Type 2 diabetes mellitus and TCF7L2 gene rs12255372 G/T polymorphism: a meta-analysis involving 7990 subjects

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.

Significant Association of Polymorphisms in the TCF7L2 Gene with a Higher Risk of Type 2 Diabetes in a Moroccan Population

Background and aims: Several studies have shown that genetic polymorphisms of the transcription factor 7-like 2 (TCF7L2) are highly associated with the development of type 2 diabetes mellitus (T2DM) and its associated complications in several populations. The aim of our study was to investigate the association of the rs7903146 (C/T) and rs12255372 (G/T) polymorphism in the TCF7L2 gene with the risk of developing T2DM in the Moroccan population. Material and methods: A total of 150 T2DM patients and 100 healthy controls were recruited for various anthropometric, biochemical and genetic parameters. Genotyping was performed by using Real Time-PCR. The frequency of genotypes, alleles, anthropometric measures, glycemia, glycated hemoglobin (HbA1c) were evaluated in patients and control, while lipid profile was available only for T2DM group. Results: Glycemia, HbA1c and body mass index (BMI) were significantly higher in T2DM group than control. Analysis of the distribution of the TCF7L2 rs7903146 genotype and allele revealed that the TT genotype was more frequent in T2DM group (24.0%) than in healthy controls (5%) (OR = 4.08, 95% confidence interval (CI = 1.95–11.80, p < 0.0001). The T allele was more frequent in diabetic patients (45.2%) than healthy control (34.5%) and it was associated with high risk of diabetes (OR = 2.13, 95% CI = 1.12–7.31, p = 0.005). The same results were found regarding rs12255372, TT genotype frequencies were 18,7% and 6.0% in T2DM and control group, respectively (OR = 3.11, 95% CI = 1.33–7.24, p = 0.004). The T allele was over-presented in diabetics compared to controls (45.3% and 38.0%, respectively) and increases the risk of T2DM (OR = 2.01, 95% CI = 1.04–3.10, p = 0.01). However, there was no significant difference between the three genotypes of rs7903146 and rs12255372 regarding age, BMI, glycemia, HbA1c and lipid profile. Conclusion: The present study confirmed a significant association of the TCF7L2 gene (rs7903146 (C/T) and rs12255372 (G/T) polymorphisms with a higher risk to T2DM in the Moroccan population. No significant difference in respect to anthropometric and metabolic parameters between different genotypes.

Solute Carrier Family 30 Member 8 Gene 807C/T Polymorphism and Type 2 Diabetes Mellitus in the Chinese Population: A Meta-Analysis Including 6,942 Subjects

BACKGROUND

Although solute carrier family 30 (zinc transporter) member 8 (SLC30A8) gene 807C/T polymorphism is associated with an increased risk of type 2 diabetes mellitus (T2DM) risk, there remains some inconsistency between individual studies.

OBJECTIVE

The aim of the study is to explore the relationship between SLC30A8 gene 807C/T polymorphism and T2DM in the Chinese population.

METHODS

The current meta-analysis compiles and analyzes the data of 6,942 participants from 10 independent studies. Either a fixed or random-effects model was adopted to evaluate the pooled odds ratio (ORs) and the corresponding 95% confidence interval (95% CI).

RESULTS

A significant association between SLC30A8 gene 807C/T polymorphism and T2DM was found in the Chinese population under allelic (OR: 0.85, 95% CI: 0.80-0.91, P = 7.42 × 10^-7), recessive (OR: 0.52, 95% CI: 0.38-0.72, P = 8.49 × 10^-5), dominant (OR: 2.40, 95% CI: 1.68-3.41, P = 1.30 × 10^-6), homozygous (OR: 0.52, 95% CI: 0.40-0.67, P = 2.90 × 10^-7), heterozygous (OR: 0.79, 95% CI: 0.71-0.88, P = 1.63 × 10^-5), and additive genetic models (OR: 0.73, 95% CI: 0.64-0.83, P = 7.05 × 10^-7).

CONCLUSION

SLC30A8 gene 807C/T polymorphism was significantly associated with an increased T2DM risk in the Chinese population. Therefore, individuals of Chinese descent with the C allele of SLC30A8 gene 807C/T polymorphism may be more susceptible to developing T2DM, while individuals with the T allele may be protected against T2DM.