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A warning against genetic testing
April 2nd, 2012
03:54 PM ET

A warning against genetic testing

If you follow health news, you’ve heard talk about a person's “genetic risk" of disease. With companies offering personalized genetic tests for as little as $200, it’s tempting to think that a world of knowledge is at our fingertips.

But a new paper from some of the leading names in science throws a bit of cold water on the promise.

According to a group from Johns Hopkins University, led by two scientists known for breakthrough discoveries on the genetics of cancer, genomic sequencing “fails to provide informative guidance to most people about their risk for most common diseases.”

The problem, they say, is not the state of current technology and knowledge –- which is limited –- but a more basic problem: genetics plays a surprisingly small role in determining the chances that we'll get sick. Score one for the environment.

That's why, at this point in time, "prudent screening, early diagnosis and prevention strategies, such as not smoking and removing early cancers, will be the keys to cutting disease death rate," according to Dr.Bert Vogelstein, M.D.,co-director of the Ludwig Center for Cancer Genetics at Johns Hopkins Kimmel Cancer Center.

He says that if someone is relying on a whole genome test to be the crystal ball that predicts their likelihood of getting cancer, they will be disappointed.

Experts are also concerned about people ordering genomes off the Internet. If someone receives information without the proper context from a doctor or genetic counselor, it could give them a false sense of security and stop them from taking preventative measures.

Nicholas Roberts, one of the study authors and a graduate student at Johns Hopkins says that even in the best case scenario, the majority of people who have their whole genome tested will get a negative test result - that means the results do not reveal any genes that cause cancer. 

But that doesn't mean they won't get cancer. More than just genes contribute to someone getting the disease.

Nathan Pearson, director of research at Knome, a company that sequences whole genomes for researchers, praised the study and said it helps to think of our genes as being like a musical score. Two performers can be seeing the same notes in front of them, yet sound quite different.

“There are many different renditions,” says Pearson. “You can improvise.”

Pearson explains what he found when he sequenced the genome of Ozzy Osbourne.

To reach their conclusion, the Hopkins group performed a set of straightforward calculations, based on the studies of identical twins. They looked at the strength of the link between genes and disease for each of 24 different ailments.  As they point out, "[Identical] twins in general do not always develop or die from the same maladies.”

While their tone is cautious, they point out that some common diseases have a much stronger genetic component than others. Based on twin studies, genetic testing might some day predict more than 90% of coronary heart disease deaths in men, and more than 90% of all Alzheimer’s cases. By contrast, testing could predict fewer than a third of lung cancers, breast cancers, leukemia and ovarian cancers.

These figures are based on a “best-case scenario,” in which complete genomes have been examined for millions or tens of millions of individuals. The state of knowledge today is much more primitive. According to Pearson, current genetic testing is most useful when analyzing individual cancer cells, or in finding the causes of rare diseases, in which a single mutation leads to devastating results.

Some pitches seem to promise more. The website of 23AndMe, a company which offers genetic tests directly to consumers, urges people to “Take a more active role in managing your health,” and promises that “knowing your genes may impact your health, can help you plan for the future and personalize your healthcare with your doctor.” 23AndMe does not analyze the full genome of its customers, but rather sections of the genome whose influence is relatively well-known.

Henry Louis Gates, Jr. on 23AndMe and genetic testing for African-Americans

David Hinds, principal scientist for statistical genetics at 23AndMe, says the company makes sure that customers don’t expect too much.

“At this stage the presumption is that this testing has no clinical utility.” He agreed with the paper’s authors, who say genetic tests will never replace current disease prevention strategies. “It’s just another piece of information.”


soundoff (52 Responses)
  1. Julnor

    It's never a bad thing when you have more information. What you do with that information is the problem.

    April 2, 2012 at 16:29 | Report abuse | Reply
    • Steve

      And having information that you have no idea what to do with makes problems more likely.

