Most importantly, however, the addition of a known TCF7L2 genotype in a validated model for predicting prevalent diabetes was not able to improve the performance of the risk score: area under ROC curve in both models equal to 0.776, ie the inclusion of TCF7L2 genotype is not better than the utilization of only clinical characteristics to predict diabetes risk in our population. This evidence concerns the gene TCF7L2 and diabetes mellitus.