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  • Dr. Scot Lewey
    Dr. Scot Lewey

    Ten Facts About Celiac Disease Genetic Testing

      Celiac disease is arguably the most common autoimmune disease. It is very common. It is easily treated. It affects 1/100 people worldwide.


    Caption: Image: CC--Stuart Caie

    Celiac.com 04/16/2019 (originally published 04/24/2008) - Genetic tests for celiac disease and gluten sensitivity are readily available. Testing can be performed on either blood and mouth swab samples. Tests can be done at home and mailed to the lab for analysis.

    A good testing laboratory will provide an accurate prediction of celiac disease risk, and will also provide information about the statistical risk to your children, your likelihood of developing more severe celiac disease, whether one or both of your parents had the risk gene, and for some laboratories, you may determine your risk of gluten sensitivity without celiac disease.

    DQ2 & DQ8 Not the Whole Story

    About 95% of celiacs carry HLA-DQ2; while about 25% carry HLA-DQ8. If any part of the high risk gene patterns DQ2 and DQ8 is missing, then the likelihood of that person getting celiac disease is 99.9% AGAINST. 

    Negative Genetic Test Only Part of the Story

    However, "negative celiac genetic testing” is not sufficient for entirely ruling out celiac disease. To definitively declare negative celiac genetic tests requires the laboratory to test for the presence or absence of the entire HLA DQ genetic pattern, including both alpha and beta subunits.

    The DQ genetic patterns DQ2 and DQ8 have two subunits, but many laboratories only test for the beta subunit. Few labs test for both. This DQ typing is complicated and difficult to understand even by physicians and scientists. I have written an updated detailed review that appears in the Spring 2008 issue of Scott-Free newsletter published by celiac.com.

    No DQ2 & DQ8 Can Still Mean Gluten Problems

    Data collected by Dr. Ken Fine of Enterolab supports the fact that the absence of DQ2 and DQ8 does not exclude the risk of being gluten intolerance or sensitive, though it is now looks likely that one or both of those genetic white blood cell patterns are required for celiac disease or celiac sprue to develop. 

    However, there is a new study that reports that being negative for DQ2 and DQ8 does not completely exclude the possibility of celiac disease, especially in men. 

    Previous studies have documented blood test negative celiac sprue, which is also more common in elderly men with long-standing severe disease. 

    Since DQ2 or DQ8 is almost universally present where tissue transglutaminase and anti-endomysial antibodies are present it is not surprising that individuals without DQ2 or DQ8 with negative blood tests are being reported that meet criteria for celiac disease.

    These new studies are also providing further information that the genetics of celiac is gender specific. If you are a man, your risk of celiac disease may be higher than a woman if you don't have the classic genetic patterns. Again, in this situation your blood tests may be negative. If you are a woman, the risk for Celiac disease is generally higher than a man, especially if you have received the at risk gene from your father instead of your mother.

    Celiac disease is arguably the most common autoimmune disease. It is very common. It is easily treated. It affects 1/100 people worldwide. However, most people with celiac disease (~90%) are unaware, undiagnosed or misdiagnosed. 

    Most adults finally diagnosed with celiac disease have suffered at least 10-11 years, and have seen 3 or more doctors. Genetic testing can be extremely helpful in determining your risk for celiac disease, potential severity, and risk for family members. Don't be one of those whose diagnosis is missed or needlessly delayed for over a decade. Get tested! Learn about the genetic tests for celiac disease and if necessary educate your doctor about this testing.

    Important Facts About Celiac Disease:

    Genetic Testing Can Determine Celiac Risk

    Celiac genetic tests can be done on blood or a mouth swab sample but your doctor may be unaware of the tests, not know how to order them, or know how to interpret the results.

    Diet Will Not Change Genetic Test Results

    Genetic testing is not affected by diet. You can be eating gluten or on a gluten-free diet. Unlike blood tests for celiac disease antibodies, which require a patient to be eating gluten, genetic tests can be done whether or not the person being tested is eating wheat or gluten. 

    Diagnostic Codes Can Help Secure Insurance Approval

    Many insurance companies pay for celiac genetic testing. Most that pay require pre-authorization. The following diagnostic codes are helpful when requesting insurance coverage: 579.0 (celiac disease); V18.59 (family history of GI disease); and/or V84.89 (genetic susceptibility to disease).

    Some Genetic Labs Perform Limited Tests

    Many laboratories do not perform the all of the necessary components of the test to completely exclude the possible genetic risk of celiac disease and most don't test for or report the other gluten sensitive DQ patterns. Before you accept that have a negative test you need to know if your test included both the alpha and beta subunits of HLA DQ or did they just perform the beta typing.

