Saturday, February 09, 2008
New changes in Prometheus celiac disease DQ genetic reporting help determine your risk of severe autoimmune gluten related disease
Prometheus Therapeutics and Diagnostics has modified their celiac genetics testing and reporting. They are now including the number of copies of DQ2 and DQ8. Along with the DQ results they also include a table that summarizes the risk of celiac disease over the general population. Previously Prometheus only reported the presence or absence of DQ2 or DQ8. If you happened to be positive for both DQ2 and DQ8 then we knew your entire DQ pattern. However, if you only had one copy of either or two copies of one the results had less value for determining your risk of celiac disease, its severity and the possible risk of your parents and children for having at least one copy of the at risk genes predisposing to celiac disease.
Now Prometheus provides a very detailed report of the DQ2 and DQ8 genes detected along with an estimate of your risk of celiac disease. They also include a table that summarizes the various at risk DQ patterns and their relative risk compared to the general population.
An example of the new Prometheus reporting method is shown below (may require zoom to see well).
As you see they report the detailed DQA1 subunit and DQB1 subunits as well as number of copies of DQ at risk genes. The two risk patterns for celiac disease are DQ2 and DQ8. The table is shown below but will likely require you to zoom on the page to be able to read it.
However, the current testing still does not include other DQ types, DQ types that are reported to carry risk of gluten sensitivity. Other DQ patterns have also been associated with specific types of gluten sensitivity and gluten related illness such as neurological problems such as balance difficulties (ataxia), skin problems and microscopic colitis.
To understand the table and the risk estimates you must also understand the terms homozygous and heterozygous. Homozygous is when you have two copies of the same gene, one from each parent. DQ patterns reside on chromosome 6. Each of us has 46 chromosomes, 23 pairs, and therefore we all have two copies of chromosome 6, one from each parent. We all have two DQ patterns, one from each of parents, such that we are all DQx/DQx, where x is a number between 1 and 9. I am DQ2/DQ7 and my wife is DQ2/DQ5. We are both therefore heterozygous for DQ2 that is we have only one copy of DQ2. Scott Adams, the founder of celiac.com is DQ8/DQ8, he is homozygous for DQ8.
Homozygous means you have two copies e.g. DQ2/DQ2 whereas heterozygous means you have one copy of DQ2 or DQ8. Some people have one copy of DQ2 and one of DQ8 (DQ2/DQ8) and they are higher risk for celiac disease than someone with only one copy of either DQ2 or DQ8 but not as high as someone with two copies of DQ2 (DQ2/DQ2). Since DQ2 carries greater celiac disease risk than DQ8 then one copy of DQ2 plus a DQ8 (DQ2/DQ8) is higher risk than having two copies of DQ8 (DQ8/DQ8).
Other laboratories besides Prometheus providing DQ testing are Kimball Genetics, LabCorp, Bonfils, Quest and Enterolab. However, Bonfils actually does the testing for Quest and Enterolab. Also, Bonfils, and therefore Quest and Enterolab, only do a portion of DQ2 and DQ8 testing. Bonfils only tests for the beta subunit portions of the DQ molecules. This means that they can miss a minor alpha subunit component of DQ2 that does carry an increase risk of celiac disease though the test may report you are DQ2 and DQ8 negative when you may or may not be.
I will be reviewing this in more detail but I wanted to provide this new information about the changes in Prometheus celiac DQ genetic testing. If you are still confused by your test results or want more personalized review of your results, symptoms or diagnostic tests I recommend you see a physician who is an expert in celiac disease and understands these tests. I also offer on-line consultation for a reasonable fee through a secure consultation site medem.com. You simply register (registration is free) for secure on-line communication and request a consultation. The fee is $50. Some insurance companies will cover on-line communication. For those in Colorado or willing to travel you can contact my office at the number or website below. I see many people from outside of Colorado Springs for consultation though my office staff inform me that my new consult office visits are booked out 6-8 weeks. A more detailed review of the celiac and non-celiac gluten sensitivity has been forwarded to my colleagues Dr. Rodney Ford (www.doctorgluten.com), Dr. Ron Hoggan (author of Dangerous Grains) and Scott Adams, editors of ScottFree newsletter. Ron is working on a book proposal that he, Rodney and I are working on for a book about the broader problem of gluten sensitivity or as Rodney has named it, "the gluten syndrome".
Copyright © 2008, The Food Doc, LLC, All Rights Reserved.
Scot M. Lewey, D.O., FACP, FAAP, FACOP
Gastroenterology Associates of Colorado Springs
1699 Medical Center Point
Colorado Springs CO 80907
719 387 2110 Fax: 719 302 6000
Dr. Scot Lewey is a digestive disease specialist doctor (board certified gastroenterologist) whose medical practice focuses on digestive and food related illness. Also, known as Dr. Celiac, the Food Doc, Dr. Lewey shares his experiential knowledge for a healthy gut, healthy life on-line. Start learning today from his extensive personal and professional experience. Dr. Lewey is uniquely qualified as an expert and one of the few GI doctors who is also gluten sensitive and dairy sensitive. He has nearly a quarter of century of experience in the diagnosis and treatment of food allergy & intolerance, colitis, Crohn's disease and IBS. He is married to someone who has Celiac disease. He and his family live gluten free in Colorado.
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