Genetic Testing
Genetic tests have been developed for more than 1,700 diseases, of which about 1,400 are currently available for use in clinical settings. Most tests look at single genes and are used to diagnose rare genetic disorders, such as Fragile X Syndrome and Duchenne Muscular Dystrophy. However, a growing number of tests look at multiple genes that may increase or decrease a person’s risk of common diseases, such as cancer or diabetes. In addition, some genetic tests look at rare genetic variants, such as BRCA1 and BRCA2, which are responsible for some hereditary breast and ovarian cancers. Such tests and other applications of genomic technologies have the potential to help prevent common disease and improve the health of individuals and populations. For example, predictive gene tests may be used to help determine the risk of developing common diseases, and pharmacogenetic tests may be used to help identify genetic variations that can influence a person’s response to medicines. Learn more.
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Limited Scientific Information for Most Genetic Tests
Despite the many scientific advances in genetics, researchers have only identified a small fraction of the genetic component of most diseases. Therefore, genetic tests for many diseases are developed on the basis of limited scientific information and may not yet provide valid or useful results to individuals who are tested. However, many genetic tests are being marketed prematurely to the public through the Internet, TV, and other media. This may lead to the misuse of these tests and the potential for physical or psychological harms to the public. At the same time, valid and useful tests, such as those for hereditary breast and ovarian cancer or for Lynch syndrome, a form of hereditary colorectal cancer, are not widely used, in part because of limited research on how to get useful tests implemented into practice across U.S. communities. Individuals can learn more about specific genetic tests by visiting the Web sites listed below or by talking with their doctor.
How Agencies are Advancing the Science
The Department of Energy Task Force on Genetic Testing at the National Institutes of Health; the former Secretary's Advisory Committee on Genetic Testing; the Secretary’s Advisory Committee on Genetics, Health and Society; and other groups have raised issues about the current status of genetic testing oversight and use. These issues include the possibility that gaps in oversight may lead to misuse and the need to develop evidence for establishing efficacy and cost-effectiveness before the tests are commercialized.1-13 They have also expressed the need for timely, reliable information that health care providers, payers, public health practitioners, policy makers, and consumers can use to make more informed decisions about the appropriate use of these tests in clinical and public health practice.
To begin addressing this need, CDC’s Office of Public Health Genomics established the Evaluation of Genomic Applications in Practice and Prevention (EGAPP) project to systematically evaluate genetic tests and other applications of genomic technology that are in transition from research to clinical and public health practice. Since 2005, the independent EGAPP Working Group has released four recommendations on the validity and utility of specific genetic tests for individuals diagnosed with specific cancers or with depression.
The U.S. Preventive Services Task Force (USPSTF) has also released recommendations on specific genetic tests used in selected clinical scenarios involving breast cancer and hemochromatosis.
Related Materials
Learn More About Genetic Testing
- Frequently Asked Questions About Genetic Testing, National Institutes of Health
- What is Direct-to-Consumer Genetic Testing?, Genetics Home Reference
- Evaluation of Genomic Applications in Practice and Prevention (EGAPP)
- U.S. Preventive Services Task Force (USPSTF)
- Genetic testing recommendations for breast and ovarian cancer and hemochromatosis
Also see the genetic testing and genetic counseling sections of CDC’s Office of Public Health Genomics’ resource guide.
CDC Activities
- Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Initiative
- ACCE Model Process for Evaluating Genetic Tests
- Laboratory Practice Evaluation and Genomics Branch, CDC
- Newborn Screening and Related Conditions, CDC
References
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Contact Us:
- CDC-INFO Contact Center
Phone: 800-232-4636 (800-CDC-INFO)
Hearing Impaired: 888-232-6348 - cdcinfo@cdc.gov
- Additional information for Public Health Genomics is available on our contact page.


