The deletion polymorphism in the angiotensin-converting enzyme gene is a moderate risk factor for venous thromboembolism

ACE displays potent vasoconstrictive effects, attenuation of fibrinolysis, and platelet activation and aggregation, thus possibly promoting venous thromboembolism (VTE). The ACE gene contains an insertion (I) or deletion (D) polymorphism accounting for 50% of the variation in serum ACE concentration. To evaluate the role of the I/D polymorphism in VTE, its prevalence was determined in 931 patients with VTE and 432 blood donors. The prevalence of the DD genotype was 27.6% in patients and 21.3% in controls (OR 1.4; p < 0.02). In multivariate analysis there was a trend of the DD genotype to be an independent risk factor (OR 1.4; p = 0.08). No differences in DD genotype prevalence according to exogenous risk factors were found. Coinheritance of FV G1691A, PT G20210A mutation, and PS deficiency with the DD genotype increased the relative risk of VTE. Thus, the ACE DD genotype is a moderate risk factor of hereditary thrombophilia. Exogenous risk factors did not alter the manifestation of VTE among carriers of the DD genotype, whereas coinheritance of the DD genotype with the aforementioned defects increased the risk for VTE considerably.     

The angiotensin-converting enzyme insertion/deletion polymorphism and serum levels of angiotensin-converting enzyme in venous thromboembolism. Data from a case control study

The angiotensin-converting enzyme (ACE) has been suggested to affect blood coagulation and fibrinolysis. Results from literature on the role of the frequent insertion/deletion (I/D) polymorphism in the ACE gene in venous thromboembolism (VTE) are controversial. Only limited data on ACE serum levels inVTE exist. We determined the ACE I/D polymorphism by genotyping and ACE serum levels by an enzymatic assay in 100 high-risk patients with objectively confirmed recurrentVTE and at least one event of an unprovoked deep venous thrombosis or pulmonary embolism. One hundred twenty-five age- and sex-matched healthy individuals served as controls. ACE genotype frequencies were not significantly different between patients (DD: 26.0%, ID: 52.0%, II: 22.0%) and controls (DD: 29.6%, ID: 44.8%, II: 25.6%; p = 0.56). Neither individuals with ACE DD genotype nor those with ACE ID genotype had a higher risk for VTE in comparison to those with ACE II genotype (odds ratio and [95% confidence interval]: 1.0 [0.5-2.1] and 1.4 [0.7-2.6], respectively). Serum ACE levels (U/l) did not differ between patients (median = 25.25, 25th -75th percentile: 20.20-33.70) and controls (24.20, 17.85-34.50, p = 0.49). In the total population involved in the study the ACE DD genotype (n = 63: 36.00 [26.40-43.00]) was associated with higher ACE levels than the ACE ID genotype (n = 108: 24.10 [19.80-31.48], p < 0.001) and the ACE II genotype (n = 54: 19.35 [15.00-22.95], p < 0.001). In conclusion, we found a significant association of the ACE I/D polymorphism with ACE serum levels. However, neither the serum levels nor the I/D genotype were associated with VTE.     

Elevated factor VIII is a risk factor for idiopathic venous thromboembolism in Canada - is it necessary to define a new upper reference range for factor VIII?

Previous studies suggest elevated factor VIII is a common, independent risk factor for venous thromboembolism (VTE); however, these studies included secondary and idiopathic VTE. We sought to explore the association between elevated factor VIII and VTE in Canadian patients with idiopathic thrombosis, and confirm the current upper factor VIII reference range was appropriate. We enrolled 300 consecutive patients with idiopathic VTE who were matched to friend controls by age, sex and ethnicity. Factor VIII levels were measured and compared between cases and controls. The optimal cut-off value to designate factor VIII levels as elevated was determined using a variety of methods. The optimal upper cut-off value for factor VIII levels was 270 IU/dl. In the logistic regression analysis, cases were more likely to have elevated factor VIII levels (OR:8.76), as were females (OR:1.93) and older subjects (OR: 1.05). Factor VIII cutoffs for a 95% specificity by age were 238 IU/dl for subjects <40 years, 248 IU/dl age 40-55 years, 261 IU/dl age 56-70 years, and 313 IU/dl age >70. Our findings confirm that elevated factor VIII is associated with an increased risk of idiopathic VTE. In our patients and matched controls, the current upper limit of normal (150 IU/dl) for factor VIII is not of clinical use. We propose that the upper limit be increased to 270 IU/dl or individual labs should establish their upper limit if they wish their assays to be discriminatory in patients with VTE. Age specific cut-offs may be clinically relevant.     

