<prompt> Dubin johnson syndrome is caused by mutation of:MRP 2MDR 1FIC 1BSEP  <response>: F1C1 is defective in progressive familial intrahepatic cholestasis type 1 PFIC1 and benign recurrent intrahepatic cholestasis type 1 BRIC1 BSEP is defective in PFIC2 and BRIC2 Mutations of MRP2 ABCC2 cause the Dubin-Johnson syndrome, an inherited form of conjugated hyperbilirubinemia A defective MDR3 ABCB4 results in PFIC3 The cystic fibrosis transmembrane regulator CFTR, ABCC7 located on bile duct epithelial cells but not on canalicular membranes is defective in cystic fibrosis This is a difficult area to understand Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 2616 