We found that insulin serum concentrations were significantly different in the 3 groups and reached a peak 30 min after the start of the OGTT in the NGT group, and after 120 min in the T2DM and IGR groups (Fig. 1a), with the areas under the curves (AUC0–180) being 7849, 10,417and 4930 for insulin, 1.593, 2015 and 1083 for C-peptide and 1.140, 1539 and 2316 for FBG in the NTG, IGR and T2DM groups. This evidence concerns the gene INS and type 2 diabetes mellitus.