Prevalence of factor V Leiden and prothrombin G20210A mutations in Chinese patients with deep venous thrombosis and pulmonary embolism

Venous thromboembolism (VTE) is a common vascular disease that results in two major clinical manifestations: deep venous thrombosis (DVT) and pulmonary embolism (PE). Several genetic risk factors, especially factor V Leiden and prothrombin G20210A mutations have been reported to be related to VTE in Caucasians, but the relationship remains controversial in other populations. Thus, the objective of the present study was to compare the frequency of the two mutations and also to investigate whether acquired risk factors other than genetic mutations may play a different role in Chinese VTE patients. Thirty-five patients were diagnosed with DVT concomitant PE, 178 patients with DVT, 54 patients with PE and 102 control subjects were recruited. The mutation was determined by the polymerase chain reaction-restriction fragment length polymorphism method. Of all subjects, none was a carrier of factor V Leiden or prothrombin G20210A mutations. The frequency of surgery was significantly higher in the PE group than that in other groups. There was no significant difference among the three groups in other known risk factors. The data presented here indicate that factor V Leiden and prothrombin G20210A mutations are very rare in the Chinese population, and the genetic risk profile of VTE in the Chinese population is different from that in Caucasians.     

Coincidence of 20210A prothrombin variant and factor V Leiden predisposing to venous thromboembolism

Coexistence of inherited and environmental risks leads to the high hazard of venous thromboembolism. In such cases, there might be difficulties in the diagnosis and treatment of recurrent episodes. The importance of Factor V Leiden and prothrombin variant 20210A in the pathogenesis of venous thromboembolic disease, is widely accepted, but the carriership of thrombophilic genes' variants is usually not sufficient for the development of the disease. We report two cases of familial thrombophilia with concurrent presence of prothrombin variant 20210A and factor V Leiden. In a 28-year-old woman: pregnancy, immobilization, obstetric intervention appeared to precipitate the thromboembolic complication. In the second patient, the genetic studies revealed both thrombophilic mutations which could predispose to the recurrent venous thromboembolism, previously thought to be idiopathic. We discuss diagnostic and therapeutic difficulties in such patients.     

Prevalence of factor V Leiden and prothrombin G20210A mutations in unselected patients with venous thromboembolism

We determined the prevalence of factor V Leiden and of prothrombin G20210A mutations in a cohort of unselected outpatients (n = 748) referred for suspected deep vein thrombosis (DVT) and/or pulmonary embolism (PE) and a pooled analysis of similar studies was also performed. Based on the clinical presentation, the prevalence of factor V Leiden was 15.7% in the 83 patients with DVT and 14.1% in the 99 patients with PE compared with 5.3% in patients without DVT and/or PE (control group). The prevalence of the prothrombin G20210A mutation did not differ among the three groups (3.9% for controls, 4. 8% for DVT and 3.9% for PE patients). We then divided the 99 patients with PE by separately analysing those with PE but without DVT (n = 57) and those with PE and DVT (n = 42). Compared with the control group, the prevalence of factor V Leiden was 10.5%, odds ratio (OR) 2.10 [95% confidence interval (95% CI) 0.68-5.45] in patients with primary PE and 19.1%, OR 4.20 (95% CI 1.54-10.30) in patients with DVT and PE. For the prothrombin G20210A mutation, no statistically significant differences were found between the control group and the three other groups. In conclusion, our data and the pooled analysis indicate that patients with primary PE are less often affected by the factor V Leiden mutation. No statistically significant differences were observed between patients and controls for the prothrombin G20210A mutation.     

