The insulin resistance seen in Cushing's syndrome causes its major symptoms (obesity, glucose intolerance, hypertension, and dyslipidemia); it is thought that a similar mechanism is responsible for the metabolic syndrome [4, 5], although patients who have the metabolic syndrome by definition do not have ACTH or cortisol producing tumors. The gene discussed is POMC; the disease is Cushing syndrome due to macronodular adrenal hyperplasia.