The angiotensin-converting-enzyme insertion/deletion polymorphism is not related to venous thrombosis

The insertion/deletion (I/D) polymorphism of the gene for angiotensin-converting-enzyme (ACE) is associated with ACE plasma levels and activity. Conflicting results have been reported about the relevance of this polymorphism for venous thrombosis. The aim of the present study was to analyze the role of this polymorphism for deep venous thrombosis. The study was designed as a case-control study, including 330 patients with documented deep venous thrombosis and 354 controls. ACE genotype was determined by size-analysis of polymerase chain reaction products. Results showed that, ACE genotype frequencies were similar between patients (II: 24.8%; ID: 43.3%; DD: 31.8%) and controls (II: 22.9%; ID: 50.6%; DD: 26.6%, P = 0.15).The adjusted odds ratio of carriers of the DD geno-type for venous thrombosis was 1.24 (95% confidence interval 0.90-1.80).The polymorphism was furthermore not associated with age at first thromboembolic event or the occurrence of pulmonary embolism. From these results, we can conclude that the ACE I/D polymorphism is not a significant risk factor for deep venous thrombosis.     

The VITA project: prothrombin G20210A mutation and venous thromboembolism in the general population

Recently a new identified genetic variant in the 3'-untranslated region of the prothrombin gene (G20210A allele) associated with increased plasma prothrombin levels has been linked to an increased risk of venous thromboembolism (VTE). Most of our knowledge on the G20210A allele as a risk factor for VTE derives from a population-based case-control study and from studies on selected series of VTE patients. To determine the importance of the G20210A allele as a causative risk factor for VTE in the general population, we analyzed the cross-sectional data of the Vicenza Thrombophilia and Atherosclerosis (VITA) Project. One hundred sixteen cases of VTE, ascertained in a random fashion within the general population aged 18-65, were age and sex-matched with 232 healthy subjects. Heterozygosity for the G20210A allele was present in 4.3% of VTE cases and in 3.4% of controls, indicating a marginal increase of VTE risk in carriers of the allele (odds ratio: 1.26; 95% CI 0.4-3.9). However, the VTE risk was substantially higher in subjects with idiopathic VTE before age 45 or with recurrent, idiopathic VTE (odds ratio: 2.8; 95% CI 0.6-13.8) or in subjects with a family history of VTE (odds ratio: 7.6; 95% CI 1.8-32.8). Accordingly, our results suggest that the G20210A allele associates with VTE only in selected cases, and that screening for this genetic variant is not warranted for all patients with VTE.     

Elevated plasma fibronectin levels associated with venous thromboembolism

Elevated plasma fibronectin levels occur in various clinical states including arterial disease. Increasing evidence suggests that atherothrombosis and venous thromboembolism (VTE) share common risk factors. To assess the hypothesis that high plasma fibronectin levels are associated with VTE, we compared plasma fibronectin levels in the Scripps Venous Thrombosis Registry for 113 VTE cases vs. age and sex matched controls. VTE cases had significantly higher mean fibronectin concentration compared to controls (127% vs. 103%, p < 0.0001); the difference was greater for idiopathic VTE cases compared to secondary VTE cases (133% vs. 120%, respectively). Using a cut-off of >90% of the control values, the odds ratio (OR) for association of VTE for fibronectin plasma levels above the 90(th) percentile were 9.37 (95% CI 2.73-32.2; p < 0.001) and this OR remained significant after adjustment for sex, age, body mass index (BMI), factor V Leiden and prothrombin nt20210A (OR 7.60, 95% CI 2.14-27.0; p = 0.002). In particular, the OR was statistically significant for idiopathic VTE before and after these statistical adjustments. For the total male cohort, the OR was significant before and after statistical adjustments and was not significant for the total female cohort. In summary, our results suggest that elevated plasma fibronectin levels are associated with VTE especially in males, and extend the potential association between biomarkers and risk factors for arterial atherothrombosis and VTE.     

