Clinical studies have reported elevated levels of plasma and urinary 20-HETE in disease states that include obesity and CYP1B1 knock out in mouse models has been reported to protect against obesity induced by a high-fat diet (Li et al., 2014; Larsen et al., 2015) and lack of CYP1B1 is linked to altered lipid metabolism, an association which may help protect against the negative health effects of obesity. Here, CYP1B1 is linked to obesity due to melanocortin 4 receptor deficiency.