Analysis of CBP (CREBBP) gene deletions in Rubinstein-Taybi syndrome patients using real-time quantitative PCR

Authors

  • Isabelle Coupry,

    Corresponding author
    1. Laboratoire de Génétique Humaine, Développement et Cancer, Université Victor Segalen Bordeaux 2, Bordeaux, France
    • Laboratoire de Génétique Humaine, Développement et Cancer, UniversitéVictor Segalen Bordeaux 2,146, Rue Léo Saignat,33076 Bordeaux, Cedex-France
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  • Laurence Monnet,

    1. Laboratoire de Génétique Humaine, Développement et Cancer, Université Victor Segalen Bordeaux 2, Bordeaux, France
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  • Azza Abd El Moneim Attia,

    1. Laboratoire de Génétique Humaine, Développement et Cancer, Université Victor Segalen Bordeaux 2, Bordeaux, France
    2. Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
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  • Laurence Taine,

    1. Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
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  • Didier Lacombe,

    1. Laboratoire de Génétique Humaine, Développement et Cancer, Université Victor Segalen Bordeaux 2, Bordeaux, France
    2. Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
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  • Benoît Arveiler

    1. Laboratoire de Génétique Humaine, Développement et Cancer, Université Victor Segalen Bordeaux 2, Bordeaux, France
    2. Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
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  • Communicated by Paolo M. Fortina

Abstract

Rubinstein-Taybi syndrome (RTS) is a well-defined syndrome characterized by facial abnormalities, broad thumbs, broad big toes, and growth and mental retardation as the main clinical features. RTS was shown to be associated with disruption of the CREB–binding protein gene CBP (CREBBP), either by gross chromosomal rearrangements or by point mutations. Translocations and inversions involving chromosome band 16p13.3 form the minority of CBP mutations, whereas microdeletions occur more frequently (about 10%). Most deletion studies in RTS are performed by FISH analysis, and five cosmids must be used to cover the whole of the CBP gene, which spreads over 150 kb. Here we report the design of gene dosage assays by real-time quantitative PCR that are targeted on three exons located respectively at the 5′ end (exon 2), in the middle (exon 12), and at the 3′ end (exon 30) of the CBP gene. This technique proved to be efficient and powerful in finding deletions and complementary to the other available techniques, since it allowed us to identify deletions at the 3′ end of the gene that had been missed by FISH analysis, and to refine some deletion breakpoints. Our results therefore suggest that real-time quantitative PCR is a useful technique to be included in the deletion search in RTS patients. Hum Mutat 23:278–284, 2004. © 2004 Wiley-Liss, Inc.

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