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What you may learn by at-home genetic testing

Man swabbing mouth for DNA, at home: People feel they have the right to directly access their genetic information. © (Getty Images) People feel they have the right to directly access their genetic information. Some consumers bypass the medical system to obtain this personal information. But it has limits.

Spit in a vial, pop it back into the test-kit carton, return it to the company and voila – within weeks you can view the results of your personal genetic analysis online. No doctor’s input or counseling required – just curiosity or concern and a couple hundred bucks or so out of pocket. 

You might learn you carry a gene strongly linked to inherited disorders like phenylketonuria, or PKU. Or you could discover you have a gene tied to a slightly higher risk of Alzheimer’s disease.

Direct-to-consumer genetic testing is becoming increasingly popular. Advocates say people have a right to access their genetic information without taking the traditional path of genomic testing. However, public health experts question the value of at-home tests or the wisdom of supplying isolated pieces of genetic information to healthy people. Without important context – such as family and medical history and lifestyle choices – or one-on-one counseling to aid interpretation, it’s hard to know what results really mean or if they matter.

Yet people feel they have the right to directly access their genetic information, according to more than 80 percent of participants in a study that will be published in the June issue of The Milbank Quarterly, a health care and health policy journal. Researchers looked at survey results from about 940 consumers who’d had personal genomic testing through either 23andMe or Pathway Genomics. 

Most study participants supported expanded access to genetic testing services without further government regulation. However, those who believed their reports showed an elevated risk of common diseaseswere less supportive of expanded access without the involvement of a medical professional.

Consumers taking power over their own health information is an advantage of at-home genetic testing, says Stacey Detweiler, a medical affairs associate and genetic counselor with 23andMe. In April, the company gained Food and Drug Administration approval to market personal genetic-risk tests for 10 specific diseases immediately.

The “tests are intended to provide genetic-risk information to consumers, but the tests cannot determine a person’s overall risk of developing a disease or condition,” the FDA noted in a news release announcing the approval. “In addition to the presence of certain genetic variants, there are many factors that contribute to the development of a health condition, including environmental and lifestyle factors,” the agency added.

At present, 23andMe offers customers genetic-risk reports on four conditions with some familial components: late Alzheimer’s disease, Parkinson’s disease, hereditary thrombophilia – a disorder involving blood-vessel clots – and alpha-1 antitrypsin deficiency. That last condition, in which the body lacks a protective protein, can lead to lung disease in early adulthood, especially among people who smoke, and can cause liver disease as well.

Detweiler points out, as does consumer information on the 23andMe website, that these tests are not diagnostic. Nor do they show whether a person will or won’t develop a tested a condition, but only represent one piece of the puzzle. What results can show is for some genes associated with these conditions, people can have variants that indicate higher risk.

Since 2015, the company has offered “carrier-status” testing to customers for about 40 conditions. A carrier is someone who doesn’t have a specific disease, like cystic fibrosis, but possesses the genetic trait. If both members of a couple carry a genetic trait for such a condition, their children would be at risk for the disease.

Earning FDA approval to market both the carrier status and genetic-risk reports involved a regulatory process. Regulation should be of interest to consumers seeking genetic tests sold online, experts say. All laboratories that perform genetic and other health-related testing are subject to federal regulatory standards, according to the Genetics Home Reference website of the National Institutes of Health. However, some direct-to-consumer genetic testing labs have not been certified to show that they meet these standards. So it can be difficult to determine the quality of these tests or whether their results are valid.

Not a Diagnosis

Three types of health reports are available from 23andMe: genetic health risk, carrier status and wellness. Carrier status reports list variants for some genes tied to conditions including cystic fibrosis, sickle cell anemia and Tay-Sachs disease – a rare, fatal disorder affecting the brain and nervous system. This could be potentially useful information for couples considering pregnancy, if they worry they both might be carriers of an inherited condition.

But, the package insert cautions: “These tests cannot determine your overall risk of developing a disease in the future. These tests are not intended to diagnose any disease.” In addition, it warns: “You should consult with a health care professional if you have any questions about your results.” 

