Variants in BRCA1/2 in a hospital-based cohort in Chile and national literature review.

Abstract

Purpose The aim was to assess the diagnostic yield of next generation sequencing (NGS) multi-gene panels for breast and ovarian cancer in a high-complexity cancer centre in Chile. Additionally, our goal was to broaden the genotypic spectrum of BRCA variants already identified in Chilean families. Methods Retrospective analysis was conducted on the genetic test results of 722 individuals from Fundación Arturo López Pérez’s genetic counselling unit between 2016 and 2021. A comprehensive literature review encompassing articles analysing the frequency of germinal pathogenic variants in BRCA1/2 within the Chilean population was undertaken. Results 23.5% of the panels had positive results, with 60% due to pathogenic variants in the BRCA1/2 genes. Seven previously unreported variants in BRCA1 from Chilean studies were identified. One or more variants of uncertain significance were detected in 31% of the results, and 11.5% of the families in this cohort presented copy number variants (CNVs) in BRCA1/2 . 8 studies analysed the frequency of pathogenic variants in BRCA1/2 in the Chilean population between 2006 and 2023, with a frequency between 7.1% and 17.1%. 51 BRCA1 variants in 149 families have been reported in Chile and 38 BRCA2 variants in 132 families. Nine founder pathogenic variants identified by one study were present in 51.9% of the total Chilean families reported. Conclusion Our findings advocate for the integration of NGS multi-gene panel testing as a primary strategy within our population. This approach allows for the comprehensive assessment of single nucleotide variants and CNVs in BRCA1/2 , alongside other high and moderately penetrant genes associated with breast and ovarian cancer.