Abstract

It is known that polymorphisms of β2-glycoprotein I (β2GPI) in exon 7 affect interaction between the phospholipid binding site and the antibodies, and that other polymorphisms in exon 8 increase the generation of antibodies. In this study, we analyzed genetic polymorphisms of β2GPI in unselected Chilean patients to determine the prevalence of β2GPI polymorphisms in the phospholipid domain in patients with venous and arterial thrombosis and the clinical correlation with thromboembolic complications. This study comprised 149 patients with venous and arterial thrombosis (62 with venous thrombosis and 87 with arterial thrombosis) and 160 healthy controls with no previous history of thrombosis. Polymorphisms of exons 7 and 8 of β2GPI, which encode for its fifth domain, were determined by PCR-RFLP. The presence of aPL or anti-β2GPI in the patients was detected by ELISA. Anti-β2GPI were present in 8/149 patients (5.4%); of these, five had aCL antibodies of low titer. The allele containing Val/Leu247 and Trp/Ser316 was significantly more frequent in patients with thrombosis than in the control group (OR=3.1, CI 1.6-6.0, p=0.0003; OR=2.9, CI 1.1-8.6, p=0.027, respectively). These polymorphisms did not correlate with aPL or anti-β2GPI but significant differences were observed with venous thrombosis (p<0.0001) and arterial thrombosis (p=0.026). In conclusion, the β2GPI polymorphisms Val/Leu247 and Trp/Ser316 are not related to the presence of anti-β2GPI antibodies in unselected Chilean patients with venous and arterial thrombosis, but they are significantly associated with venous and arterial thrombosis. © Clinical Rheumatology 2006.