GLP1R and obesity due to melanocortin 4 receptor deficiency: In recent years, glucagon-like peptide-1 receptor agonists (GLP-1 RAs, e.g., semaglutide) and hybrid gastric inhibitory polypeptide (GIP) analogs and GLP-1 RAs (GIP/GLP-1 RAs, e.g., tirzepatide) have emerged as novel pharmacological agents for the treatment of obesity [15,16].