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Closing in on a “familial cholestasis gene”
Author(s) -
Wagstaff Joseph,
Jonas Maureen M.
Publication year - 1995
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.1840220540
Subject(s) - progressive familial intrahepatic cholestasis , locus (genetics) , genetics , cholestasis , biology , haplotype , gene , allele , medicine , endocrinology , liver transplantation , transplantation
It is now feasible to map disease genes by screening the genome for linkage disequilibrium between the disease and marker alleles. This report presents the first application of this approach for a previously unmapped locus. A gene for benign recurrent intrahepatic cholestasis ( BRIC ) was mapped to chromosome 18 by searching for chromosome segments shared by only three distantly related patients. The screening results were confirmed by identifying an extended haplotype conserved between the patients. Probability calculations indicate that such segment sharing is unlikely to arise by chance. Searching the genome for segments shared by patients is a powerful empirical method for mapping disease genes. Computer simulations suggest that, in appropriate populations, the approach may be used to localize genes for common diseases. A locus for progressive familial intrahepatic cholestasis (PFIC), also known as Byler disease, has been mapped to a 19 cM region of chromosome 18 by a search for shared segments, using patients from the Amish kindred in which the disorder was originally described. A similar liver disease, benign recurrent intrahepatic cholestasis (BRIC), recently has been mapped to the same region, suggesting that these two diseases are caused by mutations in the same gene. Although PFIC and BRIC are clinically distinct diseases, episodic attacks of jaundice and pruritus, with elevated concentrations of bile acid in serum, are seen in both disorders. In PFIC patients, these attacks result in progressive liver damage and death. The clinical and biochemical features of PFIC and BRIC are suggestive of a defect in primary bile acid secretion. The biology of bile secretion is of great interest because of its vital importance in digestion of dietary fats as well as in secretion of xenobiotics and metabolic waste products. Cloning of the gene (or genes) responsible for PFIC and BRIC will likely provide important insights into this pathway. (Reprinted by permission of Oxford University Press).