Screening and characterization of BRCA2 c.156_157insAlu in Brazil: Results from 1380 individuals from the South and Southeast.

Portuguese immigration to Brazil occurred in several waves and greatly contributed to the genetic composition of current Brazilian population. In this study, we evaluated the frequency of a Portuguese founder Alu insertion in BRCA2 exon 3 (c.156_157insAlu) among individuals fulfilling Hereditary Breast and Ovarian Cancer (HBOC) syndrome criteria in 1,380 unrelated families originated from three distinct Brazilian States. We identified the c.156_157insAlu BRCA2 mutation in nine (9/1,380; 0.65%) probands analised. In carrier probands, European ancestry had the highest proportion (80%), followed by the African (10%) and Amerindian and in most families with the rearrangement, haplotype analyses were compatible with the Portuguese ancestral haplotype. In conclusion, the present study reports a low albeit relevant frequency of the Portuguese BRCA2 founder mutation c.156_157insAlu in Brazilian patients at-risk for HBOC Brazilian population.