Type:
Educational Exhibit
Keywords:
Cirrhosis, Calcifications / Calculi, Education, Cholangiography, Ultrasound, MR, Biliary Tract / Gallbladder, Abdomen
Authors:
S. Derhy1, J. Benzimra2, O. Rosmorduc1, Y. Menu1, R. Poupon1, L. Arrivé1; 1Paris/FR, 2Clichy/FR
DOI:
10.1594/ecr2013/C-0849
Background
Definition :
The LPAC syndrome is a rare genetic disorder,
characterized by three most important elements : biliary symptoms before the age of 40,
recurrence of the symptoms after cholecystectomy and intrahepatic microlithiasis or intrahepatic hyperechogenic foci.
Other minor criteria have been described,
such as mild chronic cholestasis,
at least one episode of cholangitis,
acute pancreatitis or biliary colic,
efficiency of ursodesoxycolic acid (UDCA) and similar symptoms in first degree relative.
ABCB4 gene mutations have been described in patients with LPAC syndrome in 25 to 56 % of cases.
Physiopathology :
ABCB4 gene encodes for MDR3 (multidrug resistance 3P glycoprotein).
MDR3 are phospholopid translocators involved in biliary phosphatidylcholine excretion.
The result of these mutations is a lack of phosphatidylcholine in bile.
- Phosphatidylcholine normally chaperones bila acids,
preventing damage to the biliary epithelium.
The "unchaperoned" bile acids in bile of patients with MDR3 deficiency cause a chronic chlangitis.
- Phosphatidylcholine normally also transports biliary cholesterol.
Patients with MDR3 deficiency have increased cholesterol saturation in bile,
resulting in cholesterol precipitation and gallstone formation.