In gene expression studies, we observed striking effects of Y67-FXR mutation on expression of Bsep. Intriguingly, a recent study has shown that mutations in the human FXR gene cause neonatal intrahepatic cholestasis, which is associated with undetectable Bsep expression as a consequence of loss of FXR function43. Here, ABCB11 is linked to intrahepatic cholestasis.