      April 2, 2012 at 22:18 | Report abuse |
    • chainsawhands

      What you pay for information can be problematic as well.

      December 12, 2012 at 12:12 | Report abuse |
  2. eric

    They should read up on the "epigenome". All of their "research" has already been done before.

    April 2, 2012 at 17:23 | Report abuse | Reply
    • Les

      There in lies the biggest problems in wasted research money. Many of the supposedly "new" findings have already been researched and proven (or disproven). Yet we waste billions of dollars every year on projects of "wet behind the ears" new scientists who have not bothered to avail themselves of past research data in their field before they start making their not so astounding new pronouncements.

      Every researcher should be required to gather all of the research that has come before him and prove that his/her "new" studies have more than a chance of discovering new information.

      April 3, 2012 at 21:53 | Report abuse |
    • A scientist

      Les: I have no idea where you get the idea that we are just handing out money to scientists without over-sight, and that many scientists are just reinventing the wheel, but you are staggeringly ill-informed.

      Getting any research grant money is a remarkably rigorous process. For example, grants submitted to the NIH are first reviewed by 3 primary reviewers who are experts in the field and who carefully dissect every detail of the grant. If these three feel that the grant has a chance of being funded, then the grant is discussed by a panel that consists of dozens of experts. Currently, only about 10% of grants submitted to the NIH are funded, so the bar is very high, and even the slightest logical flaw is likely to doom a grant.

      Having both written and read many such proposals, I can say that it is remarkably rare that I encounter one that is fundamentally flawed in the way you describe. I have spent more than a decade in my field, and still often spend months preparing these proposals. Put simply, if I didn't do this, I would have no hope of getting funded.

      April 3, 2012 at 22:13 | Report abuse |
  3. Kate

    After my brother went into cardiac arrest brought on by a hereditary disease, I was tested for the gene, hoping and praying I didn't have it. Unfortunately I do and I've been living with this fear I'm going to have the same problems. This article is good news to me. It takes some of the fear of the unknown away.

    April 2, 2012 at 18:08 | Report abuse | Reply
    • medschoolkid

      If you don't mind sharing, do you know what the name of the gene is? It should be all caps and 4-6 letters or so.

      April 2, 2012 at 18:20 | Report abuse |
    • power4things

      And the stress of knowing this basically doubles your chances. People should not really know their future, they'll make too many mistakes trying to correct their life to fit predictions. Too many movies have played on this topic ...

      April 3, 2012 at 08:34 | Report abuse |
    • JeramieH

      Or, knowing your risk, you can make the choice to live a healthier life because of it.

      April 3, 2012 at 11:15 | Report abuse |
    • lukejostins

      The disease you seem to be describing sounds like a familial sydrome, perhaps long QT sydrome, i.e. one of the "rare diseases in which a single mutation leads to devastating results" mentioned in the article. You should definitely not discount the risk, and while you shouldn't let it cause you undue stress, you definitely should make sure that you have discussed with your doctor the ways of reducing your risk of developing heart problems, and make sure you stick to any prevention measures she has proscribed.

      April 4, 2012 at 11:22 | Report abuse |
    • Genetic Counselor

      Hi Kate,

      To add to/echo @lukejostins response, I just wanted to clarify that the type of genetic markers being described in this study are very different from single gene mutations that are associated with very specific diseases. Please know that there is a difference between the genetic basis of the common type of heart disease and 'hereditary heart disease.' If you have had genetic testing for hereditary cardiac disease through a genetics centre or your cardiologist, it is important to not discount your results based on the information provided in this article. Please continue with any screening and follow-up that has been recommended to your by the physicians involved in your care.

      April 4, 2012 at 16:12 | Report abuse |
  4. medschoolkid

    These internet companies testing are just a scam. If people are interested they should talk to their doctor or a genetics counselor. Personal genomes contain a incredible amount of predictive information, but it might as well be Greek to someone who doesn't understand how to interpret it. I say this as a student with samples of my own DNA in the fridge, running it against assays that other students are researching and designing.

