Low prevalence of activated protein C resistance and coagulation factor V Arg506 to Gln mutation among Japanese patients with various forms of thrombosis, and normal individuals

Venous thromboembolism in Asia – an unrecognised and under-treated problem?

Venous thromboembolism (VTE) has been perceived for a long time to be less common in Asian populations, particularly in the Far East, than in Western populations. Generally, thromboprophylaxis is not implemented as frequently as it should be in high-risk patients. However, recent prospective studies undertaken in Asian countries have demonstrated higher rates of VTE after major surgery and in medical wards, approaching those observed in Western populations. Risk factors for VTE are not different in Asian patients from those of Western patients with the exception of thrombophilic mutations. Deficiencies of the natural anticoagulants (protein S, protein C, and antithrombin) are the predominant thrombophilias in Asia whereas factor V Leiden and prothrombin G20210A gene mutation are not found or rarely reported. Further large well-designed clinical studies are needed to evaluate the magnitude of the risk of VTE and the appropriate use of thromboprophylaxis in different clinical situations.

Thrombophilia in Korean patients with arterial or venous thromboembolisms

Purpose

To determine the prevalence of thrombophilia in Korean patients with an arterial thromboembolism (ATE) or a venous thromboembolism (VTE), and to evaluate the characteristic of VTE in patients with thrombophilia.

Methods

Hospital records of 294 patients (228 with VTE, 66 with ATE) including two foreign ones (mean age, 51.4 years) who underwent thrombophilia testing between August 2006 and March 2015 were reviewed retrospectively. In general, such screening was performed according to the guidelines of the international consensus statement for VTE. Thrombophilia testing included evaluations of the factor V Leiden and prothrombin G20210A mutations, levels of proteins C and S and antithrombin, and antiphospholipid antibody syndrome (APLS).

Results

A factor V Leiden mutation was not found in the 292 Korean patients. A prothrombin G21210A mutation was investigated in 33 patients but none was found. Among 226 Korean patients with VTE, 130 demonstrated no thrombophilia and 55 patients did after exclusion of 41 patients without confirmatory test. The most common form was protein S deficiency (31 of 55, 56%) followed by protein C deficiency, antithrombin deficiency, and APLS. When comparing patients with a VTE or deep vein thrombosis (DVT) according to the presence of thrombophilia, thrombophilia was associated with younger age (P = 0.001 for VTE; P < 0.001 for DVT) and a family history (P < 0.001 for VTE and DVT).

Conclusion

We did not find any factor V Leiden mutation in Korean subjects at high risk for thrombophilia. Therefore, this testing is not warranted. Thrombophilia was associated with VTE in younger age and a family history.

A survey of the clinical course and management of Japanese patients deficient in natural anticoagulants

Few data are available on the clinical course of Japanese patients deficient in natural anticoagulants (antithrombin (AT), protein C, and protein S). We conducted a nationwide survey to reveal the clinical course of these patients. Questionnaires were sent to 321 council members of the Japanese Society on Thrombosis and Hemostasis, Japanese Society for Vascular Surgery, and Japanese Society of Phlebology. A total of 103 responses were obtained and data of 183 patients were collected. Of 183 patients, 142 (78%) experienced at least one episode of venous thromboembolism (VTE). The first VTE occurred before the age of 40 years in 71 patients (45%). Venous thromboembolism recurred in 15 (39%) patients with AT deficiency and 19 (18%) patients with other deficiencies. These findings suggest that half of the first episodes of VTE in patients deficient in natural anticoagulants occur before middle age and the risk of VTE recurrence is high in patients with AT deficiency.

Epidemiology of activated protein C resistance and factor v leiden mutation in the mediterranean region

Venous thromboembolic disorders (VTE) are serious disorders with high morbidity and mortality rates. Many genetic and acquired risk factors were identified to cause VTE. The most common genetic risk factor is Factor V Leiden mutation (FVL). FVL was found in high percentage of populations of Caucasian origin but was almost absent in non-Caucasians. It was also reported in populations living in North Africa and the Middle East. This review article briefly explains FVL and how it causes VTE, the distribution of FVL worldwide, and then it elaborates on the epidemiology of FVL in the Mediterranean Region and how this brought speculations that FVL might have originated in the Eastern Mediterranean area.

