Girls with obesity presented a hormonal profile characterized by increased levels of circulating insulin (p < 0.0001), leptin (p < 0.0001), c-peptide (p < 0.0001), amylin (p = 0.0018), glucagon (p = 0.0195), and glucagon-like peptide-1 (GLP-1, p = 0.0001), relative to eutrophic controls. Here, GCG is linked to obesity due to melanocortin 4 receptor deficiency.