Prevalence of factor V Leiden and prothrombin G20210A in patients with gastric cancer

AIM: To analyze the prevalence of the two commonest thrombophilic mutations, factor V Leiden and prothrom-bin G20210A, in patients with gastric cancer. METHODS: One hundred and twenty-one patients with primary gastric carcinoma and 130 healthy subjects, comparable for age and sex, were investigated. Factor V Leiden was detected by using polymerase chain reaction and restriction enzyme digestion, and prothrombin G20210A gene mutation by allele-specific PCR. RESULTS: Among the 121 cancer patients, factor V Leiden was found in 4 cases (GA genotype: 3.3%) and prothrombin G20210A in 10 cases (GA genotype: 8.3%). Of the 130 control subjects, factor V Leiden was detected in 6 cases (GA genotype: 4.6%) and prothrombin G20210A in 8 cases (GA genotype: 6.1%). No double heterozygous carriers of both mutations were found in either group. The prevalence of both factor V Leiden and prothrombin G20210A variant was not statistically different between the cancer patients and the healthy subjects. CONCLUSION: Our study suggests that, in gastric cancer, the risk factors of thrombophilic cancer state are on acquired rather than on a genetic basis and that prothrombin G20210A does not seem to be a cofactor in gastric cancer pathogenesis.     

Risk of venous thrombosis in carriers of the prothrombin G20210A variant and factor V Leiden and their interaction with oral contraceptives

BACKGROUND AND OBJECTIVES: The prothrombin G20210A mutation and factor V Leiden have been found to be associated with an increased risk of venous thrombosis, but the reported prevalences of the prothrombin gene variant both in the normal population and in patients with deep venous thrombosis (DVT) vary greatly in the literature. Moreover, the influence of oral contraceptives (OC) on thrombotic events in patients with the prothrombin G20210A variant has not been well established. In this study we evaluate both circumstances. DESIGN AND METHODS: A case-control study was run on 229 patients with DVT and 246 healthy controls. The patients' history of thrombosis and acquired thrombotic risk factors, especially OC, were recorded. Prothrombin G20210A mutation, factor V Leiden, antithrombin, heparin II cofactor, plasminogen and proteins C and S were evaluated. RESULTS: Seven and a half percent of the patients and 2.9% of the controls were carriers of the prothrombin mutation, while 12.2% of the patients and 1.6% of the controls had factor V Leiden. Among the 229 DVT patients there were 130 patients with clinically suspected thrombophilia (first thrombotic event occurring before the age of 45 years or positive family history of thrombosis or recurrent venous thrombosis). Ten percent of these 130 patients were carriers of the prothrombin G20210A mutation and 18.5% had the factor V Leiden mutation. The odds ratios (OR) for DVT risk were: 2.4 (95% CI, 1.0-6.3) for the total DVT patients and 5.2 (95% CI, 1.4-19.5) for the patients with clinically suspected thrombophilia with the prothrombin mutation. The risk of thrombosis was 6.9 (95% CI, 2.3-20.6) for the DVT patients and 14.3 (95% CI, 3.3-64.6) for the patients with clinically suspected thrombophilia with factor V Leiden. Fifty-five percent of the patients with combined congenital defects (prothrombin mutation G20210A plus another congenital defect) had recurrent thrombosis. In women receiving OC the risk of DVT was 3.5 (95% CI, 1.5-8.2) that of the patients not receiving OC. When women with combined defects were also taking OC, the risk of thrombosis increased significantly. INTERPRETATION AND CONCLUSIONS: The prevalence of the prothrombin G20210A mutation in the healthy population in our study is similar to that observed in other southern European countries. The prothrombin G20210A mutation does not by itself seem to be a high thrombotic risk factor. However, when it is present together with other thrombotic risk factors, the predicted risk of thrombotic events increases. The use of OC by women with the prothrombin G20210A variant or FV Leiden, either alone or combined with other thrombotic risk factors, was associated with a significant increase in the risk of venous thrombosis.     

Risk of recurrent venous thrombosis in patients with G20210A mutation in the prothrombin gene or factor V Leiden mutation.