Allele 4G of gene PAI-1 associated with prothrombin mutation G20210A increases the risk for venous thrombosis

Several studies have tried to clarify the role of polymorphism 4G/5G of the PAI-1 gene in venous thromboembolism without reaching any final conclusion. It has been demonstrated that this polymorphism may induce an increased risk for venous thromboembolism (VTE) in patients with thrombophilic defects. We studied the association of prothrombin mutation G20210A with 4G/5G polymorphism in 402 VTE patients and 466 healthy controls. Patients affected by prothrombin mutation G20210A, with or without the concomitant presence of allele 4G, had a 3.7 thrombotic risk (C.I. 95% 2.3-6.0; p<0.0001). Moreover, genotype 4G/4G is a mild risk factor for VTE, irrespectively of whether the prothrombin mutation was present. Logistic regression analysis showed that patients carrying the G20210A prothrombin mutation with allele 4G gave an odds ratio for VTE of 6.1 (C.I. 95% 3.2-11.4; p<0.001). The risk increased up to 13.0 (C.I. 95% 3.0-60.4; p<0.001) when we considered the association of the prothrombin mutation with genotype 4G/4G. The G20210A mutation without allele 4G (5G/5G) was not a risk factor for VTE. In conclusion, we believe that patients affected by VTE with concomitant presence of the G20210A prothrombin mutation could be tested for genotype 4G/4G to better define their thrombotic risk.     

血管紧张素转换酶基因多态性与血管性痴呆发病关系的研究

目的　探讨血管紧张素转换酶(ACE)基因多态性与血管性痴呆(VD)的相关性。方法　采用 聚合酶链反应(PCR)技术,检测94例VD患者(VD组)、60例原发性高血压患者(EH组)及60名健康成人 (NC组)的ACE基因型及等位基因的频率,并进行比较分析。结果　有关DD型及D等位基因频率组间比较 结果:(1)VD组比NC组明显增高(均P<0.01)。(2)脑卒中后VD患者高于非脑卒中后VD患者(由于病例 数相差太大,未进行统计学分析)。(3)VD伴EH者高于VD不伴EH者(均P<0.05)。(4)VD的程度与 ACE基因型的分布无关。结论　ACE基因I/D多态性与VD有一定的相关性;DD型及D等位基因可能是 VD的危险因素。     

Estrogen receptor alpha polymorphism and venous thromboembolism in male and female: data from the EDITH study

BACKGROUND: Association between estrogen receptor (ER) alpha polymorphism c.454-397 T>C and venous thromboembolism (VTE) has been reported in postmenopausal women. Comprehensive data are lacking. We herein evaluated the risk for VTE related to c.454-397 T>C ER alpha gene polymorphism in both men and women. PATIENTS/METHODS: The EDITH Study enrolled consecutive patients, aged over 18 years, hospitalized between May 2000 and December 2004 in Brest University Hospital with an objectively proven symptomatic VTE. For each case, one control who matched the case for age within a five-year age band, gender and major acquired risk factors, was selected. The present analysis was restricted to 677 cases with a VTE event not related to major acquired risk factors and their matched controls. RESULTS AND CONCLUSIONS: The relationship between VTE and c.454-397 T>C ER alpha polymorphism was consistent with a dominant model in women and a recessive model in men. Adjusted conditional odds ratios (95% CI) were 1.37 (1.05-1.78) and 1.29 (0.85-1.94) for CT/CC genotypes in women and CC genotype in men respectively compared to TT genotype. Among women hormone use did not substantially modify effect-measure estimate. Our results further extend results from previous studies. Other investigations are required to precise underlying mechanisms.     

Interrelation of hyperhomocysteinemia and inherited risk factors for venous thromboembolism. Results from the E.D.I.TH. study: a hospital-based case-control study

BACKGROUND: Moderate hyperhomocysteinemia and factor V Leiden mutation are among the most prevalent risk factors for venous thromboembolism (VTE). The hypothesis of an interaction between those risks has been raised and conflicting results were reported. METHODS: We designed a hospital-based case-control study to test the interaction between Factor V Leiden and fasting serum total homocysteine (tHcy). We have also analysed the G20210A prothrombin gene variant. This study enrolled 904 hospitalised patients who had an objectively proven deep vein thrombosis and/or pulmonary embolism as well as 904 hospitalised control patients matched for gender, age and major acquired risk factor for VTE. RESULTS: Our data did not detect any multiplicative interaction between hyperhomocysteinemia (>15 mumol/L) and factor V Leiden mutation or G20210A prothrombin gene variant. Odds ratios (95% CI) were 4.0 (1.5-11) and 6.0 (1.3-27) for the combined effect of hyperhomocysteinemia with either factor V Leiden mutation or G20210A prothrombin gene variant, respectively. CONCLUSIONS: Current data provide further knowledge in relationship between hyperhomocysteinemia and inherited risk factors, such as factor V Leiden mutation and G20210A prothrombin gene variant. As those risk factors are not so rare among Caucasians, a better estimate of the risk related to double exposure might help to optimise venous thromboembolism prevention.     

