In supporting this hypothesis, Tmprss6 KO mice, which had high levels of hepcidin and low levels of plasma iron, were resistant to high-fat diet-induced obesity and hepatic steatosis, as indicated by less total body fat mass, reduced adipocyte sizes and weights in WAT and BAT, and diminished lipid deposits and triglyceride contents in the liver [110]. Here, TMPRSS6 is linked to obesity due to melanocortin 4 receptor deficiency.