We hypothesized that circulating levels of GHBP, IGF-1 and IGFBP-3 are altered in children with overweight or obesity (overweight/obesity) compared to lean children and that gene expression of these factors in AT cells, also considering an increased fat mass with obesity, is related to those changes. This evidence concerns the gene IGFBP3 and obesity due to melanocortin 4 receptor deficiency.