The impact of the G20210A prothrombin mutation, factor V Leiden and 677T mutation of methylene tetrahydrofalate reductase (MTHFR) in recurrent deep venous thrombosis (DVT) is not so clear. We have prospectively monitored 259 patients following a first episode of DVT in order to determine which factors influence the development of a recurrent event. Several clinical and biological factors together with the genetic polymorphisms of factor V Leiden, G20210A prothrombin and 677T MTHFR were assessed. During a median follow-up of 786 patient-years, 27 patients (14%) developed one objective episode of recurrent venous thrombosis. The carriers of a double defect, homozygous or double heterozygous for factor V Leiden and G20210A, had an increased risk after a first episode of DVT, while patients who were isolated heterozygous for factor V Leiden or G20210 had a risk of recurrent DVT similar to patients who had neither mutation (annual incidence of 12.1, 3.1, 2.9 and 2.8%). The 677T MTHFR mutation alone or combined with hyperhomocysteinemia was not associated with an increased risk of recurrent events. The development of proximal DVT (P=0.01) and the presence of a double defect (P=0.01) were the only two risk factors independently associated with a high recurrence ratio in the multivariate analysis. Thus, the annual incidence of DVT recurrence in patients without any of these two risk factors was only 0.6% (95% confidence interval, 0.2-0.9). We have identified a group of patients with DVT but at very low risk of re-thrombosis in whom an extended secondary thromboprophylaxis should be carefully considered.     

Factor V Leiden, prothrombin 20210A and the risk of venous thrombosis among cancer patients

Cancer patients have an increased risk of venous thrombosis (VT). The association of factor V Leiden (FVL) and the prothrombin 20210A variant with VT in cancer patients is not established. We genotyped 101 cancer patients with VT and 101 cancer patients without VT for these polymorphisms. Five cases and three controls were heterozygous for FVL, yielding an odds ratio of 1.7 (95% confidence interval (CI) 0.3-10.7). Five cases and no controls were heterozygous for prothrombin 20210A, for an odds ratio of 6.7 (95% CI 0.9-infinity). Prothrombin 20210A may be associated with VT risk among cancer patients.     

The prothrombin gene variant 20210A in venous and arterial thromboembolism

Several hereditary disorders affecting coagulation factors have been identified as prothrombotic risk factors. Recently, the prothrombin 20210 A/G mutation has been identified as a second important polymorphism involved in venous thrombosis. This article reviews all published information about this new procoagulant mutation. Our group has been involved in a number of studies about the role and importance of polymorphisms in thromboembolic disease, including the analysis of the prothrombin 20210 A/G mutation. Moreover, an extensive Medline literature search was made to complete the review using the key words: prothrombin mutation, 20210, venous or arterial thrombosis. The combination of environmental and genetic risk factors determines the relative risk that any individual has of suffering a thrombotic episode. Some genetic mutations affecting coagulation factors have been described. Recently, Poort et al. described a new mutation in the 3'-untranslated region of the prothrombin gene. The prothrombin 20210 G/A mutation, associated with elevated levels of factor II in plasma, significantly increases the risk of developing venous thrombosis. In fact, this polymorphism is the second most important genetic risk factor for venous thrombosis in Caucasian populations. Moreover, and supporting the multifactorial feature of thromboembolic diseases, this mutation greatly increases the possibility of developing a thrombotic episode when combined with other environmental or genetic risk factors. The role of this procoagulant mutation in arterial vascular disease is, however, unclear.     

Prevalence of factor Ⅴ Leiden and prothrombin G20210A in patients with gastric cancer

AIM: To analyze the prevalence of the two commonest thrombophilic mutations, factor Ⅴ Leiden and prothrombin G20210A, in patients with gastric cancer.METHODS: One hundred and twenty-one patients with primary gastric carcinoma and 130 healthy subjects,comparable for age and sex, were investigated. Factor Ⅴ Leiden was detected by using polymerase chain reaction and restriction enzyme digestion, and prothrombin G20210A gene mutation by allele-specific PCR.RESULTS: Among the 121 cancer patients, factor Ⅴ Leiden was found in 4 cases (GA genotype: 3.3%) and prothrombin G20210A in 10 cases (GA genotype: 8.3%).Of the 130 control subjects, factor Ⅴ Leiden was detected in 6 cases (GA genotype: 4.6%) and prothrombin G20210A in 8 cases (GA genotype: 6.1%). No double heterozygous carriers of both mutations were found in either group. The prevalence of both factor Ⅴ Leiden and prothrombin G20210A variant was not statistically different between the cancer patients and the healthy subjects.CONCLUSION: Our study suggests that, in gastric cancer, the risk factors of thrombophilic cancer state are on acquired rather than on a genetic basis and that prothrombin G20210A does not seem to be a cofactor in gastric cancer pathogenesis.     