Race differences in the prevalence of the factor V Leiden mutation in Kuwaiti nationals

Factor V Leiden mutation (FVL; G1691A) is an established risk factor for venous thromboembolic disorders. FVL was reported with high prevalence in Caucasians (1-15%) but was absent in non-Caucasians like Africans and Asians. Studies reported FVL in 5-27% of Arabs and non-Arabs living in the Middle Eastern countries northern to the Arabian Peninsula, but was almost absent in Arabs in the Arabian Peninsula itself. Kuwait is an Arabic country present on the northern border of the Arabian Peninsula, and Kuwaitis are originally from Saudi Arabia (Southern to Kuwait and within the Arabian Peninsula) or from Iran and Iraq (northern to Kuwait and the Arabian Peninsula). This study was conducted to study FVL in Kuwaitis in relation to their origin. Real-time PCR was performed on DNA samples of 285 apparently healthy Kuwaitis using specially designed primers and probes for FVL. There were 109 Kuwaitis of Iranian origin, 71 of Iraqi origin and 105 of Saudi origin. FVL was present in 7 and 5 Kuwaitis of Iranian and Iraqi origin, respectively. None of the Kuwaitis of Saudi origin had the mutation. Prevalence of FVL in Kuwaitis of Iranian (6.42%) and Iraqi (7.04%) origin were statistically different from prevalence in Kuwaitis of Saudi (0%) origin (P-value<0.05). No difference was found between females and males (P-value>0.6). In conclusion, FVL is present in Kuwaitis of Iranian or Iraqi origin only. Therefore, testing and providing genetic consultation for FVL may be needed in those Kuwaitis only which should save time, cost and efforts. However, this assumption should be confirmed by other studies and on larger number of cases.

A Case Control Study on the Contribution of Factor V-Leiden, Prothrombin G20210A, and MTHFR C677T Mutations to the Genetic Susceptibility of Deep Venous Thrombosis

BACKGROUND

Insofar as the inherited prothrombotic single nucleotide polymorphisms (SNPs) factor V G1691A (FV-Leiden), prothrombin (PRT) G20210A, and methylenetetrahydrofolate reductase (MTHFR), C677T are inherited risk factors of venous thromboembolism (VTE), the aim of this study was to determine the prevalence of single and combined SNPs in 198 patients with documented deep venous thrombosis (DVT), and 697 control subjects, and to estimate the associated risks.

METHODS

Factor V-Leiden, PRT G20210A, and MTHFR C677T were analyzed by PCR and restriction fragment length polymorphism (RFLP).

RESULTS

The prevalence of the heterozygote and homozygous variants for FV-Leiden (52.02 vs. 14.78%, RR 6.28), PRT G20210A (19.2 vs. 3.6%; RR 6.38), and to a lesser extent the T/T genotype of MTHFR C677T (20.71 vs. 11.0%; RR 1.49) were higher among DVT patients vs. controls, respectively. Two or more SNPs were detected in 90 of 198 patients (45.5%) and in 60 of 697 controls (8.6%), with odds ratios of 16.754 for joint occurrence of FV-Leiden and PRT G20210A, 10.471 for FV-Leiden and MTHFR C677T, and 6.283 for PRT G20210A SNPs and MTHFR 677T/T. Logistic regression analysis showed a further increased odds for FV-Leiden in combination with PRT G20210A (85.198) or homozygous MTHFR C677T (81.133), and to a lesser extent for PRT G20210A in combination with homozygous MTHFR C677T (20.812).

CONCLUSIONS

This indicates that FV-Leiden and PRT G20210A, more than MTHFR C677T, are important risk factors for DVT, and that the presence of more than one prothrombotic SNPs was associated with a significant risk of DVT.

Effects of coagulation Factor VII polymorphisms on the coronary artery disease in Japanese: Factor VII polymorphism and coronary disease

We investigated the relationships among Factor VII coagulant activity (FVIIc), genetic polymorphisms of Factor VII (FVII) and coronary artery disease (CAD) in 380 unrelated Japanese individuals (mean 64 years) who underwent coronary angiography and whose cholesterol levels were within normal range. CAD subjects were defined as those in whom one of the three major coronary arteries showed >50% narrowing after nitroglycerin administration. FVIIc was measured and the following polymorphisms of FVII were determined: R353Q polymorphism (M1, M2 alleles), -323 0/10 bp polymorphism (0, 10 alleles), hypervariable region 4 of intron 7 (HVR4; H5, H6, H7 alleles). FVIIc was slightly lower in M1M2/M2M2 than M1M1 (89.5+/-8.9%, 93.4+/-17.8%). Those with M2 and/or 10 allele have less chance of developing CAD (M2: OR 0.36, 95% CI 0.18-0.69, 10: OR 0.50, 95% CI 0.26-0.97). However, both alleles did not associate with myocardial infarction (MI). HVR4 was unrelated with CAD, nor with MI. In conclusion, M2 and/or 10 allele has protective effects on the developing CAD in individuals with a normal cholesterol level.

