Clinical and Molecular Characterization of Bardet–Biedl Syndrome in Consanguineous Populations: The Power of Homozygosity Mapping

Leen Abu Safieh¹, Mohammed Aldahmesh¹, Hanan Shamseldin¹, Mais Hashem¹, Ranad Shaheen¹, Hisham Alkuraya², Salwa Hazzaa¹, Ali Al-Rajhi², Fowzan Alkuraya^1,*

¹ KFSHRC, Saudi Arabia;
² KKESH, Saudi Arabia

Correspondence to: , ; alkuraya{at}mobilyconnect.com.sa

Accepted 24 September 2009

Bardet–Biedl syndrome (BBS) is a ciliopathy with pleiotropic effect that manifests primarily as renal insufficiency, polydactyly, retinal dystrophy, and obesity. Current phenotype/genotype correlation is insufficient to predict the likely causative mutation which makes sequencing of all 14 BBS genes often necessary but highly complicated way to identify the underlying genetic defect in affected patients. In this study we show that homozygosity mapping is a robust approach that is highly suited for genetically heterogeneous autosomal recessive disorders in populations where consanguinity is prevalent. This approach allowed us to quickly identify seven novel mutations in seven families with BBS. Some of these mutations would have been missed by unguided routine sequencing which suggests that missed mutations in known BBS genes could be more common than previously thought. This study, the largest to date on Saudi BBS families, also revealed interesting phenotypic aspects of BBS including the first report of nonsyndromic retinitis pigmentosa as a novel BBS phenotype.

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