Dinucleotide repeat polymorphism of heme oxygenase-1 promotor region is not associated with IBD risk or disease course

Haem oxygenase-1 (HO-1) up-regulation was suggested to reduce mucosal tissue damage in inflammatory bowel disease (IBD) and an up-regulation of HO-1 expression in patients with Crohn's disease (CD) and ulcerative colitis (UC) was demonstrated. A HO-1 gene promoter microsatellite (GT)(n) dinucleotide repeat polymorphism was associated with regulation of HO-1 in response to inflammatory stimuli. We therefore hypothesized that IBD patients might segregate into phenotypes with high or low HO-1 inducibility. Ethylenediamine tetraacetic acid blood samples were obtained from 179 CD patients, 110 UC patients and 56 control patients without inflammation. Genomic DNA was purified and the 5'-flanking region of the HO-1 gene containing the (GT)(n) dinucleotide repeat was amplified. Polymerase chain reaction (PCR) products were purified and the length of the PCR fragments was analysed. The number of (GT)(n) repeats in the population studied ranged from 13 to 42. The distribution of the allele frequencies was comparable in patients and controls for both the short and the long alleles. The frequencies of short-, middleand long-sized alleles were not changed among the groups studied. No correlation was found between IBD and microsatellite instability detected in five individals. Our data indicate that (GT)(n) dinucleotide repeats of the HO-1 promotor region have no significance for the pathophysiology and disease course of IBD. (GT)n Dinucleotide repeat polymorphism of heme oxygenase-1 promotor region is not associated with IBD risk or disease course Martin Hausmann , Gisela Paul, Silvia Kellermeier, Isabelle Frey, Jürgen Schölmerich, Werner Falk, Katrin Menzel, Michael Fried, Hans Herfarth, Gerhard Rogler 1 Department of Internal Medicine I, University of Regensburg, Germany 2 present address: Clinic of Gastroenterology and Hepatology, Department of Internal Medicine, University Hospital of Zurich, Switzerland 3 present address: Division of Gastroenterology, UCSD Medical Center, San Diego, USA 4 present address: Department of Medicine, Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, USA Running Title: Polymorphism of HO-1 promotor Address for correspondence: Martin Hausmann, PhD Clinic of Gastroenterology and Hepatology Department of Internal Medicine University Hospital of Zurich 8091 Zurich, Switzerland Tel. 41-44-255 9479 E-mail: martin.hausmann@usz.ch Hausmann et. al.: Polymorphism of HO-1 promotor region is not associated with IBD risk 2 ___________________________________________________________________________ Supported by the Deutsche Forschungsgemeinschaft (Ro 1236/8-1) and the BMBF “Kompetenznetz Chronisch entzündliche Darmerkrankungen“ (Core facility Regensburg)