    April 2, 2012 at 18:18 | Report abuse | Reply
  5. Delia

    I have been tested through 23andme, and it is not a scam. Everything in the health results you get is FULLY explained, and any studies that the results are based on are listed and explained as well. It is all made very clear in numerous ways. It is absolutely not necessary to talk to a doctor or a genetics counselor unless after reviewing your results, you still have questions.

    I highly recommend it. Anyone with Parkinson's Disease can join in the research at 23andme and get free testing (your doctor must tell them you have been diagnosed with PD). It's a great way to take part in Parkinson's research as well as research in other diseases.

    April 2, 2012 at 18:37 | Report abuse | Reply
    • Sorenna

      23 and Me is certainly no scam. If you go into it knowing the risks and limitations, it not only helps you, but you can also contribute to research. Saw some disturbing things, but more importantly, my family was able to assess risks, too.

      We are able to manage our health goals much better with the help of 23 and Me and our physicians.

      August 5, 2012 at 10:57 | Report abuse |
  6. Lulu

    Trying to scare people out of submitting a spit sample for genetic testing fro a reasonable price is just another way for doctors to try and monopolize health information and get more money for themselves. Sure I could pay thousands of dollars for each genetic test I wanted the doctor to run (none of which would be covered by insurance unless I am already showing symptoms of the disorder, and at that point, what is the point of even getting the genetic test). Or I could pay $99 for the 23andme genetic test that sends me monthly updates in scientific studies related to my genes, explains the findings in my gene compared to others for hundreds of different disorders (citing studies if I am interested in looking at the primary sources of the information). 23andme tells me what medications I am allergic to (that I would never have known otherwise). Tells me what medications are more likely to work in connection with my gene code. Tells me what disorders I carry the gene for (but do not exhibit) etc. I would never pay a doctor tens of thousands of dollars for all of these genetic tests, when a cheaper and easier solution exists. Patient empowerment should be encouraged, CNN, not discouraged. Shame on your for pandering to the doctor lobby yet again.

    April 2, 2012 at 18:38 | Report abuse | Reply
    • Soulcatcher

      Bravo! Touche!

      April 3, 2012 at 07:44 | Report abuse |
  7. Lulu

    Obviously environmental factors also play a part. But some diseases are far more attributable to genetics than environment (ie alzheimers, breast cancer, etc). The 23andme tests tells you the percentage range that each disease is attributable to genetics versus environment and what to do to reduce environmental risk for each disease that does have environmental components. Just because genetics don't make up 100% of one's health doesn't mean one shouldl completely ignore genetics and not get easy and affordable genetic tests to better understand their health and cater their vitamin intake and diet to accommodate their health risks. Scaring people out of genetic testing is doing a major disservice to society, CNN. I suggest you do far more research on 23andme and other genetic testing services before carelessly dissuading people from them.

    April 2, 2012 at 18:43 | Report abuse | Reply
    • jill

      actually lulu both of your comments are incorrect. the 23andme testing does not test for all genes known to be connected to a condition and it does not check every gene for all mutations. for example It is possible that you carry a BRCA gene mutation that puts you at increased risk of cancer, but 23andme does not screen for it. You would end up with a reduced risk for cancer by their test when in fact your risk is 80%. Another example would be that you were told by their panel that you are not a carrier of a condition that runs in your family, when you were never actually checked for your family's mutation. What the article is saying is that the testing gives the consumer the impression that the testing is complete and accurate when in fact it is not. They may test for the most common genetic mutation for a disorder but the panel is not complete testing for all gene mutations known to cause the disorder. The reason the testing is cheap is that is it not full sequencing of the genes in question and is basically a worthless test that gives people false reassurance. A genetic counselor knows the difference between the testing options and can make sure the correct testing is performed based on your family history.

