NEW YORK – Population-based genetic screening can identify people at increased risk of developing inherited conditions who might otherwise be missed, according to a new study.
As part of a community health study called Healthy Nevada Project, a team led by researchers at the Renown Institute for Health Innovation and genetic testing firm Helix screened participants for three inherited autosomal dominant conditions: BRCA-related hereditary breast and ovarian cancer, Lynch syndrome, and familial hypercholesterolemia. All three have been deemed US Centers for Disease Control and Prevention Tier 1 genetic conditions, meaning there are steps that can be taken to prevent the disease.
In a paper appearing in Nature Medicine on Monday, the researchers reported that their screening process identified 358 individuals out of about 27,000 people screened who were carriers for one of the three conditions. Of these, only about a quarter met clinical guidelines for screening and about 20 percent had a clinical diagnosis related to their genetic condition — suggesting many at-risk individuals are not caught by clinical guidelines.
"We're at a point now where it's possible to do clinical-grade genetic screening at population scale," James Lu, co-founder and CSO of Helix and senior co-author of the study, said in a statement. "What this study demonstrates is the potential impact of doing so. By making genetic screening available more broadly, we can help the millions of Americans who are unaware that they are living at increased risk for highly actionable, genetic conditions take action."
Renown Health launched the Health Nevada Project in 2016, offering free genetic testing through 23andMe before partnering with Helix for exome analysis. The project gathered clinical, genetic, environmental, and socioeconomic data from Nevada's diverse population and began returning results from its familial hypercholesterolemia testing to participants in 2018. At the American College of Medical Genetics and Genomics annual meeting in 2019, the investigators presented initial results that suggested population screening could identify people at risk of inherited disease who were not aware of their genetics.
In their publication, the researchers present results from an analysis of 26,960 participants. Within this cohort, they identified 358 individuals who were carriers of a pathogenic or likely pathogenic variant for HBOC, Lynch syndrome, or familial hypercholesterolemia, a population prevalence of 1.33 percent.
By sifting through medical records that were available for a portion of participants, the researchers found that 21.9 percent of the carriers they identified already had a clinical diagnosis related to that condition. For instance, 28 of the 135 HBOC carriers had breast or ovarian cancer.
But many of the individuals identified would have been missed through usual screening approaches, which are typically based on personal or family history of disease and other demographic characteristics. A quarter of the 273 carriers with medical record data met established criteria for genetic screening, about half of whom had undergone testing. But most patients' records, 63.3 percent, did not provide an inkling that there was an underlying genetic condition.
Genetic screening for the three CDC tier one conditions could identify 90 percent of the at-risk carriers who are not picked up through current medical practice, the researchers concluded.
"For the first time, we are providing information at the individual level so study participants can make life-saving changes to reduce their risk based on their genetics," Anthony Slonim, president and CEO of Renown Health and co-director of the study, said in a statement.