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.     

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 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.     

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.     

The risk of recurrent venous thromboembolism among heterozygous carriers of factor V Leiden or prothrombin G20210A mutation. A systematic review of prospective studies

Factor V Leiden (FVL) and prothrombin G20210A mutation (PTM) are the two most common genetic polymorphisms known to predispose to a first episode of venous thromboembolism (VTE). However, whether these thrombophilic abnormalities are also risk factors for recurrent VTE is unclear. We conducted a systematic review of prospective studies to assess the risk of recurrent VTE associated with heterozygous carriage of each of these mutations. All randomized controlled trials and prospective cohort studies that reported the incidence of recurrent VTE in patients with and without FVL and PTM after discontinuation of anticoagulant treatment were collected and analyzed. The risk ratios (RR) and their 95% confidence intervals (CI) for recurrent VTE were calculated in heterozygous carriers of FVL or PTM and compared to those of non-carriers. Eleven studies fulfilled the inclusion criteria. Recurrent VTE occurred in 114 out of 557 heterozygous carriers of FVL (20.5%) as compared to 382 out of 2,646 non-carriers (14.4%); and in 38 out of 212 heterozygous carriers of PTM (17.9%) compared to 428 of 2,996 non-carriers (14.3%). The RR of VTE recurrence conferred by the heterozygous carriage of FVL and PTM was 1.39 (95% CI, range 1.15 to 1.67) and 1.20 (range 0.89 to 1.61), respectively, using the Mantel-Haenszel fixed-effects model; 1.45 (1.13 to 1.85) and 1.36 (1.02 to 1.82), respectively, using the Der Simonian and Laird random effects method. In symptomatic patients with VTE, heterozygous carriage of FVL is clearly associated with a definitely increased risk of recurrent thromboembolism. The risk is lower with PTM and is difficult to interpret since it varies according to the assessment method used.     

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.     

Prevalence of the G1691A mutation in the factor V gene (factor V Leiden) and the G20210A prothrombin gene mutation in the Thai population

We investigated the prevalence of a genetic variation in the factor V gene (G1691A Leiden mutation) and the prothrombin gene (G20210A) using polymerase chain reaction techniques in samples from 500 normal Thai population and among 50 unselected Thai patients with an objectively confirmed history of deep venous thrombosis. The prevalence of factor V Leiden and the prothrombin G20210A gene mutation in a group of 500 healthy controls was 0.2% in both groups (allele frequency of 0.1%). Of the 50 adult patients studied, none was a carrier of factor V Leiden or the prothrombin G20210A gene mutation. Our findings confirm that the prevalence of factor V Leiden and prothrombin G20210A gene mutation is lower among Asians than Caucasians and that the distribution of factor V Leiden is similar to that of the prothrombin G20210A variant. The low prevalence of these two mutations can, at least in part, account for the lower frequency of deep venous thrombosis reported in the Thai population. Screening for factor V Leiden and prothrombin gene mutation is of limited benefit and may not be cost-effective in Thai patients with the first episode of deep venous thrombosis.     

Prevalence of factor V Leiden and prothrombin 20210 A variant in Bulgarian patients with pulmonary thromboembolism and deep venous thrombosis.

Factor V Leiden mutation and prothrombin variant 20210 A are well-known risk factors for venous thrombosis (DVT). Recent papers have reported a lower prevalence of factor V Leiden in patients with pulmonary thromboembolism (PTE) than in patients with deep venous thrombosis. The aim of the present study was to compare the prevalence of factor V Leiden and the prothrombin 20210 G <-- A mutation in patients with DVT and in patients with PTE. We studied 128 consecutive patients (45 with DVT, 40 with PTE, and 43 with DVT and PTE) for factor V Leiden and prothrombin 20210 A. One hundred healthy persons matched by age and sex were used as controls. Factor V Leiden was present in five of the patients with PTE [12.5%; 95% confidence interval (CI), 1.5-23.5%; not significant], 15 of the patients with DVT (33.3%; 95% CI, 9.6-38.7%; P < 0.001), and 12 of the patients with DVT and PTE (27.9%; 95% CI, 4.8-33%; P = 0.001). Results for the prothrombin 20210 A mutation were as follows: four of 40 patients with PTE (10%; 95% CI, 0-13.3%; P = 0.46), nine of 45 (20%) of the patients with DVT (95% CI, 0.5-25.5%; P < 0.05) and eight of 43 with DVT and PTE were heterozygous (18.6%; 95% CI, 0-23.9%; P = 0.02). In conclusion, there is a significantly higher frequency of factor V Leiden among patients with DVT than in patients with PTE. However, there is no significant difference of factor V Leiden or 20210 A prothrombin mutation in patients with DVT than in patients with combined DVT/PTE, therefore patients with DVT, carriers of the mutations, do not appear to be at lower risk for pulmonary embolism.     

