GIPR and obesity due to melanocortin 4 receptor deficiency: GLP-1R agonists (GLP-1RA) are utilized clinically for the treatment of type 2 diabetes (T2D) and obesity (2, 3) and a single GIP receptor–GLP-1 receptor (GIPR–GLP-1R) coagonist, tirzepatide (TZP), is approved for the treatment of T2D (2, 4) and obesity (5).