No cases of diabetes, impaired glucose tolerance, and acanthosis nigricans; lower fasting glucose in subjects <30 years old vs controls; HbA1c insignificantly higher in patients ≥30 than <30 years old; increased area under the curve for insulin in oral glucose tolerance test in all patients; higher 2-hour insulin in patients ≥30 years old vs controls; higher area under the curve for insulin after oral glucose load in I172N group vs controls and vs null and I2G genotypes. This evidence concerns the gene INS and diabetes mellitus.