BRCA1 and BRCA2 mutations in breast cancer patients from Venezuela.

A sample of 58 familial breast cancer patients from Venezuela were screened for germline mutations in the coding sequences and exon-intron boundaries of BRCA1 (MIM no. 113705) and BRCA2 (MIM no. 600185) genes by using conformation-sensitive gel electrophoresis. Ashkenazi Jewish founder mutations were not found in any of the samples. We identified 6 (10.3%) and 4 (6.9%) patients carrying germline mutations in BRCA1 and BRCA2, respectively. Four pathogenic mutations were found in BRCA1, one is a novel mutation (c.951_952insA), while the other three had been previously reported (c.1129_1135insA, c.4603G>T and IVS20+1G>A). We also found 4 pathogenic mutations in BRCA2, two novel mutations (c.2732_2733insA and c.3870_3873delG) and two that have been already reported (c.3036_3039delACAA and c.6024_6025_delTA). In addition, 17 variants of unknown significance (6 BRCA1 variants and 11 BRCA2 variants), 5 BRCA2 variants with no clinical importance and 22 polymorphisms (12 in BRCA1 and 10 in BRCA2) were also identified. This is the first genetic study on BRCA gene mutations conducted in breast cancer patients from Venezuela. The ethnicity of our population, as well as the heterogeneous and broad spectrum of BRCA genes mutations, must be considered to optimize genetic counseling and disease prevention in affected families.