Turkish Journal of Hematology (Mar 2010)
Association of FXII 5’UTR 46C>T polymorphism with FXII activity and risk of thrombotic disease
Abstract
Objective: Thrombotic diseases are caused by genetic and environmental factors. There are a number of well-characterized genetic defects that lead to increased risk of thrombosis. Results from previous studies have indicated that FXII is involved in the pathogenesis of thrombophilic diseases. However, the results in this regard are highly controversial. One of the most important determinants of Plasma FXII level is 46CgT polymorphism in the FXII gene. In the present study, the risk of thrombophilic diseases related to this polymorphism was investigated in a case-control study. Material and Methods: One hundred and sixty subjects were studied: 120 patients diagnosed with thrombophilia (96 venous thromboembolism, 24 arterial thrombosis), and 40 age-gender-matched controls. For each subject, FXII activity level was measured by a one-step clotting assay with FXII-deficient plasma, and 46CγT polymorphism was genotyped using a restriction fragment length polymorphism (RFLP) method. Results: In this study, the previous observation that individuals with different genotypes for the 46 CγT polymorphism show significant differences in FXII activity levels was confirmed. Most importantly, FXII activity ≤68% was associated with an increased risk of venous thrombosis with an adjusted odds ratio (OR) of 4.7 (95% confidence interval [CI]: 1.03-21.1, p=0.04). However, it was not a risk factor for arterial thrombosis with adjusted OR of 5 (95% CI: 0.91-27.1, p=0.09). In CT and TT genotype, the adjusted ORs were 2 (95% CI: 0.9-4.4, p=0.11) and 2.3 (95% CI: 0.45-11, p=0.48), respectively, for patients with venous thrombosis compared with the controls. Similarly, the adjusted ORs in arterial thrombosis were 1.2 (95% CI: 0.4-3.6, p=0.76) for CT and 1.8 (95% CI: 0.2-14.9, p=0.59) for TT genotype. Thus, we did not find any association of the mutated T allele in the heterozygous or homozygous state with an increased risk of venous or arterial thrombosis. Conclusion: Lower FXII activity is not a risk factor; rather, it simply represents a risk marker for thrombosis.
