Open Access Research

First report of molecular diagnosis of Tunisian hemophiliacs A: Identification of 8 novel causative mutations

Hejer Elmahmoudi1*, Houssein Khodjet-el-khil1, Edvard Wigren2, Asma Jlizi1, Kaouther Zahra3, Dorothé Pellechia4, Christine Vinciguerra4, Balkis Meddeb3, Amel Ben Ammar Elggaaied1 and Emna Gouider3

Author affiliations

1 Laboratory of Genetics, Immunology and Human Pathologies, Tunis, Tunisia

2 Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden

3 Hemophilia Treatment Center, Aziza Othmana Hospital, Tunis, Tunisia

4 Biological hematology department EAM 4174, Hospices Civils de Lyon Université de Lyon, Lyon, France

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Citation and License

Diagnostic Pathology 2012, 7:93  doi:10.1186/1746-1596-7-93

Published: 10 August 2012

Abstract

Introduction

Hemophilia A is an X linked recessive hemorrhagic disorder caused by mutations in the F8 gene that lead to qualitative and/or quantitative deficiencies of coagulation factor VIII (FVIII). Molecular diagnosis of hemophilia A is challenging because of the high number of different causative mutations that are distributed throughout the large F8 gene. Molecular studies of these mutations are essential in order to reinforce our understanding of their pathogenic effect responsible for the disorder.

Aim

In this study we have performed molecular analysis of 28 Tunisian hemophilia A patients and analyzed the F8 mutation spectrum.

Methods

We screened the presence of intron 22 and intron 1 inversion in severe hemophilia A patients by southern blotting and polymerase chain reaction (PCR). Detection of point mutations was performed by dHPLC/sequencing of the coding F8 gene region. We predict the potential functional consequences of novel missense mutations with bioinformatics approaches and mapping of their spatial positions on the available FVIII 3D structure.

Results

We identified 23 different mutations in 28 Tunisian hemophilia A patients belonging to 22 unrelated families. The identified mutations included 5 intron 22 inversions, 7 insertions, 4 deletions and 7 substitutions. In total 18 point mutations were identified, of which 9 are located in exon 14, the most mutated exonic sequence in the F8 gene. Among the 23 mutations, 8 are novel and not deposited in the HAMSTeRS database nor described in recently published articles.

Conclusion

The mutation spectrum of Tunisian hemophilia A patients is heterogeneous with the presence of some characteristic features.

Virtual slides

The virtual slide(s) for this article can be found here:

http://www.diagnosticpathology.diagnomx.eu/vs/1693269827490715 webcite

Keywords:
Hemophilia A; Mutations; Intron 22 inversion; Intron 1 inversion; Inhibitors; Molecular analysis; Tunisia