The results indicated that the TCF7L2 rs11196172 polymorphism increases the risk of CRC independently, with no evidence of an interaction with diabetes or obesity.
We genotyped four single nucleotide polymorphisms (SNPs) of TCF7L2 (rs7901695, rs7903146, rs11196205 and rs12255372) in 831 subjects with diabetes and 437 control subjects.
We examined whether the two most strongly associated variants (rs12255372 and rs7903146) predict the progression to diabetes in persons with impaired glucose tolerance who were enrolled in the Diabetes Prevention Program, in which lifestyle intervention or treatment with metformin was compared with placebo.
In subjects without known diabetes (n=961) recruited from the Chennai Urban Rural Epidemiology Study (CURES), OGTT, IDRS, and genotyping of rs12255372 (G/T) and rs7903146(C/T) of TCF7L2 polymorphisms were done.
Risk alleles of the TCF7L2 gene showed increased risk of diabetes even when controlled for traditional diabetes risk factors (diabetes in family, waist circumference, physical activity, BMI, SBP and total and HDL-cholesterol) in both a cross-sectional and prospective setting (cross-sectional: rs12255372 OR 1.61 (1.31-1.99), rs7903146 OR 1.48 (1.20-1.83) and prospective: rs12255372 OR 1.59 (1.22-2.07), rs7903146 OR 1.47 (1.11-1.93)).
Specifically, the same risk allele of single nucleotide polymorphism (SNP) rs12255372 that is associated with diabetes (T allele) has recently been associated with an increased risk of breast cancer.
An interaction (p = 0.048) between TCF7L2 variants and coffee intake was apparent, with an inverse association between coffee and type 2 diabetes present among carriers of the diabetes risk allele (T) in rs12255372 (GG: HR 0.99 [95% CI 0.97, 1.02] per cup of coffee; GT: HR 0.96 [95% CI 0.93, 0.98]); and TT: HR 0.93 [95% CI 0.88, 0.98]).
We genotyped four single nucleotide polymorphisms (SNPs) of TCF7L2 (rs7901695, rs7903146, rs11196205 and rs12255372) in 831 subjects with diabetes and 437 control subjects.
Diabetes disease stage was marginally significantly associated with the frequency of the T variant at rs12255372 (p=0.057; adjusted p=0.017) but not at rs7903146 (p=0.5; adjusted p=0.2).
In the DPS, the TT genotype of rs12255372 was significantly associated with an adjusted 2.85-fold risk (95% CI 1.17-6.95, p = 0.021) of incident diabetes in the control group, but not in the intervention group.
Furthermore, we identified a common protective haplotype defined by these four SNPs that was significantly associated with type 2 diabetes and age at diagnosis (P = 4.2 x 10(-5), relative risk [RR] 0.69; P = 6.7 x 10(-6), respectively) and a haplotype that confers diabetes risk that contains the rare alleles at SNPs rs10885390 and rs12255372 (P = 0.02, RR 1.64).
Over an average follow-up period of 5.43 years, participants with the rs7903146 T allele or variants in the same LD block, but not those with the rs290481 G allele, were more likely to progress to diabetes (hazard ratio = 2.61, 95% confidence interval, 1.27-5.39, P = 0.009) than were non-carriers.
In addition, the TCF7L2 rs290487 TT genotype was associated with abdominal obesity and the GCG rs12104705 CC genotype was associated with both general obesity and abdominal obesity in case of new-onset diabetes.
Of 100K SNPs, one (rs7100927) was in moderate LD (r2 = 0.50) with TCF7L2 (rs7903146), and was associated with risk of diabetes (Cox p-value 0.007, additive hazard ratio for diabetes = 1.56) and with tFPG (GEE p-value 0.03).
Of 100K SNPs, one (rs7100927) was in moderate LD (r2 = 0.50) with TCF7L2 (rs7903146), and was associated with risk of diabetes (Cox p-value 0.007, additive hazard ratio for diabetes = 1.56) and with tFPG (GEE p-value 0.03).
However, the T allele (conferring higher risk of diabetes) at rs7903146 was associated with higher fasting proinsulin at baseline (P<0.001), higher baseline proinsulin:insulin ratio (p<0.0001) and increased proinsulin:insulin ratio over a median of 2.5 years of follow-up (P = 0.003).
Resequencing and analysis of variation in the TCF7L2 gene in African Americans suggests that SNP rs7903146 is the causal diabetes susceptibility variant.
We studied 120 individuals of whom one-half were homozygous for the diabetes-associated allele TT at rs7903146 and one-half were homozygous for the protective allele CC.
We investigated the association between the TCF7L2 rs7903146 polymorphism and incident IFG defined as fasting serum glucose levels of 100-125 mg/dL (5.6-6.9 mmol/L) in 1377 African American and 5152 Caucasian participants without diabetes and IFG at intake who participated in the Atherosclerosis Risk in Communities (ARIC) Study from 1987 to 1989 and were followed for 9 years.
Using four TCF7L2 single nucleotide polymorphisms (SNPs; including the two most associated in the previous study), we conducted a case-control study in 2,158 type 2 diabetic subjects and 2,574 control subjects and a family-based association analysis in 388 parent-offspring trios all from the U.K. All SNPs showed powerful associations with diabetes in the case-control analysis, with strongest effects at rs7903146 (allele-wise relative risk 1.36 [95% CI 1.24-1.48], P = 1.3 x 10(-11)).
TCF7L2 rs7903146 C>T polymorphism is associated with diabetes in the general population but its independent impact on cardiovascular disease is debated.
The minor allele frequency for rs7903146 was different between TCP and FCPD patients carrying the N34S SPINK1 variant but did not reach statistical significance (OR = 1.59, 95% CI = 0.93-2.70, P = 0.09), while, TCF7L2variant showed a statistically significant association between TCP and FCPD patients carrying the 26V allele (OR = 1.69, 95% CI = 1.11-2.56, P = 0.013).