Why is Genetic Testing a Public Health Issue?

Genetic testing has the potential to become a great resource in public health. No longer just a tool for treating rare hereditary diseases, genetic testing may help the public health community combat major illnesses, from cancer to diabetes. Tests that can help diagnose or predict widespread diseases and even guide drug prescriptions would be useful. However, tests that reveal little or are misleading could be harmful. Hundreds of new genetic tests are in development. It is important for doctors and clinicians everywhere to understand what information these tests provide.

New Generation of Genetic Tests

Nearly all diseases are caused in part by variations in the genes or DNA that dictate our development and traits. We inherit our DNA from our parents. Some relatively rare diseases, such as cystic fibrosis, Taysach's disease and Huntington's disease, are caused by a single variation in a single gene. Genetic tests have been most useful for detecting these variations and showing the likelihood of a person having or developing that disease.

However, most diseases are caused by variations in several genes. And usually, the disease is a result of those multiple gene variations combining with something in a person's living conditions. Until recently, genetic tests could not reliably trace multiple gene variations. However, the Human Genome Project has ushered in a new generation of genetic tests.  In 2003, scientists with the project mapped all of a person's genetic material, called a genome.

This remarkable achievement has paved the way for a new generation of genetic tests , which can trace multiple gene variations. A growing number of new genetic tests are being developed to show an individual's likelihood of developing common diseases, including asthma, diabetes, and several forms of cancer.  Entire populations could benefit from these tests. The potential public health impact is huge.

Making Sure New Genetic Tests Work

If large populations are going to rely on these new tests, it is vital that they work, and that doctors and clinics can provide them at a reasonable cost. There is an urgent need to develop evidence about the effectiveness of these tests, both pre- and post-market. With that information, health care providers and consumers can use tests appropriately.

Oversight of Genetic Testing

Recommendations for developing and overseeing safe and effective genetic tests have been made by expert panels such as the National Institutes of Health (NIH)-Department of Energy Task Force on Genetic Testing and the Health and Human Services (HHS) Secretary's Advisory Committee on Genetic Testing (SACGT). However, a coordinated approach for the effective translation of genomic applications into clinical practice and health policy is needed.  HHS has implemented several initiatives to address this need:

The Office of Rare Diseases at NIH has recently launched the Collaboration, Education, and Test Translation (CETT) Program for Rare Genetic Diseases. CETT helps pay for the development of genetic tests from research laboratories to clinical practice. In the CETT model, a collaborative group (i.e., a research laboratory, a clinician involved in the study of a disease, and a patient advocacy group) may apply for funds to develop a new clinical test. 

The Centers for Disease Control and Prevention (CDC) has launched the Evaluation of Genomic Applications in Practice and Prevention (EGAPP) project to help address key questions such as: How do we determine whether genetic tests and applications are safe and useful? How do we effectively test the tests? What is the best methodology and process to help scientists do this consistently?

Evidence-Based Review is Key

A reliable process for considering genetic tests, pre- and post-market, should include "evidence-based" review, a systematic assessment of all relevant medical literature, studies, and clinical trials. Evidence-based review allows clinicians to use the best science available, and ensures that a balance of evidence is used to evaluate the test.

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