Severe venous thromboembolism in a young man with Klinefelter's syndrome and heterozygosis for both G20210A prothrombin and factor V Leiden mutations.

Klinefelter's syndrome is the most common cause of primary testicular failure, resulting in impairment of both spermatogenesis and testosterone production. It is a chromosomal disorder characterized by small, firm testes, azoospermia, gynecomastia, varying degrees of eunuchoidism and testosterone deficiency with elevated gonadotropin plasma levels. In Klinefelter's syndrome there is an increase of certain systemic diseases including venous thromboembolism. An increased thromboembolic risk in hypogonadic men has been explained with hypofibrinolysis due to androgen deficiency. Only two cases have been reported about the association between Klinefelter's syndrome and well-known congenital or acquired thrombophilias. We report the case of a 39-year-old patient with Klinefelter's syndrome who underwent severe deep venous thrombosis with pulmonary embolism, in the absence of any circumstantial triggering event. Further examinations also showed a double heterozygosis for G20210A prothrombin and factor V Leiden mutations. This case suggests that the increased thromboembolic risk, reported in Klinefelter's syndrome, can be worsened by the co-existence of one or more well-known thrombophilic conditions, as shown by the relatively young age of the patient. More studies are needed to clearly understand the pathogenesis of venous thromboembolism in males affected by Klinefelter's syndrome.     

Factor V Leiden, prothrombin G20210A, and protein C mutation frequency in Turkish venous thrombosis patients

Several inherited polymorphisms are associated with risk of venous thrombosis, including mutation at codon 506 of the factor V gene, mutation at position 20210 of the prothrombin gene, and mutations in the protein C gene. In this study, genotyping for factor V, prothrombin, and protein C mutations was performed in 50 patients and 25 control subjects by polymerase chain reaction-based analysis. The prevalence of factor V and prothrombin mutations was not significantly different from that in the general population. Nine of the patients had heterozygous protein C mutation. There was a high prevalence of the mutated protein C allele in the pulmonary emboli group (42.8%). Protein C mutation incidence was higher in the pulmonary emboli group than in the deep vein thrombosis (8.33%) and cerebral vein thrombosis (16.1%) groups. These results indicate that patients with protein C deficiency have a greater risk of thrombosis than patients with factor V or prothrombin G20210A mutation.     

The prothrombin 20210A allele and the factor V Leiden are associated with venous thrombosis but not with early coronary artery disease.

This study was performed in order to establish the role of the prothrombin 20210 G/A and factor V Leiden (R506Q) polymorphisms in the susceptibility to develop venous thromboembolism and early coronary artery disease (CAD). These polymorphisms were determined in 82 consecutive patients with venous thromboembolism, 175 male patients with early CAD, and 200 healthy controls from the same Caucasian population (Asturias, Northern Spain). DNA was amplified using polymerase chain reactions and digested with the appropriate restriction enzymes in order to define the prothrombin and factor V genotypes. The prevalence of the heterozygous for the prothrombin A allele was 3.5% in the general population and 15.8% in patients with venous thrombosis (P = 0.0007); the frequency was 4% in patients with early CAD. No sex-related differences in the prevalence of the A allele were observed, and the average age at the first venous thromboembolic event was similar between GG and AG patients. The frequency of carriers of the factor V Leiden polymorphism was 9.75% among patients with venous thromboembolism, compared with 3.5% among controls, and 3.4% in the patients with CAD. Our data showed an association between venous thromboembolism and the AG genotype at the prothrombin 20210 G/A polymorphism. This polymorphism was not related to an increased risk for early CAD in our population of male patients.     

