Do MYO9B genetic variants predispose to coeliac disease? An association study in a cohort of South Italian children.

BACKGROUND: Coeliac disease is a complex disorder influenced by environmental and genetic factors. A genome wide linkage study identified the myosin IXB (MYO9B) as a gene possibly associated with coeliac disease. Recently, a Dutch study reported a strong association of a single SNP, rs 2305764, of MYO9B with coeliac disease. However, two successive studies carried out on British and Swedish/Norwegian cohorts reported lack of association of the MYO9B variant with coeliac disease. AIMS: The aim of the present study is to verify the effects of the MYO9B rs 2305764 polymorphism on disease risk in a Mediterranean population of coeliac children. PATIENTS AND METHODS: To address this issue, an association study was performed in 223 (127 females) Italian coeliac children and adolescents and in 600 controls. RESULTS: The allelic frequencies of the MYO9B rs 2305764 polymorphism found in our patients and in the population control were not statistically different (P=0.46). CONCLUSION: The MYO9B gene rs 2305764 polymorphism is not associated to coeliac disease in coeliac children from Southern Italy. This is in accordance with the most recent reports. Ethnic differences or a false positive result might explain the discrepancy with the Dutch study.

[The role of anti-endomysium and anti-transglutaminase antibodies in the diagnosis and follow-up of celiac disease]. / Ruolo degli anticorpi antiendomisio e antitransglutaminasi nella diagnosi e nel follow-up della malattia celiaca.

Available, non invasive, serological tests such as the anti-endomysium antibodies (EmA) and anti-transglutaminase antibodies (Anti-tTg) has allowed better outlining of the clinical presentation as well as the pathogenesis of Coeliac Disease (CD). The aim of the study was to evaluate the reliability and concordance of EmA and anti-tTg at the diagnosis (T0) of CD and after 12 months (T12) of Gluten-Free Diet (GFD). Serum EmA and Anti-tTg were evaluated in 78 patients aged 6.3 +/- 4.7 SD yrs at diagnosis, in 56 of them at T0 and T12, as well as in a control group of 88 children aged 6.9 +/- 3.8 yrs. EmA were evaluated by indirect immunofluorescence and Anti-tTg by ELISA. All subjects had normal circulating IgA levels. In the control group, EmA and Anti-tTg resulted negative in all cases. At T0, 77/78 pts had both EmA and Anti-tTg positive, one pt (1.3%) had only EmA positive, demonstrating an overall positive concordance of 98.7%. At T12, 16 pts (28.6%) had both tests positive, 8 (14.3%) had only Anti-tTg positive (all of them were no fully compliant to GFD) and 32 (57.1%) had both tests negative. The overall concordance at T12 was 85.7%. The concordance between EmA and Anti-tTg at T0 is nearly absolute (98.7%). The higher prevalence of elevated anti-tTg than of positive EmA at T12 suggests a higher sensitivity of anti-tTg following intake of even small amounts of gluten.