    Negative Results Can Still Mean Celiac in Rare Cases

    In rare cases, some people, especially men, may have a negative genetic test and still have celiac disease. As with blood tests, men more commonly have negative genetic tests, especially older men with long-standing severe disease.

    DQ Type Can Influence Celiac Risk and Severity

    Both the DQ type, and number of copies you have, matter when determining not only your risk, but also the possible severity of celiac disease. Two copies of DQ2 carries more risk than one copy of DQ8 or only partial DQ2. Even a single copy of DQ2 alpha subunit ("half DQ2 positive") carries risk for celiac disease, but most of the commonly used laboratories for Celiac genetics do not test for or report the presence of this component of the celiac genes.

    Negative DQ2 and DQ8 Can Still Mean Gluten Intolerance

    The absence of at risk genes DQ2 and/or DQ8 does not exclude the possibility of being gluten intolerant or sensitive. You may respond to a gluten free diet, even if you don't have DQ2 or DQ8, or true autoimmune celiac disease.

    No Prescription Needed for Genetic Celiac Testing

    You can get genetic testing without a doctor's order and the tests can be done without having blood drawn or insurance authorization if you are willing to pay between $99-300 (www.enterolab.com).

    Genetic Testing Labs for Celiac Disease

    Laboratories in the U.S. that are known to offer complete alpha and beta subunit genetic testing include Kimball Genetics, Prometheus, and LabCorp. Bonfils, Quest and Enterolab only test for the beta subunit portions and therefore their test can miss part of a minor alpha subunit that carries a risk of celiac disease. A negative DQ2 and DQ8 report from these labs may not necessarily be truly negative for the risk of celiac disease.

    Celiac Genetic Testing References and Resources:

     


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    Thank you for this very informative article.

    I am a self diagnosed Coeliac…

    I had all the “classic†symptoms but was misdiagnosed by all the doctors that I've seen over a 13 year period!

    I have a sister that was properly diagnosed as Coeliac at 9 months old. At 15 years old, I had severe Anemia that didn't respond to any treatment, Fatigue, Nausea, terrible abdominal pains, weight gain etc but the doctors convinced me (and not my mum…) that I didn't have Coeliac based on a negative blood test and endoscopy.

    Finally, at 28, when the stomach pain attacks grew too close together I insisted on another blood test- which came out positive

    On the advice of my GP, I skipped the biopsy and started a gluten-free diet straight away. I had immediate positive affect on my overall health

    Since then, my 2 kids have been genetically tested. As they carry 1 gene only, the official result was “Coeliac disease cannot be ruled outâ€

    I chose to put them on a strict gluten-free diet, based on my experience. I just had a 3rd child and not even going to bother testing this time….

    My concern is regarding the effect of the 13 year long exposure to Gluten on the risk of bowl cancer

    If anyone could point me to some information regarding that I would appreciate it

    Hi, celiac myself and wanting to make a difference in the world by helping others. I would like to know if you are interested in sharing your story. You say touch the life of another going threw the same thing. I am writing a book of people wrongly diagnosed. Could you help me please. I would love to share your story.

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    My 3 yr old just had the genetic tests done - and those results, according to the doctor, not only diagnosed my son but helped treat my daughter (7 yrs old)

    My daughter (7) was finally diagnosed with Celiac earlier this spring, after years of tummy issues dating back before she could walk. Her case is so severe, that 10 months on the strict diet haven't cleared up her diarrhea or tummy cramps.

    My son (3) has been "failure to thrive" since before he could walk, but tested negative against Celiac this spring.

    He finally started gaining weight when we began our gluten-free quest for my daughter. After 10 months of the gluten-free diet for him, he's finally at the 50% for his age/weight/stature.... I didn't think I'd ever see that number again.

    Our doctor ran the genetic test on my son & his results were the double DQ2 - the highest risk factor for Celiac, associated with the most severe symptoms.

    He firmly declared my son officially "Celaic" based on history of failure to thrive & then growing exponentially on the diet, paired with his genetic results.

    He also said this genetic pairing of double DQ2 is dominant, and is certain my daughter is the same way. We are bypassing several passive tests on her, and going straight for immunosuppressive therapy. We finally have a confident doctor, and finally have answers.

