Identification of a locus for progressive familial intrahepatic cholestasis PFIC2 on chromosome 2q24

Progressive familial intrahepatic cholestasis (PFIC; OMIM 211600) is the second most common familial cholestatic syndrome presenting in infancy. A locus has previously been mapped to chromosome 18q21-22 in the original Byler pedigree. This chromosomal region also harbors the locus for benign recurrent intrahepatic cholestasis (BRIC) a related phenotype. Linkage analysis in six consanguineous PFIC pedigrees from the Middle East has previously excluded linkage to chromosome 18q21-22, indicating the existence of locus heterogeneity within the PFIC phenotype. By use of homozygosity mapping and a genome scan in these pedigrees, a locus designated "PFIC2" has been mapped to chromosome 2q24. A maximum LOD score of 8.5 was obtained in the interval between marker loci D2S306 and D2S124, with all families linked.