assessed using a self-reported, structured, eight-item questionnaire. The polymorphisms were identified by PCR-RFLP and sequencing method.

RESULTS

A strong association of T2DM with polymorphisms was observed, including rs12255372 (p = 0.0004) and rs7903146 (p = 0.005). It was observed that the risk genotype at rs12255372 was associated with age (p = 0.009), a family history of diabetes (p < 0.0001), and HbA1C (p < 0.0001). Furthermore, it was found that rs12255372 was substantially associated with hypertension (p = 0.03), eye problems (p = 0.01), and neurological abnormalities (p = 0.02).

CONCLUSION

This study postulates that TCF7L2 genetic polymorphism is associated with the risk of T2DM among the studied Bangladeshi population. The findings should be replicated through more studies with a large number of samples and in different populations.

Role of rs7903146 polymorphism and adropin serum level in patients with diabetes mellitus; a case-control study from Isfahan, Iran

BACKGROUND

Type-2 diabetes mellitus (T2DM) is the common endocrinopathy which characterised by insulin resistance, insufficient expression or secretion of insulin and decrement of insulin effectiveness. Although T2DM has unknown aetiology, the strongest susceptible gene in this disease is TCF7L2. Adropin peptide may have roles in T2DM pathogenesis due to several roles in glucose tolerance, decrement of insulin resistance, lipid metabolism and energy homoeostasis.

AIM

To evaluate the serum level of adropin in T2DM patients and comparing with healthy individuals as well as assessing frequency of rs7903146 genotypes/alleles in patients and control groups.

METHODS

We analysed the frequency of rs7903146 genotypes/alleles in 93 patients with T2DM disease and 53 healthy individuals by the method of polymerase chain reaction-restriction fragment length polymorphism analysis. The serum level of adropin was measured by using enzyme-linked immunosorbent assay technique.

RESULTS

The mean serum level of adropin was 12.32 ± 2.98 and 9.51 ± 2.73 in patients and control groups, respectively (p value < .001). Also, there were significant difference in frequency of genotypes and alleles of rs7903146 in patients and controls groups (p < .001). The rs7903146T/T and rs7903146C/T genotypes increased risk of T2DM disease (OR: 6.035 and OR: 3.082, respectively). Interestingly, the highest level of adropin was detected in T2DMpatients with rs7903146T/T genotype.

CONCLUSION

Our analysis showed higher level of adropin in T2DM patients and increased risk of T2DM with rs7903146T/T and rs7903146C/T genotypes.

PPARɣ2, aldose reductase, and TCF7L2 gene polymorphisms: relation to diabetes mellitus

Purpose

Diabetes mellitus (DM) is a growing global health concern. Genetic factors play a pivotal role in the development of diabetes. Therefore, the present work aimed to study the relation between peroxisome proliferator-activate receptors (PPARɣ2) (rs3856806), aldose reductase (AR) (rs759853), transcription factor 7 like 2 (TCF7L2) (rs7903146) gene polymorphism with diabetes in the Egyptian population.

Methods

The study included 260 diabetics and 120 healthy subjects. Genotyping was done using polymerase chain reaction-restriction fragment length polymorphism.

Results

Regression analysis revealed that PPARɣ2 TT, TCF7L2 TT were suggested to be independent risk predictors for T1DM and TCF7L2 TC, CC genotype were suggested to be independent protective factors against T1DM development. On the other hand, PPARɣ2 TT, AR TT genotypes were suggested to be independent risk predictors for T2DM susceptibility, and PPARɣ2 CT genotypes were suggested to be independent protective factors against T2DM development.

Conclusion

The present study revealed that PPARγ2 (rs3856806), TCF7L2 (rs7903146) and AR (rs759853) gene polymorphism may play an important role in the susceptibility of diabetes. Therefore, these polymorphisms may have a prognostic value for diabetes in the Egyptian population. Further work is required to confirm the role of these polymorphisms in diabetes.

