Common genomic sequence variation of the prothrombin gene and risk of non-fatal myocardial infarction in white women

Functional polymorphisms of the coagulation factor II gene (F2) and susceptibility to systemic lupus erythematosus

OBJECTIVE

Two F2 functional polymorphisms, rs1799963 (G20210A) and rs3136516 (A19911G), are known to be associated with elevated levels/activity of prothrombin (encoded by F2) and risk of thrombosis. Since patients with systemic lupus erythematosus (SLE) have high risk of thrombosis and accelerated atherosclerosis and also high prevalence of anti-prothrombin antibodies, we hypothesized that these two F2 polymorphisms could affect risk of SLE.

METHODS

We investigated these polymorphisms in 627 women with SLE (84% Caucasian Americans, 16% African Americans) and 657 female controls (78% Caucasian Americans, 22% African Americans).

RESULTS

While the rs1799963 A allele was almost absent in African Americans, it was present at ~2% frequency in Caucasian Americans and showed no significant association with SLE. The rs3136516 G allele frequency was significantly higher in Caucasian SLE cases than in controls (48.4% vs 43.7%, respectively) with a covariate-adjusted odds ratio (OR) of 1.22 (95% CI 1.03-1.46, p = 0.023). The association was replicated in African Americans (rs3136516 G allele frequency 91.2% in cases vs 82.2% in controls) with an adjusted OR of 1.96 (95% CI 1.08-3.58, p = 0.022). Stratification of Caucasian SLE patients based on the presence or absence of cardiac and vascular events (CVE) revealed stronger association with the CVE-positive SLE subgroup than the CVE-negative SLE subgroup (OR 1.42 vs 1.20). Prothrombin activity measurements in a subset of SLE cases demonstrated higher activity in the carriers of the rs3136516 G allele.

CONCLUSION

Our results suggest a potential role for prothrombin and the crosstalk between hemostatic and immune/inflammatory systems in SLE and SLE-associated cardiovascular events, which warrants further investigation in independent samples.

The association of prothrombin A19911G polymorphism with plasma prothrombin activity and venous thrombosis: results of the MEGA study, a large population-based case-control study

BACKGROUND

Prothrombin (FII) G20210A mutation and elevated plasma prothrombin activity are known risk factors for venous thrombosis. The risk of venous thrombosis among 19911G carriers of the prothrombin A19911G polymorphism has not been extensively investigated.

OBJECTIVES AND METHODS

We assessed prothrombin activity, FIIG20210A, and FIIA19911G polymorphisms in a large population-based case-control study, the Multiple Environmental and Genetic Assessment (MEGA) study of risk factors for venous thrombosis. Four thousand three hundred and sixty-five consecutive patients with a first episode of deep vein thrombosis of the leg or pulmonary embolism were included. The control group (n = 4779) consisted of partners of patients or persons gathered using a random-digit dialing method. We studied the effect of FIIA19911G polymorphism on prothrombin activity and thrombosis risk, also in combination with factor V Leiden.

RESULTS

Among FII20210-GG control subjects, FII19911-GG carriers had 7.1% [95% confidence interval (CI): 5.7-8.5] higher mean prothrombin activity than FII19911-AA carriers and the risk for GG carriers was 1.43-fold increased compared to AA carriers [odds ratio (OR) 1.43; 95% CI: 1.27-1.61]. Among FII20210-GA control carriers, the mean prothrombin activity in both FII19911-AA and -AG carriers was nearly equivalent [131.7% and 133.4%; mean difference (95% CI) = 1.7% (-7.2-10.7)]. Because of genetic linkage, FII19911-GG carriers were very rare on a FII20210-GA background, as only one FII20210A carrier had FII19911-GG. In FII20210-GA carriers, the OR increased from 3.05 (95% CI: 2.17-4.27) in subjects with FII19911-AA to 3.33 (2.28-4.85) in subjects with FII19911-AG, compared to those with FII20210-GG and FII19911-AA.

CONCLUSIONS

The FIIA19911G polymorphism is associated with mildly elevated prothrombin activity and is a risk factor for venous thrombosis.