Background
Progressive familial intrahepatic cholestasis (PFIC) is a group of rapidly progressive autosomal recessive disorders characterized by intrahepatic cholestasis. PFIC-3 is caused by mutations in the ATP-binding cassette subfamily B member 4 gene (ABCB4), which encodes multidrug resistance protein 3 (MDR3/ABCB4). Patients are usually in infancy or childhood, but cirrhosis and portal hypertension may be the first manifestation in older children or young adults. Case presentation: A 25-year-old young woman with recurrent abnormal hepatic function was mainly characterized by increased gamma glutamyl transpeptidase (GGT) and bile acid with cryptogenic cirrhosis. After 7 months of treatment with ursodeoxycholic acid (UDCA), her hepatic pathology suggested there were also obvious widening and venous fibrosis around the portal vein, and slight bile duct hyperplasia at the edge of the portal area. Infiltration of inflammatory cells around the portal vein and hepatocyte ABCB4/MDR3 protein was basically normal. Sequencing indicated the patient had heterozygous mutations in the ABCB4 gene: c.2696C > G and wes [hg19]7q21.12(87032513-87033422) × 1. Through SWISS-MODEL Predict for protein structures, the missense mutation
Conclusion
Novel heterozygous mutations are the molecular pathological cause of PFIC3 in this patient. All young adult patients with occult cirrhosis should be tested for ABCB4. Early diagnosis of PFIC3 and continued treatment with UDCA are key to improving prognosis and delaying the onset of end-stage liver disease.