遗忘型轻度认知障碍与血管紧张素转换酶的基因多态性和血清水平关系的研究

目的 探讨遗忘型轻度认知障碍(aMCI)与血管紧张素转换酶(ACE)基因插入和缺失(I/D)多态性及血清ACE活力水平的关系.方法 对符合美国Meyo诊所Petersen等制定的aMCI诊断标准的90例aMCI患者(aMC[组)及90名与aMCI组相匹配正常对照者(对照组)进行神经认知功能评估,并应用聚合酶链反应检测ACE基因I/D多态性,用紫外分光光度法检测血清ACE活力水平.结果 (1)aMCI组的各项神经认知测试成绩均差于对照组(P<0.01).(2)aMCI组ACE基因型(χ2=1.510)及等位基因频率(χ2=6.945)与对照组的差异均有统计学意义(P<0.01),其中aMCI组DD基因型(23%)及D等位基因频率(57%)高于对照组(分别为16%和43%).(3)两组DD基因型(n=35)及DI基因趔(n=109)者的听觉词语记忆、符号数宁转换测试、复杂图形及类别词语流畅性得分低于Ⅱ基因型者(n=36;均P<0.05-0.01).(4)aMCI组(F=7.491)和对照组(F=4.970)ACE基因型各亚组问血清ACE活力水平的差异均有统计学意义(P<0.01),两组ACE活力水平均为DD型组>DI型组>II型组.(5)aMCI组血清ACE活力与听觉词语记忆测试的延迟回忆得分呈负相关(r=-0.249,P<0.05).结论 D等位基因可能为aMCI的发病危险因子,其调控的血清ACE高活力水平与aMCI患者情节记忆损害有关.     

Association of Angiotensin-converting enzyme insertion(I)/deletion (D) genotype in Alzheimer's disease patients of north Indian population

Several lines of evidence support for the role of angiotensin-converting enzyme (ACE) in Alzheimer's disease (AD) patients. Most human genetic studies have focussed on ACE insertion (I)/deletion (D) polymorphism and have yielded conflicting results. We have evaluated the association of ACE polymorphism with serum ACE activity in 95 AD patients and 110 healthy controls from north Indian population. In Alzheimer's patients a higher frequency of D allele was detected (I/D ratio 0.53:0.47) compared with the control group (I/D ratio 0.54:0.45), the difference being not statistically significant (p > .05). AD patients were found to be more homozygous for the D allele (26.3%) compared with controls (20.8%). The observed genotype distribution was in agreement with Hardy-Weinberg equilibrium. We observed that the D/D genotype is more in patients with a higher serum ACE activity. The D allele and the D/D genotype in AD patients may influence increased risk of cognitive impairment.     

Association between the plasminogen activator inhibitor-1 4G/5G polymorphism and venous thrombosis. A meta-analysis

The effect of the 675 insertion/deletion (4G/5G) polymorphism of plasminogen activator inhibitor-1 (PAI-1) gene on the risk of venous thromboembolism (VTE) remains controversial. In this study, we performed a meta-analysis of published data regarding this issue. A comprehensive electronic search was carried out up until September 2006. A total of 22 articles were included in the analysis that was performed using random effects models. Eighteen papers, concerning patients without another known risk factor, comprised 2,644 cases and 3,739 controls. The alleles contrast (4G vs. 5G allele) yielded a statistically significant odds ratio (OR) of 1.153 (95% confidence interval [CI]: 1.068-1.246). In a sub-analysis of five studies that included 256 cases with another genetic risk factor and 147 controls, the combined per-allele OR was still significant (OR: 1.833,95% CI: 1.325-2.536). On the contrary, the analysis of five studies regarding cases with a non-genetic risk factor for VTE (antiphospholipid antibody syndrome, Behcet disease) provided insignificant results in all aspects. There was no evidence for heterogeneity and publication bias in all analyses. Based on our findings, the 4G allele appears to increase the risk of venous thrombosis, particularly in subjects with other genetic thrombophilic defects. Recommendation for detection of this polymorphism in evaluating thrombophilia in such patients might be considered.     

