Association between the Rs7903146 and Rs12255372 Variants of the TCF7L2 Gene and Metabolic Phenotypes in Pre-Diabetes (Pre-DM) Subjects

Special Article - Diabetes and Polymorphisms

Austin J Endocrinol Diabetes. 2019; 6(1): 1066.

Association between the Rs7903146 and Rs12255372 Variants of the TCF7L2 Gene and Metabolic Phenotypes in Pre-Diabetes (Pre-DM) Subjects

Perez-Luque E*, Rocha-Ortiz LR, Reyes-López R, Cardona-Alvarado MI and Malacara Juan M

Department of Medical Science, University of Guanajuato, México

*Corresponding author: Elva Perez-Luque, Department of Medical Science, Division of Health Sciences, León Campus, University of Guanajuato, 20 de Enero 929, Colonia Obregón, C.P. 37320. León Guanajuato, México

Received: June 15, 2019; Accepted: July 16, 2019; Published: July 23, 2019


Aim: The term “prediabetes” (pre-DM) is used to define individuals with Impaired Fasting Glucose (IFG) and/or Intolerance Glucose Test (IGT). In this study, we analyzed the association between rs12255372 and rs7903146 variants of the TCF7L2 gene and metabolic phenotypes in pre-DM subjects.

Methods: We included 247 unrelated subjects between 25 to 60 years old, 114 were apparently healthy subjects with glucose levels ‹100 mg/dl (5.5 mmol/l), and 133 subjects with IFG (fasting glucose ›100 mg/dl to ‹125 mg/dl). Metabolic and anthropometric variables were measured, polymorphisms were genotyped by PCR. Homeostasis model assessment was used to estimate insulin resistance and β-cell function (HOMA-IR, HOMA β-cell function).

Results: The subjects with CT/TT rs7903146 genotypes showed a decrease in weight, BMI, triglycerides, and β-cell function. The pre-DM subjects with these genotypes showed weight and BMI significantly lower than CC genotype. The pre-diabetic subjects with GT and TT rs12255372 genotypes, showed insulin levels, HOMA-IR, and β-cell function significantly decreased (24%, 22%, 31% respectively). BMI (OR=1.26 95% 1.18-1.34, p‹0.00001), the age (OR=1.05 95% 1.02-1.08, p=0.0008), and rs7903146 polymorphism (OR=3.11, 95% 1.58- 6.1, p=0.0009) are associated with the development of pre-DM. An interaction of rs7903146 was observed when omitting to BMI (OR=1.83, 95% 1.05-3.19, p=0.03). The rs1225372 shows no association with the development of pre-DM

Conclusion: Weight and BMI were lower in pre-DM subjects with CT or TT rs7903146 genotypes. Insulin, HOMA-IR levels, and β-cell function were significantly decreased in pre-diabetic subjects with GT or TT rs12255372 genotypes. BMI, age, and rs7903146 are predictors for development of Pre-DM.

Keywords: Prediabetes; rs7903146; rs12255372; BMI; Metabolic phenotypes


Hyperglycemia that does not reach the diagnostic criteria for Diabetes Mellitus (DM) is known as “prediabetes” (pre-DM), and is the term used to include individuals with Impaired Fasting Glucose (IFG) and/or Impaired Glucose Tolerance (IGT), and/or A1C 5.7- 6.4% [1]. Prediabetes should not be viewed as a clinical entity but as an increased risk for diabetes and cardiovascular disease [1]. In addition to IFG and IGT, there are other risk factors as first-degree family history, abdominal obesity, dyslipidemia, ethnic group, among others [1,2]. Reports indicate that age-adjusted prevalence of IFG (49.5% and 50.5%), IGT (49.1% and 50.9%), and IFG+IGT (57.3% and 42.7%) are similar in Mexican men and women [3].

Since 2006, specific Single Nucleotide Polymorphisms (SNPs) within the TCF7L2 gene are known to be associated with increased risk of Type 2 Diabetes (T2DM) [4]. There is evidence in many ethnic groups, that rs12255372 and rs7903146 in TCF2L7 gene are more strongly associated with T2DM [5]. The analysis of these markers in a sample of controls and patients with T2DM from Mexico City indicates that the rs12255372T allele is associated with diabetes risk [6]. A more recent analysis has shown that eight SNPs and rs7903146 are associated with early-onset T2DM [7]. In Caucasian people, the rs7903146T allele risk was independently associated with increased fasting glucose [8,9]. For the TCF7L2 and WFS1 diabetes risk genes, which are associated with impaired incretin signaling, the level of glycemia determines SNP effects on insulin secretion, it indicates the importance of these SNPs during the progression of prediabetes stages toward clinically overt type 2 diabetes [10]. The TCF7L2 variants rs7903146 and rs12255372 have an effect on the risk of T2DM, at least in part, by modifying the effect of incretins on insulin secretion [11,12]. Other Reports show that the rs7903146 variant increases the risk of IGT/T2DM in obese adolescents and middle-aged subjects by impairing β-cell function [13,14]. Both TCF7L2 rs7903146 and rs12255372 variants increase the risk of diabetes among subjects with impaired glucose tolerance also acting on the β-cell function [15]. In individuals with IGT, the variant rs12255372 was significantly associated with decreased insulin secretion and with incident T2DM [16].

