The search strategy incorporated Medical Subject Headings (MeSH) and free-text terms combined with Boolean operators, including keywords such as "bariatric surgery", "metabolic surgery", "Roux-en-Y gastric bypass", "sleeve gastrectomy", "gastric bypass", "obesity", "overweight", "type 2 diabetes", "T2DM", "GLP-1 receptor agonist", "SGLT2 inhibitor", "metformin", and "randomized controlled trial". Only peer-reviewed, full-text articles published in English were included. The gene discussed is GLP1R; the disease is obesity due to melanocortin 4 receptor deficiency.