ATP8B1 and intrahepatic cholestasis: Progressive familial intrahepatic cholestasis (PFIC) is a group of rare cholestatic liver diseases caused by autosomal mutations in several genes, including ATP8B1 (encoding familial intrahepatic cholestasis 1 [FIC1]; PFIC type 1 [PFIC1]) and ABCB11 (encoding bile salt export pump [BSEP]; PFIC type 2 [PFIC2]) [1,2,3].