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.     

G20210A mutation in the prothrombin gene and the risk of recurrent venous thromboembolism

OBJECTIVES: The study was done to determine whether the G20210A mutation in the prothrombin gene increases the risk of recurrent venous thromboembolism (VTE), both alone and in combination with factor V Leiden. BACKGROUND: Several inherited defects of coagulation are associated with increased risk of first VTE, including a recently identified G20210A mutation in the prothrombin gene. However, whether the presence of this mutation confers an increased risk of recurrent venous thromboembolism is controversial. METHODS: A total of 218 men with incident venous thromboembolism were genotyped for the prothrombin mutation and for factor V Leiden and were followed prospectively for recurrent VTE over a follow-up period of 7.3 years. RESULTS: A total of 29 men (13.3%) suffered recurrent VTE. Five of the 14 carriers of the prothrombin mutation developed recurrent VTE (35.7%; incidence rate = 8.70 per 100 person-years), while 24 of 204 individuals who did not carry the prothrombin mutation developed recurrent VTE (11.8%; incidence rate = 1.76 per 100 person-years). Thus, presence of the G20210A mutation was associated with an approximate fivefold increased risk for recurrent VTE (crude relative risk [RR] 4.93; 95% confidence interval [CI] 1.9-12.9; p = 0.001; age-, smoking-, and body mass index-adjusted RR 5.28; 95% CI 2.0-14.0; p = 0.001). In these data, recurrence rates were similar among those with an isolated mutation in the prothrombin gene (18.2%) as compared to those with an isolated factor V Leiden mutation (19.2%). However, all three study participants who carried both mutations (100%) suffered a recurrent event during follow-up. CONCLUSIONS: In a prospective evaluation of 218 men, the presence ofprothrombin mutation was associated with a significantly increased risk of recurrent VTE, particularly among those who co-inherited factor V Leiden.     

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.     

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.     

Factor V Leiden and prothrombin gene G20210A mutations are uncommon in portal vein thrombosis in India.

BACKGROUND: Extra-hepatic portal vein obstruction due to portal vein thrombosis (PVT) is an important cause of portal hypertension in several regions including India. The cause of thrombosis in these patients remains unclear. We studied the frequency of mutations in genes for coagulation factors V and II (prothrombin) in 61 Indian patients with PVT and 49 healthy control subjects. METHODS: The presence of factor V Leiden mutation and of G20210A prothrombin gene mutation was determined using polymerase chain reaction followed by restriction fragment length polymorphism. Chi-squared test was used to compare patients and controls. RESULTS: Of the 61 patients (median age 11 years; 47 male) studied, 49 were children. One of 61 (1.6%) patients with PVT was heterozygous for factor V Leiden mutation and none had the G20210 prothrombin gene mutation. The frequencies of these mutations were not different from those in control subjects (2/49 and 0/46, respectively). CONCLUSION: Factor V Leiden and G20210 prothrombin gene mutations are infrequent in Indian patients with PVT. Thus, these mutations are unlikely to be responsible for PVT in the Indian population.     

The O blood group protects against venous thromboembolism in individuals with the factor V Leiden but not the prothrombin (factor II G20210A) mutation.

We investigated the influence of the ABO blood group in the observed prevalences of the recently described factor V R506Q and factor II G20210A mutations in a thrombotic population. We determined the ABO blood group in a sample of 178 unselected patients (aged 17-83 years), diagnosed at our center with deep vein thrombosis or pulmonary embolism. The results of this study show a high prevalence of thrombosis in the non-O blood group. In the general population, the prevalence as a fraction of the O blood group was 2.69 (confidence interval 1.90-3.82). Of the factor V R506Q carriers (n = 28), only one had O group blood and 27 of 28 were non-O (24 A, one B and two AB). However, within the group of factor II G20210A carriers (n = 17), seven had O, nine A and one B type blood. The prevalence of the factor V R506Q mutation within the O blood group was 2.4% (one of 42), significantly lower than in the A group (23.3%, 24 of 103; P = 0.002), or in the overall non-O group (19.9%, 27 of 136; P = 0.006). This prevalence was similar to that observed previously in the non-thrombotic population in our area (3.5%; P = 0.9). We analyzed the clotting activity of factor VIII and we found higher levels in the non-O group (1.78+/-0.61 U/ml) than in the O blood group (1.30+/-0.51 U/ ml; P < 0.0001). We speculate that factor Va in individuals with the factor V Leiden mutation could interact with the high levels of factor VIII clotting activity as a necessary cofactor.