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<p>Abstract</p> <p>Background</p> <p>The <it>BRCA2</it>-8765delAG mutation was firstly described in breast cancer families from French-Canadian and Jewish-Yemenite populations; it was then reported as a founder mutation in Sardinian families. We evaluated both the prevalence of the <it>BRCA2</it>-8765delAG variant in Sardinia and the putative existence of a common ancestral origin through a haplotype analysis of breast cancer family members carrying such a mutation.</p> <p>Methods</p> <p>Eight polymorphic microsatellite markers (D13S1250, centromeric, to D13S267, telomeric) spanning the <it>BRCA2 </it>gene locus were used for the haplotype analysis. Screening for the 8765delAG mutation was performed by PCR-based amplification of <it>BRCA2</it>-exon 20, followed by automated sequencing.</p> <p>Results</p> <p>Among families with high recurrence of breast cancer (≥ 3 cases in first-degree relatives), those from North Sardinia shared the same haplotype whereas the families from French Canadian and Jewish-Yemenite populations presented distinct genetic assets at the BRCA2 locus. Screening for the <it>BRCA2</it>-8765delAG variant among unselected and consecutively-collected breast cancer patients originating from the entire Sardinia revealed that such a mutation is present in the northern part of the island only [9/648 (1.4%) among cases from North Sardinia versus 0/493 among cases from South Sardinia].</p> <p>Conclusion</p> <p>The <it>BRCA2</it>-8765delAG has an independent origin in geographically and ethnically distinct populations, acting as a founder mutation in North but not in South Sardinia. Since <it>BRCA2</it>-8765delAG occurs within a triplet repeat sequence of AGAGAG, our study further confirmed the existence of a mutational hot-spot at this genomic position (additional genetic factors within each single population might be involved in generating such a mutation).</p>