Table 1 Main characteristics of Progressive Familial Intrahepatic Cholestasis (PFIC)
| Â | PFIC1 (Byler's disease) | PFIC2 (BSEP deficiency) | PFIC3 (MDR3 deficiency) |
|---|---|---|---|
Transmission | autosomal recessive | autosomal recessive | autosomal recessive |
Pruritus | severe | severe | moderate |
Serum GGT activity | normal | normal | high |
Ductular proliferation | absent | absent | present |
Serum primary bile acid concentration | very high | very high | high |
Bile composition | low primary bile acid concentration | very low primary bile acid concentration | low phospholipid concentration |
Chromosomal locus | 18q21-22 | 2q24 | 7q21 |
Gene/protein | ATP8B1 FIC1 | ABCB11 BSEP | ABCB4 MDR3 |
Hepatocyte location | canalicular membrane | canalicular membrane | canalicular membrane |
Other sites of expression | Cholangiocytes Intestine, Pancreas | none | none |
Functional defect | ATP-dependent aminophospholipid transport | ATP-dependent bile acid transport in bile | ATP-dependent phosphatidylcholine translocation in bile |