Nature and mRNA effect of 282 different NF1 point mutations: focus on splicing alterations

Authors

  • Eva Pros,

    1. Departament de Genètica, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
    2. Laboratori de Recerca Translacional, Institut Català d'Oncologia, IDIBELL, L'Hospitalet de Llobregat, Spain
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  • Carolina Gómez,

    1. Departament de Genètica, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
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  • Thamar Martín,

    1. Departament de Genètica, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
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  • Pere Fábregas,

    1. Departament de Genètica, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
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  • Eduard Serra,

    1. Departament de Genètica, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
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  • Conxi Lázaro

    Corresponding author
    1. Departament de Genètica, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
    2. Laboratori de Recerca Translacional, Institut Català d'Oncologia, IDIBELL, L'Hospitalet de Llobregat, Spain
    • Laboratori de Recerca Translacional, Institut Català d'Oncologia, Hospital Duran i Reynals, Gran Via s/n, km 2.7, L'Hospitalet de Llobregat, 08907, Spain
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  • Communicated by Mark H. Paalman

Abstract

Neurofibromatosis type 1 (NF1) is a common autosomal dominant genetic disorder caused by mutations in the NF1 gene. In this paper we report our experience using the cDNA-SSCP/HD analysis as a mutational screening approach and the double characterization of all mutations at the DNA and RNA levels. Two hundred and eighty-two different mutations (in 374 independent patients) were identified, 140 of which were novel in our population. Most of these mutations are unique and distributed along the gene. However, we also detected 37 recurrent mutations. Our approach is limited with respect to the detection of single base substitutions, but it is highly effective in the detection of frameshift mutations and mutations that affect the correct splicing. Due to this bias we focus here in the characterization of these two types of mutations. Forty-seven percent of mutations found were frameshift mutations, with small deletions being 2.3 times more common than small insertions. At the mRNA level, 44% of mutations affected the correct splicing, 80% of them located in the consensus sequences, with the donor site being much more frequently involved. The remaining 20% consisted of mutations located in deep intronic sites and mutations located in the coding region. In general the latter group produces different types of mutated transcripts with specific proportions for each mutation. The double characterization of mutations at the DNA and RNA levels enables to detect a broader spectrum of mutations than any single level approach, and provides a greater understanding of their molecular pathogenesis. © 2008 Wiley-Liss, Inc.

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