ACMG secondary findings in the Brazilian rare genomes project: insights from 5402 genome sequencing

Secondary findings (SF) are pathogenic or likely pathogenic variants in genes unrelated to the primary purpose of genetic testing. The American College of Medical Genetics (ACMG) provides guidelines on which SF should be reported, involving 81 genes linked to different conditions. With the increasing use of genome sequencing (GS), SF are more frequently detected, presenting challenges for healthcare systems. The Brazilian population is often underrepresented in genomic studies, which limits population-specific knowledge. This study aimed to outline the profile of SF in the Brazilian Rare Genomes Project (BRGP). We analyzed retrospectively SF (ACMG) data from GS of 5402 BRGP individuals. Of the 5316 cases who consented to receive SF, 3.6% (191 cases) had at least one SF. The most common genes identified were TTR, TTN, and BRCA2. SF were mainly related to cardiovascular conditions (40.2%) and cancer predisposition (37.6%). Some variants, such as TTR: c.424G>A; p. (Val142Ile) and TP53: c.1010G>A; p. (Arg337His), were recurrent, reflecting population-specific traits and founder effects. Novel variants were 10.6% of SF. SF rate varies across studies and populations. While SF can aid early diagnosis, their relevance is debated due to potential psychological and healthcare burdens. Effective genetic counseling and public health policies are essential.