A novel intronic mutation of PDE6B is a major cause of autosomal recessive retinitis pigmentosa among Caucasus Jews.
Year: 2019
Type: article
Study design: Observational Study
Abstract: Purpose: To identify the genetic basis for retinitis pigmentosa (RP) in a cohort of Jewish patients from Caucasia. Methods: Patients underwent a detailed ophthalmic evaluation, including funduscopic examination, visual field testing, optical coherence tomography (OCT), and electrophysiological tests, electroretinography (ERG) and visual evoked potentials (VEP). Genetic analysis was performed with a combination of whole exome sequencing (WES) and Sanger sequencing. Bioinformatic analysis of the WES results was performed via a customized pipeline. Pathogenicity of the identified intronic variant was evaluated in silico using the web tool Human Splicing Finder, and in vitro, using a minigene-based splicing assay. Linkage disequilibrium (LD) analysis was used to demonstrate a founder effect, and the decay of LD over generations around the mutation in Caucasus Jewish chromosomes was modeled to estimate the age of the most recent common ancestor. Results: intron 15. The c.1921-9C>G variant was predicted to generate a novel acceptor splice site, nine bases upstream of the original splice site of intron 15. In vitro splicing assay demonstrated that this novel acceptor splice site is used instead of the wild-type site, leading to an 8-bp insertion into exon 16, which is predicted to cause a frameshift. The presence of a common ancestral haplotype in mutation-bearing chromosomes was compatible with a founder effect. Conclusions: c.1921-9C>G intronic mutation is a founder mutation that accounts for at least 40% (6/15 families) of autosomal recessive RP among Caucasus Jews. This result is highly important for molecular diagnosis, carrier screening, and genetic counseling in this population.
Source: Europe PMC (PubMed Central)
Institutions: Technion – Israel Institute of Technology, Bnai Zion Medical Center, Università Cattolica del Sacro Cuore, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Azienda Socio Sanitaria Territoriale Grande Ospedale Metropolitano Niguarda, Hadassah Medical Center, Tel Aviv University, Hillel Yaffe Medical Center, Rambam Health Care Campus
Language: English
Subfield: Ophthalmology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2941269147