Global and tissue specific knock-out or mutation of clock genes (Rev-erbα/β-/-, Cry1/2-/-, Bmal1-/- and ClockΔ19, Bmal1Δhep) promote hepatic steatosis, and alter blood glucose and lipid homeostasis in lean and high fat diet (HFD) fed obese mice24–28. This evidence concerns the gene CLOCK and fatty liver disease.