Tips for Celiacs – Understanding Risk in the Gene Pool
Genetics was not my field of study in college. As a matter of fact, the last course in which I studied genetics was a biology class taken in high school back in the days before fruit flies were discovered, or thereabouts. My knowledge of genetics is so rudimentary that I consider it an achievement to understand that the reason for my having celiac disease is that my life emerged from a gene pool for which there was no lifeguard. However, my lack of formal instruction on the subject does not prevent me from being quite curious about the connection between celiac disease and genetics.
Therefore, it was with considerable interest that I read Scot Lewey’s article “Celiac Disease Genetics,” published in the Spring 2008 edition of Celiac.com’s Scott-Free Newsletter and currently available online at http://www.celiac.com/articles/21628/1/Celiac-Disease-Genetics/Page1.html. Dr. Lewey began his discourse by explaining that each human being has 46 chromosomes, 23 from each parent. Of these chromosome pairs, it is chromosome 6 that contains the gene associated with celiac disease. Because the gene is made up of a contribution from each parent, it is designated by two DQ patterns. Consequently, a person’s DQ pattern can be expressed as DQx⁄DQy where x and y are numbers between 1 and 9. For example, a person’s DQ pattern could be DQ1⁄DQ7 or DQ2⁄DQ4.
As most of us are aware, the majority of people who are diagnosed with celiac disease have at least one DQ2 pattern, while a much smaller percentage of individuals have only a DQ8 pattern. A very small fraction of diagnosed celiacs have neither the DQ2 nor the DQ8 pattern. Therefore, knowing a person’s DQ pattern can help predict his risk of having or developing a sensitivity to gluten. Dr. Lewey’s article continued with a discussion on the relative risks for developing celiac disease depending on specific combinations of DQ patterns. Having one DQ2 or DQ8 pattern presented more risk of developing celiac disease than not having either, having two DQ2 patterns presented more risk than having just one, and so on. As fascinating as the explanation was, it was written in the style of the logic problems I used to give my math students: “If a is greater than c and b is greater than a….” Though uneducated in the study of genetics, I was intimately acquainted with mathematics and logic; untangling the information and creating an orderly array was something I could do. I grabbed a pencil and paper, and with careful analysis of the paragraph, constructed a chart to organize Dr. Lewey’s assessment of the risk levels in ascending order. To this I added my own tongue-in-cheek interpretations of the genetic risks.
| DQ Pattern | Gluten Sensitivity Risk |
|---|---|
| DQ4⁄DQ4 | Whatever your problem is, it isn’t celiac disease or even non-autoimmune gluten sensitivity. Rejoice! |
| DQ4⁄DQ(1,3,5, 6,7, or 9) |
There is a slight possibility that you could have “symptoms of gluten sensitivity that responds to a gluten free diet,” but you should probably look somewhere else first for an explanation of any symptoms. |
| DQ(1,3,5,6,7, or 9)⁄DQ(1,3, 5,6,7, or 9) |
Less than 2 per cent of diagnosed celiacs have this DQ pattern. Therefore, if you are in this group and have a proven gluten sensitivity, you are very special – or very unlucky. Do not play poker, Russian Roulette, or invest heavily in the stock market. |
| DQ8⁄DQ(1,3,5, 6,7, or 9) |
I hate to break it to you, but you are at increased risk of having CD. I wouldn’t begin investing in rice cakes yet, but if you have symptoms, get tested. |
| DQ2⁄DQ(1,3,5, 6,7, or 9) |
Things are not looking good for you if you want to forget about celiac disease but have symptoms. Bite the bullet and get tested. |
| DQ8⁄DQ8 | Two copies of risky genes? You and the guy with the lone DQ2 are in the same boat. Go get tested together and then go out for a cup of coffee together. Skip the doughnuts, just in case. |
| DQ2⁄DQ8 | I’m sorry, but your parents shouldn’t have married each other, or they should have been more careful about which of their genes they were giving you. |
| DQ2⁄DQ2 | Before you get tested, gather all your friends and family around you and have a “Last Supper” comprised of all your favorite foods. If the test is positive, your diet will change forever, and you will have to discover new favorite foods or new ways to fix the old ones. If the test is negative, gather all your friends and family together and have the same dinner again but in celebration. Be aware, though, that the celebration (and negative results) may be only temporary. |
