Absence of factor V Leiden in the Japanese

Recurrent PROC and novel PROS1 mutations in Vietnamese patients diagnosed with idiopathic deep venous thrombosis

INTRODUCTION

Genetic mutations of PROC and PROS1 are well-known risk factors for deep venous thrombosis (DVT) in the Asian population. However, the genetic profile of Vietnamese patients with DVT remains elusive. This study aimed to investigate the spectrum of genetic mutations of these two genes in Vietnamese patients diagnosed with idiopathic DVT.

MATERIALS AND METHODS

A total of 50 Vietnamese patients diagnosed with idiopathic DVT were recruited in this study. The entire coding regions of the protein C and protein S genes were amplified and directly sequenced to determine genetic alterations.

RESULTS

Four and six genetic mutations were detected in protein C and protein S genes, respectively, in 24 Vietnamese DVT patients. PROC c.565C > T (p.R189W) was the most common mutation found in 13 out of 50 patients, while the mutations of PROS1 comprised three missense and three nonsense variants which diffuse along the gene.

CONCLUSIONS

This study shows that mutations of protein C and protein S genes are prevalent in Vietnamese patients diagnosed with idiopathic DVT, and PROC c.565C > T (p.R189W) was the most common genetic alteration.

Factor V Leiden

Factor V Leiden (FVLeiden ) is a common hereditary thrombophilia that causes activated protein C (APC) resistance. This review describes many of the most fascinating features of FVLeiden , including background features, mechanisms of hypercoagulability, the founder mutation concept, the "FVLeiden paradox," synergistic interaction with other thrombotic risk factors, the intertwined relationship between FVLeiden and APC resistance testing, and other, uncommon mutations implicated in causing APC resistance. In addition, there are several conditions where laboratory tests for APC resistance and FVLeiden are or can be discrepant, including lupus anticoagulants, anticoagulants such as direct thrombin inhibitors (dabigatran, argatroban, and bivalirudin) and rivaroxaban, as well as pseudohomozygous, pseudo-wildtype, liver transplant, and bone marrow transplant patients. The laboratory test error rate for FVLeiden is also presented.

Contribution of fetal ANXA5 gene promoter polymorphisms to the onset of pre-eclampsia

OBJECTIVE

A common haplotype M2 consisting of minor SNP alleles located in the ANXA5 gene promoter region has been described as a risk factor for various obstetric complications such as recurrent pregnancy loss, pre-eclampsia and pregnancy-related thrombophilic disorder. However, the question of whether it is the maternal or fetal genotype that contributes to the onset of these disorders remains to be resolved.

METHODS

We analyzed ANXA5 gene variants in the blood and placental tissues from pre-eclampsia patients and normotensive controls. ANXA5 expression was examined by qRT-PCR, Western blotting and immunostaining. Results were compared between M2 and non-M2 carriers.

RESULTS

The M2 haplotype was found to be significantly frequent in placentas from pre-eclamptic patients relative to the controls (25.5% versus 10%, P = 0.044), In contrast, no significant differences were observed in maternal blood (13.0% versus 11.3%, P = 0.597). The placental expression of ANXA5 mRNA was found to be lower in M2 carriers. When examined by Western blot and immunostaining, the ANXA5 protein levels were found to be affected more by the placental than the maternal genotype. Histological examination of the placentas from the pre-eclamptic patients demonstrated that a placental M2 haplotype correlated more closely than maternal M2 with the severity of perivillous fibrin deposition.

CONCLUSIONS

Although preliminary, these results suggest that hypomorphic M2 alleles in the in placental ANXA5 promoter, whether transmitted maternally or paternally, might be an essential determinant of an increased risk of pre-eclampsia via local thrombophilia at the feto-maternal interface.

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.

Risk-factor profile, drug usage and cardiovascular events within a year in patients with and at high risk of atherothrombosis recruited from Asia as compared with those recruited from non-Asian regions: a substudy of the REduction of Atherothrombosis for Continued Health (REACH) registry

OBJECTIVE

To clarify the differences in the baseline characteristics, prevalence and incidence of atherothrombosis in patients recruited from Asia versus non-Asian regions.

DESIGN

International Prospective Cohort Study.

SETTING

Region focused substudy.

PATIENTS

The Reduction of Atherothrombosis for Continued Health (REACH) Registry recruited 68 236 stable outpatients with established atherothrombosis or ≥3 atherothrombotic risk factors from 44 countries.

INTERVENTIONS

No intervention.

