Exome sequencing in a Romanian Bardet-Biedl syndrome cohort revealed an overabundance of causal BBS12 variants

Sheraz Khan, Ina Ofelia Focșa, Magdalena Budișteanu, Cristina Stoica, Florina Nedelea, Laurențiu Bohîlțea, Lavinia Caba, Lăcrămioara Butnariu, Monica Pânzaru, Cristina Rusu, Claudia Jurcă, Adela Chirita-Emandi, Claudia Bănescu, Wasim Abbas, Azita Sadeghpour, Shahid Mahmood Baig, Mihaela Bălgrădean, Erica E. Davis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Bardet-Biedl syndrome (BBS), is an emblematic ciliopathy hallmarked by pleiotropy, phenotype variability, and extensive genetic heterogeneity. BBS is a rare (~1/140,000 to ~1/160,000 in Europe) autosomal recessive pediatric disorder characterized by retinal degeneration, truncal obesity, polydactyly, cognitive impairment, renal dysfunction, and hypogonadism. Twenty-eight genes involved in ciliary structure or function have been implicated in BBS, and explain the molecular basis for ~75%–80% of individuals. To investigate the mutational spectrum of BBS in Romania, we ascertained a cohort of 24 individuals in 23 families. Following informed consent, we performed proband exome sequencing (ES). We detected 17 different putative disease-causing single nucleotide variants or small insertion–deletions and two pathogenic exon disruptive copy number variants in known BBS genes in 17 pedigrees. The most frequently impacted genes were BBS12 (35%), followed by BBS4, BBS7, and BBS10 (9% each) and BBS1, BBS2, and BBS5 (4% each). Homozygous BBS12 p.Arg355* variants were present in seven pedigrees of both Eastern European and Romani origin. Our data show that although the diagnostic rate of BBS in Romania is likely consistent with other worldwide cohorts (74%), we observed a unique distribution of causal BBS genes, including overrepresentation of BBS12 due to a recurrent nonsense variant, that has implications for regional diagnostics.

Original languageEnglish (US)
Pages (from-to)2376-2391
Number of pages16
JournalAmerican Journal of Medical Genetics, Part A
Volume191
Issue number9
DOIs
StatePublished - Sep 2023

Keywords

  • ciliopathy
  • pleiotropy
  • polydactyly
  • retinal dystrophy
  • second-site modifiers
  • urogenital malformations

ASJC Scopus subject areas

  • Genetics(clinical)
  • Genetics

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