Study Highlights Challenges for Population Genetic Screening

Despite the benefits of population screening for identifying people with genetic risk for preventable conditions, participant engagement remains a significant challenge that should be considered when implementing a screening program, according to a study appearing this week in Genome Medicine. As much as two percent of the population carries genetic variants linked to high risk for cancer or cardiovascular diseases that could be mitigated by early interventions, but identifying these individuals is difficult as many have no family history of the disease and do not have access to healthcare that includes routine genetic screening. Population screening has been proposed as a strategy to identify at-risk people who would not have been identified under current genetic testing guidelines, but the effectiveness of such screening remains unclear. In the new study, University of Washington researchers invited around 40,000 patients within the institution's medical care system who had no personal or family history of hereditary disease to participate in a genetic screening program. They developed a sequencing panel covering 25 genes associated with preventable adult-onset disease and mailed saliva collection kits to the individuals. Only about 2,800 people enrolled in the program, and actionable variants were found in 103 of these individuals, a third of whom already knew of the results from prior genetic testing. Overall, diagnostic yield was 2.6 percent for individuals screened. The findings, the study's authors write, highlight the implementation difficulties of such screening programs, particularly around recruitment and sample collection. "These challenges to widespread adoption of population screening reduce actual enrollment and diagnostic yield and should not be overlooked in intervention planning or in cost and benefit analysis," they write.