IL12B gene haplotype influences the risk of ankylosing spondylitis in Romanians

Abstract

Event Abstract Back to Event IL12B gene haplotype influences the risk of ankylosing spondylitis in Romanians Olivia Mihaela Popa1*, Eva Kriegova2, Luis Popa3, Marius Cherciu1, Monica Dutescu4, Mihai Bojinca5, Violeta Bojinca6, Petra Schneiderova2, Constantin Bara1 and Martin Petrek2 1 Department of Immunology and Pathophysiology, Faculty of Medicine, University "Carol Davila", Romania 2 Laboratory of Immunogenomics and Immunoproteomics, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Czechia 3 Molecular Biology Department, Grigore Antipa National Museum of Natural History, Romania 4 National Institute of Blood Transfusion, National Institute of Blood Transfusion, Romania 5 Department of Rheumatology, Faculty of Medicine, University "Carol Davila", "I.C. Cantacuzino" Hospital, Romania 6 Department of Rheumatology, Faculty of Medicine, University "Carol Davila", "Sf. Maria" Hospital, Romania Ankylosing spondylitis (AS) is a chronic inflammatory disease with predominant involvement of the spine. Recent findings showed that variations of the genes coding for members of the Th17 axis influence the risk of AS (1, 2). Among these genes, IL12B that encodes the common subunit p40 of the heterodimeric cytokines IL12 and IL23 was less studied. Our aim was to investigate the possible influence of IL12B gene single nucleotide polymorphisms (SNPs) on the risk of AS in Romanian population. Four SNPs mapping to IL12B gene were genotyped in 168 consecutive AS patients and 161 healthy controls of Romanian ethnicity using the Sequenom MassARRAY platform (Sequenom, San Diego, CA). Association tests for each polymorphism and haplotype frequency estimations were performed with the software packages PLINK v 1.07 and HaploView version 4.2. The intronic SNP rs1363670 was associated with a lower risk of AS (OR 0.59, 95%CI 0.358-0.998, p=0.04). The other polymorphisms were not associated with AS at individual level. The SNPs were not in linkage disequilibrium in the studied population (r2≤0.22). Four haplotypic combinations (AAAC, CAAC, ACAC, ACGG) of the investigated SNPs (rs32132227/rs2853694/rs1433048/rs1363670) had frequencies over 5% in either controls or patients. Of these, the haplotype AAAC was significantly overrepresented in patients compared with controls (35.5% versus 26.8%, p=0.01, OR 1.61), with a population attributable risk of 17.8%. In conclusion, our results suggest that a particular haplotype of IL12B gene may increases the risk of AS in Romanian population. Acknowledgements Grant support: CZ.1.05/2.1.00/01.0030, IGA_UP_ LF_2010_008 and 2013_009