Celiac disease is caused by damage to the lining of the small bowel after exposure to gluten, a type of protein found in wheat, barley and rye. Oats may also be involved because they are contaminated with grains containing gluten during the milling process. In children with celiac disease, the small bowel is not able to perform one of its most important functions, which is absorption of important nutrients, minerals and water.
Children with celiac disease often present with many different symptoms. Most of the symptoms are due to poor absorption of nutrients from the small intestine. Children will present with diarrhea, vomiting, constipation and poor weight gain. If the condition is left untreated for several months it can lead to deficiency of important minerals and vitamins which cause anemia, malnutrition, loss of muscle mass, and ultimately affect the overall growth of the child resulting in short stature. Untreated celiac disease is also linked to intestinal cancer (lymphoma). This is rare and it appears only later in adult life. The presentation of the condition ranges from mild to severe and in some children it may remain silent.
The incidence of celiac disease in children with DS ranges from 10% to 16%. One reason children with Down syndrome have this disease is because of increased susceptibility to autoimmune diseases. In children with Down syndrome who are genetically predisposed to celiac disease, exposure to gluten causes an immunologic reaction in the lining of the small bowel resulting in flattening and thinning of the normal hair like projections (villi) of the lining. This is the part of the intestine which is the absorptive surface of the small bowel.
A biopsy of the small intestine is the best way to diagnose celiac disease. Because a biopsy is not easy to do and may be expensive, a blood test has been developed to screen for celiac disease.
The blood test looks for IGA antibodies to the enzyme transglutaminase. This test is very sensitive and specific and it has become valuable to identify children who do not have symptoms of the disease. However in patients with IGA deficiency, the results will be unreliable and we may need to look at IGG antibodies to the enzyme transglutaminase. This test is not very sensitive and specific. New testing protocols are underway. Changes in the biopsy and blood test will only be seen if the child has been on a diet containing gluten. Testing for celiac disease should only be done after gluten containing foods have been added to the diet.
Celiac disease is treated by eliminating products containing gluten from the child's diet. Because gluten is present in many commonly eaten foods, it is very difficult and also expensive to consume a gluten-free diet. Products containing wheat, barley and rye, and some sources also recommend oats, must be removed from the diet. Some of the products which can be consumed freely are corn, potatoes, lentils, peas, milk, and eggs. Working with a dietician is extremely valuable in managing this disease.