Several physiological changes are observed in obese patients, which could potentially influence the distribution and clearance of certain drugs.47 Clearance of drugs primarily metabolized by UGT, such as olanzapine, appears to be higher in obese patients, and trends suggesting higher clearance values were observed in some studies, but not all, for drugs metabolized through CYP1A2.48 Obesity is often associated with chronic low-grade inflammation,49 which may decrease CYP1A2 activity. The gene discussed is CYP1A2; the disease is obesity due to melanocortin 4 receptor deficiency.