Association of IL18RAP and CCR3 with coeliac disease in the Spanish population

Background and aims: Genome-wide association studies in coeliac disease ( CD) have resulted in the finding of eight new genetic regions associated with disease susceptibility. However, a replication study performed in the Italian population could not confirm two of those new regions: 2q12 (IL18RAP) and 3p21 (CCR3). The aim of this study was to investigate the role of those regions in CD risk in a different Mediterranean population, the Spanish population. Methods: A case-control study with 722 patients with CD and 794 ethnically matched healthy controls was performed. Two single-nucleotide polymorphisms, rs917997 (2q12) and rs6441961 (3p21), were genotyped and their genetic frequencies were compared between both groups using the chi(2) test. Results: An association was found with rs6441961 (p = 0.0004, OR = 1.32, 95% CI 1.13 to 1.54). A non-significant result (but concordant with the initial study) was obtained for rs917997. Conclusion: The association of the 3p21 genetic region with CD susceptibility in the Spanish population was confirmed. In 2q12, the initially described OR is most probably overestimated and therefore the real situation may be the existence of a genuine but weak risk factor, which generates statistical power limitations.