Case reports, when effective, help clinicians understand meaningful differences in disease presentation; in addition, they highlight practical treatment approaches. An excellent example of one such case report is the following:
- Zellos A et al. JPGN 2012; 55: 88-90
These authors present a case with unique features that highlight some of the clinical problems with benign recurrent intrahepatic cholestasis (BRIC) and progressive familial intrahepatic cholestasis (PFIC). BRIC1 and PFIC1 are associated with mutations in ATP8B1; BRIC2 and PFIC2 are associated with mutations in ABCB11. The primary difference between BRIC and PFIC is the phenotypic expression. In BRIC, individuals have episodes of cholestasis; in PFIC, progressive chronic liver disease develops in the first months of life. PFIC2/ABCB11 mutations cause defective bile salt export pump (BSEP) at the bile-canniculus membrane.
Both ATP8B1 and ABCB11 intrahepatic cholestasis conditions present in a similar fashion with low GGT values. In this case report, a 5-year-old presented with jaundice, acholic stools and dark urine. His laboratory values revealed an ALT of 60 U/L, direct bilirubin of 7.6 mg/dL and gamma-glutamyl transpeptidase (GGT) of 10 U/L. Initially, after exclusion of other liver conditions (eg. NL MRCP, copper studies, α-1 antitrypsin, autoimmune serology, infectious etiologies), the authors suspected ‘a clinicopathologic intergrade between BRIC and PFIC’ likely due to ATP8B1 as there was BSEP expression on liver biopsy immunostaining. After sequencing did not demonstrate any ATP8B1 mutations, the authors identified two heterozygote mutations in ABCB11.
From a treatment standpoint, once nasobiliary drainage (NBD) was in place, the patient quickly improved. This occurred after >6 weeks of failure with urosdeoxycholic acid/conservative measures. As a precaution, the authors cultured the bile once a week and instituted antibiotic treatment when positive cultures were identified.
One other point alluded to by the authors is that the natural history of BRIC2 is poorly described. Whether this disorder is truly ‘benign’ as the name suggests is unclear. In patients with similar mutations who develop PFIC2, there is a high risk of hepatocellular carcinoma (HCC).
Intrahepatic Cholestasis Genes/Disorder (Clin Liver Dis 2006; 10: 27-53.)
Gene: Disorder (protein)
ABCB11: PFIC 2, BRIC 2 (BSEP)
ABCB4: PFIC 3, ICP (MDR3)
CFTR: CF (CFTR)
ATP8B1: PFIC1 -Byler’s (FIC1), BRIC, GFC -Greenland Familial
CLDN1: NISCH (Claudin 1) -neonatal sclerosing cholangitis/icthyosis
VPS33B: ARC syndrome (Vascular protein sorting 33) -arthrogryposis-renal dysfn-cholestasis, low GGT
AKR1D1: BAS: Bile acid synthetic defect: neonatal cholestasis with giant cell hepatitis
HSD3B7: BAS (C27-3β-HSD)
CYP7BI: BAS (CYP7BI)
TJP2: (ZO-2) FHC: Familial hypercholanemia (tight junction protein)
BAAT: FHC (BAAT)
EPHX1: FHC (epoxide hydrolase)
JAG1: Alagille (JAG1) JAG1 is transmembrane cell-surface protein important in regulating cell fate during embryogenesis
PKHD1: ARPKD (fibrocystin -important in ciliary function and tubulogenesis)
PRKCSH: ADPLD (hepatocystin)
ABCC2: Dubin-Johnson syndrome (MRP2)
CIRH1A: NAIC -N Amer Indian childhood cirrhosis (Cirhin)
Additional references for BRIC/low GGT PFIC:
- -JPGN 2010; 51: 494. Use of biliary diversion –helpful in 18 PFIC2 cases with long-term f/u.
- -Liver Transplantation 2010; 16: 856. 6 patients developed recurrent low gamma-glutamyl transpeptidase cholestasis, that mimics BSEP disease, following transplantation. All had documented genetic defects in ABCB11 that were predicted to lead to a congenital absence of BSEP protein.
- -NEJM 2009; 361: 1359. Recurrence of BSEP deficiency p OLT due to antibodies against BSEP
- -Hepatology 2010; 51: 1645. n=62 children & clinical course.
- -Gastroenterol 2008; 134: 1203. Severe BSEP –82 different mutations in 109 families. (n=132 patients)
- -JPGN 2008; 46: 241. Excellent review. FIC1 caused by mutations in ATP8B1, PFIC 2 caused by mutations in ABCB11 which encodes BSEP – bile salt export pump. Increased risk of HCC in PFIC2 especially.
- -J Pediatr 2007; 150: 556. Increase risk of HCC in PFIC2.
- -Hepatology 2006; 44: 478-486. Cases of pediatric HCC in PFIC-2
- -Gastroenterol 2006; 130: 908. Review of canalicular transport defects.
- -Hepatology 2005; 42: 222. summary of cholestasis workshop
- -Gastroenterol 2004; 126: 322. Review of bile salt transporters.
- -JPGN 2002; 34: 7A. FTT, diarrhea persist p biliary diversion or transplant.
PFIC3 -High GGT
- -Gastroenterol 2003; 124: 1037-42. MDR3 mutations causing cholelithiasis, cholestasis, biliary cirrhosis, & pregnancy cholestasis.
- -Gastroenterol 2001; 120: 1448-1458. n=31 cases. MDR3 mutations. ABCB4 gene
- -Gastroenterol 2001; 120: 1459-67. Gallbladder stones & chronic cholestasis in 6 MDR3+ pts. Avg age of presentation: 2.9yrs. Avg age of Tx: 7.5yrs. Sx/S : high ggt cholestasis, pruritus, intrahepatic cholestasis of pregnancy in heterozygotes (& c contraception)
- -Hepatology 1996; 23: 904-8. MDR3 gene assoc c PFIC