Celiac Testing Myth #5 - DNA = Proof

Over the past decade, DNA has emerged as a source of accessible, irrefutable proof. You don’t even need a doctor visit or blood draw. Just mail order a kit, swab your cheek and send it off. Who was at the crime scene? DNA! Who’s your Baby Daddy? DNA! Got celiac? DNA! But wait… like most things to do with celiac disease, it’s not as simple as that.

DNA image from http://www.elements4health.com

First, a little about DNA testing. As the human genome gets mapped, researchers are discovering certain alleles to be associated with certain diseases. But just because you have a certain allele doesn’t mean you have the disease. Many diseases have a genetic component, but also rely on other factors to “turn them on.”

Some people are born with their celiac gene turned on, others don’t develop celiac disease until much later. There is speculation that events such as pregancy, high stress, dietary change, and other illnesses can turn on the celiac gene. But it’s not the same for everyone, and there is still a lot of research to be done.

There are several ways to have the “celiac gene,” and they carry different levels of risk. The details are way more complex than I’m outlining here:

  • HLA-DQ2, HLA-DQ2.5, HLA-DQ7.5 (also known as HLA DQ2.5trans), and HLA-DQ8 are the alleles known to be risk factors for celiac disease.
  • Around 1% of the population has celiac damage, while in the United States about 30-40% of the population have typically celiac genes. This means that you can have celiac genes without having celiac disease.
  • Scientists are still uncovering genes that hold risk for celiac disease. There are a few individuals who have celiac damage yet do not have the known risk factors.
  • You do not need to have celiac genetics to be sensitive to gluten in other ways.

That said, DNA testing can provide useful information. Many people who went gluten-free before screening for celiac disease decide that knowing their genetic information will help them decide how seriously to take their gluten-free diet. Some people with negative blood work or biopsy but a strong family history of celiac disease want to confirm their negative genetic status before deciding to risk a diet containing gluten.

If you choose to get genetic screening for celiac disease, use a lab that will:

  • Test both HLA-DQ beta and HLA-DQ alpha The celiac risk factors can be present on either or both, but not all labs test alpha.
  • Report your full results rather than just “negative” or “positive.” For example, many people with gluten ataxia have DQ1 or DQ3, “nonceliac” genes. This could be very interesting information to have! Also, as research progresses, the interpretation of whether your genetics carry a risk could change.
  • If you want insurance to pay for your test, you will need a doctor to submit the appropriate diagnostic codes. These are some that are typically accepted: 579.0: celiac disease, V18.59: family history or V84.89: genetic susceptibility to other disease

We used Kimball Genetics division of Labcorp. They returned a summary of the results, then I was able to call the genetic councilor and receive a copy of the full results. The full results are tricky to read, but with some persistence and Google it’s doable!

I have heard that Prometheus tests the alpha chain and returns full results, but do not have experience with them. MyCeliacID uses Prometheus.

So… DNA = Proof? Myth: Busted

Check out the other myths we’ve exposed so far:

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11 comments to Celiac Testing Myth #5 – DNA = Proof

  • SDC(aka curlyqueen)

    Great Blog! Very helpful but also raises more questions particularly for me because I’m still in the pre-diagnosis phase. I have been eating gluten lite. I eat a lot of gluten free things but I haven’t eliminated it from my health and beauty products. I have had the genetic test and I was told it was negative. I also had the blood test come back negative. But I feel a lot better after going gluten free. My GI suspects that its possible that it could be that I had an ulcer and still wants to rule out other possible conditions before settling on a gluten sensitivity. I think is reasonable but your article brings up a good point. Its not good enough to just know if the genetic testing says its negative or positive. It seems like genetic testing is saying based on your genes its likely or unlikely. Definitely gave me some food for thought to think about bringing up with my doctor.

    • Joy

      Thanks SDC.

      Did you get your full results from the genetic test and your blood tests? I always get a copy of my results. Sometimes even negative results can give you more information when you see it all spelled out. It can also let you know which tests were run, which is important.

      Ruling out other conditions is always a good idea. We can’t blame everything on celiac all the time! But if you feel better gluten-free, it likely is a problem for you as well, and you’re better off without it!

      I hope you get your answers soon :)
      Joy

      • SDC(aka curlyqueen)

        No I didn’t get the results they called me with the results but I do have the blood test results. Thats a good point that everyone should know when they go to the doctor. They should always get a copy of their medical info.

  • Marie

    For the last year, Cyrex Labs has been offering a more extensive blood test than the normal “Celiac” test. You can find it at the below link. I learned about it from an interview of Dr. Thomas O’Bryan (thedr.com) on the Underground Wellness radio show. To listen, search the iTunes store for “Underground Wellness” and then find the Jul 2010 and Jan 2011 interviews (all free). Eye opening stuff.

    http://www.cyrexlabs.com/CyrexTestsArrays/tabid/136/Default.aspx
    (look for Array #3)

  • Sharon

    We have celiac in the family and gave used Enterolab very successfully. We had our daughter tested (who has celiac siblings). Her results for celiac were negative but they identified 2 copies of another gene that could indicate gluten sensitivity. We were thrilled with the detail they gave in their report. We are now having our newborn tested through them as well. I would highly recommend enterolab!

  • There is another gene allele that everyone should know about. The gene is MTHFR an acronym and the allele is 677C>T. It prevents your body from methylating folic acid (and possibly some other things) into methylfolate, the only form your body can use. No methylfolate = no B12 and high homocysteine.

    The problem is fairly widespread. 11% of the population have the TT variant, the most malevolant and 39% have the CT variant. The consequences of these variants can be devastating: Spina Bifida and a whole host of mental dysfunctions, early onset heart attacks and strokes, early onset dementia and problems like varicose veins, all caused by extensive placque development, and lack of proper brain development, which folate has a part in regulating.

    The solution is fairly simple if you know there is a problem – supplement with methylfolate. Here are two links that give more info:

    en.wikipedia.org/wiki/Methylenetetrahydrofolate_reductase
    http://www.genecards.org/cgi-bin/carddisp.pl?gene=MTHFR

  • Unfortunately, the advice that if you have the gene, you might not have the condition is out of date. Epigenetics tells us if you were born in North America since 1930 and especially since 1945 when vitamin D serum levels started to plummet, and chemical exposure to the genes in utero began to explode, the genes are read as active and you have the disease or condition. Assume the genes are on as this is the prudent stance to take.
    For the sake of the children, if there is a question of doing a gluten free diet or not, do a gluten free diet and don’t put them at risk of a 40% increased risk of death by age 20, 190% increased risk of schizophrenia, 120% increase risk of autoimmune disease such as OCD, or diabetes type 1, or a 40% increased risk of cancer. It can happen in a blink of an eye.

    Respectfully

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