title: A novel pathogenic germline mutation in the adenomatous polyposis coli gene in a Tunisian family with FAP.
abstract: Familial adenomatous polyposis (FAP) is an autosomal dominant disorder which typically presents with colorectal cancer in early adult life, secondary to extensive adenomatous polyps of the colon. In addition to the colonic manifestations, the syndrome presents several extracolonic features including, congenital hypertrophy of the retinal pigment, osteomata and desmoid tumors. In this study, we aimed to investigate the clinical and genetic features in a Tunisian family with FAP. Sequence of the APC gene (Adenomatous Polyposis Coli) revealed a novel mutation (c.2016-2017 del TA) in exon 15, present in all affected individuals in an heterozygous state. The frameshift mutation generates a premature stop codon at amino acid 677 of the APC protein (p. H672Qfs X5). The unaffected family members did not harbor this mutation, however, a first degree relative of the patient aged of 32-year-old was phenotypically normal but carries the c.2016-2017 del TA mutation. This discrepancy can be explained by the effect of modifier gene which can affect the expressivity of the disease.
authors: Centre de Biotechnologie de Sfax, Route Sidi Mansour, BP 1177, 3038, Sfax, Tunisia.
authors: Imen
authors: I
authors: Miladi-Abdennadher
authors: Ali
authors: A
authors: Amouri
authors: Lobna
authors: L
authors: Ayadi
authors: Abdelmajid
authors: A
authors: Khabir
authors: Sameh
authors: S
authors: Ellouze
authors: Nabil
authors: N
authors: Tahri
authors: Mounir
authors: M
authors: Frikha
authors: Tahia
authors: T
authors: Sellami-Boudawara
authors: Raja
authors: R
authors: Mokdad-Gargouri
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