In people with symptoms of celiac disease, a positive tTG antibody test is an indication to start a gluten free diet. Endomysial antibody tests are also available but because of their expense, the tTG antibody test is considered superior. Tests for reticulin antibodies are also available but because they are only seen in about 65 percent of patients with celiac disease, this test is falling out of favor. Because people with celiac disease are often deficient in immunoglobulin A (IgA), negative tests for IgA gliadin antibodies in people who are strongly suspected of having celiac disease or who have IgG gliadin antibodies should be followed up with IgA levels. Deamidated Gliadin Peptide Antibodies Early tests for gliadin antibodies were useful but not as specific or sensitive as the other antibody assays used for celiac disease. However, the new test for deamidated gliadin peptides (DGP) antibodies, which was introduced in 2007, is an excellent diagnostic tool. Sensitivity and specificity for celiac disease are respectively 83.6 and 90.3% for IgA and 84.4 and 98.5% for IgG antibodies to deamidated gliadin peptides. In studies, DGP antibody tests displayed higher diagnostic accuracy than antigliadin antibody tests and, although less sensitive than antiendomysial and tissue transglutaminase antibodies, tests for DGP antibodies showed significantly higher specificity than tissue transglutaminase antibodies (P < 0.001). In addition, persistence of peptide antibodies after gluten withdrawal can be interpreted as an expression of low compliance with the diet and of the lack of improvement of the intestinal mucosa. The combined use of tissue transglutaminase and deamidated gliadin peptide antibodies is regarded as a very useful tool for celiac disease diagnosis and follow-up. Testing Genetic Susceptibility The new MyCeliac ID saliva-based test by Prometheus Laboratories identifies the specific gene sequence associated with celiac disease. Positive test results confirm genetic risk and are of particular value in families in which first-degree relatives have celiac disease. People who test negative for these genes have a very low likelihood of developing celiac disease. As a direct access test (DAT) individuals can self-order the test kit, send in their saliva samples, and receive secure online results that have been reviewed by a physician. Sources: Kelly Graham.
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No association between celiac disease, autism
Having a prior ASD was not associated with celiac disease (odds ratio 0.93; 95% CI: 0.51-1.68) or inflammation (OR, 1.03; 95% CI: 0.40-2.64), but was associated with an increased risk of having normal mucosa with a positive celiac disease serologic test result (OR, 4.57; 95% CI: 1.58-13.22), Jonas F. Ludvigsson, MD, PhD, from the Karolinska University Hospital in Stockholm, and colleagues reported in JAMA Psychiatry. Although previous case reports have suggested a potential link between the two conditions, results from larger studies have been contradictory. To better understand the association between celiac disease and ASDs, Ludvigsson and colleagues analyzed data from 28 Swedish biopsy registers. They identified 26,995 people with celiac disease, 12,304 individuals with inflammation, and 3,719 individuals with normal mucosa but positive celiac disease serologic test results, and compared them with 213,208 age- and sex-matched controls. “Although this study found no association between celiac disease or inflammation and earlier ASDs, there was a markedly increased risk of ASDs in individuals with normal mucosa but a positive celiac disease serologic test result,” the researchers wrote. Among individuals who did not have an ASD diagnosis at the time of biopsy, celiac disease (HR 1.39; 95% CI, 1.13-1.71) and inflammation (HR 2.01; 95% CI, 1.29-3.13) were both associated with moderate excess risks of developing an ASD later. This risk was even higher in individuals with normal mucosa, but a positive celiac disease serologic test result (HR 3.09; 95% CI, 1.99-4.80). The researchers note that the mechanism of association with a positive celiac disease antibody is not clear. They speculate the association could be due to increased mucosal permeability in some patients with celiac disease or in individuals with elevated levels of some antibodies. Our data are consistent with earlier research in that we found no convincing evidence that celiac disease is associated with ASD except for a small excess risk noted after celiac disease diagnosis, they added. References