Are single nucleotide polymorphisms rs7903146 and rs12255372 in transcription factor 7-like 2 gene associated with an increased risk for gestational diabetes mellitus in Egyptian women?

BACKGROUND

Genetic variants in the transcription factor 7-like 2 (TCF7L2) gene are related with type 2 diabetes (T2D) and gestational diabetes mellitus (GDM) in various populations, but there are not enough statistics regarding GDM among Egyptian women. We aimed by this study to evaluate the effect of two polymorphisms of rs7903146 and rs12255372 in the TCF7L2 gene with the development of GDM among Egyptian women.

RESULTS

We enrolled 114 pregnant women with normal glucose tolerance and 114 with GDM according to the International Association of Diabetes and Pregnancy Study Groups (IADPSG) guidelines. We gathered records on blood pressure, body mass index (BMI), blood glucose level, hemoglobin A1C (HbA1c), and lipid profile. The genotyping of rs7903146 and rs12255372 polymorphisms was carried out using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The statistical significance of prepregnancy BMI, fasting blood sugar (FBS), HbA1c, low-density lipoprotein (LDL), and total cholesterol (Tch) was higher, P < 0.001, in GDM women in comparison to pregnant women without GDM. CT and TT genotypes in rs7903146 SNP were 46.5% vs. 54%, P <0.04, OR; CI = 1.9 (1.0 to 3.78); TT carriers were 37.7% vs. 9.6%, P <0.001, OR (CI) = 8.9 (3.7-21.1), respectively. For the TCFL2 gene rs12255372 SNP, GT carriers were 48.2% vs. 39.5%, P= 0.004, OR (CI) = 2.3 (1.3-4.2), while TT carriers were 24.6% vs. 7.9%, P < 0.001, OR (CI) = 6 (2.5-14.3).

CONCLUSION

The study showed there is a significantly higher incidence of CT/TT genotypes in rs7903146 SNP and GT/TT genotypes in rs12255372 SNP in TCF7L2 gene among GDM women in comparison to healthy pregnant women (controls).

Genetic variants of TCF7L2 gene and its coherence with metabolic parameters in Lithuanian (Kaunas district) women population with previously diagnosed gestational diabetes mellitus compared to general population

OBJECTIVE

To determine the association of genetic variants rs7901695, rs7903146, rs7895340, rs11196205, rs12255372 of transcription factor 7 like 2 (TCF7L2) gene and its coherence with metabolic parameters in Lithuanian (Kaunas district) women population with previously diagnosed gestational diabetes mellitus (GDM) and to compare the prevalence of TCF7L2 single nucleotide polymorphism (SNP) results to general population.

METHODS

Women with previously diagnosed GDM participated in the study. Anthropometric measurements were taken. Carbohydrate and fat metabolism were evaluated. TCF7L2 SNP common variants (rs7901695, rs7903146, rs7895340, rs11196205, rs12255372) were set. The prevalence of TCF7L2 the same SNP alleles were also evaluated for women of the general population. The results were compared to the main study group (women with previously diagnosed GDM). The results were calculated in a ratio of 1:2. General population group comprised 300 women who were selected from the random sample of the Kaunas city population. Statistical analysis was made with the statistical package IBM SPSS Statistics version 21. Quantitative parametric variables presented as mean and standard deviation, qualitative variables - as absolute numbers and percentage. ANOVA test was used, for the comparison between three or more groups. Quantitative variables were compared using Student's t-test. Categorical variables were compared using chi-square test. Correlation analysis of parametrical data was performed by Pearson's correlation. Odds ratios (OR) with 95% CIs were presented. The results were considered statistically significant at p < 0.05.

RESULTS

158 women with previously (15-47 years ago) diagnosed GDM participated in the study. The mean age of participants was 53.0 ± 8.2 years and 60.2 ± 7.5 years (p < 0.001), BMI - 31.4 ± 7.9 kg/m2 and 29.9 ± 5.8 kg/m2 (p < 0.001) in GDM group and general population respectively. GDM group women had significantly larger waist, hip circumference and waist to hip ratio compared to general population women: 98.9 ± 18.1 cm vs. 89.2 ± 13.3 (p < 0.001), 112.5 ± 14.8 cm vs. 105.6 ± 10.9 cm (p < 0.001), 0.87 ± 0.08 vs. 0.84 ± 0.07 (p < 0.001). There was no significant difference in blood pressure results between groups (p > 0.05). Carbohydrate dysmetabolism was set for 57.6% women with previously diagnosed GDM: 11 (7.0%) were diagnosed with impaired fasting glycemia (IFG), 14 (8.9%) with impaired glucose tolerance (IGT), type 2 Diabetes Mellitus (DM) was diagnosed for 58 (36.7%), DM type 1 for 7 (4.4%), MODY2 (maturity onset diabetes of the young) - 1 (0.6%) patients. TCF7L2 SNPs in women with previously diagnosed GDM and various carbohydrate metabolism groups did not differed (p > 0.05). Body weight, body mass index (BMI), waist and hip circumference in GDM group participants with different TCF7L2 SNP alleles did not differ (p > 0.05). There was no statistically significant difference in fasting plasma glucose (FPG), oral glucose tolerance test (OGTT) results, cholesterol levels and different TCF7L2 SNP alleles in GDM group (p > 0.05). We found higher prevalence of TCF7L2 SNP rs7901695 CC/CT, rs7903146 CT/TT and rs12255372 GT/TT alleles in women previously diagnosed GDM compared to general population women's group. The OR of being in GDM group with TCF7L2 SNP: rs7901695 CC/CT alleles, was 1.703 (95% CI 1.153-2.515); rs7903146 CT/TT - 1.708 (95% CI 1.149-2.538); rs12255372 GT/TT - 1.575 (95% CI 1.058-2.343).

CONCLUSIONS

No statistically significant difference in glucose, cholesterol levels and different TCF7L2 SNP alleles in GDM group was found. TCF7L2 SNPs did not differed in women with previously diagnosed GDM and various carbohydrate metabolism groups, though a significantly higher incidence of TCF7L2 rs7901695 SNP CC/CT, rs7903146 SNP CT/TT, rs12255372 GT/TT alleles in study subjects compared to the general population women were observed.