    Paula, wow, glad to her you have found a great doctor and answers you need!!! my daughter started vomiting and diarrhea Dec 12 2010.. there was no obvious reason as to why.. at first we thought she ate too much cotton candy. after it was all out of her system, she seemed to do a little better... then a week later vomiting again! no apparent reason. Dr said it was some sort of tummy virus and it could take up to a month to clear. Funny part was no one else in the house "caught" this virus. Another ok week passed and boom vomit again..poor baby seemed to have tummy aches prior to getting sick (cramping, chills, crying, and saying ouch)..

    again another week went buy. the only pattern was she would get sick once a week like clock work (no matter how normal she was feeling earlier). finally took her in to be seem yet again and the Dr mentioned celiac disase as a long shot (but still mentioned it) i have since noticed how certain foods trigger a tummy ache and even gas.... her stools were normal for a full week (finally) but threw up after crying a lot. Not sure if the vomiting was caused by crying or something more ... another "normal" week went by and just this Friday 1/14 2011 she vomited a ton..... she was in the middle of crying, she gagged and then a few moments later it all just came out! again not 100% sure what was the exact cause... i am super bummed about this. poor kid has been having issues for a few months now and I don't want to continue to give her things that will keep her sick. Her pediatrician has asked me to log all the foods I give her...Ii am just considering asking for her to be tested and stop with the guessing game. I'm over her feeling bad and having what seems to be tummy aches. I am scared of getting negative results but my daughter actually having celiac. I need to make sure i test correctly. Paula, i am wondering what city you live in and the Dr you see for your children? i live in FL and i just wanna go straight into trusted Dr.'s

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    I am pondering whether or not to get all the testing. I went gluten free for 2 months and my symptoms were gone, went back on gluten to get tested and the symptoms were worse than before. So I cancelled my endoscopy because I knew I would need to be gluten free regardless of if it is celiac. So my question is, how important is it to be tested? Is it a matter of knowing how strictly gluten free I need to be i.e. cross contamination issues? My daughter has been diagnosed with gastroparesis but got a neg biopsy for gluten but I think it was a false neg. She always had gastro issues especially with whole grains.

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    I am pondering whether or not to get all the testing. I went gluten free for 2 months and my symptoms were gone, went back on gluten to get tested and the symptoms were worse than before. So I cancelled my endoscopy because I knew I would need to be gluten free regardless of if it is celiac. So my question is, how important is it to be tested? Is it a matter of knowing how strictly gluten free I need to be i.e. cross contamination issues? My daughter has been diagnosed with gastroparesis but got a neg biopsy for gluten but I think it was a false neg. She always had gastro issues especially with whole grains.

    Not sure where you live, however if you are Canadian and are diagnosed with celiac disease as a result of a biopsy then you can use your food receipts for gluten free products against your income taxes. You must have the biopsy to do this though!

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    I actually just got my testing done, and they tested for and provide results for the beta and alpha subunits.Thank you for all of the information though, it was great.

    Thanks for sharing this...my blood test came negative so I want to get tested with gene testing. Can you tell where did you get tested and how much it cost. And if you want to tell me what was your result. Please reply because I'm suffering with this problem.

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    When Prometheus does the testing, and reports "HLA-DQ2 and other low-risk allele" does anyone know what they usually find as the other low-risk gene unit? I know I have HLA DQ2.2, but would like to find out the part they did not tell.

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    I wish I had seen this article previously. Last summer I paid Enterolab for genetic testing and received what I consider to be an ambiguous reply where I was identified as having 2 gluten intolerant beta genes HLA-DQB1 0202 and 0301, my Iga was elevated and I had an autoimmune reaction. Since I was told I did not have the main celiac genes I assumed I was in the clear not knowing that there was still a risk. I thought either you had it or you didn't. When I later inquired about the results after noticing the word "main" I was told that an individual with the two beta genes I carry has less than a 1% chance of developing Celiac. They never offered any info about alpha testing or genes. Several months later I found out about the alpha gene component and now have to pay a different lab to gain the rest of the picture since I am still not feeling well and have a whole host of symptoms. I did try to write to Enterolab again for answers, but this time they did not respond at all. Still waiting for the results from the second lab, however, I finally feel like I might have some closure. It's been a bit of a roller coaster. Initially, after months of feeling poorly I saw a homeopath, who told me I had a wheat intolerance, among others, and to try a gluten free diet. I had never heard of celiac and she never told me of the concern. I have been gluten free for 2 years. But haven't been completely strict with it thinking it was only a sensitivity. So, a secondary problem are professionals advising to go on a gluten free diet without also educating about celiac first.

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    Guest arnold zimmerman

    Posted

    Hi, celiac myself and wanting to make a difference in the world by helping others. I would like to know if you are interested in sharing your story. You say touch the life of another going threw the same thing. I am writing a book of people wrongly diagnosed. Could you help me please. I would love to share your story.

    Celiac is still under the radar no matter how much we hear about it. The Gluten Free Diet and these diets are no better than the SAD in full bloom. Allopathic doctors are true dinosaurs in this field and I do not think the brainwashing they received in med school and paid for, will be easily undone. Many people by choice do not eat grains, even without celiac and I think that is a good idea. When a "gluten free" recipe by a celebrity celiac sufferer begins with rice flour, sorghum flour, white sugar, margarine and canned icing, run like hell!

