Genetics in primary sclerosing cholangitis.

Primary sclerosing cholangitis (PSC) is a chronic and severe inflammatory disease leading to fibrotic bile duct destruction and in most cases liver cirrhosis. As in other complex genetic diseases, the sibling risk of PSC is more than ten times that of the general population. Recent genome-wide association studies have consistently identified several genetic susceptibility loci. The overlap of these loci with susceptibility loci in other chronic inflammatory diseases is considerable, and offers intriguing opportunities for transfer of pathogenetic knowledge and potentially treatment options. In the present article we summarise the present knowledge on PSC genetics with a particular emphasis on the major histocompatibility complex (MHC). We discuss the clinical relevance of the risk loci and elaborate on the insight that may be obtained from associated inflammatory conditions and existing murine knock-out models.