Article Text
Abstract
Background and aims: The aim of this study was to investigate the genetic aetiology of intrahepatic cholestasis of pregnancy (ICP) and the impact of known cholestasis genes (BSEP, FIC1, and MDR3) on the development of this disease.
Patients and methods: Sixty nine Finnish ICP patients were prospectively interviewed for a family history of ICP, and clinical features were compared in patients with familial ICP (patients with a positive family history, n=11) and sporadic patients (patients with no known family history of ICP, n=58). For molecular genetic analysis, 16 individuals from two independently ascertained Finnish ICP families were genotyped for the flanking markers for BSEP, FIC1, and MDR3.
Results: The pedigree structures in 16% (11/69) of patients suggested dominant inheritance. Patients with familial ICP had higher serum aminotransferase levels and a higher recurrence risk (92% v 40%). Both segregation of haplotypes and multipoint linkage analysis excluded BSEP, FIC1, and MDR3 genes in the studied pedigrees. Additionally, the MDR3 gene, previously shown to harbour mutations in ICP patients, was negative for mutations when sequenced in four affected individuals from the two families.
Conclusions: These results support the hypothesis that the aetiology of ICP is heterogeneous and that ICP is due to a genetic predisposition in a proportion of patients. The results of molecular genetic analysis further suggest that the previously identified three cholestasis genes are not likely to be implicated in these Finnish ICP families with dominant inheritance.
- intrahepatic cholestasis of pregnancy
- obstetric cholestasis
- linkage analysis
- ICP, intrahepatic cholestasis of pregnancy
- BSEP, bile salt export pump gene
- FIC1, familial intrahepatic cholestasis 1 gene
- MDR3, multiple drug resistance 3 gene
- PFIC, progressive familial intrahepatic cholestasis
- ATP8B1, ATPase class I type 8B
- BRIC, benign recurrent intrahepatic cholestasis
- ABCB11, ATP binding cassette subfamily B member 11
- γ-GT, gammaglutamyl transferase
- PGY3, P-glycoprotein 3
- HBV, hepatitis B virus
- HCV, hepatitis C virus
- ASAT, serum aspartate aminotransferase
- ALAT, serum alanine aminotransferase
- LOD score, logarithm of odds score
- PCR, polymerase chain reaction
- dNTPs, deoxynucleotidetriphosphates
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- ICP, intrahepatic cholestasis of pregnancy
- BSEP, bile salt export pump gene
- FIC1, familial intrahepatic cholestasis 1 gene
- MDR3, multiple drug resistance 3 gene
- PFIC, progressive familial intrahepatic cholestasis
- ATP8B1, ATPase class I type 8B
- BRIC, benign recurrent intrahepatic cholestasis
- ABCB11, ATP binding cassette subfamily B member 11
- γ-GT, gammaglutamyl transferase
- PGY3, P-glycoprotein 3
- HBV, hepatitis B virus
- HCV, hepatitis C virus
- ASAT, serum aspartate aminotransferase
- ALAT, serum alanine aminotransferase
- LOD score, logarithm of odds score
- PCR, polymerase chain reaction
- dNTPs, deoxynucleotidetriphosphates
Footnotes
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↵* M Savander, K Avela, and A Ropponen contributed equally to this work