      April 2, 2012 at 21:07 | Report abuse |
    • Johan S

      Jill .. 23andme will tell you if you have the common disease risk oriented mutation, sure it will miss disease causing mutations for ones it doesn't know about ... But then it never tells you that you won't get it. If they miss a mutation, you are still no worse off than if you hadnt tested and don't know you have a breast cancer gene. In other words, you'd be silly to stop eating broccoli because 23andme said you can't get breast cancer. For one thing 23andme never makes an assurance that you won't get a disease .. So this ting about "false sense of security" is bogus .. It will leave any person wi reasonable intelligence at the same sense of security you had before you took the test. Plus they will know if they havink own increased risks .. For things they can avert or prepare for. If you are the type not to understand that, then maybe 23andme isn't right for you. But it's very useful for people who wouldn't be stupid about how they handle the information.

      April 3, 2012 at 21:13 | Report abuse |
    • A scientist

      Lulu and Johan: Unfortunately, your comment highlights the exact problem with testing companies such as 23andMe. While the information that they provide is technically accurate, it is often misleading.

      For example, 23andMe only tests for 3 BRCA (breast cancer) mutations. Johan argues that these are "the common disease risk oriented mutation" and that the test just misses mutations that "it doesn't know about ." While I can see how one could get this impression for the material provided by 23andMe, it is factually wrong. There are hundreds of BRCA mutations known to cause cancer. 23andMe tests for the three that are common among the Ashkenazi Jewish population, but these are not the most common mutations in other populations. In other words, while this test is useful for a subset of the Jewish population, it borders on worthless for other populations. The problem is that a non-expert reading 23andMe's literature might wrongly assume (as demonstrated by Johan) that this is a reasonably comprehensive test.

      This exact problem is why doctors recommend that genetic testing be done in consultation with a genetic counselor. Genetic testing is extremely complicated, and what is known is constantly changing. A professional counselor can help a patient choose the right test and understand the full signficance of their test results. Companies do not like to advertise the limitations of their products, so very commonly, people who get genetic testing through these mail companies misinterpret their results. Ironically, Johan, in defending 23andMe, simply proved this point.

      April 4, 2012 at 10:17 | Report abuse |
  8. Delia

    @ Lulu – YES – all very well stated, in both your posts. Thank you!

    April 2, 2012 at 18:51 | Report abuse | Reply
  9. medschoolkid

    I'm sorry I wasn't trying to bash 23andme in my earlier posts. I just know some of these companies do not give you the information you need to understand results. I most definitely agree that is important to get genetic screening for certain things. It is important to know if you are a carrier for a specific trait, especially if you have a family history or are from certain ethnic groups. I would encourage Lulu or Delia to share these results with their doctor, they may give you more insight and a better explanation of some of the information. I do think the next generation of doctors will emphasize genetics much more than the current generations. Personally I'm glad I have access to a lab where I can do the testing that I want, but it does require a good amount of technical expertise.

    April 2, 2012 at 19:07 | Report abuse | Reply
  10. Steve

    I look forward to when whole genome sequencing is available for a few hundred dollars. Widespread sequencing of many different people with many different diseases and correlating side-effects and effectiveness of drugs with individual genomes will greatly increase our understanding of what IS genetically influenced and what isn't.

    There are many drugs which are very effective and with no bad side effects for some people, but are ineffective or have very bad side effects for others. Having a full gene sequence could be used to directly indicate and contraindicate specific drugs, making treatment much more effective.

    April 2, 2012 at 21:07 | Report abuse | Reply
  11. Mary

    I think this article is trying to undermine genetic testing. 23&Me is owned by the wife of the co-founder of google who also happens to have a Phd in Biotechnology from Stanford, if I am not mistaken. No where on the website do they say that genetics can predict the diseases you will be potentially exposed to. All they say is you can manage you health better by knowing your genes better. It is another tool along with regular check-ups that can help us manage our health better, In fact they recommend that we go with the test results to doctors and have a chat with him/her about the findings.

