Genomic Tests and Population Health: An Online Catalog to Promote a Conversation on Evolving Evidence

Posted on by Muin J Khoury, Director, Office of Public Health Genomics, Centers for Disease Control and Prevention


stacked boxed with A T C G on themWith the rapid emergence of genomic tests, healthcare providers, patients and policy makers need to know how useful they are and whether the benefits of their use outweigh potential harms to patients, families, and the population.

CDC’s Office of Public Health Genomics now offers a list of health-related genomic tests and applications, stratified into three tiers according to the availability of scientific evidence and evidence-based recommendations.  The list is intended to promote information exchange and dialogue among researchers, providers, policy makers, and the public. It will be updated on an ongoing basis and with references and links to key publications and online materials. 

Tier 1 genomic applications have been recommended for use by groups such as the U.S. Preventive Services Task Force or EGAPP, based on a systematic review of the evidence for their validity and utility in specific clinical scenarios. We encourage the use of tier 1 applications in practice because they can lead to improved health outcomes. To date, very few genomic applications have risen to tier 1.

Tier 2 genomic applications have demonstrated analytic and clinical validity. Providers and patients may find them useful for informed decision making but the evidence for their utility has either not been reviewed or has been found insufficient.  With a few exceptions, we have classified nearly all tests for single gene disorders—as well as the collection of family history in primary care—as tier 2. This classification reflects a lack of sufficient data (especially for rare conditions) or the lack of evidence-based recommendations. Further development and review of evidence will help close the gap.

Tier 3 genomic applications have not yet demonstrated adequate analytic validity, clinical validity, or clinical utility. This tier also includes applications that evidence-based panels have recommended against after evaluating the balance of related benefits and harms.   Such applications are not ready for use in practice but may be considered for use in clinical and population research.

Our goal is to encourage conversation on the appropriate use of genomic applications in practice and to promote the translational research needed to fill evidence gaps. The tables also highlight some mature genomic applications in tier 1 that if implemented could save thousands of lives and reduce morbidity among affected people and their families. Evaluating the population-level balance of benefits and harms will require further research.

A true partnership between clinical medicine and public health is needed to implement evidence-based genomic applications using a combination of education, policy changes, population surveillance and programs.

We invite comments and suggestions from our readers about our classification scheme, specific genetic tests and applications, and sources of evidence.

Posted on by Muin J Khoury, Director, Office of Public Health Genomics, Centers for Disease Control and PreventionTags , , , , ,

4 comments on “Genomic Tests and Population Health: An Online Catalog to Promote a Conversation on Evolving Evidence”

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    Thank you for this update….
    I note ….”A true partnership between clinical medicine and public health is needed to implement evidence-based genomic applications using a combination of education, policy changes, population surveillance and programs…”

    How will this happen? Does NIH/IOM have metrics, goals and dates certain with Funding, in collaboration with PHS and CDC? Is DTC part of the partnership to shepard? What about EDRN engagement, redirection?

    Thank you for opening a dialogue on how to develop partnerships between clinical medicine and public health that are needed to implement evidence-based genomic applications. The recent guest post on this blog, Making Universal Screening for Lynch Syndrome a Reality: The Lynch Syndrome Screening Network, provides one example where health care and public health professionals are working together to promote implementation of universal screening for Lynch syndrome among people newly diagnosed with colorectal cancer to benefit their family members as recommended by the Evaluation of Genomic Applications in Practice and Prevention Working Group. These efforts grew out of discussions of a public health/clinical collaborative meeting, held in September 2010 on implementing the Lynch syndrome recommendation, which was summarized in a recent article. A September 2012 meeting, sponsored by CDC’s Office of Public Health Genomics and partners, is planned to provide a forum for health care and public health stakeholders to discuss new strategies in public health genomics to realize health impact through the implementation of evidence-based practices.

    Hi, members of my family have familial hypercholesterolemia. However, we have not gotten them tested because the risk in FH comes from having high LDL, and LDL can be measured with a lipid panel. Can you comment on whether people with FH should have genetic testing, when the testing would not change treatment?

    It seems to me that cascade screening for FH would be useful, but I am not aware that any such program exists in the U.S.

    Also, you and any FH patients or family members who happen to see this are invited to join the Familial Hypercholesterolemia Discussion Group on Facebook!/groups/47098836197/

    Marilyn Mann

    Dear Ms. Mann,
    Thank you for your comment, and for sharing your family’s experience with familial hypercholesterolemia (FH). We are not able to offer clinical advice in regard to the appropriateness of genetic testing for FH for individuals or families; however, generally speaking, FH guidelines and recommendations differ in regard to recommended approaches to genetic testing for the diagnosis of FH, as the following excerpts illustrate. For example, the UK National Institute for Health and Clinical Excellence (NICE) guideline on the Identification and Management of Familial Hypercholesterolemia states that:
    1.1.12 Healthcare professionals should offer people with a clinical diagnosis of FH a DNA test to increase the certainty of their diagnosis and to aid diagnosis among their relatives.
    1.1.13 Healthcare professionals should inform all people who have an identified mutation diagnostic of FH that they have an unequivocal diagnosis of FH even if their LDL-C concentration does not meet the diagnostic criteria (see appendix E).
    1.1.14 In a family where a DNA mutation is identified, not all family members may have inherited the mutation. When DNA testing has excluded FH in a member of a family, healthcare professionals should manage the person’s coronary heart disease risk as in the general population.
    The Familial Hypercholesterolemia: Screening, diagnosis, and management of pediatric and adult patients clinical guidance from the U.S. National Lipid Association Expert Panel on Familial Hypercholesterolemia states that:
    1.6.1 Genetic screening for FH is generally not needed for diagnosis or clinical management but may be useful when the diagnosis is uncertain.
    1.6.2 Identification of a causal mutation may provide additional motivation for some patients to implement appropriate treatment.
    1.6.3 Importantly, a negative genetic test does not exclude FH, since approximately 20% of clinically definite FH patients will not be found to have a mutation despite an exhaustive search using current methods.
    The National Cholesterol Educational Program Adult Treatment Panel III report on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults and the U.S. Preventive Services Task Force recommendation on Screening for Lipid Disorders in Adults do not include recommendations on genetic testing for FH.
    The CDC-funded Genomics Knowledge Synthesis Center recently began an evidence review on familial hypercholesterolemia to include an assessment of the evidence to support the validity and utility for genetic testing for FH screening, diagnosis and management. The independent Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Working Group will consider issuing a recommendation statement on FH based on the evidence review.
    In regard to cascade screening programs in the U.S., the Make Early Diagnosis to Prevent Early Death (MEDPED) program at the University of Utah Salt Lake City is a research project and a nonprofit organization funded to register and help treat people with inherited cholesterol disorders, such as FH. CDC recently convened stakeholders to discuss public health strategies for implementing evidence-based recommendations for genetic testing applications, including cascade screening for FH, and a report from that meeting will be available soon.
    In regard to any specific questions about your family history, you might consider contacting a genetics professional in your area through the National Society of Genetic Counselors Find a Genetic Counselor resource.
    Thanks again for joining the discussion,
    Muin Khoury

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Page last reviewed: April 8, 2024
Page last updated: April 8, 2024