What genetic tests tell us about our health

Chromosome 4

Genome Management Information System, Oak Ridge National Laboratory

I am what I do with the beautiful information that has flowed through millions of years through billions of organisms and has, now, finally been entrusted to me.    Lone Frank

Genetic tests for consumers now cost as little as $99.

Send in a sample of your DNA (usually a swab of saliva) and you’ll be notified of the results by mail, email, or online. (In some states, such as New York, genetic tests must be requested by a physician.)

Science journalist Lone Frank purchased a genetic test kit and sent in her sample of saliva. In My Beautiful Genome, she describes going online and finding out her risk for Alzheimer’s, glaucoma, asthma, gallstones, arteriosclerosis, and other conditions.

Breast cancer is Lone’s number one concern; her mother and maternal grandmother died relatively young from it. At first, she’s relieved, because the test says she has a 7.7 percent risk for breast cancer, lower than a woman’s average risk of 12%.

But when Lone interviews the founder of the genetic testing company, he advises her to get a BRCA gene test because of her family history. Mutations in these genes can mean up to an 80% risk for breast cancer.

When Lone tries to get a BRCA test, she’s turned down, because the testers want evidence of breast cancer in her family going back one more generation, and Lone doesn’t have that information. Nonetheless, she manages to convince them to give her the test.

I’ll permit myself one spoiler and tell you Lone doesn’t have the BRCA genes. She’s tremendously relieved, of course – between that and her lower-than-average 7.7 % risk, maybe the genetic roll-of-the-dice is in her favor.

Not so fast.

The genetic counselor tells Lone that, because both her mother and grandmother died of breast cancer, there could be another risk factor at play – a genetic anomaly for breast cancer that hasn’t been discovered yet.

Let’s say another genetic risk factor for breast cancer comes to light and Lone has it. That would mean her risk rating would increase from 7.7% to something much higher.

The risk ratings from consumer genetic testing are based on limited information, because there is so much we don’t know yet about the human genome and disease. As more of the human genome is decoded, people’s risk ratings change.

The fact of the matter is, every human has over 20,000 genes, and consumer genetic tests examine only a handful of them.

So, just how useful are these tests?

I asked my general practitioner, an excellent physician, what he thinks of direct-to-consumer genetic tests. He’s not enthusiastic.  They yield information that’s incomplete, possibly inaccurate, and worrying. He believes specific genetic tests for specific conditions – the kind of test you’d obtain after a discussion with your health care provider – can be useful, but only if you’re prepared to act on the information. A woman may get a BRCA test, for example, with the intention of having a double mastectomy if the results are not in her favor.

I’m not going to be asking him to request a genetic profile for me anytime soon. When I first began reading My Beautiful Genome, I considered it, but I’m not convinced I’ll learn anything useful, I’ll wonder about accuracy and, depending on the results, I’ll probably worry.

There are lots of other drawbacks, too, which Lone discusses in her book. But she gives equal time to the potential benefits of genetic testing, and writes about what is being done on the cutting edge. Some of what she has to say sounds like science fiction, but it’s really happening.

Lone Frank wants very much to know her own genome; I’ve decided to postpone exploring my own DNA for health reasons until more is known. If and when I do, I’d want to discuss the results with a genetic counselor or other qualified expert.

Still, I’m excited about the prospect of someday knowing something about my own genetic code. I hope that day isn’t too far away.

And if I ever have the opportunity to participate in a research study about the genetics of something I care about – schizophrenia, for example – I’d volunteer in a heartbeat.

Would you choose to explore your DNA with a genetic test? Have you already been tested? What do you think of consumer genetic tests? Please share your thoughts in the comments below.

Would I have my DNA analyzed for ancestry? That’s another story. In my next and last post about My Beautiful Genome, I’ll write about what Lone learned about her genetic roots.

7 responses

  1. I’ve considered it, as I’ve wondered about various health issues in the family (I’m not sure I want to know!). Unrelated to health, my Dad has done the test on his Y chromosome. My husband and I had our twins tested for zygosity, not quite the same thing, but still a DNA test. It was very neat, but rather expensive for an answer we probably would’ve figured out on our own if we had waited until they were a bit older!

    • I’m not sure I would want to know about certain health issues either. And I think a lot of this testing is only as good as the counseling and expert interpretation you need to get along with it. Thank you for visiting and commenting!

  2. I think it’s really interesting that this technology is out there, and the study of genetics is generally fascinating, but I think I’d feel differently about learning more about my own genetic code. If there was a practical purpose, maybe, but just as information, I feel like your doctor does, that it’s more likely to be worrying than anything. At least for me.

  3. This is all very interesting. My concerns are cancer and Alzheimer’s .. but would I really want to know if I have the gene for the latter? On the one hand I would want to know, but then I have to ask myself … would it do any good to know ahead of time when there is not yet the medical knowledge to stop the disease. Athough Nova Scotia is a main leader in advancements in Alzheimer’s research, we aren’t there yet.

    • Thanks for commenting, Lynn. Apparently, some recent studies indicate genetic testing doesn’t change people’s behavior much. For example, having a higher risk for obesity or heart disease doesn’t seem to make people eat healthier or exercise more. Also that the test results don’t seem to raise anxiety in the long run. It’s so early with all of this.
      I visited your blog, it’s terrific.

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