TCF7L2 Gene Polymorphisms and Susceptibility to Type 2 Diabetes Mellitus, A Pilot Study

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.

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.

TCF7L2 gene polymorphism as a risk for type 2 diabetes mellitus and diabetic microvascular complications

BACKGROUND

Type 2 Diabetes Mellitus (T2DM) is a chronic metabolic condition with various genetics and environmental influences that affects the capacity of the body to produce or use insulin resulting in hyperglycemia, which may lead to variable complications. It is one of the world's rising health problems. There is emerging evidence that some genetic polymorphisms can impact the risk of evolving T2DM. We try to determine the relationship of (rs7903146) variant of the Transcription factor 7-like 2 (TCF7L2) gene with T2DM and its microvascular complications.

METHODS AND RESULTS

This case-control study included 180 subjects: 60 diabetic patients without complications, 60 diabetic patients with microvascular complications and 60 matched healthy controls. Genotypes of rs7903146 (C/T) SNP in the TCF7L2 gene were evaluated by real-time polymerase chain reaction via TaqMan allelic discrimination. Logistic regression was used to detect the most independent factor for development of diabetes and diabetic microvascular complications. Variant homozygous TT and heterozygous CT genotypes were significantly increased in diabetic without complications and diabetic with complications groups than controls (p = 0.003, 0.001) respectively. The T allele was more represented in both patient groups than controls with no significant difference between patient groups. TT genotype as well as T allele was significantly associated with increased T2DM risk.

CONCLUSION

The T allele of rs7903146 polymorphism of TCF7L2 confers susceptibility to development of T2DM. However, no significant association was found for diabetic complications.

Interaction between TCF7L2 rs7903146 Genotype, HbA1c Levels, and the Periodontal Status of Dental Patients

OBJECTIVE

 The aim of the study was to investigate the potential interaction between TCF7L2 rs7903146 genotype, which is implicated for type-2 diabetes mellitus genetic susceptibility, HbA1c levels, and the periodontal status of dental patients.

MATERIALS AND METHODS

HbA1c levels, clinical periodontal parameters (probing depth, clinical attachment level, bleeding on probing, and plaque index), and several parameters (such as body mass index [BMI], smoking habits, education level, and age) were recorded in 150 patients who fulfilled the criteria for screening for prediabetes/diabetes of the Centers for Disease Control and Prevention. DNA was extracted and the TCF7L2 single nucleotide polymorphism (SNP) rs7903146 was genotyped in all participants.

RESULTS

 Thirty-one patients out of 150 tested were found with unknown hyperglycemia (20.7%). Regarding sex, education, parent with diabetes, normal BMI, smoking, age ≥45 years and prior testing for diabetes, no differences were observed between patients displaying HbA1c < 5.7 and ≥ 5.7% (Pearson's Chi-square test, p > 0.05). Regarding periodontal parameters and differences between subgroups (HbA1c levels ≥ 5.7 and HbA1c levels < 5.7), statistically significant differences were observed for probing depth (3.20 ± 0.94 vs. 2.81 ± 0.78 mm), clinical attachment level (3.54 ± 1.20 vs. 3.18 ± 1.06 mm) and bleeding on probing (0.62 ± 0.25 vs. 0.50 ± 0.24%) with hyperglycemic patients exhibiting worse periodontal conditions (Mann-Whitney test p < 0.05). The allelic and genotype frequencies for the transcription factor 7-like 2 (TCF7L2) gene, SNPs 7903146 did not exhibit a significant difference between the HbA1c > 5.7 and HbA1c < 5.7 groups and the periodontitis and nonperiodontitis subgroups respectively (Fisher's exact test >0.05). Statistical Analysis Patient characteristics and their association with prediabetes were tested by Pearson's Chi-square test (asymptotic, two sided). Differences of periodontal parameters between subgroups were tested with the Mann-Whitney U-test. The associations of allele and genotype frequencies in the patient and control groups were analyzed using the Fisher's exact test of independence.The significance level was set at the 0.05 for all tests.

CONCLUSION

 A statistically significant association between TCF7L2 rs7903146 genotype and periodontal condition or HbA1c levels was not observed in contrast to statistically significant differences of clinical parameters of periodontitis in patients with hyperglycemia.

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.

The Association of Transcription Factor 7 like 2 Gene Polymorphism with Diabetic Nephropathy in Patients with Type 2 Diabetes Mellitus

BACKGROUND

The exact relationship between the different TCF7L2 gene polymorphisms and the development of diabetic nephropathy (DN) remains unclear.

OBJECTIVE

To investigate the association of TCF7L2 rs12255372 (G/T) gene polymorphism and diabetic nephropathy (DN) in patients with type 2 diabetes (T2D).

METHODS

100 patients with T2D (50 patients without DN and 50 patients with DN) and 50 age and sex-matched healthy controls (HC) were enrolled in the study. Genotyping for the rs12255372 (G>T) polymorphism in the TCF7L2 gene was performed by real-time PCR.

RESULTS

The rs12255372 polymorphism showed a statistically significant difference between HC and patients with and without DN in both the genotype and allele frequency. However, the rs12255372 polymorphism genotype or allele frequency was not statistically different between patients with DN and those patients without DN. The G allele was found to be higher in patients and the T allele was higher in HC suggesting that the G allele was the risk allele for developing T2D & DN and that the T allele was protective.

CONCLUSION

rs12255372 TCF7L2 gene polymorphism was strongly associated with type 2 diabetes mellitus and DN. The association between rs12255372 polymorphism and DN was a mere reflection of a complicated diabetes mellitus rather than a direct independent association.