The role of transcription factor 7-like 2 in metabolic disorders

Transcription factor 7-like 2 (TCF7L2), a member of the T cell factor/lymphoid enhancer factor family, generally forms a complex with β-catenin to regulate the downstream target genes as an effector of the canonical Wnt signalling pathway. TCF7L2 plays a vital role in various biological processes and functions in many organs and tissues, including the liver, islet and adipose tissues. Further, TCF7L2 down-regulates hepatic gluconeogenesis and promotes lipid accumulation. In islets, TCF7L2 not only affects the insulin secretion of the β-cells but also has an impact on other cells. In addition, TCF7L2 influences adipogenesis in adipose tissues. Thus, an out-of-control TCF7L2 expression can result in metabolic disorders. The TCF7L2 gene is composed of 17 exons, generating 13 different transcripts, and has many single-nucleotide polymorphisms (SNPs). The discovery that these SNPs have an impact on the risk of type 2 diabetes (T2D) has attracted thorough investigations in the study of TCF7L2. Apart from T2D, TCF7L2 SNPs are also associated with type 1, posttransplant and other types of diabetes. Furthermore, TCF7L2 variants affect the progression of other disorders, such as obesity, cancers, metabolic syndrome and heart diseases. Finally, the interaction between TCF7L2 variants and diet also needs to be investigated.

Associations of transcription factor 7-Like 2 (TCF7L2) gene polymorphism in patients of type 2 diabetes mellitus from Khyber Pakhtunkhwa population of Pakistan

Background

Type 2 diabetes mellitus (T2DM) is the most prevalent component of metabolic syndrome. Environmental factors and various complex genes like transcription factor 7-like 2 (TCF7L2) gene have involved in the disease development.

Objective

To determine TCF7L2 genetic association (rs7903146C/T and rs12255372G/T) in T2DM patients of Khyber Pakhtunkhwa population of Pakistan.

Subjects and methods

This study comprised of 176 subjects including 118 T2DM patients and 58 healthy controls. Genomic DNA was extracted and genotype of common variants (rs7903146 C/T and rs12255372 G/T) was carried out by amplification-refractory mutation system (ARMS)-PCR of sequence specific oligonucleotides.

Results

The distribution of genotype of TCF7L2 SNPs (rs7903146 C/T and rs12255372 G/T) was significantly associated with T2DM as compared to the controls (p <0.0001). The genetic models of the rs7903146 (C/T) and rs12255372 (G/T) SNPs were significantly associated between cases and controls (p <0.0001). On the other hand, the significant association was observed between the two SNPs and different biochemical parameters like serum fasting glucose, lipid profile, creatinine and blood HbA1c levels (p <0.05).

Conclusion

It is concluded that the SNPs of the TCF7L2 gene are significantly associated with T2DM disease susceptibility in the population of Khyber Pakhtunkhwa of Pakistan.

Polymorphic genetic markers and how they are associated with clinical and metabolic indicators of type 2 diabetes mellitus in the Kazakh population

Background

Type 2 diabetes mellitus is a serious public health problem worldwide. The aim of the study was to analyze the relationship of eight polymorphic gene variants with the development of clinical-metabolic rates of type 2 diabetes mellitus inside Kazakh population.

Materials and methods

139 patients with type 2 diabetes mellitus and 100 patients in the control group were examined. Genotyping of polymorphisms of candidate genes was carried out on a next generation QuantStudio 12 K Flex unit.

Results

Gene TCF7L2 locus rs7901695 and rs7903146, gene KCNQ1 locus rs2237892, rs7756992, and gene CDKAL1 locus rs7754840 demonstrated statistically significant associations with glucose metabolism, lipid profile and body mass index (BMI) in type 2 DM inside the population. Statistically significant difference in anthropometric and biochemical measures of rs17584499, rs4712523 and rs163184 has not been revealed.

Conclusions

Genetic polymorphisms that influence pancreatic gland beta-cells insulin release and secretion associate with metabolic and anthropometric measures definitive for type 2 DM in Kazakh population.

