What Home DNA Tests Really Tell Us

23andMe, the DNA testing company that can tell you your ethnic ancestry based on your DNA, has been cleared by the FDA to market genetic tests directly to consumers that can inform them about their risk for 10 diseases or conditions. These are the first direct-to-consumer tests that provide information on whether an individual has a predisposition to certain diseases.

People send in a sample of saliva and receive an email six to eight weeks later that lets them know their private genetic report is available on-line. The test service is called Personal Genome Service Genetic Health Risk (GHR). 23andMe says that the information will allow individuals to make informed decisions about their lifestyle choice and help with discussions with health-care providers based on the genetic factors found by the test.

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“The key is that these genetic factors signal increased risk and do not guarantee disease will develop,” said Peter Hulick, MD, Medical Director of the Center for Personalized Medicine and Center for Medical Genetics at NorthShore University HealthSystem in Illinois. “They can guide medical decision making, but it is important that individuals who pursue this testing share this information with their health-care provider.”   

While certain genetic variants may be found by the test, there are many factors in the environment and in a person’s lifestyle choices that contribute to the development of a health condition. “This information needs to be placed into the context of other factors. Risk is like a giant jigsaw puzzle and you try to uncover as many pieces as possible so one can make an informed decision,” Hulick said in an email to Drug Topics.

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Although the 23andMe tests gives percentages of increased risk in its reports, there are serious limitations to what the tests can tell someone about their disease risk. “Even if you test negative for all known [disease] genes, your risk for that disease may still be increased based on your family history,” said Mary Freivogel, President of the National Society of Genetic Counselors told Stat. “A negative 23andMe test might provide false assurance.” 

“A major issue, and one that is not new, is most providers have very basic understanding of how to incorporate genomic information into the care of their patients,” Hulick said. “While we cannot make everyone a genomics expert, we can leverage tools within the electronic medical record to help facilitate incorporation of genomic information into the care of patients. This is the approach NorthShore is taking and is a large part of the Center for Personalized Medicine’s efforts to bring genomics to our frontline physicians and health providers.”

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23andMe offered direct-to-consumer reports on disease risk in the past, but the FDA stopped it in 2013, saying that the company had to prove its tests were accurate. Now, the FDA has created what it is calling special controls that allow the company, and any others that want to enter this field, to meet its requirements.

Other companies offer GHR tests through physicians’ offices and genetic counselors. A few companies now offer pharmacogenetic testing for individuals, done in community pharmacies. After test results come in, the pharmacist goes over the information with that individual to evaluate how genetic factors affect any of the drugs they take.

The FDA has approved the use of GHR for diseases and conditions that include Parkinson’s, late-onset Alzheimer’s, celiac, alpha-1 antityprsin deficiency, factor XI deficiency, and Gaucher disease type1.

The 23andMe GHR test costs $199, which includes a report on ethnic ancestry, inherited traits like hair color, and the presence of genes for inherited diseases such as cystic fibrosis and sickle cell anemia.