TCF7L2 and type 2 diabetes mellitus: For each studied locus, we selected the most T2D-associated SNP, including TCF7L2 rs7903146 (N = 15) in order to assess their cumulative effects on T2D prevalence as well as potential gene-gene interactions (i.e., deviation from a multiplicative model) in the complete set of French individuals (4,232 T2D and 4,595 NGT) [6].