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BioMed Research International
Volume 2014 (2014), Article ID 256245, 8 pages
http://dx.doi.org/10.1155/2014/256245
Research Article

A Founder Large Deletion Mutation in Xeroderma Pigmentosum-Variant Form in Tunisia: Implication for Molecular Diagnosis and Therapy

1Laboratoire de Génomique Biomédicale et Oncogénétique (LR 11 IPT 05), Institut Pasteur de Tunis, Université de Tunis El Manar, El Manar I, BP 74, 13 Place Pasteur 1002 Tunis Belvédère, 2092 Tunis, Tunisia
2Département de Dermatologie, Hôpital Charles Nicolle de Tunis, 1006 Tunis, Tunisia
3Département d’Anatomie-Pathologique Humaine et Expérimentale, Institut Pasteur de Tunis, 1002 Tunis, Tunisia
4Département d’Oncologie Médicale, Hôpital Abderrahman Mami, 2080 Ariana, Tunisia
5Département d’Oncologie Médicale, Hôpital La Rabta de Tunis, 1007 Tunis, Tunisia

Received 22 February 2014; Accepted 23 March 2014; Published 4 May 2014

Academic Editor: Margit Burmeister

Copyright © 2014 Mariem Ben Rekaya et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Xeroderma pigmentosum Variant (XP-V) form is characterized by a late onset of skin symptoms. Our aim is the clinical and genetic investigations of XP-V Tunisian patients in order to develop a simple tool for early diagnosis. We investigated 16 suspected XP patients belonging to ten consanguineous families. Analysis of the POLH gene was performed by linkage analysis, long range PCR, and sequencing. Genetic analysis showed linkage to the POLH gene with a founder haplotype in all affected patients. Long range PCR of exon 9 to exon 11 showed a 3926 bp deletion compared to control individuals. Sequence analysis demonstrates that this deletion has occurred between two Alu-Sq2 repetitive sequences in the same orientation, respectively, in introns 9 and 10. We suggest that this mutation POLH NG_009252.1: g.36847_40771del3925 is caused by an equal crossover event that occurred between two homologous chromosomes at meiosis. These results allowed us to develop a simple test based on a simple PCR in order to screen suspected XP-V patients. In Tunisia, the prevalence of XP-V group seems to be underestimated and clinical diagnosis is usually later. Cascade screening of this founder mutation by PCR in regions with high frequency of XP provides a rapid and cost-effective tool for early diagnosis of XP-V in Tunisia and North Africa.