Factor V Leiden and prothrombin gene G20210A mutation in children with cerebral thromboembolism

We investigated whether there is an association between factor V Leiden (FVL) and/or prothrombin gene G20210A mutation (PT20210A) and cerebral thromboembolism in a pediatric Argentinean population. From May 1992 to January 2002, 44 consecutive children with arterial ischemic stroke (AIS) and 23 children with cerebral sinovenous thrombosis (SVT) were prospectively studied at a single center. The prevalence of both mutations was compared with a 102 age-matched controls. In children with AIS, the frequencies (patients vs. controls), odds ratio (OR), and 95% confidence interval (95% CI) for the presence of FVL were as follows: 2.3% vs. 2%, OR/95% CI, 1.16/0.2 to 13.2; P value = 0.99. No cases of PT20210A were found in this group. In children with SVT, the frequencies (patients vs. controls), OR, and 95% CI were as follows: FVL (4.3% vs. 2%, OR/95% CI, 2.27/0.22 to 6.2; P value = 0.99) and PT20210A (4.3% vs. 1%; OR/95% CI, 4.6/0.3 to 76.3; P value = 0.3354). One child with PT20210A also had an inherited protein C deficiency. In 12 (18%) out of the 67 children with cerebral thromboembolism, without the aforementioned mutations, other prothrombotic disorders were detected. Although a multi-center prospective study with a large number of Argentinean pediatric patients is needed to obtain considerable evidence, no association between factor V Leiden and/or prothrombin gene G20210A mutation and cerebral thromboembolism was found in this pediatric series.     

Effect of the MTHFRC677T variant on risk of venous thromboembolism: interaction with factor V Leiden and prothrombin (F2G20210A) mutations

Odds ratios for the MTHFR C677T variant were determined in a large case–control study of 558 unselected patients with venous thromboembolism and 500 control subjects. The odds ratios for MTHFR C677T heterozygosity and homozygosity were 1.07 (95%CI 0.84–1.36) and 0.71 (95%CI 0.48–1.03). In patients with the factor V Leiden or the F2 G20210A mutations there was no apparent increase in risk of venous thromboembolism due to the MTHFR C677T polymorphism.
Thrombophilia testing should not include genotyping for the MTHFR C677T polymorphism.     

Prevalence of mild hyperhomocysteinaemia and association with thrombophilic genotypes (factor V Leiden and prothrombin G20210A) in Italian patients with venous thromboembolic disease

Mild hyperhomocysteinaemia is an established risk factor for deep vein thrombosis (DVT); few data concerning its potential interaction with thrombophilic genotypes are available at the present time. We investigated 121 thrombosis-free individuals and 111 patients with at least one objectively confirmed episode of DVT. A thrombophilic condition (deficiency in antithrombin, protein C and S, factor V Leiden, prothrombin G20210A) was detected in 25.2% of the patients; mutant factor V or prothrombin genotypes were present in 6.6% of the controls. Hyperhomocysteinaemia was found in 14.4% of patients and 3. 3% of the controls, with a 3.7-fold increase in risk for DVT (95% CI 1.1-12.3). Adoption of different cut-off levels for definition of hyperhomocysteinaemia did not substantially change the magnitude of the risk. Carriership of both hyperhomocysteinaemia and factor V Leiden or prothrombin G20210A was detected in 2.7% of patients for each combination and in none of the controls. An approximate estimate of 30-fold increased risk in carriers of both hyperhomocysteinaemia and factor V Leiden and 50-fold increased risk in carriers of both hyperhomocysteinaemia and prothrombin G20210A was calculated, suggesting a synergistic interaction between hyperhomocysteinaemia and such thrombophilic genotypes. Yet statistical analysis is highly unstable due to the small number of individuals with combined defects. Further investigations on large series of patients are needed.     

