Blog

How Can DNA Screening Help Guide Preventive Healthcare

May 4, 2021

As our DNA sequencing capabilities and understanding of genetic diseases improves over time, our ability to predict genetic disease also improves.  

DNA strand

Until now, most genetic diseases were identified via a diagnostic testing pathway, where:

     1.    A patient demonstrates signs, symptoms and/or a positive family history of a
            disease
     2.    A physician performs an exam and reviews family history
     3.    Diagnostic tests are performed
     4.    A causative DNA variant (change) is identified
     5.    The genetic disease is diagnosed

The important point to note about the diagnostic pathway is that patients experience signs or symptoms of a disease or a positive family history prior to DNA testing. Advances in our knowledge of genetic disease and DNA sequencing efficiency will soon facilitate population-scale genetic disease testing that doesn’t require individuals to demonstrate disease symptoms or a positive family history: Ultimately, these advances will facilitate DNA-based health screening tests.

Health screening tests are commonly used today to detect disease prior to the development of symptoms. Colonoscopies, for example, are routinely ordered to detect colon cancer, and mammograms are periodically performed to identify tumors in breast tissue. These screenings are designed to improve population health by diagnosing diseases at earlier stages when treatments may be more effective. With an increased understanding of genetic disease, DNA-based health screenings have the potential to identify the genetic risk of an individual to develop a particular disease, ideally before the disease ever manifests. Remarkably, DNA sequencing has become so cost-efficient and routine that the American College of Medical Genetics and Genomics (ACMG) recently released a list of considerations for any healthcare facility considering population-level, DNA-based health screenings.1 Here, we summarize some of the ACMG’s considerations.

Health screening via DNA testing would change the way many genetic diseases are diagnosed, moving from a diagnostic pathway to a screening pathway, where:

     1.    A DNA variant associated with a genetic disease is identified
     2.    A physician evaluates any signs, symptoms and/or positive family history of the
            disease
     3.    A physician performs an exam
     4.    Diagnostic tests are performed
     5.    The genetic disease is either diagnosed or the patient is periodically reevaluated
            for disease

Under a screening model, most genetic disease diagnoses are initiated by a DNA-based health screening rather than the presentation of disease symptoms and/or a positive family history. With this approach, more patients will undoubtedly be identified with genetic disease-associated variants, and a great deal could be learned about the penetrance of these variants, or the likelihood that a variant will in fact cause a particular disease, such as hereditary cancer or cardiomyopathy. Additionally, DNA-based health screenings will likely result in the diagnosis of patients with less severe forms of a particular genetic disease, which may facilitate a better understanding of the entire disease spectrum.

Importantly, population-scale DNA testing will not improve population health unless it is paired with the clinical care required to lower risk and effectively treat disease. DNA-based health screening can particularly benefit patients that harbor a disease-causing variant but lack overt disease, provided they have access to appropriate clinical care. Genetic disease screening can provide actionable information for patients, clinicians and their families regarding their specific disease risks and how best to not only mitigate risk, but monitor indicators and diagnose disease at the earliest possible stage. 

Future DNA-based health screenings will allow individuals to be screened for genetic diseases with tests that were at one time reserved only for symptomatic patients or those referred for hereditary testing based on a strong family history of disease. Over time, as we learn more and more about genetic disease penetrance and causative variants, genetic screening will be available for a whole host of diseases, ideally establishing an individual’s genetic risk prior to disease development. Fortunately, with hereditary cancers, the future is now, and comprehensive hereditary cancer screenings, like the ExpedioTM Hereditary Cancer Screening test, are available to screen for pathogenic variants in dozens of genes associated with hereditary cancer syndromes. Click here to learn more about ExpedioTM, or contact us with any questions you may have regarding genetic screenings.
 

1Murray, M.F., Giovanni, M.A., Doyle, D.L. et al. DNA-based screening and population health: a points to consider statement for programs and sponsoring organizations from the American College of Medical Genetics and Genomics (ACMG). Genet Med (2021). https://doi.org/10.1038/s41436-020-01082-w