Hyperhomocysteinemia and venous thromboembolism: a risk factor more prevalent in the elderly and in idiopathic cases

Fasting plasma homocysteine level and the related clinical findings were analysed in 240 consecutive patients with venous thromboembolism. Hyperhomocysteinemia, defined as a plasma level above 20 micromol/l (corresponding to the percentile 95th in the controls), was present in 11.2% of the patients. Plasma homocysteine level was similar in patients presenting with either deep venous thrombosis, pulmonary embolism or both conditions. It was significantly higher in patients with primary (unprovoked) VTE than in patients with secondary disease (associated with at least one risk factor): 12.3 vs. 9.55 micromol/l (p < 0.005). Mean homocysteine was higher in male than in female patients (14.51 vs. 12.9 micromol/l, p < 0.05) and increased significantly with age. Hyperhomocysteinemia was more frequent in patients with relapsing disease (14 of 76, 18.4%) than in those presenting with a single episode (13 of 164, 7.9%) (p = 0.034). Furthermore, hyperhomocysteinemia was correlated with reduced protein C level (p = 0.013). In a multivariate analysis, two factors were significantly associated with hyperhomocysteinemia: older age (p < 0.0001) and idiopathic occurrence (p < 0.02). Since the frequency of homozygous MTHFR thermolabile variant was rather similar in patients and controls, testing for C677T mutation was not helpful in screening VTE patients. However, the homozygous mutation was significantly more prevalent among hyperhomocysteinemia patients, confirming its role in the genesis of hyperhomocysteinemia. According to its prevalence, to the putative role in venous and arterial disease and the availability of an effective and low-cost corrective therapy, hyperhomocysteinemia deserves interest, especially in the elderly and in the patients with idiopathic VTE disease.     

Are myocardial infarction and venous thromboembolism associated? Population-based case–control and cohort studies

Introduction

Because the association of myocardial infarction (MI) and venous thromboembolism (VTE) is uncertain, we tested MI as a VTE risk factor and VTE as a predictor of MI.

Materials and Methods

Using Rochester Epidemiology Project resources, we identified all Olmsted County, MN residents with objectively-diagnosed incident VTE over the 13-year period, 1988–2000 (n = 1311), one to two resident controls per VTE case (n = 1511), and all residents with incident MI over the 31-year period, 1979–2010. For VTE cases and controls, we reviewed their complete medical records in the community for VTE and MI risk factors. Using conditional logistic regression we tested MI as a potential VTE risk factor, both unadjusted and after adjusting for VTE risk factors. We also followed VTE cases and controls without prior MI forward in time for incident MI through 12/31/2010, and using Cox proportional hazards modeling, tested VTE as a predictor of MI, both unadjusted and after adjusting for MI risk factors.

Results

The number (%) of MI prior to VTE among cases and controls were 75 (5.7) and 51 (3.4), respectively, and the number (%) of MI after VTE among cases and controls were 58 (4.4) and 77 (5.1), respectively. In univariate analyses, MI was significantly associated with VTE but not after adjusting for VTE risk factors. In both univariate and multivariate analyses, VTE (overall or idiopathic) was not a predictor of MI.

Conclusions

MI is not an independent risk factor for VTE, and VTE is not a predictor of MI.     

The -33T-->C polymorphism in intron 7 of the TFPI gene influences the risk of venous thromboembolism,independently of the factor V Leiden and prothrombin mutations

We have previously identified, in intron 7 of the TFPI gene, a T to C single-base polymorphism (-33T-->C) which is strongly associated with total circulating TFPI antigen levels. Here we examined the influence of this polymorphism on the risk of venous thromboembolism. The polymorphism was identified in the PATHROS study population (330 cases with venous thromboembolism and 826 controls). The CC genotype was found in 6.4% of cases and 10.2% of controls (age-adjusted odds ratio 0.6; 95% CI 0.3-0.9; p = 0.03). This protective effect persisted after adjustment for oral contraception and the factor V Leiden and prothrombin gene polymorphisms. In 171 controls and 49 cases in whom blood was taken at least three months after the thrombotic event, the CC genotype was associated with significantly higher total TFPI levels than the TT genotype. These results suggest that the CC genotype of the TFPI intron 7 polymorphism is an independent protective factor for venous thromboembolism, an effect probably mediated by increased TFPI levels.     