MAIN OUTCOME MEASURES

Risk factors, use of medications, vascular disease bed location, and 1-year cardiovascular (CV) outcomes (CV death, myocardial infarction, stroke).

RESULTS

The percentages of patients recruited with CVD (Cerebrovascular Disease) were higher in Asia (41.0%) than in non-Asian regions (25.1%) (p<0.0001). The prevalence of diabetes mellitus was higher in Asia (46.6%) than in non-Asian regions (43.3%) (p<0.0001) despite the former having a lower body mass index (BMI) (24.4±3.9 vs 28.8±5.6) (p<0.0001). The combined endpoint of CV death/myocardial infarction/stroke of patients recruited from non-Asian regions of 4.38% (95% CI 4.20 to 4.56) is equivalent to those from the Asian region excluding Japan of 4.65% (95% CI 4.04 to 5.25), but that is significantly lower in patients recruited from Japan of 3.40% (95% CI 2.76 to 4.04, p<0.05).

CONCLUSIONS

There is a higher prevalence of CVD and higher prevalence of diabetus mellitus with lower body mass index in patients recruited from the Asian region as compared those recruited from non-Asian regions. The CV event rate in patients recruited from non-Asian regions is equivalent to that of patients recruited from the Asian region excluding Japan, but significantly lower in patients recruited from Japan.

Portal vein thrombosis and pulmonary artery thromboembolism after laparoscopic colectomy

Portal vein thrombosis is a rare and potentially lethal complication of laparoscopic colectomy. In this paper, we present a case of portal vein thrombosis and pulmonary artery thromboembolism on the 11(th) day after laparoscopic colectomy without an evident congenital thrombotic disorder. Laparoscopic surgeons and their patients should be aware of such events, because the patients are usually discharged before the symptoms begin.

Factor V Leiden and its effect on children with cardiac pathology

Factor V Leiden thrombophilia, formed by a genetic mutation, slows the body's anticoagulation response to clot formation. First described in 1994, factor V Leiden mutation has been identified as a contributing risk factor for venous thromboembolism. Although venous thromboembolism is considered rare in the pediatric population, Factor V Leiden has implications for certain at-risk pediatric patients.

Acquired activated protein C resistance, high tissue factor expression, and hyper-homocysteinemia in systemic lupus erythematosus

Activated protein C resistance (APCR), high tissue factor (TF) expression, and hyper-homocysteinemia are associated with thromboembolic diseases. Thromboembolism is a frequent complication of systemic lupus erythematosus (SLE). In this study, we evaluated the prevalence of APCR, high TF, and homocysteine with correlation of the thrombotic tendency in SLE. Ninety-four SLE patients and 28 normal controls were included. APC ratio and TF antigen were measured using commercial kits. Plasma homocysteine level was measured using HPLC. The prevalence of APCR, high TF antigen level, and hyper-homocysteinemia in our SLE patients were 21.3%, 66.0%, and 23.4%, respectively. The median plasma level of TF antigen in SLE patients was 145.23 pg/mL (range, 31.00-778.50 pg/mL), which was significantly higher than the control value of 39.83 pg/mL (range, 1.55-168.50 pg/mL). The median APC ratio in SLE patients was 2.76 (range, 1.48-13.47), which was significantly lower than the control value of 3.59 (range, 0.26-5.66). The plasma level of homocysteine was not significantly different from that of control. A significant association was observed between the presence of APCR (OR = 8.59, P < 0.0001) but not with the presence of high plasma TF antigen level (OR = 1.24, P = 0.67) and thrombotic complications in SLE patients. In conclusion, APCR and high plasma TF levels are common in SLE, but a significant association was observed only between the presence of APCR and thrombosis in SLE patients.

Activated protein C resistance, the factor V Leiden mutation, and a laboratory testing algorithm

OBJECTIVES

To present the current understanding of factor V Leiden and activated protein C resistance, and to propose a laboratory testing algorithm.

DATA SOURCES

Publications on MEDLINE with the terms factor V Leiden or activated protein C resistance through mid 2001, as well as publications in the authors' files, were screened for inclusion in this report.

STUDY SELECTION

Original studies that report a novel finding on testing or clinical features of activated protein C resistance or factor V Leiden are included. Data Extraction.-The novel or key findings from the selected studies are analyzed.

DATA SYNTHESIS

Protein C and protein S are the integral components of an anticoagulation pathway that limits fibrinogen conversion to fibrin through the degradation of factors Va and VIIIa. When factor Va is resistant to degradation by activated protein C, this anticoagulation pathway does not operate properly, and patients have an increased risk for thrombosis. This report describes the protein C/protein S pathway, the significance of activated protein C resistance and the factor V Leiden mutation, and the clinical testing used to detect activated protein C resistance and the factor V Leiden mutation. A proposed laboratory testing algorithm is also provided.

