Instead, deficiency of the bile salt export pump BSEP (causing progressive familial intrahepatic cholestasis type 2, PFIC2) and FIC1 (causing PFIC1), in which bile acids enter hepatocytes but cannot be efficiently secreted into bile, causes severe liver injury [10, 21]. Here, ABCB11 is linked to progressive familial intrahepatic cholestasis type 2.