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.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!
So… DNA = Proof? Myth: Busted
Check out the other myths we’ve exposed so far:
- Celiac Testing Myth #1 – No Symptoms = No Celiac
- Celiac Testing Myth #2 – Go Gluten-Free First
- Celiac Testing Myth #3 – Gluten-Free 4 Life = No Reason to Test
- Celiac Testing Myth #4 – Doctor Knows Best
- Celiac Testing Myth #6 – Negative Results = No Problems
- Wheat Allergy and Non-celiac Gluten Intolerance