CONCLUSIONS

Factor V Leiden is a risk factor for venous thrombosis and it is particularly common in white populations. A laboratory testing algorithm is proposed.

Frequency of natural coagulation inhibitor (antithrombin III, protein C and protein S) deficiencies in Japanese patients with spontaneous deep vein thrombosis

One hundred and thirteen consecutive Japanese patients with deep venous thrombosis (DVT) were studied for the incidences of antithrombin III (AT-III), protein C (PC) and protein S (PS) deficiencies, and the results were compared with those of normal subjects. Ten of the 392 normal Japanese subjects were found with PS deficiency (n = 8, 2.02%) or PC deficiency (n = 2, 0.5%). PS deficiencies comprised type I (1/8, 12.5%), type 11 (4/8, 50%), and type III (3/8, 37.5%). All PC deficiencies were type I. Among patients with DVT, 32 (28.3%) were deficient in AT-III, PC and PS. These patients consisted of two AT-III deficiency (1.77%), nine PC deficiency (7.96%), 20 PS deficiency (17.7%), and one combined deficiency of PC and PS (0.88%). Both of the patients with AT-III deficiency were classified as type II, all those with PC deficiency as type I, and those with PS deficiency as type I in 25% (5/20), type II in 55% (11/20) and type III in 20% (4/20). The frequency of PC and PS deficiencies in patients with DVT were 15.6 and 7.38 times the control population frequency, respectively, and this difference was statistically significant (P < 0.05). These data suggest that the Japanese population has a high frequency of PC and PS deficiencies. We recommend that PS activity should be measured for screening of thrombosis since type II deficiency accounted for approximately 50% of PS deficiency cases in both patients and the normal group in the Japanese.

DNA technology for the detection of common genetic variants that predispose to thrombophilia

With the identification of common single locus point mutations as risk factors for thrombophilia, many DNA testing methodologies have been described for detecting these variations. Traditionally, functional or immunological testing methods have been used to investigate quantitative anticoagulant deficiencies. However, with the emergence of the genetic variations, factor V Leiden, prothrombin 20210 and, to a lesser extent, the methylene tetrahydrofolate reductase (MTHFR677) and factor V HR2 haplotype, traditional testing methodologies have proved to be less useful and instead DNA technology is more commonly employed in diagnostics. This review considers many of the DNA techniques that have proved to be useful in the detection of common genetic variants that predispose to thrombophilia. Techniques involving gel analysis are used to detect the presence or absence of restriction sites, electrophoretic mobility shifts, as in single strand conformation polymorphism or denaturing gradient gel electrophoresis, and product formation in allele-specific amplification. Such techniques may be sensitive, but are unwielding and often need to be validated objectively. In order to overcome some of the limitations of gel analysis, especially when dealing with larger sample numbers, many alternative detection formats, such as closed tube systems, microplates and microarrays (minisequencing, real-time polymerase chain reaction, and oligonucleotide ligation assays) have been developed. In addition, many of the emerging technologies take advantage of colourimetric or fluorescence detection (including energy transfer) that allows qualitative and quantitative interpretation of results. With the large variety of DNA technologies available, the choice of methodology will depend on several factors including cost and the need for speed, simplicity and robustness.

The factor V Leiden mutation in Japanese couples with recurrent spontaneous abortion

Thrombosis of placental vessels can be a major cause of recurrent spontaneous abortion (RSA). The factor V Leiden (FVL) mutation, a single point mutation in the factor V gene, is the most common genetic predisposition to thrombosis in European countries and the United States. However, even among Caucasian populations, the association between the FVL mutation and RSA is still controversial. The objectives of the present study were to investigate the prevalence of the FVL mutation in Japanese women who have experienced RSA and to clarify the contribution of the FVL mutation to recurrent miscarriages. A total of 52 Japanese women with a history of three or more consecutive idiopathic first trimester miscarriages and 41 of their male partners were studied. The control group consisted of 55 parous women without obstetric complications. Peripheral blood cell DNA was examined for the presence of the FVL alleles by polymerase chain reaction with Mnl I restriction fragment length polymorphisms. None of the 52 women with RSA and the 41 partners carried the mutation. We also found no subject carrying the FVL alleles in the control group. These results suggest that the FVL alleles are not concentrated in women with RSA at least to clinically significant levels and that there is no apparent association between the FVL mutation and RSA in our Japanese population.