In Mexico, the prevalence of T2DM varies from 8.9% to 25.3 (ENSANUT 2012), in low-income people and for prediabetes 18.9% (13.8-24.0) [17]. However, there are not enough data on factors associated with the development of prediabetes, neither of the metabolic characteristics associated with these polymorphisms. Therefore, the aim of this study was to analyze the association between rs12255372 and rs7903146 variants of the TCF7L2 gene and metabolic phenotypes in pre-DM subjects.


We studied a total of 247 unrelated subjects that were within 25 to 60 years old, in two groups, 114 apparently healthy with glucose levels ‹100 mg/dl (5.5 mmol/l), and 133 with pre-DM diagnosed according to ADA criteria (fasting glucose levels ›100 mg/dl to ‹126 mg/dl in two subsequent days) [1]. None of the subjects had clinical evidence of heart, liver, renal or other endocrine disease. The subjects were recruited from the city of León in the central region of Mexico by means of home visits and public announcements. Informed consent was obtained from all individual participants included in the study. The study was conducted in accordance with the ethical standards laid down in the Declaration of Helsinki in 1983 and in agreement with the Good Clinical Practice guidelines. The study was approved by the Institutional Ethics Committee of the University of Guanajuato.

Material and Methods

Anthropometric and metabolic measurements

All participants were interviewed to obtain clinical data and T2DM family history. Weight, height, waist and hip circumferences were obtained with indoor clothing and without shoes. BMI (weight (kg)/height (M2)) and Waist/Hip Ratio (WHR) were calculated. Blood samples were drawn after 12 h fasting in order to measure serum glucose, and lipids profile using enzymatic methods with a chemistry analyzer (Auto KEM II, Kontrollab, Italy). Insulin serum concentrations were measured by radioimmunoassay with a commercial kit (MILLIPORE Research Charles, Missouri USA). Insulin Resistance (IR) and β-cell function were assessed with the Homeostatic Model Assessment (HOMA) [18].

Genotyping of rs7903146 and rs12255372 variants

Genomic DNA was obtained from peripheral blood leukocytes using standard methods and stored at -20°C until batch genotyping. The rs7903146 polymorphism was genotyped using the PCR-RFLP method. The region was amplified with the following primers 5’-TTAGAGAGCTAAGCACTTTTTAGGTA-‘3 (forward) and 5’-ACTAAGTTACTTGCCTTCCCTG-‘3 (reverse), and for genotyping of rs12255372 polymorphism, we used the following primers 5’-CCCAGGAATATCCAGGCAAGGAT-’3 (forward) and 5’-CAAATGGAGGCTG- AATCTGGCA-‘3 (reverse). The PCR reaction was carried out using 50 ng DNA, 2.0 mM MgCl2, 0.5 mM dNTPs (Invitrogen), 10 μMol primers and 2 U Taq polymerase (Platinum Invitrogen) for both polymorphisms. The amplification program consisted in: one cycle of 94°C for 3 min, 35 cycles of 94°C for 30 sec, 60°C for rs12255372 in a Thermal cycler Gene Amp PCR System 2700 (Applied Biosystems, Life Technologies Corporation, Singapore). The PCR products for the genotyping of rs7903146 were digested with RsaI restriction enzyme (New England Biolabs Ipswich, MA, USA) that generated two fragments 91 and 22 bp for C allele and one fragment 113 pb for T allele [6]. The Fok I restriction enzyme (New England Biolabs Ipswich, MA, USA) that was used to typing rs12255372 variants generated two fragments 94 and 24 pb for G allele and one fragment 118 pb for T allele [6]. We carried out genotype replications in 25% of the DNA samples obtaining a 99% rate of a coincidence for both SNPs.

Statistical analysis

Data for anthropometric and metabolic characteristics of the volunteers were expressed as the mean ± SD or median (25-75 quartiles). Differences between groups were examined using the t-test for independent samples, Mann & Whitney U test, ANOVA or Kruskal-Wallis test. Risk factors associated with pre-Diabetes were analyzed with the logistic regression analysis. The Analyses were conducted using a statistical package (Statistica 7.0, Statsoft Inc., Tulsa, OK, USA).


The total group included 66 men and 181 women with an average age of 42 ± 11 years, 114 healthy subjects, and 133 pre-diabetic subjects. The weight, BMI, age, blood pressure, triglycerides, insulin, and HOMA-IR were significantly higher, but HDL-c and β-cell function lower in pre-DM subjects than in healthy subjects (Table 1). There are no differences in the allelic and genotypic frequencies of rs7903146 between healthy and pre-DM groups (Table 2). A marginal difference in genotypic frequencies of rs12255372 TCF7L2 between healthy and pre-DM subjects was observed (p=0.05) (Table 2). The distribution of genotype frequencies of both polymorphisms is in the agreement of the Hardy-Weinberg distribution.