The frequency of TT genotype in rs3856806 was significantly higher in prediabetes/diabetes subjects than in the normal glucose tolerance subjects; logistic regression analysis showed that subjects with TT genotype of rs3856806 in PPARγ had higher risk for diabetes compared to CC (OR: 1.58, 95%CI: 1.104–2.761, P = 0.032). The gene discussed is PPARG; the disease is diabetes mellitus.