Sequence variants in four genes underlying Bardet-Biedl syndrome in consanguineous families

PURPOSE: To investigate the molecular basis of Bardet-Biedl syndrome (BBS) in five consanguineous families of Pakistani origin. METHODS: Linkage in two families (A and B) was established to BBS7 on chromosome 4q27, in family C to BBS8 on chromosome 14q32.1, and in family D to BBS10 on chromosome 12q21.2. Family E was investigated directly with exome sequence analysis. RESULTS: Sanger sequencing revealed two novel mutations and three previously reported mutations in the BBS genes. These mutations include two deletions (c.580_582delGCA, c.1592_1597delTTCCAG) in the BBS7 gene, a missense mutation (p.Gln449His) in the BBS8 gene, a frameshift mutation (c.271_272insT) in the BBS10 gene, and a nonsense mutation (p.Ser40*) in the MKKS (BBS6) gene. CONCLUSIONS: Two novel mutations and three previously reported variants, identified in the present study, further extend the body of evidence implicating BBS6, BBS7, BBS8, and BBS10 in causing BBS.