Incidence of arterial cardiovascular events in patients with idiopathic venous thromboembolism. A retrospective cohort study

Recent data have shown a higher incidence of arterial events in patients with venous thromboembolism (VTE) of unknown origin than in those with the secondary form of disease. Whether patients with idiopathic VTE have a higher risk of subsequent arterial events than the general population is unknown. The aim was to evaluate the rates of subsequent arterial events in patients with idiopathic VTE and control subjects. In a retrospective cohort study we compared the rates of subsequent arterial events (i.e. acute myocardial infarction, ischemic stroke and peripheral arterial disease) in 151 consecutive patients with objectively confirmed spontaneous VTE and 151 control subjects randomly selected from the database of two family physicians. We collected information about cardiovascular risk-factors (hypertension, hypercholesterolemia, diabetes, obesity and smoke) at the time of VTE episode, or corresponding date for the controls, and considered the follow-up from this time. Patients and controls who had suffered from arterial events before the index date were excluded. During a mean follow-up of 43.1 (+/- 21.7) months there were 16 arterial events in the VTE patients and six in the control group (HR, 2.84;95% CI,1.11 to 7.27; p = 0.03). The difference remained significant after adjusting for age and other cardiovascular risk factors (HR 2.86;95% CI,1.07 to 7.62). Overall mortality was also higher in the VTE patients (12 vs.4 deaths). In conclusion, arterial events are more common in patients with previous idiopathic VTE than in the general population. These findings may have practical implications.     

Insertion/deletion polymorphism of the angiotensin-converting enzyme gene is associated with schizophrenia in a Spanish population

A number of factors make the angiotensin-converting enzyme (ACE) a candidate gene for psychiatric disorders, including its action on neurotransmitters such as dopamine. An insertion/deletion (I/D) polymorphism in an ACE gene intron is associated with ACE levels. Here we examine whether the ACE I/D polymorphism is a risk factor for schizophrenia. Participants comprised 243 subjects diagnosed with schizophrenia and related disorders, and 291 hospital-based controls. The D allele of the ACE gene was identified as a protective factor, significantly reducing the risk of developing schizophrenia and related disorders (by 40%) and of developing schizophrenia (by 50%). This protection is explained by the additive genotype risk model, in which the protection increases with the number of D alleles. Our results indicate that the ACE D allele is involved in the development of schizophrenia.     

Combined effect of factor V Leiden and prothrombin 20210A on the risk of venous thromboembolism--pooled analysis of 8 case-control studies including 2310 cases and 3204 controls. Study Group for Pooled-Analysis in Venous Thromboembolism

Factor V Leiden and factor II G20210A mutations are two frequent genetic risk factors involved in venous thromboembolism (VTE). The goal of this pooled analysis of 8 case-control studies, comprising a total of 2310 cases and 3204 controls, was to precisely estimate the risk of VTE in patients bearing both mutations (double heterozygotes). Odds ratios for VTE were 4.9 (95% CI; 4.1-5.9) for the factor V Leiden and 3.8 (3.0-4.9) for the factor II G20210A mutation. Fifty-one cases (2.2%) and none of the controls were double heterozygotes. The odds ratio for venous thrombosis in double heterozygotes was 20.0 (11.1-36.1). Twelve percent of patients heterozygous for factor V Leiden were also heterozygous for factor II G20210A and conversely 23% of patients heterozygous for factor II G20210A were also heterozygous for factor V Leiden. Furthermore, in this large population we analyzed the effect of oral contraceptive (OC) in women carrying one of these mutations. Odds ratio for VTE associated with OC was 2.29 (1.72-3.04). In factor V Leiden carriers using OC, the odds ratio for VTE was 10.25 (5.69-1 8.45). The odds ratio of the association of factor II mutation and OC use was 7.14 (3.39-15.04). Finally, we also confirmed that the frequency of factor V Leiden was lower in patients with pulmonary embolism than in patients with deep vein thrombosis without PE (odds ratio 0.69). Conversely, factor II G20210A mutation was equally balanced in both patient groups.