ORIGINAL ARTICLE The association between P selectin glycoprotein ligand 1 gene variable number of tandem repeats polymorphism and risk of thrombosis in Behc ßet’s disease Fulya COSAN, 1,2 Basar OKU, 3 Ozgun M. GEDAR TOTUK, 4 Neslihan ABACI, 3 Duran USTEK, 3 Reyhan DIZ KUCUKKAYA 5 and Ahmet GUL 2 1 Division of Rheumatology, Department of Internal Medicine, Faculty of Medicine, Bahcesehir University, 2 Division of Rheumatology, Department of Internal Medicine, Faculty of Medicine, Istanbul University, 3 Department of Genetics, Institute for Experimental Medicine, Istanbul University, 4 Department of Ophthalmology, Faculty of Medicine, Bahcesehir University, and 5 Division of Hematology, Department of Internal Medicine, Istanbul Bilim University, Istanbul, Turkey Abstract Objectives: Behc ßet’s disease (BD) has been recognized as an unclassified type of vasculitis with an accompany- ing tendency to thrombosis. No disease-specific pathology has been demonstrated so far to explain the pro- thrombotic state, and this predisposition is considered to be associated with endothelial activation/dysfunction. P-selectin glycoprotein ligand-1 (PSGL-1) variable number of tandem repeat (VNTR) polymorphism has an impact on the protein length, and heterozygosity affect of the PSGL-1 to P-selectin interaction, which has been found to be associated with an increased risk of thrombosis in patients with antiphospholipid syndrome. We aimed to analyze the association of PSGL-1 gene polymorphism, in a group of BD patients with and without thrombosis. Methods: The study group consisted of 136 BD patients (112 male, 24 female) with thrombosis, 120 BD patients without thrombosis (54 male, 66 female) during at least 5 years disease course, and 190 healthy con- trols (103 male, 87 female) All patients fulfilled the International Study Group criteria for classification of BD. Genotyping for the PSGL-1 gene exon 2 VNTR polymorphism was carried out with the amplification of genomic DNA and running of the polymerase chain reaction product on agarose gel electrophoresis. Results: The frequency of heterozygous genotypes (AB+AC+BC) was greater in BD patients with thrombosis compared to BD patients without thrombosis (33.1% vs. 20.8%, P = 0.028, odds ratio = 1.85). However, the increased frequency of heterozygous genotypes in BD patients with thrombosis did not reach a statistically sig- nificant level compared to healthy controls (33.1% vs. 32.6%). Conclusions: PSGL-1 VNTR polymorphism may have limited contribution to the thrombotic tendency in patients with BD. Key words: Behc ßet’s disease, inflammation, P-selectin glycoprotein ligand-1 (PSGL-1), thrombosis, variable number of tandem repeats (VNTR). INTRODUCTION Behc ßet’s disease (BD) has been recognized as a systemic inflammatory disorder characterized by recurrent attacks of oral and genital ulceration, uveitis, arthritis, and intestinal, neurological, pulmonary and vascular Correspondence: Dr Ozgun M. Gedar Totuk, Bahcesehir Univer- sity Faculty of Medicine, Department of Ophthalmology, Goz- tepe Medical Park Hospital – E-5 Uzeri 23 Nisan sk. No:17 Merdivenkoy, Kadikoy, Istanbul, Turkey. Email: melikegedar@gmail.com © 2017 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd International Journal of Rheumatic Diseases 2017