TCF7L2 Gene Rs7903146 Polymorphism May Confer Expression of Gestational Diabetes Mellitus in Relatively Young and Lean Mothers

To observe the impact of clinical characteristics and TCF7L2 rs7903146 polymorphism on GDM, pregnant women without history of glucose intolerance [N=100; age 26.22 ± 4.56 years; body mass index (BMI) 26.39 ± 3.85; mean ± SD; GDM=50, normal glucose tolerance (NGT)=50 according to WHO 2013 criteria] were studied for TCF7L2 rs7903146 polymorphism using Sanger sequencing technique (genotype CC=63, CT/TT=37) of genotyping. Women with CC and CT/TT genotypes had no significant difference of age (CC vs. CT/TT: 26.10 ± 4.46 vs. 26.43 ± 4.79 years, p=0.723; mean ± SD) or BMI (CC vs. CT/TT: 26.21 ± 3.90 vs. 26.69 ± 3.79 kg/m2, p=0.548; mean ± SD). While GDM women with CC genotype had higher age and BMI than NGT women (GDM vs. NGT: age 27.96 ± 3.79 vs. 24.60 ± 4.45 years, p=0.002; BMI: 27.67 ± 3.93 vs. 25.04 ± 3.50 kg/m2, p=0.006; mean ± SD), GDM women with CT/TT genotype had no significant difference of age and BMI with NGT women (GDM vs. NGT: age 27.00 ± 5.22 vs. 25.60 ± 4.10 years, p=0.390; BMI: 26.48 ± 3.63 vs. 27.00 ± 4.13 kg/m2, p=0.688; mean ± SD). In women of age <25 years, frequency of GDM was significantly higher in those with CT/TT genotype than those with CC [CT/TT vs. CC: 58.3% vs. 17.4%, p=0.022] having an odds ratio (OR) of 6.650 (95% CI 1.377- 32.114) for GDM; but not in women ≥25 year old (CT/CC vs. CC 60% GDM in both groups, p=1.000, OR=1.000, 95% CI 0.361-2.773). Using BMI cut-off at 25 kg/m2, women with BMI <25 kg/m2 had significantly higher frequency of GDM in those with CT/TT genotype than those with CC (CT/TT vs. CC: 61.5% vs. 18.2%, p=0.024) with an OR of 7.200 (95% CI 1.518-34.139); but not in women having BMI ≥25 kg/m2 (CT/TT vs. CC 58.3% vs. 58.5%, p=0.987, OR=0.992, 95% CI 0.357-2.86). It is concluded that polymorphism of TCF7L2 rs7903146 may confer increased risk of GDM even in mothers with young age and lean BMI