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    I wish I had seen this article previously. Last summer I paid Enterolab for genetic testing and received what I consider to be an ambiguous reply where I was identified as having 2 gluten intolerant beta genes HLA-DQB1 0202 and 0301, my Iga was elevated and I had an autoimmune reaction. Since I was told I did not have the main celiac genes I assumed I was in the clear not knowing that there was still a risk. I thought either you had it or you didn't. When I later inquired about the results after noticing the word "main" I was told that an individual with the two beta genes I carry has less than a 1% chance of developing Celiac. They never offered any info about alpha testing or genes. Several months later I found out about the alpha gene component and now have to pay a different lab to gain the rest of the picture since I am still not feeling well and have a whole host of symptoms. I did try to write to Enterolab again for answers, but this time they did not respond at all. Still waiting for the results from the second lab, however, I finally feel like I might have some closure. It's been a bit of a roller coaster. Initially, after months of feeling poorly I saw a homeopath, who told me I had a wheat intolerance, among others, and to try a gluten free diet. I had never heard of celiac and she never told me of the concern. I have been gluten free for 2 years. But haven't been completely strict with it thinking it was only a sensitivity. So, a secondary problem are professionals advising to go on a gluten free diet without also educating about celiac first.

    Whether you have celiac disease or just gluten sensitivity, it is my understanding that ingesting gluten causes intestinal damage. If you have a negative reaction to eating gluten, why bother getting tested? Especially since you can be gluten sensitive without testing positive on any test. I don't believe that there's a cure for celiac disease or gluten sensitivity, just a treatment; avoid ingesting gluten and your problem is solved!

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    While it's helpful to know the diagnostic (ICD-9) codes that will cover the genetic testing with your insurance, your doctor may only use those codes if you either already have the disease, or a family member has the disease, or if you are "predisposed" to the disease. You cannot say that you have the disease in order to test for the disease. That would be fraudulent, and now your insurance company thinks you have the disease. This goes into your medical record, and the next time you want to apply for life insurance, you will likely be turned down. So, consider that before you allow your doctor to use celiac disease as your diagnosis code. I'm certain Dr. Lewey would agree with that.

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    Genes don't mean you HAVE anything, only that you could, if the environment is right, develop whatever it is. Also, you don't need a biopsy for celiac disease if you have positive blood tests. It has been shown fairly accurately that the blood tests reflect the biopsy findings. The only people who need biopsy are those with 'possible' positive blood tests. Never the negative, nor the strongly positive. This is recent studies looking at patients who have had biopsies. You just need the right blood tests.

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    Genes don't mean you HAVE anything, only that you could, if the environment is right, develop whatever it is. Also, you don't need a biopsy for celiac disease if you have positive blood tests. It has been shown fairly accurately that the blood tests reflect the biopsy findings. The only people who need biopsy are those with 'possible' positive blood tests. Never the negative, nor the strongly positive. This is recent studies looking at patients who have had biopsies. You just need the right blood tests.

    None of this happens to be correct, Beatrice. Sorry to burst your bubble but number one, most are not sent for intestinal biopsy due to under-suspicion as a general rule among physicians for celiac. Intestinal biopsy does, by and large, detect most celiac disease when performed. The blood tests are rife with problems of false negatives and therefore despite pronouncements by well-meaning yet totally uninformed physicians, reliance upon these is not justified. Genetic tests can show the proclivity and likelihood of celiac and thus, a positive gene test for either DQ2 or DQ8 is most certainly more helpful and also less invasive than any other single form of testing. Many of us prefer to feel that what we do, ie, lifestyle and environment and such is more important than our genes and yet, science is telling a totally different story with respect to celiac sprue.

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  • About Me

    A practicing gastroenterologist in direct patient care but who also participates in teaching medical students and physicians in training as a Clinical Professor of Medicine at Rocky Vista University College of Osteopathic Medicine and at Kansas City University of Medicine and Biosciences. In addition to authoring peer review articles, book chapters and presenting clinical research Dr. Lewey has conducted, he has authored over 50 online articles, numerous blog posts and tweets about digestive and food related issues. As a physician who is a fellow of six professional societies Dr. Lewey serves at a national level on several committees, as a reviewer for journal articles and case reports, a media representative for the AOA Media and ACG on digestive health and disease and has been featured in various print, television, podcast and online media publications about digestive issues. As a expert in digestive diseases Dr. Lewey is also a medical legal consultant and expert witness. Dr. Lewey can be reached at Facebook.com/thefooddoc, on twitter @thefoodgutdoc and at www.thefooddoc.com, and his blog www.thefooddoc.blogspot.com.

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