My Close Relative Has Celiac Disease. Should I Be Tested Too?

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When one family member has celiac, others may too. Morso Images/Getty Images

Question: My close family member was diagnosed with celiac disease. Should I be tested?

Answer: Most likely, you'll need to be tested as well, especially if you have symptoms of celiac disease. These can range from digestive issues such as diarrhea and constipation to neurological problems such as migraine headaches, plus skin disorders and joint pain. People with celiac disease may also have infertility, osteoporosis, depression and thyroid dysfunction.

In families with at least one diagnosed celiac, first-degree relatives — parents, children and siblings — carry at least a one-in-22 chance of also having the condition, while second-degree relatives (aunts, uncles, nieces, nephews, grandparents, grandchildren or half-siblings) carry at least a one-in-39 chance of having it.

Some studies have shown even higher odds: In one study, for example, 12% of first-degree relatives (that's one in every eight relatives) showed the characteristic intestinal damage known as villous atrophy, which means they had celiac disease.

Several influential groups, including the American Gastroenterological Association and the World Gastroenterology Organization, call for all first-degree relatives of people with celiac to be tested themselves. Both groups also recommend testing for second-degree relatives; even though those more distant relatives don't carry as high a risk, many families have two or more cousins with the condition.

However, research is inconclusive so far whether it's worth the hassle to test second-degree relatives who have no symptoms.

Family Members Screened with Celiac Blood Tests

If you're a family member to someone who's been diagnosed with celiac disease, you should be screened using celiac blood tests. These blood tests (there are five in a full celiac panel, although some doctors don't order all five) look for antibodies to gluten that circulate in your bloodstream.

If you have positive blood tests (meaning the tests show your body is reacting to gluten), you'll need to undergo an endoscopy, a surgical procedure used to examine your small intestine. During the endoscopy, the physician will remove some small samples of your intestine to examine under a microscope. In people with celiac disease, those samples should show gluten-induced damage.

For the testing to be accurate, you need to be following a standard gluten-containing diet, which means eating foods that contain wheat, barley and rye. That's because the testing looks for your body's reaction to those foods; if the foods aren't present in your diet, the reaction in your body won't be present, either.

Repeated Celiac Screening May Be Necessary

Even if your first test for celiac disease proves negative, you can't consider yourself in the clear — you could develop it at any time. A study from Columbia University's Celiac Disease Center found that more than 3% of those family members who initially tested negative for celiac tested positive when they were tested a second or third time.

It didn't take long, either: the time between the negative and the positive test results ranged from as little as six months for some people to just three years and two months for others. The average time between negative and positive tests was just a year and a half, according to the study.

Only one of the people who tested negative initially but then positive afterward had diarrhea — the rest of the people reported no symptoms, making them so-called "silent celiacs," or people with the condition who don't have symptoms. In addition, none of those people reported a change in symptoms between testing, meaning that you can't rely upon your symptoms to determine if you're developing celiac disease.

The researchers concluded that one-time testing in relatives of people with celiac disease isn't sufficient, and that repeat testing should occur even if the relative isn't experiencing symptoms. However, more research is needed to determine if family members should be repeatedly tested if they've shown no tested signs of celiac.

Sources:

Agency for Healthcare Research and Quality National Guideline Clearinghouse. Diagnosis and Management of Celiac Disease. Accessed Nov. 28, 2011.

Goldberg D. et al. Screening for celiac disease in family members: is follow-up testing necessary?Digestive Diseases and Sciences. 2007 Apr;52(4):1082-6.

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