Inborn errors of biliary canalicular transport are mainly progressive familial intrahepatic cholestasis (PFICs)
Progressive familial intrahepatic cholestasis (PFICs) [PFIC1 or Byler disease), type 2 (PFIC2) and type 3 (PFIC3)] are genetic disorders of bile secretion in which the fundamental abnormality is the direct or indirect defective hepatobilary transport of bile acids and/or phospholipids.
PFIC2
PFIC type 2 (PFIC2) is due to primarily impaired bile acid transport. In these patients, high levels of serum bile acids, together with severe progressive liver disease, are found.
PFIC type 2 is caused by a mutation in the bile salt export pump (BSEP, gene symbol ABCB11), the main agent responsible for the ATP-dependent secretion of monoanionic bile acids across the canalicular membrane.
The less severe variant of PFIC type 2 is benign recurrent intrahepatic cholestasis (BRIC) type 2. This is a mild condition characterized by intermittent crises of cholestasis without permanent liver damage. BRIC type 2 is also caused by mutations in ABCB11.
Intrahepatic cholestasis of pregnancy
Mutations in the BSEP gene have also been related to the aetiology of intrahepatic cholestasis of pregnancy.
References
Bile acids: chemistry, physiology, and pathophysiology. Monte MJ, Marin JJ, Antelo A, Vazquez-Tato J. World J Gastroenterol. 2009 Feb 21;15(7):804-16. PMID: 19230041