Excerpt
Methods: We ascertained 11 kindreds containing 25 affected individuals with ARC syndrome. Initially we excluded linkage to the potential candidate genes, ABCB4 and ATP8B1, which are implicated in other disorders that cause neonatal cholestasis with low gGT activity. We then undertook a genome-wide linkage scan using the Affymetryx 10K SNP chip in 7 affected individuals from 6 consanguineous ARC kindreds.
Results: Inspection of the results from the 10,000 SNPs revealed 8 regions of extended homozygosity shared by all affected individuals. These were further analysed by typing microsatellite markers in 64 individuals from 11 consanguineous families. A 3 Megabase region of homozygosity (maximum two-point LOD score of 9.8) within 15q25-q26 was identified.
Conclusion: We have mapped the ARC syndrome locus and mutation analysis of candidate genes by direct sequencing is in progress. Identification of the ARC syndrome gene will offer families a possibility for prenatal diagnosis and novel insights into the pathophysiology of this complex disease.