Interest and advances in genetic testing are booming. A recent study published in the journal Public Health Genomics showed that 6 out of 10 Americans are interested in genetic testing. Today, genetic testing is available for over 2000 rare and common conditions, according to the NIH. The CEO of the Cleveland Clinic has called gene testing a “huge breakthrough” for people suffering from cancer and other fatal diseases. But some wonder if this early-stage science is ready for “prime-time,” or if our ability to understand and apply that science is not keeping pace with the hype.

According to the American Medical Association, “Genetic testing still is in its early stages, so both patients and experienced physicians may need guidance when it comes to navigating this new and complex territory.” Here’s an overview of this rapidly advancing science, and how to talk to your patients about the benefits and risks of genetic testing.

Types of genetic testing

While genetic testing has been used for decades to test fetuses for hereditary conditions such as Down syndrome, cystic fibrosis, and Duchenne muscular dystrophy, new discoveries have advanced the science far beyond prenatal testing. Other types of genetic testing include:

Diagnostic testing. This identifies a genetic condition or disease that may be making a patient ill now or might in the future. Results can affect patients’ decisions about treating or managing the disease.

Predictive and pre-symptomatic genetic testing. This finds genetic variations that increase a person’s chance of developing specific diseases. Results can impact patients’ lifestyle and health care choices.

Carrier testing. These tests tell patients if they carry a genetic change that can cause a disease, which may be passed on to their children. Results may influence a person’s choice to have children.

Pharmacogenetic testing. This type of testing provides information about how certain medicines are processed in a person’s body, and can help a health care provider choose the medicines that work best with a person’s genetic makeup.

Whole-genome and whole-exome sequencing. This examines the entire genome or exome to discover genetic alterations that may be the cause of disease. Currently, this type of test is used most often in complex diagnostic cases, but in the future it may be used to predict disease.

Ophthalmologists’ role in genetic testing

Genetic testing can make a positive impact on many patients, including those affected with inherited eye disease. In fact, the Genetic Eye Disease (GEDi) diagnostic test has been proven to be highly accurate and reproducible—far more so than other genetic tests.

“Sensitive and specific genetic tests now exist for dozens of inherited eye diseases,” reports the American Academy of Ophthalmology. Among the resources to help ophthalmologists choose appropriate genetic tests and to locate knowledgeable genetics professionals to assist them with specific patients is the National Institutes of Health Genetic Testing Registry. For additional clinical referral resources, check out the AAO’s Recommendations for Genetic Testing of Inherited Eye Diseases – 2014.

“When properly performed, interpreted, and acted on, genetic tests can improve the accuracy of diagnoses and prognoses,” can reduce the risk of disease occurrence or recurrence in at-risk patients, and can help doctors deliver the best possible care for those patients, notes the AAO. However, like all medical interventions, genetic testing has some risks.

What are the risks?

While genetic testing generally poses a low risk to physical health, it can have a negative impact on patients, both financially and emotionally. Genetic testing can cost anywhere from less than $100 to more than $2,000, according to the National Human Genome Research Institute (NHGRI), and may not be covered by health insurance.

The results of a genetic test can also cause fear, anxiety, guilt, and depression, and oftentimes can raise more questions for patients than answers. “[Genetic testing] gives you a lot of data but the devil is in the details,” said Dr. Beth Tarini, senior author of the previously mentioned study on predictive genetic testing published in Public Health Genomics, in a press release. “First, interpreting the data is challenging because we are not sure what all of the data means. Second, even if you can interpret the data then you may not know what to do with the interpretation. Perhaps you learn you have a slightly higher risk of getting prostate cancer or diabetes — neither of which is for certain or in the near future. Now what?”

For these reasons, skilled counseling should be provided to all patients who choose to undergo genetic testing in order to maximize the benefits and minimize the risks associated with each test. The doctor who orders the tests should provide genetic counseling himself if qualified to do so, or she should seek out a trained board-certified medical geneticist or genetic counselor to provide counseling to patients, recommends the AAO. The websites of the, American Board of Genetic Counseling and the National Society of Genetic Counselors provide listings of genetics professionals by zip code.

Other potential pitfalls

The number of laboratories offering direct-to-consumer genetic testing is growing – advise your patients to avoid this route. These tests “may or may not have been adequately validated, and sometimes there are reports where a specific test is ordered, but the results are ‘bundled’ with other genetic tests that may or may not be relevant to the patient in question,” notes J. Leonard Lichtenfeld, deputy chief medical officer of the American Cancer Society. Emphasize to patients the importance of involving a trained physician or genetic counselor who can appropriately interpret genetic test results.

To help clinicians and patients have conversations about making wise choices related to genetic testing, perhaps an expansion of the American College of Medical Genetics and Genomics (ACMG) Choosing Wisely® campaign is necessary, suggests Lichtenfeld. In the meantime, the NHGRI provides FAQ and resources about genetic testing.

The future of genetic testing is exciting. “We will live in a time of more effective ‘personalized medicine’,” predicts the NIH. “Information from genetic testing will help to detect risk for disease, guide strategies for maintaining health, offer more accurate diagnosis, and guide treatment choices for a wide variety of conditions.”

Has the issue of genetic testing come up in your practice? If so, how do you talk to patients about it?

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