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DNA Testing – Good, the Bad and the Ugly
By Mark Schauss | April 9, 2009
DNA testing is the latest fad to hit the health market. Companies like Navigenics are selling test kits that will supposedly tell you if you have increased risks for developing a number of diseases like Alzheimer’s, breast cancer, cardiovascular disease, macular degeneration and many more. From there, you can make the appropriate lifestyle changes that will bring your risk back down. Sounds great doesn’t it? Well not so fast, there are real problems with this type of testing.
First off, say you have a 20% greater risk for developing Multiple Sclerosis that the average person. That would make you concerned right? Well, according to this article from MSNBC.com, that only would lift your risk from .3% to .5% (3 out of every 1,000 versus 5 out of every 1,000, respectively). This is inconsequential yet the lab highlighted it which would cause unwanted concern for most lay people who are not geneticists or statisticians.
Secondly, do we really understand what all the genetic variants mean? Does one abnormality really increase the risk for developing a disease or is it really a combination of interactions that is most important? It is my belief, which is backed by a lot of research and the opinions of a lot of people in the field, that we are truly in the infancy of genetic testing and that claiming that a genes configuration means that you are more likely to develop a disease. We don’t fully fathom all the subtle nuances that make up our genes.
Next problem lies in those supposed markers that might indicate you have a lowered risk of developing a disease. Do you then not concern yourself with the possibility of getting sick? Lifestyle and environmental causes of disease are far, far more likely to cause a disease than a supposedly abnormal gene would.
Another problem I have is when you use the myopic line of thinking that if you have a gene that increases your risk of developing a disease and turning it off is definitely a good thing. Do we know that by turning off the gene we aren’t increasing the risk of developing another more deadly disease? We don’t.
Here is an extreme example of this problem. People with sickle cell anemia, a life-shortening disease actually protects the person with the genetic disorder from malaria. Think of living in equatorial Africa with the high levels of malaria. Many children would have died without the sickle cell protective gene. There are literally thousands of other examples, many we are not sure of.
In the case of breast cancer, having the bad gene is one thing, but prophylacticaly removing ones breast is an extreme case of acting on the bad gene news. Environmental and lifestyle choices such as depressed vitamin D, exposure to toxins, smoking, and alcohol intake vastly increases your risk of developing the disease, more so than the gene. If you choose to do these things, do you remove your breasts to reduce the risk of developing the disease? Of course not. Having the gene increases your risk but working to increase your vitamin D3 level, avoiding toxic exposure and detoxing regularly, not smoking and reducing or eliminating your alcohol intake would be more beneficial and would actually lower the risk to those women with the gene.
In a nutshell, lifestyle choices have a greater impact on overall health than genetics. This is the concept of metabolomics, but that is a whole other blog.
Topics: Environment, Health, Healthcare, Laboratory Tests, Opinion, Research, Toxicity | 3 Comments »
April 9th, 2009 at 12:55 pm
Whoa. I take fault with a lot of what you have said. I was diagnosed with breast cancer, and found genetic testing very helpful. If I had had the BRCA variants (and fortunately I did not), it was widely recommended to me by my surgeon and my oncologist to opt to remove the breast rather than try breast-conserving surgery. Genetic testing was a very helpful and powerful tool for me. I have since encouraged many friends to try testing through companies like Navigenics. They provide genetic counseling, so people understand exactly what their results mean and don’t worry needlessly.
You mention lifestyle issues. Lifestyle issues and genetics often team up to cause disease. As much as some of us know we should be exercising more or eating more leafy green vegetables, some people need to be told they have a genetic susceptibility to a disease and therefore really need to improve their lifestyle. If my blood pressure is high, my doctor would tell me that. Why wouldn’t I want my doctor to tell me honestly about my genes? That’s very short-sighted.
Also, what’s with all of the “supposedly” comments? Increased genetic risk is increased risk, period. Some of the issues you point out as fact – vitamin D to prevent breast cancer, for example – are still preliminary findings and need to be replicated in additional studies. And yet you didn’t say “vitamin D supposedly prevents breast cancer.”
I don’t mean to be rude. But genetic testing was so valuable for me. I would hate for others to be discouraged from benefitting from it by someone who has obviously never undergone genetic testing.
April 9th, 2009 at 1:11 pm
Kara,
With all due respect, I disagree with a number of points you make. Did you read the article about genetic testing I linked to?
Increased genetic risk is not necessarily true increased risk. The MS example shows a 20% increase, supposedly, that in reality isn’t that much of a increased risk after all since going from a risk of .3% to .5% isn’t significant while the lab said it was.
Lifestyle changes are well known to be a rate reducing way of avoiding disease. Most women who develop breast cancer do not have the genetic marker and I would hate for people to not do lifestyle changes because they took a genetic test.
You also don’t address one of my big concerns which is that because we are in such an infancy with genetic testing, we honestly do not know whether turning a gene that supposedly leads to a disease can actually cause another disease to occur. Until our knowledge base is better, it is still my opinion that genetic testing is not as beneficial as companies like Navigenics would have you believe and this opinion is shared by a lot of medical researchers as well.
April 9th, 2009 at 3:44 pm
If I may add some silver lining . .
I’ve worked quite a bit with Charles Poliquin and his assoc..
He coined the phrase,
“Genes are the gun, environment is the trigger, with correct supplements we can virtually disarm the gun” (I paraphrase- it was 3 yrs ago).
Anyhow- without the testing, my Dad died of prostate cancer at 74, Mum beat breast cancer and has been clear for 12 . .
That said, I avoid environmental estrogens, take “prostate formulae”,vitamin D to selenium to melatonin to all puported to address Prostate health and track my PSA and digital tests . .
I guess we’ve been answering familial history as we would gene screening already, yeah ?