Transcription Factor 7-Like-2 (<b><i>TCF7L2</i></b>) rs7903146 (C/T) Polymorphism in Patients with Type 2 Diabetes Mellitus

<b><i>Introduction:</i></b> Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by the incapability of pancreas to increase insulin secretion to compensate for insulin resistance in the peripheral tissues. T2DM is a multifactorial disease including several environmental factors with the presence of genetic predisposition. The transcription factor 7-like-2 gene (<i>TCF7L2</i>) rs7903146 (C/T) polymorphism is one of the most susceptible genes to T2DM discovered to date, with contribution to the disease through the Wnt/β-catenin signaling pathway affecting pancreatic islet development, expression of several genes involved in insulin granules exocytosis, and the incretin glucagon-like peptide 1 (<i>GLP-1</i>) gene. Then, <i>TCF7L2</i> gene seems to affect diabetes susceptibility through B-cell dysfunction that is why we studied its association with T2DM in particular. <b><i>Objectives:</i></b> To investigate the potential association of the transcription factor 7-like-2 (<i>TCF7L2</i>) rs7903146 (C/T) gene polymorphism in patients with T2DM. <b><i>Methods:</i></b> A case-control study conducted on 70 T2DM patients recruited from the endocrinology clinic at Ain Shams University Hospitals, and 30 non-diabetic healthy controls age- and sex-matched with the patients. All subjects underwent full history taking; thorough clinical examination; routine laboratory investigations including hemoglobin A1c, total cholesterol, triglycerides, high-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol; and determination of <i>TCF7L2</i> gene polymorphism by qRT-PCR. <b><i>Results:</i></b> The minor T allele of the rs7903146(C/T) SNP was associated with high risk of development of T2DM with an OR of 1.35 (95% CI: 0.68–2.6) and the heterozygous genotype (CT) with an OR 1.16 (95% CI: 0.49–2.7); however, they were statistically insignificant (<i>p</i> value &#x3e;0.05). <b><i>Conclusion:</i></b> Our study did not confirm the presence of significant association between the <i>TCF7L2</i> rs7903146(C/T) polymorphism and T2DM; however, it pointed out the possibility of presence of high risk of development of T2DM in patients with TT genotype. Further studies with higher sample size are needed to clarify the association.

Association of transcription factor 7-like 2 (rs7903146) gene polymorphism with diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is one of the most common diabetic complications. Genetic factors play an important role in the development and progression of DR. So, the present study aimed to investigate the association of TCF7L2 (rs7903146) gene polymorphism with the risk of DR in type1 and type2 DM (T1DM and T2DM) in the Egyptian population.

MATERIALS AND METHODS

This work is a case-control study in which 550 diabetic patients were enrolled. Among them, 280 diabetics with DR (120 T1DM and 160 with T2DM) and 270 diabetic patients without DR (120 T1DM and 150 with T2DM). Besides, 120 healthy subjects as a control group. Genotyping of TCF7L2 (rs7903146) (C/T) was done following DNA extraction using polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

C allele and CC genotype of TCF7L2 (rs7903146) were significantly associated with increased risk for DR within T2DM in multiplicative and recessive models. While dominant model showed no significant association with DR. Although TC may be associated with a decreased risk for DR in T1DM and T2DM in over dominant model, there was no significant association of TCF7L2 (rs7903146) with the risk of DR susceptibility within T1DM in multiplicative, dominant, and recessive models.

CONCLUSION

The present study revealed the association of TCF7L2 (rs7903146) polymorphism with DR susceptibility within diabetic patients. Therefore, TCF7L2 (rs7903146) gene polymorphism may have a prognostic value for diabetic retinopathy in the Egyptian population. Further work is required to confirm the association of this polymorphism as a risk for DR.

Association between the UBE2Z rs46522 and TCF7L2 rs7903146 polymorphisms with type 2 diabetes in south western Iran

BACKGROUND

Transcription factor 7-like 2 Protein (TCF7L2) has a strong role in the pathogenesis of type 2 diabetes mellitus (T2DM). Association between rs7903146 and T2D risk reported in some of populations. Also many loci such as UBE2Z rs46522 are affecting by TCF7L2 transcription factor have been found associated with T2D. The present study aimed to evaluate association of the SNPs with risk of T2D among our population.

METHODS

This case-control study was conducted on 150 T2D patients and 150 healthy people (as a control group) in south western Iran. Genotyping was performed by PCR-RFLP.

RESULTS

The frequency of genotypes showed no remarkable difference between T2DM patients and control group. The odds ratios of rs7903146 (C/T) polymorphism for CC and TC genotypes were 1.9 (95% CI, 0.85 to 4.24; P=0.12) and 0.81 (95% CI, 0.47 to 1.38; P=0.43) compared with the TT genotype, respectively. The odds ratios of rs46522 (C/T) polymorphism for TT and TC genotypes were 1.75 (95% CI, 0.86 to 3.59; P=0.13) and 1.38 (95% CI, 0.81to 2.35; P=0.24) compared with the CC genotype, respectively.