Incidence of pulmonary thromboembolism in Japan

Pulmonary thromboembolism (PTE) is considered an uncommon disease in Japan and there are not any reported prospective studies on the incidence of PTE in Japan. The objective of the present study was to determine the number of patients with PTE per year in a prospective study using a questionnaire. Letters were sent to clinical departments in university schools of medicine or medical colleges, and to hospitals with more than 100 beds. The diagnosis of PTE was to be confirmed by (1) pulmonary artery stenosis or occlusion on pulmonary angiography, (2) mismatch of pulmonary perfusion scintigraphy and pulmonary ventilation scintigraphy, (3) changes on pulmonary perfusion scintigraphy performed twice, or (4) autopsy. The questionnaire elicited 2,341 replies (the withdrawal rate was 40.7%). In 231 hospitals, 237 patients were diagnosed definitely during the study period of 2 months from 1 August to 30 September 1996. From this it was estimated that there are 3,492 (95% confidence interval: 3,280-3,703) patients with PTE per year, which implies that the incidence is 28 persons per 1,000,000 people per year, confirming that PTE is rare in Japan.

Laboratory evaluation of hypercoagulable states

The number of well-characterized hereditary and acquired hypercoagulable conditions is increasing, such that in many thrombophilic patients, the laboratory can now identify a hypercoagulable condition. This review describes the currently known hypercoagulable states that predispose patients to venous, and in some instances, arterial thrombosis. For each condition, the discussion includes the incidence, magnitude of the thrombotic risk in the general population in comparison with symptomatic families, synergistic interactions among the various hypercoagulable conditions, molecular pathogenesis, and interpretation of laboratory test results. In addition, recommendations for laboratory testing are summarized.

Role of factor V Leiden mutation in patients with angiographically demonstrated coronary artery disease

The study sought to determine whether coagulation factor V Leiden (FV Leiden) plays a role in the pathogenesis of coronary artery disease and/or myocardial infarction. Association of FV Leiden with venous thromboembolism is well established in the literature, but the role of the mutation in arterial thrombotic events is controversial. Some studies have documented an association between the mutation and myocardial infarction and stroke in juveniles. Few studies have explored its possible contribution to coronary atherosclerosis. We screened FV genotype in 850 predominantly white coronary angiography patients. Coronary artery disease risk factors and history of myocardial infarction were then analyzed by genotype. The FV Leiden mutation occurred in 54 (6.4%) patients. There was one homozygote; a 37-year-old, white male smoker with a history of myocardial infarction. Gene frequencies for white males and females were similar: 0.965 for the normal allele and 0.035 for FV Leiden. Gene frequencies for both genders were in Hardy-Weinberg equilibrium. FV Leiden was not a useful predictor (p=0.23) of the presence of clinically defined atherosclerosis (> or = 50% stenosis) in a logistic regression model adjusting for age, lipoprotein (a), total cholesterol, triglycerides, high density lipoprotein cholesterol, and fibrinogen. In addition, there was no difference in frequency of FV Leiden among those with and without medical histories of myocardial infarction (p=0.51). Allelic frequencies of FV Leiden in this patient group do not differ significantly from those reported for white populations. The FV Leiden mutation in its heterozygous state is not independently associated with coronary artery disease or myocardial infarction.

Evaluation of role of factor V Leiden mutation in fatal pulmonary thromboembolism

Association of a mutation in the coagulation factor V gene (FV Leiden) with deep vein thrombosis and pulmonary thromboembolism has been well documented in the literature, but no study has specifically screened cases of fatal pulmonary thromboembolism for the mutation. This study sought to determine whether FV Leiden plays a role in the pathogenesis of fatal pulmonary thromboembolism. We isolated DNA from archived paraffin-embedded tissues derived from 46 necropsy cases in which pulmonary thromboembolism was listed as the cause of death (n = 27) or was secondarily associated with death (n = 19). FV Leiden genotypes were determined by using polymerase chain reaction and MnlI digestion of amplified products. The Leiden mutation occurred in the heterozygous state in one (2.1%) of the necropsy specimens. The prevalence of the mutation was higher (8.7%) in gender- and ethnic-matched blood donor controls. The FV Leiden mutation is not independently associated with fatal pulmonary thromboembolism in the group of patients analyzed. The results suggest different etiologies for nonfatal, chronic deep vein thrombosis/pulmonary thromboembolism and fatal, acute pulmonary thromboembolism.