Whole Exome Sequencing Identifies a Novel and a Recurrent Mutation inBBS2Gene in a Family with Bardet-Biedl Syndrome

Abstract

Bardet-Biedl syndrome (BBS) is a rare autosomal recessive disorder known to be caused by mutations in at least 19 BBS genes. We report the genetic analysis of a patient with indisputable features of BBS including cardinal features such as postaxial polydactyly, retinitis pigmentosa, obesity, and kidney failure. Taking advantage of next-generation sequencing technology, we applied whole exome sequencing (WES) with Sanger direct sequencing to the proband and her unaffected mother. A pair of heterozygous nonsense mutations in BBS2 gene was identified in the proband, one being novel and the other recurrent. The novel mutation, p.Y644X, resides in exon 16 and was also found in the heterozygous state in the mother. This mutation is not currently found in the dsSNP and 1000 Genome SNP databases and is predicted to be disease causing by in silico analysis. This study highlights the potential for a rapid and precise detection of disease causing gene using WES in genetically heterogeneous disorders such as BBS.

Meta‐analysis of genotype‐phenotype associations in Bardet‐Biedl syndrome uncovers differences among causative genes

“…The literature search was performed according to the protocol preregistered in Prospero (CRD42018096099) and it followed the PRISMA guidelines whenever applicable (Table S1 and Figure S1). In total, we identified 85 relevant studies (Abu Safieh et al, ; Agha et al, ; Ajmal et al, ; Al‐Hamed et al, ; Alazami et al, ; Aldahmesh et al, ; Azari et al, ; Badano, ; Baker et al, ; Bee, Chawla, & Zhao, ; Bennouna‐Greene et al, ; Billingsley et al, ; Billingsley, Vincent, Deveault, & Heon, ; Branfield Day et al, ; Braun et al, ; Bujakowska et al, ; Castro‐Sanchez et al, ; Chaki et al, ; Chul Yoon et al, ; Cox et al, ; Davies, ; Deveault et al, ; Ece Solmaz et al, ; Esposito et al, ; Estrada‐Cuzcano, Koenekoop, et al, ; Estrada‐Cuzcano, Neveling, et al, ; Fan et al, ; Fattahi et al, ; Fedick et al, ; Frank et al, ; Gerth, Zawadzki, Werner, & Heon, ; Ghadami et al, ; González‐del Pozo et al, ; Harville et al, ; Heon et al, ; Hjortshoj, Gronskov, Brondum‐Nielsen, & Rosenberg, ; Hjortshoj et al, ; Hulleman et al, ; Iannaccone et al, ; Innes et al, ; Iurian, Arts, Brunner, & Fintina, ; Janssen et al, ; Kamme, Mayer, Strom, Andréasson, & Weisschuh, ; Katsanis et al, ; Katsanis et al, ; Kerr, Bhan, & Héon, ; A. O. Khan, Decker, Bachmann, Bolz, & Bergmann, ; S. Khan et al, , S. A. Khan et al, ; Laurier et al, ; Leitch et al, ; Lim et al, ; Lindstrand et al, ; Lindstrand et al, ; M'Hamdi et al, ; Maria et al,…”

A systematic review of genetic syndromes with obesity

“…WES limits the capture and sequencing to gene exons, and is well suited for rare Mendelian disorders. Bee et al utilized this approach to identify a novel mutation (p.Y644X) in the BBS2 gene (74).…”

Established and emerging strategies to crack the genetic code of obesity

“…However, difficulty in distinguishing between causal and coincidental obesity in unique cases necessitates replication of these results in additional patients. WES has also discovered novel mutations and/or structural variants for syndromic obesity in previously implicated genes and revealed clinical heterogeneity in several obesity syndromes . For example, in a study of individuals with atypical Alström syndrome, novel ALMS1 mutations were identified using WES secondary to a negative classical genetic test of ALMS1 mutational hotspots .…”