Take Alzheimer’s, for example – a devastating condition with no known cure and only a few potential but unproven preventive measures. The obvious question is: What good does it do to learn from a test that you might be at higher risk?

Alzheimer’s testing typically centers on the APOE gene, specifically the variety known as APOE4, says Lawrence Brody, a senior investigator with the National Human Genome Research Institute. “Having that version does increase your risk of having Alzheimer’s,” he explains. “That said, I think most people who carry it will never get Alzheimer’s disease.”

For those who carry two copies of this gene, he says, “they’re not highly predictive, but they’re really good indicators that you’re at increased risk compared to someone who doesn’t have it.” Conversely, If you don’t have the APOE4 gene, you would be at slightly decreased risk.

Genetic testing is much more powerful for strongly familial diseases, Brody says. Positive test results for conditions such as Huntington’s disease, sickle cell disease, cystic fibrosis and even inherited breast cancers are highly meaningful, he says. “But those are the exceptions, not the rule,” he adds.

At-home tests for conditions that are not genetic–such as kits to detect pregnancy or HIV – might provide the most useful, actionable information for consumers. On the other hand, Brody says, direct-to-consumer genetic testing falls a little bit more into the realm of “recreational” genetics. That is, the information might be nice to know but not necessarily useful from a medical standpoint.

If anything, your regular health provider may brush off these results or lack the knowledge to interpret them. “I don’t think the medical community is that interested at this point in dealing with the results of a home test,” Brody says.

Most geneticists don’t believe in blocking this type of direct-to-consumer access, Brody says. Instead, he adds: “We think if we’re going to have people learn about their own genome, we want to make sure they really understand it and are comprehending what things mean and don’t mean.”

For now, “Think before you spit,” is the public message on at-home genetic testing from the Centers for Disease Control and Prevention. In an ever-evolving arena, the agency has adopted a “cautionary” approach to these tests, Dr. Muin Khoury, director of the CDC’s Office of Public Health Genomics, posted in his ongoing blog on the hot health topic. The agency has given such tests a “tier 3” rating, implying there’s no evidence to support their clinical validity or usefulness for healthy people.

On the positive side, the blog notes, most evidence reveals little or no harm to personal genomic testing. What’s missing is evidence of benefit: whether having this genomic information really spurs people to change their behavior. It hasn’t been shown that people go on to make changes under their control – like quitting smoking – to reduce their risk of developing common diseases, since they can’t alter their genetic risk.

“As a consumer, if I’m a healthy person with no overt disease, I wouldn’t waste my time,” Khoury says. “If you are sick and have a condition, go to your provider, who will take a family history and depending on what that is, may or may not direct you to genetic counseling.”

It’s possible, as proponents suggest, that learning you have a higher-risk gene variant could motivate you to change your lifestyle or explore your medical history. But you don’t need a genetic test to start exercising or eating healthier. And in most (but not all) cases, you don’t need a genetic-risk report to spur a discussion on family history – just reach out to your relatives and ask.

Diagnostic Odyssey: It took 18 years for Patricia Weltin to get the correct diagnosis. Her daughters have <a href="http://health.usnews.com/wellness/articles/2016-11-11/ehlers-danlos-syndrome-more-than-just-stretchy-skin-and-bendy-joints">Ehlers-Danlos syndrome</a>, a connective tissue disorder involving too-loose joints that easily dislocate as well asoverly elastic, fragile skin and many complications. That long road to the right diagnosis is known as the "diagnostic Odyssey," says <a href="https://ncats.nih.gov/director/bio">Dr. Christopher Austin</a>, director of the National Center for Advancing Translational Sciences, part of the National Institutes of Health. With rare diseases, he says, most doctors have never seen a case, so "patients go from doctor to doctor to doctor." Now, he says, with the ease of worldwide communication, the journey to diagnosis takes an average two-and-a-half to three years. Read on for more rare disorders. 5 Rare Diseases You’ve Never Heard Of (Until Now)

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