reported reduced clearance of cortisol, a partial CYP3A substrate, in anorexia nervosa patients compared to healthy subjects.16 Cachectic patients have been reported to have both increased and decreased CYP3A metabolism,17, 18 but not to have altered liver content of CYP3A proteins.19 Altogether, conflicting reports make it difficult to conclude whether CYP3A metabolism in underweight patients diverges from normal‐weight subjects. The gene discussed is CYP3A4; the disease is anorexia nervosa.