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Will home genetic tests become as useful as home pregnancy tests and cram drugstore shelves?
With the ability to sequence genomes, the interpretation of genetic tests has become complex. The field of genetics has been turned on its head. Mutated genes we once thought certain to cause a disease are deemed innocent. More and more genes are joining the lineup. The complex interpretation of genetic results and the decisions that follow have made home testing more challenged than ever. The twists and turns in the world of genetics are just beginning.
Home genetic tests can fill the needs of those curious about their ancestry and why their DNA sequences gave them funny earlobes, freckles or brown eyes. It’s the medically challenged who won’t find what they need in a home genetic test. Even with the assistance of their primary doctor and genetic counselor, the current test results are not part of standard prevention or health care plans.
What are the DTC tests?
The way home tests work is the companies sell you a testing kit via the Internet (this is what we call a direct-to-consumer test, or DTC, test). You then spit into a tube and mail the tube to the company. The company runs the test and sends you the results. The DTC genetic testing companies only tell you which gene changes they’ve found. Rarely do they tell you something that impacts your health and if it does, it will need to be readdressed with your doctor.
A couple years ago 23andMe, a DTC service, was outlawed by the Food and Drug Administration (FDA) from returning health reports associated with their $99 test to consumers. Prior to this, attempts to understand if there were health implications buried in the multi-page 23andMe reports for our clinic patients were exercises in futility.
Similarly, a newly revamped test (now costing $199) from 23andMe is approved to analyze for “carrier status.” This tests for mutations that could lead to a specific disease in offspring if the other parent has a mutation in the same gene and the child inherits both mutated genes. These types of syndromes are cystic fibrosis, sickle cell anemia and many more diseases few of us have heard of. Doctors have the ability to test patients for “carrier status” too – and the tests they order, not home DTC tests, are the tests they use for patient care.
Even for medical professionals, genetic confusion is common. Genetics has always been a difficult topic for lay people and doctors alike. In the 1990s we began to discover the mutated genes like MLH1, MSH2, MSH6, PMS2, BRCA1, BRCA2 and TP53 in people with family cancer syndromes but we didn’t know what to do with the information. Although we now know more, it’s still a difficult topic -- even for geneticists and even more with the tsunami of data from genome sequencing.
What are the pros and cons of DTC tests?
There are certainly positive aspects to DTC tests. Their mere existence gives you the courage to get a genetic analysis in privacy. Going through this process can bestow a feeling of responsibility and take charge empowerment. After all, you know how you are doing more than anybody else does. Furthermore, it’s relatively cheap (with prices ranging from $99 to $999) and your insurance company need not weigh in about whether or not the test is indicated.
And the cons? A negative test allows us to put our heads in the sand and not have a complete genetic analysis. Genetic analysis is not a single event, it’s a process. Genetic progress has led to updated testing. Over time new genetic information is acquired and a need for new discussions with your doctor and counselor arise.
The biological significance of what is reported on DTC tests can be unclear (statistical and biological significance are different). What parts of your DNA are sequenced and what parts are not, can be hard to verify. This puts DTC and other genetic tests at risk for garden variety chicanery, false leads, hypes and data misrepresentation.
Finally, since the doctor and genetic counselor don’t order the DTC test, there’s nobody sitting next to you to objectively explain what it means, to prod you to obtain accurate family information and to help you make healthy decisions.
Why input from the patient, the doctor and the counselor is still a need.
Few of us want to revert to the old days of paternal care when the doctor was all-knowing and information gathering and input from the patient were ignored. But doctors don’t go to medical school and genetic counselors don’t go to graduate school only for the fun. The truth remains they’ve acquired the knowledge, experience, and wisdom of education and practice to share with you. A good genetic counselor is likely to have the biggest wealth of genetic knowledge and your doctor the biggest wealth of medical knowledge.
Patients who don’t understand their genetic situation are not able to make the next decision and frequently take no action. With this in mind a shift to home genetic tests has been touted as valuable patient tool of involvement and responsibility. The concept of “informed consent” is less the consent and more the informed. Patients who understand and are deeply involved in each decision feel better about their decisions. But to make these decisions, experts are required. Even as a trained oncologist, I lean on my genetic counselors when choosing what tests to order and what do when test results come back.
Your doctor and geneticist work together to help you with medical decisions. The geneticist has the genetic education, as well as a high emotional IQ to be empathetic and objective at the same time. To make the best decisions about what to do with test results, the geneticist, the doctor and the patient can form a team and complement each other’s strengths.
Conclusion?
One day, the home genetic test may occupy the shelves of our drug stores like home pregnancy tests do now, but the reality of the genetic situation is messier than a simple pregnancy test. Genetics has gone from difficult to very difficult. The interpretation of genetic test results is fraught with caveats. We have 20,000 genes and many sequences in between. Most genetic material is yet to be understood.
And as rule of thumb, when a genetic test is sold for a price ending in a “9” -- $199 or $99 or a recent $999 for your full genome -- there’s probably more than your health at stake. Appropriately, the sellers of these tests are selling. Their genetic counselors, the ones that are paid by the company that makes the test, are not yours. Your counselor is the one your doctor refers you to or you can find from the National Society of Genetic Counselors website. Your counselor and doctors will seek only to know your genetic inheritance and help you manage its outcomes.
Without a good doctor, a good genetic counselor and good amounts of back and forth, the home genetic test won’t help you and your family stay healthy or become healthier.