Two common genetic thrombotic risk factors: factor V Leiden and prothrombin G20210A in adult Turkish patients with thrombosis

The prevalence of genetic risk factors for thrombosis varies greatly in different parts of the world, both in patients with thrombosis and in the general population. Factor V Leiden (FVL) and prothrombin G20210A (PT G20210A) mutations are the most common genetic defects leading to thrombosis. We have previously reported that those two thrombotic risk alleles are frequently found in Turkish children with thrombosis. The aim of the present study was to investigate the frequency of FVL and PT G20210A and their clinical manifestations in adult Turkish patients with thrombosis. Between January 1997 and February 2000, 146 patients with documented thrombosis were investigated in our center for the presence of the FVL and PT G20210A mutations. Forty-five of 146 patients with thrombosis (30.8%) were detected to have FVL mutation. Among those cases with the FVL mutation, seven (4.8%) had homozygote and 38 (26%) had heterozygote mutation. The PT G20210A mutation was detected in 10 of the 146 patients with thrombosis (6.8%). Another six cases (4.1%) had both FVL and PT G20210A mutations. The overall frequency of these two common risk alleles in our adult population with thrombosis was 41.6%. Our findings reveal that FVL and PT G20210A mutations are significant genetic risk factors contributing to the pathophysiology of thrombosis in the Turkish population.     

Prevalence of genetic prothrombotic factors (factor V Leiden and II20210 prothrombin mutation) in glomerular nephropathies with or without thrombosis

The presence of genetic prothrombotic factors (factor V Leiden and the prothrombin II20210 mutation) was investigated in 38 patients with glomerulonephritis with or without a history of thrombotic events and/or nephrotic syndrome. We found an increased prevalence (36%) of heterozygous factor V Leiden in those patients with a history of thrombotic events. This is ten times the prevalence in the normal Spanish population. Carrier status for this mutation may be a determining factor in the development of thrombotic events along with the acquired disorders of coagulation to which these patients are prone. We found only one patient who was a carrier of the G-A II20210 mutation of the prothrombin gene; this patient had no history of venous thrombosis or embolism. Our findings suggest the need to measure activated protein C resistance and to look for the most frequent genotype causing it, Factor V Leiden, in patients with glomerulonephritis to identify those at risk who may benefit from prophylaxis against thrombosis.     

Factor V Leiden and prothrombin gene G20210A mutations in Italian patients with Behçet's disease and deep vein thrombosis

Objective

To evaluate the frequency and type of vascular lesions and to study the association of factor V gene G1691A (Leiden) and prothrombin gene G20210A polymorphisms with venous thrombosis in Italian patients with Behçet's disease (BD).

Methods

Included were 118 consecutive Italian BD patients followed over a 3‐year period (1997–1999) who satisfied the International Study Group criteria for BD. The control group consisted of 132 healthy Italian blood donors. All BD patients and controls were genotyped by polymerase chain reaction and allele‐specific restriction enzyme techniques for factor V Leiden and prothrombin gene G20210A polymorphisms.

Results

Vascular lesions were observed in 37 (31.4%) patients. The 2 most common lesions were subcutaneous thrombophlebitis (10.2%) and deep vein thrombosis (DVT) of the legs (22.8%). No significant demographic and clinical differences between patients with and without DVT were present. The distribution of allele and genotype frequencies of prothrombin gene G20210A and factor V Leiden polymorphisms did not differ significantly between BD patients and healthy controls. The frequencies of carriage rates of prothrombin gene G20210A and factor V Leiden polymorphisms in BD patients with and without DVT were similar. However, the frequency of 20210A allele was significantly higher in BD patients with ocular disease than in those without, particularly in the patients with posterior uveitis/retinal vasculitis.

Conclusions

The frequency and types of vascular lesions in Italian BD patients were similar to those reported in studies from other countries. No association between factor V Leiden mutation and G20210A mutation in the 3′‐untranslated region of the prothrombin gene with DVT was found. However, a prothrombin gene G20210A mutation may influence the development and severity of ocular involvement in BD.