DRD2 and obesity due to melanocortin 4 receptor deficiency: We identified 31 genes linked to both obesity and pain, including MC4R (appetite regulation and obesity), CYP19A1 (estrogen synthesis affecting body fat distribution), IRS1 (insulin signaling linked to obesity), FAAH (endocannabinoid system in appetite regulation), and DRD2 (dopamine in reward and pleasure affecting food consumption) [54], which play key roles in pain, obesity, and appetite regulation.