FASN and polyostotic fibrous dysplasia: In the liver from WD-fed MC4R-KO mice, PFD did not affect expression of de novo lipogenic genes such as sterol regulatory element-binding protein-1c (Srebp1c), fatty acid synthase (Fasn), and acetyl-CoA carboxylase (Acc1) as well as fatty acid β-oxidation genes such as acyl-CoA oxidase 1 (Acox1) and carnitine palmitoyltransferase 1a, liver (Cpt1a), and triglyceride transfer protein (Mttp) (Fig. 2a).