Frecuencia de mutación y de variantes de secuencia para los genes brca1 y BRCA2 en una muestra de mujeres Colombianas con sospecha de síndrome de cáncer de mama hereditario: Serie de casos

Objective: To describe sequence variants in the BRCA1 and BRCA2 genes in a sample of Colombian patients with a personal or family history of breast cancer suggestive of genetic risk. Materials and methods: Case series consisting of 67 patients referred for genetic testing because of suspected hereditary breast and ovarian cancer syndrome (HBOC). Of the 67 cases, 42 (62.7%) met the medical indication criteria of the 2013 National Comprehensive Cancer Network (NCCN) and they were subjected to the entire sequencing of the BRCA1 and BRCA2 genes. A determination was made of the frequency of sequence mutation, variants, and of the clinical significance of the variants found based on the Breast Cancer Information Core (BIC). Results: Mutations were identified for the BRCA 1 gene in six patients (14.3%), no mutation was documented for the BRCA 2 gene, and 43 genetic variants were found in 27 patients (64.2% of 42 cases). Of these, 21 (48.8%) were identified in the BRCA1 gene and 22 (51.2%) in the BRCA 2 gene. Among these variants, 5 pathogenic mutations were found only in the BRCA1 gene and, of those, only 1 had been reported previously in Colombia. Conclusions: This study identifies pathogenic genetic variants in the BRCA1 gene not described previously in the Colombian population, as well as others known in different populations. Therefore, it helps expand knowledge regarding the variants of the BRCA1 and BRCA2 genes in the Colombian population. However, additional studies are required with sufficient power and methodological quality to estimate the frequency of sequence mutations and variants for the BRCA1 and BRCA2 genes in Colombian women suspected of having the hereditary breast or ovarian cancer syndrome.