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Data shows incidental findings most frequent in cancer risk genes

A study using Electronic Medical Records and Genomics Network have tracked the frequency and type of secondary or incidental findings that occur in participants who were profiled with targeted panel sequencing and found reportable findings in around 3% of individuals.

Adam Gordon, a researcher affiliated with Northwestern University and the University of Washington and the first author of the study stated that the findings are important as they “serve as a resource to inform decision making in patients and research participants undergoing genomic testing, aid the ongoing development of practice standards and guidelines in genomic medicine and drive future research efforts in variant interpretation and secondary finding return”.

The study was reported in Genetics in Medicine last week, and the researchers searched for medically actionable incidental findings and their frequencies. 21,915 EMERGE II network participants who were assessed with a 109-gene “EMERGEseq” panel at CLIA-certified sequencing labs and focused on risk variants in 67 genes and another 14 SNP sites.

The team found that more than 2.5% of participants, who were enrolled at 10 sites in the US carried pathogenic or likely pathogenic variants in one or more of the 59 genes flagged for reporting by the American College of Medical Genetics and Genomics. They also found a further 0.48% carried clinically actionable changes in the other genes and SNP considered.

Throughout the study, the investigators discovered 661 actionable incidental findings, including 556 pathogenic variants in ACMG 59 genes and 105 incidental findings involving actionable variants in high-penetrance risk genes. Overall, the incidental findings turned up most frequently in genes related to cancer susceptibility, followed by cardiovascular disease risk genes.

The study also took the participants ancestry into account and found secondary findings in a similar proportion across the different ancestry groups except for a risk allele for the HFE haemochromatosis-related allele which is more common in people of European ancestry.

The authors warned that the analysis did not include participants of Ashkenazi Jewish individuals, who are known to have a risk of carrying alterations in breast and ovarian cancer-related genes BRCA1 and BRCA2. However, the researchers noted that removing known Ashkenazi Jewish founders alleles from the analysis does not alter the result that secondary findings were more likely to be in genes associated with cancer risk.

Image credit: – Background photo created by kjpargeter –

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Cancer / Genetics / Sequencing