In families with at least one person who has been diagnosed with celiac, so-called first-degree relatives—parents, children, and siblings—carry at least a one-in-22 chance of also having the condition. So-called second-degree relatives (aunts, uncles, nieces, nephews, grandparents, grandchildren or half-siblings) carry at least a one-in-39 chance of having celiac disease.
Some studies have shown even higher odds: In one study, for example, 11% of first-degree relatives (that’s one in every nine relatives) showed the characteristic intestinal damage known as villous atrophy, which means they had celiac disease.
Medical Groups Recommend Screening
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 of a risk, many families have two or more cousins with the condition.
For first- or second-degree relatives who have celiac disease symptoms, screening definitely is warranted. Symptoms 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.
However, research is inconclusive as whether 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 healthcare providers don’t order all five) look for antibodies to gluten that circulates 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 procedure that uses a small camera to examine your small intestine. During the endoscopy, the healthcare provider 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 conventional 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 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 the condition 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 signs of celiac.
A Word from Verywell
Don’t worry if you get a call from a close relative saying they’ve been diagnosed with celiac disease and you should be screened for it. As you can see from the numbers above, while the condition does run in families, you’re more likely not to develop it, even if your close relative has it. If you’re concerned about celiac—and especially if you have symptoms—talk to your healthcare provider about getting screened for the condition.
