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Key Points

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  • Disease summary:

    • Celiac disease (CD) is a chronic inflammatory disease of the small intestine manifests as a dysregulated immune response to a known environmental trigger (gluten and its related proteins) in genetically susceptible individuals. The mainstay of treatment is a gluten-free diet.

    • CD is a common disease with a prevalence of up to 1% in Caucasian populations, but remains underdiagnosed. Classical presentation with malabsorption and gastrointestinal (GI) symptoms such as diarrhea or abdominal discomfort is relatively rare; more commonly, patients have vague symptoms or extraintestinal presentations including dermatitis herpetiformis, anemia, osteoporosis, short stature, infertility, fatigue, or transaminitis.

    • Serologic testing can aid in diagnosis of CD. The most sensitive and specific tests are antitissue transglutaminase (anti-tTG) or antiendomysial IgA antibodies. However, the gold standard of diagnosis is still demonstration of villous atrophy on duodenal biopsy and a clinical response to a gluten-free diet. Nearly all CD patients have HLA-DQ2 or HLA-DQ8 although a significant percentage of the normal population also carries these human leukocyte antigen (HLA) alleles; testing for HLA-DQ2 or DQ8 has excellent negative predictive value. A high prevalence of IgA deficiency mandates that when serology is negative but there is high clinical suspicion of CD, measurement of total IgA levels is indicated.

    • Patients with CD have an increased risk of malignancy (small intestinal adenocarcinoma and enteropathy-associated T-cell lymphoma). A subset of CD patients has refractory disease that will not respond to a gluten-free diet and is associated with a poorer prognosis.

    • CD is associated with other immune-mediated diseases, such as type 1 diabetes and inflammatory bowel disease, suggesting a common genetic background for these disorders.

  • Differential diagnosis:

    • Collagenous sprue, Whipple disease, tropical sprue, Crohn disease, food intolerance (such as lactose), intestinal lymphoma, pancreatic insufficiency, bacterial overgrowth

  • Monogenic forms:

    • No single gene is known to cause CD.

  • Family history:

    • CD has a prevalence of 5% to 15% among first-degree relatives of affected patients.

  • Twin studies:

    • Monozygotic twins have a 75% concordance rate in CD; dizygotic twins have an 11% concordance rate.

  • Environmental factors:

    • The known triggering environmental antigen in CD is gluten, the protein found in wheat, and related proteins found in barley and rye. Gluten is composed of gliadin and glutenin proteins and has a high content of glutamine. tTG enhances the immunogenicity of gluten by deamidating glutamine, allowing gluten peptides to bind more strongly to HLA-DQ2 or DQ8 molecules on antigen-presenting cells (APCs) which then activate CD4+ T cells. A possible role for intestinal infections, such as rotavirus, in increasing the risk of CD has been implicated in the pathogenesis of CD.

  • Genome-wide associations:

    • Genome-wide association study (GWAS) has confirmed the strong association of HLA-DQ2 and DQ8 with CD and uncovered many other susceptibility loci in CD, many of which encode genes involved in the immune response.

  • Pharmacogenomics:

    • Pharmacogenetic testing currently does not have a role in CD.

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Diagnostic Criteria and Clinical Characteristics

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Diagnostic Criteria for CD

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Diagnostic ...

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