We found a significant negative correlation between PPARGΔ5/cPPARG ratio and SLC2A4 expression only in patients with overweight/obesity as well as in those having altered glucose metabolism (i.e., with impaired glucose tolerance or T2D), but not in individuals with normal BMI or with normal glucose tolerance. This evidence concerns the gene SLC2A4 and obesity due to melanocortin 4 receptor deficiency.