Factor V Leiden: a clinical review

Factor V Leiden is the most prevalent genetic thrombophilia in people of European descent. Since its discovery, much clinical information has been gathered regarding the distribution and prevalence of the genetic mutation, the mechanism of thrombophilia, and its association with clinical thromboembolic events. Although its association with venous thromboembolism is clear, the role of Factor V Leiden in other disease states is not clear. A review of the literature regarding the mechanism of hypercoagulability, genetic versus functional diagnostic tests, screening issues, relationship to arterial thromboses, pregnancy and pregnancy complications, and treatment are discussed.

Transthoracic echocardiographic demonstration of massive pulmonary thrombus caused by protein C deficiency

Few cases of pulmonary embolism detected by transthoracic echocardiography (TTE) have been reported. We present a case of a patient affected by pulmonary embolism caused by protein C deficiency. Transthoracic echocardiography showed a thrombus in transit (ie, visualization of a thrombus within the pulmonary artery). A hypercoagulable state caused by deficiency of protein C is a rare cause of pulmonary thromboembolism. Our experience demonstrates a massive pulmonary thrombus resulting from such a deficiency. Transthoracic echocardiography should be considered as the first diagnostic method for patients with suspected pulmonary embolism.

Evidence for association between paraoxonase gene polymorphisms and atherosclerotic diseases

Paraoxonase 1 (PON1) is proposed to have an anti-atherogenic action. Two polymorphisms at the PON1 (M/L55 and Q/R192) have been shown to be associated with coronary artery disease (CAD). This conclusion is not drawn universally, however, and specific ethnic characteristics may be important determinants in this association. Recently two homologues of PON1 - PON2 and PON3 - were identified and Sanghera et al. demonstrated C/S311 polymorphism at PON2 was associated with the risk of CAD. Within that context, we investigated the association between the aforementioned three polymorphisms and CAD and ischemic stroke in a Japanese population. The study population included 431 control subjects, 210 CAD patients, and 235 ischemic stroke patients. Genotype distributions and allele frequencies of M/L55 and C/S311 were similar among the control and patient groups, whereas the R192 allele frequency was significantly higher (P<0.001) in CAD (75%) and ischemic stroke (76%) patients than in control subjects (65%). When confounding influences of other risk factors were controlled for by multivariate analysis, R192 remained an independent risk determinant (additive model: OR (95% CI), P value CAD: 2.01 (1.45-2.79), 0.0001; ischemic stroke: 1.84 (1.34-2.52), 0.0002 (three genotypes into calculation)). Taken together, our data indicate that the Q/R192 is principally associated with both CAD and ischemic stroke in Japanese.

Single and combined prothrombotic factors in patients with idiopathic venous thromboembolism: prevalence and risk assessment

The inherited thrombophilias--deficiencies of protein C, protein S, and antithrombin III--and the prothrombotic polymorphisms factor V G1691A and factor II G20210A predispose patients toward venous thromboembolism (VTE). The aim of this study was to determine the prevalence of single and combined prothrombotic factors in patients with idiopathic VTE and to estimate the associated risks. The study group consisted of 162 patients referred for work-up of thrombophilia after documented VTE. The controls were 336 consecutively admitted patients. In all subjects factor V G1691A, factor II G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T were analyzed by specific polymerase chain reactions and restriction enzymes. Activities of antithrombin III and protein C, free protein S antigen, and lupus anticoagulant were determined in a subset of 109 patients who were not receiving oral anticoagulants. The prevalences of heterozygotes and homozygotes for factor V G1691A and factor II G20210A among patients and controls were 40.1% versus 3.9% and 18.5% versus 5.4%, respectively (P=0.0001). The prevalence of homozygotes for MTHFR C677T in patients was 22.8% and in controls, 14.3% (P=0.025). Heterozygous and homozygous factor V G1691A, factor II G20210A, and homozygous MTHFR C677T were found to be independent risk factors for VTE, with odds ratios of 16.3, 3.6, and 2.1, respectively. Two or more polymorphisms were detected in 27 of 162 patients (16.7%) and in 3 of 336 controls (0.9%). Logistic regression analysis disclosed odds ratios of 58.6 (confidence interval [CI], 22.1 to 155.2) for joint occurrence of factor V and factor II polymorphisms, of 35.0 (CI, 14.5 to 84.7) for factor V and MTHFR polymorphisms, and of 7.7 (CI, 3.0 to 19.6) for factor II and MTHFR polymorphisms. Among 109 patients in whom a complete thrombophilic work-up was performed, 74% had at least 1 underlying defect. These data indicate that in most patients referred for evaluation of thrombophilia due to idiopathic VTE, 1 or more underlying genetic predispositions were discernible. The presence of >1 of the prothrombotic polymorphisms was associated with a substantial risk of VTE.