Cholestase intrahépatique familiale progressive à activité gamma-glutamyl-transférase basse

Progressive familial intrahepatic cholestasis (PFIC) is a group of familial cholestatic conditions caused by defects in biliary epithelial transporters. The clinical presentation usually occurs first in childhood with progressive cholestasis. This usually leads to failure to thrive, cirrhosis, and the need for liver transplantation. Types of progressive familial intrahepatic cholestasis are as follows: Type 1 (OMIM #211600), also called Byler disease Type 2 (OMIM #601847), also called ABCB11 deficiency or BSEP deficiency Type 3 (OMIM #602347), also called ABCB4 deficiency or MDR3 deficiency Type 4 (OMIM #615878), from mutation in TJP2 The onset of the disease is usually before age 2, but patients have been diagnosed with PFIC even into adolescence. Of the three entities, PFIC-1 usually presents earliest. Patients usually present in early childhood with cholestasis, jaundice, and failure to thrive. Intense pruritus is characteristic; in patients who present in adolescence, it has been linked with suicide. Patients may have fat malabsorption, leading to fat soluble vitamin deficiency, and complications, including osteopenia. 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. It was previously identified as clinical entities known as Byler's disease and Greenland-Eskimo familial cholestasis. Patients with PFIC-1 may also have watery diarrhea, in addition to the clinical features below, due to FIC-1's expression in the intestine. How ATP8B1 mutation leads to cholestasis is not yet well understood. 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. PFIC-3 is caused by a variety of mutations in ABCB4, the gene encoding multidrug resistance protein 3 (MDR3), which codes for a floppase responsible for phosphatidylcholine translocation.