CONCLUSION

Our study indicates no association of T2D in south western Iran with the rs7903146 and rs46522 variants.

Case-control study on the association between the GATA2 gene and premature myocardial infarction in the Iranian population

In recent decades, due to the high prevalence of coronary artery disease (CAD) and myocardial infarction (MI), numerous studies have attempted to elucidate genetic contributing factors in these complex disorders. A very interesting gene in this regard is GATA-binding protein 2 (GATA2), an important regulator of various gene expressions in vascular endothelial cells. Accordingly, the association of different GATA2 polymorphisms with CAD and MI has already been evaluated. Rs2713604 is a genetic marker whose association with CAD has not been reproduced in previous studies. Considering the importance of replicating the initial association, the present case-control study aimed to examine the association of this intronic variant with premature MI in a sample of the Iranian population. In this study, 193 participants from Jahrom Hospital (Jahrom, Iran) were consecutively recruited during a 1.5-year period, and, following blood sampling, genomic DNA was extracted. We then proceeded to genotype rs2713604 using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and statistically analyzed the data. After adjustment for hyperlipidemia, hypertension, and type 2 diabetes mellitus, the results of the multivariate regression analysis showed no significant association between rs2713604 and premature MI. Interestingly, the risk allele (A-allele) of rs2713604 displayed a slightly higher frequency among controls compared to cases.

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.

Association of transcription factor 7-like 2 (TCF7L2) gene polymorphism with type 2 diabetes mellitus in Chinese Korean ethnicity population

Presently, data on the type 2 diabetes mellitus (T2DM) in Chinese Korean ethnicity are very scarce. This study aimed to explore the relationship between the transcription factor 7-like 2 (TCF7L2) and T2DM in Chinese Korean ethnicity population. This case-control study involved 43 T2DM Chinese Korean ethnicity patients (T2DM group) and 43 healthy Chinese Korean ethnicity normoglycemic subjects as controls (Control group). All included participants aged from 40 to 75 years old. Clinical and biological data were collected to determine the phenotypic traits. The restriction fragment length polymorphism-polymerase chain reaction was used to analyze the TCF7L2 by genotyping for rs7903146 (C/T). Spectrophotometer with Chronolab kits was used to conduct the biochemical analyses. TCF7L2 was associated with T2DM in the Chinese Korean ethnicity population (P < .01 for alleles, and P < .05 for genotypes). Significant differences were found 2 groups regarding the T allele (37.2% T2DM patients vs 15.1% healthy subjects, P < .01), and G allele (62.8% T2DM patients vs 84.9% healthy subjects, P < .01). The risk genotypes were GG (83.7% T2DM patients, vs 44.2% healthy control, P < .01), GT (4.7% T2DM patients, vs 20.9% healthy control, P = .04), and TT (11.6% T2DM patients, vs 34.9% healthy control, P = .01). The results of this study demonstrated that TCF7L2 is associated with T2DM in the Chinese Korean ethnicity population, which is an important risk factor for T2DM in this population.

The antileukemic effects of saffron (Crocus sativus L.) and its related molecular targets: A mini review

Saffron (Crocus sativus L.), and its main constituents, crocin, and crocetin have shown promising effects as an antileukemic agent in animal models and cell culture systems. Saffron retards the growth of cancer cells via inhibiting nucleic acid synthesis and enhancing antioxidative system. It can induce apoptosis and chemosensitivity via inhibiting multidrug resistance proteins. Saffron also induces differentiation pathways via inhibiting promyelocytic leukemia/retinoic acid receptor-α, histone deacetylase1, and tyrosyl DNA phosphodiesterase-1 as well. The present review highlights the most recent findings on the antileukemic effects of saffron and its underlying molecular targets. The emerging evidence suggests that saffron has a selective toxicity effect against leukemic cells while is safe for the normal cells.

