ATP8B1 and progressive familial intrahepatic cholestasis: PFIC3 is formed because of a defect in ABCB4, which encodes the MDR3 protein, eventually impairing biliary tract phospholipid secretion.38,39 The main clinical presentation of PFIC is cholestasis, jaundice, and pruritus, with symptoms typically appearing in infancy (for PFIC1 and PFIC2) or early childhood (for PFIC3).40 The biochemical features of PFIC1/2 are normal or low levels of GGT, elevated serum BA, and reduced primary BA concentration, while GGT levels are elevated in patients with PFIC3.