MDR3 gene defect in adults with symptomatic intrahepatic and gallbladder cholesterol cholelithiasis.
OBJECTIVE
Many studies indicate that gallstone susceptibility has genetic components. MDR3 is the phosphatidylcholine translocator across the hepatocyte canalicular membrane. Because phospholipids are a carrier and a solvent of cholesterol in hepatic bile, we hypothesized that a defect in the MDR3 gene could be the genetic basis for peculiar forms of cholesterol gallstone disease, in particular those associated with symptoms and cholestasis without evident common bile duct stone.


METHODS
We studied 6 adult patients with a peculiar form of cholelithiasis. MDR3 gene sequence was determined by reverse-transcription polymerase chain reaction amplification of mononuclear cell RNAs followed by direct sequencing. Hepatic bile was analyzed in 2 patients.


RESULTS
All patients shared the following features: at least 1 episode of biliary colic, pancreatitis, or cholangitis; biochemical evidence of chronic cholestasis; recurrence of symptoms after cholecystectomy; presence of echogenic material in the intrahepatic bile ducts; and prevention of recurrence by ursodeoxycholic acid therapy. Hepatic bile composition showed a high cholesterol/phospholipid ratio and cholesterol crystals. In all patients, we found MDR3 gene mutations involving a conserved amino acid region.


CONCLUSIONS
These preliminary observations suggest that MDR3 gene mutations represent a genetic factor involved in this peculiar form of cholesterol gallstone disease in adults. They require further studies to assess the prevalence of MDR3 gene defects in symptomatic and silent cholesterol gallstone disease.
Rosmorduc
O
O
Service d'Hépato-gastroentérologie, Hôpital Saint-Antoine, Assistance publique-Hôpitaux de Paris, France.
Hermelin
B
B
Poupon
R
R
D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics*; D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D001646:Bile / Q000737:chemistry; D002769:Cholelithiasis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002784:Cholesterol / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014580:Ursodeoxycholic Acid / Q000627:therapeutic use
D018435:ATP Binding Cassette Transporter, Subfamily B; D018528:ATP-Binding Cassette Transporters; D014580:Ursodeoxycholic Acid; D002784:Cholesterol; C095122:multidrug resistance protein 3