ABSTRACT. Objective. The association of celiac disease (CD) and type 1 diabetes is now clearly documented. Immunoglobulin A (IgA) antitransglutaminase antibodies were measured to determine the prevalence of celiac disease in a diabetic population of children and to determine the temporal relationship between type 1 diabetes onset and CD.Methods. We measured IgA antitransglutaminase antibodies using human recombinant antigen in parallel with classical markers (IgA and IgG antigliadin, IgA antiendomysium) in 284 children with diabetes.Results. In the population studied, the prevalence of CD was 3.9% (11 of 284). Two cases of CD were diagnosed before the onset of diabetes, and in 8 patients, the diagnoses of CD and diabetes were concomitant, suggesting that CD was present before the onset of diabetes. In 1 case, a girl who presented with thyroiditis, serology for CD became positive after diabetes had been diagnosed.Conclusion. An excellent correlation was observed between IgA antiendomysium and IgA antitransglutaminase antibodies. We therefore propose using IgA antitransglutaminase as a screening test for practical reasons. Furthermore, IgA antitransglutaminase levels and mucosa abnormalities were closely correlated. The presence of antitransglutaminase antibodies should alert pediatricians to the atypical forms of CD. This study indicates that CD is most often present before the onset of diabetes. Pediatrics 2004;113:e418 -e422. URL: http: //www.pediatrics.org/cgi/content/full/113/5/e418; celiac disease, type 1 diabetes, children, screening test, antitransglutaminase autoantibodies, prevalence, autoimmune diseases.

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