Twenty-five type 2 diabetes mellitus patients and 25 glucose-tolerant humans (CON) matched for sex, age, and BMI underwent mixed-meal tests to assess insulin sensitivity (OGIS) and beta cell function (ΔAUC(C-peptide)0–180 min/ΔAUC(glucose)0–180 min) in a cross-sectional study. This evidence concerns the gene INS and diabetes mellitus.