CD is a chronic gastrointestinal disorder caused by an abnormal immune response to gluten containing cereals such as wheat, rye and barley. About 1% of the population is thought to have coeliac disease. The disease is characterised by the flattening of the small bowel mucosa. Certain HLA genotypes (HLA-DQ2,HLA–DQ8) are required for the development of CD. This information can be used diagnostically as the absence of these HLA genotypes virtually rules out the presence of CD.
Diagnosis of coeliac disease involves serological tests for the presence of anti-tissue transglutaminase (tTG) and anti- deamidated gliadin peptide (DGP) antibodies with tissue transglutaminase being the autoantigen target. Anti-tTG antibodies recognise the same antigen as anti-endomysial antibodies (EMA). A deficiency in IgA can also be seen in a small percentage of patients suffering from coeliac disease making IgA based serology unreliable. A duodenal biopsy is generally performed to confirm coeliac disease and its severity.
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