There are multiple reasons why a young child may need to be evaluated for Celiac Disease. The most obvious reason is if he or she has symptoms, such as chronic diarrhea, poor growth, and/or anemia. Other reasons include having a first degree relative (parent or sibling) who has Celiac Disease or having another autoimmune disorder, such as Type 1 diabetes.
The main blood tests to screen for Celiac Disease are tissue transglutaminase IgA (TTG IgA) antibodies and endomysial IgA (EMA IgA) antibodies. These tests are highly sensitive, which means that if the tests are negative, Celiac Disease can be ruled out most of the time. The problem with using these tests in infants and toddlers is that the sensitivity of these tests is much lower for children under the age of 2 than it is for older children and adults. Some believe that this is because young children with Celiac Disease have not had enough time to develop TTG and EMA IgA antibodies which can be measured. Needless to say, there are probably many toddlers with Celiac Disease who are walking around undiagnosed because they did not have elevated TTG and/or EMA IgA antibodies when they were tested.
Deamidated gliadin peptides (DGPs) are a new test for antibodies against gliadin and are being used with increased frequency for screening for Celiac Disease in the U.S. and Europe. A group of Italian researchers recently studied the utility of using DGP IgG antibodies to screen for Celiac Disease in children under the age of 2. They found that 100% of children under the age of 2 with biopsy-proven Celiac Disease had abnormally high DGP IgG antibodies on blood testing. They also found that DGP antibodies were abnormally high in 4 toddlers who had malabsorption (diarrhea) but who did not have a biopsy consistent with Celiac Disease. One of the 4 children with an abnormal DGP did have mild villous blunting and eventually developed Celiac Disease. The other 3 children with diarrhea and elevated DGPs all had the genes that predispose to Celiac Disease. They plan to follow these 3 children closely for the development of Celiac Disease. The researchers also found that DGP levels correlate very well with the extent of damage on the duodenal biopsies of the children with Celiac Disease and postulate that in the future, children with markedly elevated DGP antibodies may not need to be biopsied for diagnosis with Celiac Disease.
Out of curiosity, I went to the internet sites of some of the major labs that perform Celiac Disease blood screening tests. Labs which DO include DGP IgG antibodies on their celiac panels include Prometheus, Labcorp, ARUP, and Mayo Medical Labs. Labs which DO NOT include DGP IgG antibodies on their celiac panels include Kimball Genetics and Quest Diagnostics (as of 4/17/2013).
If you suspect that your young child may have Celiac Disease, but he or she did not have positive antibodies, it may be helpful to find out which lab their blood was sent to so that you can learn whether or not DGP IgG antibodies were part of the testing. I recommend that you discuss any concerns with your child’s physician.
1. Antibodies to deamidated gliadin peptides: an accurate predictor of celiac disease in infancy. Amarri, S., et al. J Clin Immunol. Published online 4/5/2013.
2. ARUP Consult. A Physician’s Guide to Laboratory Test Selection and Test Interpretation. Celiac Disease. www.arupconsult.com/assets/print/CeliacDisease.pdf.
3. Screening for celiac disease in average-risk and high-risk populations. Aggarwal, S., Lebwohl, B, and Green, P. Therap Adv Gastroenterol. Jan 2012; 5 (1): 37-47.