In line with our results, a previous study found that the C allele of rs6741949 SNP (within the non-T/G haplotypes) was associated with higher fasting glucose levels in subjects at increased risk for T2DM without difference in circulating DPP4 levels according to genotypes (DPP4 activity was not assessed) (23), and this could be because DPP4 is a ubiquitously expressed transmembrane protein and that our measurement was restricted to its proteolytically generated free circulating form. Here, DPP4 is linked to type 2 diabetes mellitus.