The incretin hormones glucagon‐like peptide‐1 (GLP‐1) and glucose‐dependent insulinotropic polypeptide (GIP), for example, increase postprandial insulin secretion (Nauck & Müller, 2023), with GLP‐1 being shown to lower plasma glucose in people with type 2 diabetes (Nauck et al., 1993), which led to the development and surge in clinical use of GLP‐1 receptor (GLP1R) agonists and, more recently, GLP1R/GIP receptor (GIPR) dual agonists for the treatment of type 2 diabetes and obesity (Gallwitz, 2022; Guccio et al., 2022; Nauck & Müller, 2023). The gene discussed is GIPR; the disease is obesity due to melanocortin 4 receptor deficiency.