Progressive familial intrahepatic cholestasis

[3] PFIC-1 is caused by a variety of mutations in ATP8B1, a gene coding for a P-type ATPase protein, FIC-1, that is responsible for phospholipid translocation across membranes.

[citation needed] PFIC-2 is caused by a variety of mutations in ABCB11, the gene that codes for the bile salt export pump, or BSEP.

Retention of bile salts within hepatocytes, which are the only cell type to express BSEP, causes hepatocellular damage and cholestasis.

[citation needed] PFIC-3 is caused by a variety of mutations in ABCB4, the gene encoding multidrug resistance protein 3 (MDR3),[5] which codes for a floppase responsible for phosphatidylcholine translocation.

End-stage disease in all forms of PFIC defined to date is characterized by bridging fibrosis with duct proliferation in peri-portal regions.

Serum cholesterol levels are typically not elevated, as is seen usually in cholestasis, as the pathology is due to a transporter as opposed to an anatomical problem with biliary cells.