While no association was observed between the rs724030 variant in MTNR1B and prediabetes risk in the overall cohort (P > 0.05), we found the G allele of this variant was associated with higher fasting and 30-minute plasma glucose levels, decreased Insulinogenic Index (IGI), and oral disposition index (DIo) (P = 0.009, 0.001, 0.001, and 0.007, respectively) in the normal glucose tolerance (NGT) individuals with normal BMI levels. The gene discussed is MTNR1B; the disease is prediabetes syndrome.