CD79A and Cowden disease: Serological tests to show the existence of autoantibodies when the patient is on a regular gluten-containing diet, followed by gastroduodenoscopy and duodenal biopsies, are the last methods for diagnosing CD.9,10 Because of its high sensitivity and NPV, IgA-tTG (Tissue Transglutaminase) antibody concentration should be determined as the initial screening test.