An HFD hasbeen shown to increase CYP1B1 expression in adipose tissue in mice, whilstCYP1B1 deficiency attenuates HFD-induced obesity and improves insulinsensitivity without changing calorific intake, suggesting CYP1B1 may modulateenergy metabolism.118 Furthermore, inhibition of the aryl hydrocarbon receptor, an upstreamactivator of CYP1B1 expression, resulted in the downregulation of CYP1B1 andinhibited hypertrophy and hyperplasia in visceral adipose tissue, reversing theeffects of HFD.121. The gene discussed is CYP1B1; the disease is obesity due to melanocortin 4 receptor deficiency.