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Evidence for an ancient BRCA1 pathogenic variant in inherited breast cancer patients from Senegal.

BRCA1 and BRCA2 are the most incriminated genes in inherited breast/ovarian cancers. Several pathogenic variants of these genes conferring genetic predisposition have been described in different populations but rarely in sub-Saharan Africa. The objectives of this study were to identify pathogenic variants of the BRCA genes involved in hereditary breast cancer in Senegal and to search for a founder effect. We recruited after free informed consent, 27 unrelated index cases diagnosed with breast cancer and each having a family history. Mutation screening of the genes identified a duplication of ten nucleotides c.815_824dupAGCCATGTGG, (p. Thr276Alafs) (NM_007294.3) located in exon 11 of BRCA1 gene, in 15 index cases (allelic frequency 27.7%). The pathogenic variant has been previously reported in African Americans as a founder mutation of West African origin. Haplotypes analysis of seven microsatellites surrounding the BRCA1 gene highlights a shared haplotype encompassing ~400 kb between D17S855 and D17S1325. This haplotype was not detected in none of 15 healthy controls. Estimation of the age of the pathogenic variant suggested that it occurred ~1400 years ago. Our study identified a founder pathogenic variant of BRCA1 predisposing to breast cancer and enabled the establishment of an affordable genetic test as a mean of prevention for Senegalese women at risk.

Auteur(s) : Ndiaye R., Diop J.P.D., Bourdon-Huguenin V., Dem A., Diouf D., Dieng M.M., Diop P.S., Gueye S.M.K., Ba S.A., Dia Y., Ka S., Mbengue B., Thiam A., Syll
Année de publication : 2020
Revue : npj Genom. Med.
Type : Article
Mise en ligne par : SYLLA Maguette Dème