Associations of TCF7L2 gene polymorphisms with the risk of diabetic nephropathy: A case-control study

The aim of the study was to explore the correlation between rs7903146 and rs290487 polymorphisms in transcription factor 7-like 2 (TCF7L2) gene and diabetic nephropathy (DN) in Chinese Han population.Polymerase chain reaction-restriction fragment length polymorphism was used to determine genotypes of TCF7L2 polymorphisms in 90 patients with DN and 96 diabetes patients without DN. The linkage disequilibrium (LD) and haplotype analysis were performed with haploview software. Hardy-Weinberg equilibrium was assessed in the control group based on the genotype distributions of TCF7L2 polymorphisms. The genotype, allele, and haplotype distribution differences between the case and control groups were analyzed by chi-squared test, and odds ratio (OR) and 95% confidence interval (CI) were used to indicate the relative risk of DN.People carrying TT genotype of rs7903146 were more easily to be attacked by DN than CC genotype carriers (P = .02, OR = 4.26, 95% CI = 1.12-16.24). Meanwhile, T allele also showed 1.85 times risk to suffer from DN compared with C allele (OR = 1.85, 95% CI = 1.02-3.10). However, there was no significant difference in genotypes and alleles frequencies of rs290487 between 2 groups. The strong LD existed between the 2 single nucleotide polymorphisms and haplotype T-T (rs7903146-rs290487) increased the susceptibility to DN (OR = 2.63, 95% CI = 1.31-5.25).TCF7L2 rs7903146 polymorphism may be associated with the susceptibility to DN in Chinese Han population, but rs290487 is not. Additionally, haplotype is also a risk factor for DN.

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.

Transcription factor 7-like 2 single nucleotide polymorphisms are associated with lipid profile in the Balinese

Transcription factor 7-like 2 (TCF7L2) protein plays an important role in glucose and lipid metabolisms. Single nucleotide polymorphisms (SNPs) in the TCF7L2 gene contribute to increased fasting plasma glucose (FPG) and body mass index (BMI), and altered lipid concentrations in various population. We investigated whether the TCF7L2 SNPs were associated with obesity, high FPG and altered lipid profile in the Balinese. A total of 608 Balinese from rural and urban Bali, Indonesia, were recruited. Triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC) and FPG were measured, and BMI was calculated. Ratios of TG/HDL-C, LDL-C/HDL-C, and TC/HDL-C were determined. Genotyping of SNPs rs7903146, rs10885406, and rs12255372 were done in all samples. Genetic association analyses under a dominant model showed that the rs7903146 (OR 5.50, 95% CI 2.34-12.91, p = 8.5 × 10^-5), rs12255372 (OR 4.15, 95% CI 1.66-10.33, p = 0.003) and rs10885406 (OR 2.43, 95% CI 1.39-4.25, p = 0.003) were significantly associated with high TC/HDL-C ratio. The rs10885406 also presented a significant association with high TG (OR 2.21, 95% CI 1.29-3.81, p = 0.004) and low HDL-C (OR 3.02, 95% CI 1.58-5.80, p = 0.001) concentrations, as well as high TG/HDL-C ratio (OR 1.95, 95% CI 1.16-3.27, p = 0.013). None of the SNPs exhibited significant association with obesity or high FPG. SNPs in the TCF7L2 gene are associated with altered lipid profile in the Balinese.

Significant SNPs Related to Telomere Length and Hepatocellular Carcinoma Risk in Chronic Hepatitis B Carriers

Chronic hepatitis B virus (HBV) infection increases the risk of developing cirrhosis and hepatocellular carcinoma (HCC) with suspected interactions between virus replication and host immune responses. A number of reports have suggested that telomerase function may be involved in chronic hepatitis B (CHB) pathogenesis, but positive or negative associations with HCC risk remain for discussion. Mean telomere length is an indicator of biological aging and it has been reported that reduction in NBV carriers compared to normal individuals. In somatic cells, telomeres contain simple, tandemly repeated G-rich sequences that frequently are reduced by 50 to 200 base pairs at each cell division. Several genome-wide association studies (GWAS) in diverse ethnic populations have revealed eleven single nucleotide polymorphisms (SNPs) linked to telomere length. Two of these, rs398652 and rs621559, have prognostic value and could be used as genetic markers. This review describes current knowledge concerning telomerase activity and telomere length as well as significant polymorphisms in HBV-related HCC patients. In particular, to cast light on genotype-phenotype interactions, we used SNPnexus to evaluate effects of the two SNPs on risk of disease and complex disorders.