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Published Online: 1 February 2017

Design and Validation of a New MLPA-Based Assay for the Detection of RS1 Gene Deletions and Application in a Large Family with X-Linked Juvenile Retinoschisis

Publication: Genetic Testing and Molecular Biomarkers
Volume 21, Issue Number 2

Abstract

Aims: X-linked juvenile retinoschisis (XLRS) is a severe ocular disorder that can evolve to blindness. More than 200 different disease-causing mutations have been reported in the RS1 gene and approximately 10% of these are deletions. Since transmission is X-linked, males are always affected and females are usually carriers. The identification of female carriers is always important and poses a technical challenge. Therefore, we sought to develop a multiplex ligation dependent probe amplification (MLPA)-based method to identify deletions or duplications in this gene. We then used our assay to study a large XLRS family.
Methods: We designed six probes specific for each RS1 exon and then optimized and validated our method using control samples with known gene deletions. In the XLRS family, RS1 gene copy number variation was assessed by “home-made” MLPA analysis and by single nucleotide polymorphism (SNP) array analysis using the CytoScan HD Array. Direct sequencing was used for deletion breakpoint mapping.
Results: Our assay detected all deletions in control samples. All affected males of the family were positive for a deletion of exon 2 of the RS1 gene (RS1:NM_000330:c.53-?_78+?del). Carrier females were also identified.
Conclusion: Our method is easily replicated, reliable, and inexpensive and allows female carriers to be detected. This is the first report of deep characterization of a whole exon deletion in the RS1 gene.

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References

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Published In

cover image Genetic Testing and Molecular Biomarkers
Genetic Testing and Molecular Biomarkers
Volume 21Issue Number 2February 2017
Pages: 116 - 121
PubMed: 27997221

History

Published in print: February 2017
Published online: 1 February 2017
Published ahead of print: 20 December 2016

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    Affiliations

    Annalisa Nicoletti
    MAGI Non-Profit Human Medical Genetics Institute, Rovereto, Trento, Italy.
    Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy.
    Lucia Ziccardi
    “G.B. Bietti” Foundation—IRCCS, Roma, Italy.
    Paolo Enrico Maltese
    MAGI Non-Profit Human Medical Genetics Institute, Rovereto, Trento, Italy.
    Sabrina Benedetti
    MAGI Non-Profit Human Medical Genetics Institute, Rovereto, Trento, Italy.
    Orazio Palumbo
    Medical Genetics Service, “IRCCS Casa Sollievo della Sofferenza,” San Giovanni Rotondo, Italy.
    Michelina Rendina
    Medical Genetics Service, “IRCCS Casa Sollievo della Sofferenza,” San Giovanni Rotondo, Italy.
    Leonardo D'Agruma
    Medical Genetics Service, “IRCCS Casa Sollievo della Sofferenza,” San Giovanni Rotondo, Italy.
    Benedetto Falsini
    Institute of Ophthalmology, Policlinico Gemelli, Catholic University, Roma, Italy.
    Xinjing Wang
    DNA Diagnostic Laboratory, Ophthalmic Genetics and Visual Function Branch, National Eye Institute/NIH, Bethesda, Maryland.
    Matteo Bertelli
    MAGI Non-Profit Human Medical Genetics Institute, Rovereto, Trento, Italy.

    Notes

    Address correspondence to:Paolo Enrico Maltese, PhDMAGI Non-Profit Human Medical Genetics InstituteRoveretoTrentoItaly
    E-mail: [email protected]

    Author Disclosure Statement

    No competing financial interests exist.

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