The rs7903146 variant in the <i>TCF7L2</i> gene increases the risk of IGT/T2D in obese adolescents by impairing β-cell function, and hepatic insulin sensitivity predicts the development of IGT/T2D over time.
Despite no associations between incidence of glucose intolerance and SNPs of the TCF7L2 gene in Japanese-Brazilians, we found that carriers of the CT genotype for rs7903146 had significantly lower insulin levels 2 h after a 75-g glucose load than carriers of the CC genotype.
In adults, the TCF7L2 rs7903146 T allele, commonly associated with type 2 diabetes (T2D), has been also associated with a lower body mass index (BMI) in T2D individuals and with a smaller waist circumference in subjects with impaired glucose tolerance.
Over an average period of three years, participants with the risk-conferring TT genotype at rs7903146 were more likely to have progression from impaired glucose tolerance to diabetes than were CC homozygotes (hazard ratio, 1.55; 95 percent confidence interval, 1.20 to 2.01; P<0.001).