When Is It Time to Test for Celiac Disease?

Lately, it seems that wherever food is sold — the grocery store, your local restaurant, airplane menus — gluten-free options are highlighted. Gluten-free diets, intended for those with celiac disease, have become popular among others striving for a “healthier” lifestyle. Since we know that celiac disease is more common in individuals with Down syndrome, should children without the diagnosis of celiac disease be kept on a gluten-free diet as well?

About celiac disease

First, let’s review the basics of celiac disease itself. Celiac disease is a disorder of the immune system, triggered by proteins found in products made with certain grains, including wheat, barley, rye and possibly oats. In people with a genetic make-up that predisposes them to the condition, antibodies are formed that cause inflammation and damage in the small intestine. As a result, a range of symptoms can develop. These include abdominal pain, diarrhea, constipation, poor appetite or difficulty gaining weight. Some patients with the disease have atypical symptoms such as behavior changes, anemia or certain skin rashes. And some patients have no symptoms at all.

In recent years, celiac disease has been increasingly recognized, in part because of better awareness of the condition and better tests to diagnose early cases. Individuals with Down syndrome are specifically at risk, with 16 percent of people with trisomy 21 affected; that’s 20 times the risk seen in the general population.

Testing

Yet, there is some controversy regarding the need for routine screening for celiac disease in children with Down syndrome. While some experts advocate for early identification of the disease, there is no proven benefit to treating patients who do not have symptoms. The American Academy of Pediatrics advises testing for celiac disease only when symptoms are present, while the National Down Syndrome Society suggests all children with Down syndrome should undergo a blood test before 3 years of age. Most doctors lean toward testing, especially considering the variety and subtlety of symptoms in some cases.

There are several blood tests used to diagnose celiac disease. The most valuable is a test for anti-transglutaminase antibodies (anti-TTG) because it picks up most cases with few false  positives. The diagnosis is usually confirmed with an intestinal biopsy performed through endoscopy. These tests must be done while the child is still eating gluten; a strict gluten-free diet can reverse the test from positive to negative within weeks. Another test that is potentially helpful looks for the genetic susceptibility pattern, known as HLA DQ2/DQ8. This test costs more (and may not be covered by insurance) and, if positive, only the risk of celiac disease is confirmed. It cannot predict when and if the disease will ever occur. 

Treatment

The treatment for celiac disease is a gluten-free diet. As mentioned, strict adherence to the diet improves symptoms of the disease. Working toward a gluten-free diet should be done in coordination with a doctor and/or nutritionist, to be sure that nutritional deficiencies resulting from poor absorption are corrected and the elimination of offending foods will not lead to additional nutrition problems. For most people, a gluten-free diet is a significant challenge, especially for children who don’t understand the importance of eliminating their favorite foods.

Prevention

Many parents of children with Down syndrome consider starting a gluten-free diet “just in case.” But there is no evidence that a gluten-free diet provides any benefit for a child with Down syndrome who does not have celiac disease. Furthermore, there is limited information regarding the circumstances that shift a person with a genetic susceptibility to a full-blown, symptomatic case.

Studies aimed at identifying best practices for prevention of celiac disease suggest continuing to breastfeed an infant while gluten is introduced into the diet, introducing gluten between 4 to 7 months of age and offering smaller, gradually increasing amounts of gluten during that time period.

Rather than subjecting a child to the difficulties of maintaining a gluten-free diet, children with Down syndrome should be monitored closely for symptoms of celiac disease and tested for anti-TTG antibodies when there is any suspicion. Because of autoimmune associations, there should be particular caution regarding celiac disease for children who have also been diagnosed with type I diabetes and autoimmune thyroid disease. For those who are known to be HLA DQ2/DQ8-positive, perhaps periodic testing for anti-TTG is reasonable as well.