    April 2, 2012 at 21:53 | Report abuse | Reply
  12. jordan

    Im 14 and battled with health issues ever sense I was born and just now a month ago they said I had the rarest genetic disorder number 2 combined with 3 the genetic counselor said they no know nothing about it until the next ten years it kinda makes me sad because doctors don't really know what is wrong but I get viruses and stuff like that easily

    April 2, 2012 at 22:25 | Report abuse | Reply
    • P S

      Try http://www.raw-food-health.net/#axzz1qyJzM5rd
      This may be able to help you. I have seen people with various ailments cure themselves.

      April 3, 2012 at 06:31 | Report abuse |
  13. wasso

    I guess this is akin to IQ testing in the sense that genes probably play less of a role in overall intelligence than the environment.

    April 3, 2012 at 07:20 | Report abuse | Reply
  14. katie

    Sure, you may be predispositioned for a disease but you could be hit by a car tomorrow...

    April 3, 2012 at 07:51 | Report abuse | Reply
    • power4things

      Exactly – what's the gene sequence for "likely to be hit by a bus"?

      April 3, 2012 at 08:36 | Report abuse |
  15. Bailey

    Important to remember that 23 and me takes your DNA from saliva and so can only pick up congenital mutations and traits. However, it can't look at mutations and gene alterations in cancers- you can only do this by sequencing the genome of cells from that tissue.

    April 3, 2012 at 07:53 | Report abuse | Reply
  16. power4things

    Internet scammers must have a field day with this genetic testing malarky – 21st-century version of Tarot cards and Runes. Except, you can charge 4 figures because it's "scientific".

    April 3, 2012 at 08:39 | Report abuse | Reply
    • JeramieH

      Are you saying your genes have no impact on your life?

      April 3, 2012 at 11:31 | Report abuse |
  17. JeramieH

    > if someone is relying on a whole genome test to be the crystal ball

    There's your problem statement right there. It's only one piece of a larger puzzle, but people may either assume it's a death sentence or a free pass to live irresponsibly.

    April 3, 2012 at 11:23 | Report abuse | Reply
  18. donrijo

    It's no wonder the author didn't have his name on the article.

    April 3, 2012 at 12:37 | Report abuse | Reply
    • Les

      A careful reading of all the info contained on the story page reveals that this column is written by one of two people. Either Dr. Gupta or Ms. Cohen. I suspect it was a combined effort of the two.

      April 3, 2012 at 22:07 | Report abuse |
  19. thinkifyoucan

    Here's the point: Unless you have a genetic disorder, genetic testing will only reveal where you fit with trending information. They create a scatter plot, draw a bold line, and then determine where you fall with regards to that line. With cancer, you may end up without a cancer linked gene in your genome. However, if you live to 105, smoke, tan, and are exposed to all sorts of additional carcinogenics, you will likely get cancer. Gene's can reveal weaknesses, but nothing is more accountable than stupidity.

    April 3, 2012 at 16:32 | Report abuse | Reply
  20. Keith

    Lets not do anything because it isn't perfect and we don't know enough. What ignorant reasoning

    April 3, 2012 at 23:04 | Report abuse | Reply
  21. Wayne J

    The technology to predict diseases five years ahead of clinical symptoms was developed by Dr. Terrinichi, Dept of Agriculture, in California way back in 1974. But it was not marketed. He could predict a disease state based on urine testing 5 years ahead of clinical symptoms. It used a pattern recognition program, a special gas chromatograph and a rather large urine sample. A chart measuring the metabolites in the Urine would emerge with 2000+ peaks (ppb range). Samples from people with diseases were used to calibrate the program. All this for $8 a pop at that time. Amazing, we just don't see this machine is use. Wonder why? Poor countries would greatly benefit. One day, these may show up in every home. What a stupid dream, business greed will prevent this.

    April 4, 2012 at 08:14 | Report abuse | Reply
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  32. I Wish I Had Been Warned

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  34. Katrice Bambi

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Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.