GLP1R and obesity due to melanocortin 4 receptor deficiency: Within the past 2 decades, glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) have emerged as effective agents to improve glycaemic control in type 2 diabetes and to reduce body weight in people with overweight or obesity (Müller et al., 2019; Nauck et al., 2020).