Alpha-Defensin DEFA1A3 Gene Copy Number Elevation in Danish Crohn’s Disease Patients

Background and Purpose of Study Extensive copy number variation is observed for the DEFA1A3 gene encoding alpha-defensins 1–3. The objective of this study was to determine the involvement of alpha-defensins in colonic tissue from Crohn’s disease (CD) patients and the possible genetic association of DEFA1A3 with CD. Methods Two-hundred and forty ethnic Danish CD patients were included in the study. Reverse transcriptase PCR assays determined DEFA1A3 expression in colonic tissue from a subset of patients. Immunohistochemical analysis identified alpha-defensin peptides in colonic tissue. Copy number of DEFA1A3 and individual alleles, DEFA1 and DEFA3, were compared with those for controls, by use of combined real-time quantitative PCR and pyrosequencing, and correlated with disease location. Results Inflammatory-dependent mRNA expression of DEFA1A3 ( P