Unlike general obesity, which develops over time and can be managed by lifestyle changes, TTR-HO is related to fundamental changes in satiety and energy expenditure systems, leading to hyperphagia, reduced energy expenditure, and rapid weight gain4,5, and treatments for general obesity are largely ineffective for patients with TTR-HO9. The gene discussed is HMOX1; the disease is obesity due to melanocortin 4 receptor deficiency.