CYP3A4 and obesity due to melanocortin 4 receptor deficiency: False positive results might occur in relationship with obesity, anorexia, chronic alcohol consumption, psychiatric illness, advanced age, oral contraception, and use of CYP3A4 inhibitors (which enhance the dexamethasone bioavailability) or in conditions causing a reduced cortisol-binding globulin, such as proteinuria [82,83,84,85,86].