Autozygosity mapping of Bardet-Biedl syndrome to 12q21.2 and confirmation of FLJ23560 as BBS10

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous autosomal recessive disorder characterized by variable obesity, pigmentary retinopathy, polydactyly, mental retardation, hypogonadism and renal failure. In order to identify novel BBS loci we undertook autozygosity mapping studies using high-density SNP microarrays in consanguineous kindreds. We mapped a BBS locus to a 10.1Mb region at 12q15 - q21.2 in a large Omani BBS family ( peak lod score 8.3 at theta = 0.0 for marker D12S1722) that contained the recently described BBS10 locus. Mutation analysis of candidate genes within the target interval, including the BBS10 gene, revealed a homozygous frameshift mutation in FLJ23560 and mutations were also detected in four smaller consanguineous families with regions of autozygosity at 12q21.2. These findings (a) confirm a previous report that FLJ23560 ( BBS10) mutations are a significant cause of BBS, and (b) further demonstrate the utility of high-density SNP array mapping in consanguineous families for the mapping and identification of recessive disease genes.