It is also interesting to note that UDCA treatment may contribute to the relocalisation of ABCB4 at the canalicular membrane of hepatocytes in in vivo systems, as proposed for ABCB11 and ABCC2 in cholestatic rat models45,46 and ABCB11 in PFIC2 patients47. The gene discussed is ABCB4; the disease is progressive familial intrahepatic cholestasis type 2.