Risk of cerebral venous thrombosis and novel gene polymorphisms of the coagulation and fibrinolytic systems

Venous thromboembolism risk in adults with hereditary thrombophilia: a systematic review and meta-analysis

This systematic review and meta-analysis assesses venous thromboembolism (VTE) risk in adults with hereditary thrombophilia, including Factor V Leiden (FVL) mutation, prothrombin G20210A (FII) mutation, compound heterozygosity, protein C (PC), protein S (PS), and antithrombin (AT) deficiency. Eligibility criteria included studies suitable for quantitative synthesis with extractable information on VTE risk in adults (> 15 years). There were no restrictions on VTE type, location, or occurrence. Two authors reviewed all studies and extracted data from 107 publications, encompassing 107,130 individuals (21,560 experiencing VTE). We used a random effects model and calculated odds ratios (ORs) with 95% confidence intervals (CIs). The highest risk was associated with homozygous FVL (OR 5.58, 95% CI 4.61-6.74), homozygous FII (OR 5.16, 95% CI 3.12-8.52), and compound heterozygosity (OR 4.64, 95% CI 2.25-9.58). In contrast, VTE risk was lowest for FVL heterozygosity (OR 2.97, 95% CI 2.41-3.67) and FII heterozygosity (OR 2.21, 95% CI 1.70-2.87), whereas PC (OR 3.23, 95% CI 2.05-5.08), PS (OR 3.01, 95% CI 2.26-4.02), and AT deficiency (OR 4.01, 95% CI 2.50-6.44) demonstrated an intermediate VTE risk. These results highlight an increased risk of venous thromboembolism in adults with hereditary thrombophilia. However, the risk for patients with PC, PS, and AT deficiency appears to be lower than previously stated, likely due to varying thrombogeneity of the underlying genetic mutations. Further research addressing this aspect of VTE risk in hereditary thrombophilia is imperative to improve patient management. TRIAL REGISTRATION: PROSPERO registration number CRD42022376757.

The genetic risk factors for cerebral venous thrombosis: a case-control study in a Chinese national comprehensive hospital

BACKGROUND

About 13-25% of cerebral venous thrombosis (CVT) cases lack clear etiology, which may be associated with underlying genetic factors. This study aims to investigate genetic factors in CVT patients using whole exome sequencing (WES).

METHODS

Thirty-eight CVT patients hospitalized underwent WES. 977 subjects with WES data from a community cohort study --the Shunyi cohort were as the control group. Using bioinformatics analysis, differential genes with rare damaging variants between two groups were filtered (P < 0.05). KEGG enrichment analysis was performed on the screened genes to identify pathways associated with CVT.

RESULTS

Through analysis of medical history, routine tests, and imaging examinations, the etiology of 38 patients: 8 cases of antiphospholipid syndrome, 6 cases with hematologic diseases, 3 cases of protein C deficiency, and 2 cases of protein S deficiency. Five cases occurred during pregnancy or puerperium, and 3 cases had a history of oral contraceptive use, and so on. The etiology was unknown in 12 cases (31.6%), and the etiology of 4 patients were further clarified through WES: F9 c.838 + 1_838 + 16del, Hemizygote: F9 EX1-EX7 Dup; CBS c.430G > A, CBS c.949 A > G; F2 c.1787G > A; SERPINC1 c.409-11G > T. Comparing the WES data of two groups, a total of 179 different genes with rare damaging variants were screened (P < 0.05), with 5 genes of interest (JAK2, C3, PROC, PROZ, SERPIND1). Enrichment analysis of the 179 different genes revealed the complement and coagulation pathway and the mitogen activated protein kinases (MAPK) pathway were associated with CVT.

CONCLUSION

For CVT patients with unknown etiology, WES could help identify the cause of CVT early, which is of great significance for treatment decisions and prognosis. In addition to the complement and coagulation pathway, MAPK pathway is associated with CVT, potentially related to platelet regulation and inflammatory response.

Factor V Leiden, Factor II, Protein C, Protein S, and Antithrombin and Ischemic Strokes in Young Adults: A Meta-Analysis

Ischemic strokes are one of the leading causes of death worldwide. The aim of this meta-analysis is to elaborate on the role of inherited predisposition to thrombophilia in the etiology of ischemic strokes in young adults. The keywords factor V Leiden (FVL), factor II, prothrombin (PT), protein C (PC), protein S (PS), antithrombin (AT), ischemic stroke, and young were used to search different databases. We selected studies with participants who were between 18 and 65 years. A total of 104 studies were eligible for inclusion in the meta-analysis. All the studied genetic markers were risk factors for ischemic stroke according to our results (FVL OR = 1.74; PT OR = 1.95; PC OR = 10.20; PS OR = 1.74; AT OR = 3.47; p < 0.05). There was moderate heterogeneity for most of the results, and subgroup analyses were conducted by dividing the studies according to the geographic location, gender ratio, and selection criteria of the performed study. There were no significant differences between the groups, but different geographic location was a probable source of heterogeneity. All of the studied markers—FVL, prothrombin, PC, PS, and AT—were significantly associated with increased risk of ischemic stroke in young adults and, if tested, could improve the quality of care.

Impact of ex vivo Sample Handling on DNA Methylation Profiles in Human Cord Blood and Neonatal Dried Blood Spots

The profiling of DNA methylation modifications in peripheral blood has significant potential to determine risk factors for human disease. Little is known concerning the sensitivity of DNA methylation profiles to ex vivo sample handling. Here, we studied typical conditions prior to sample storage associated with cord blood samples obtained from clinical investigations using reduced representation bisulfite sequencing. We examined both whole blood collected shortly after birth and dried blood spots, a potentially important source of neonatal blood for investigation of the DNA methylome and the Developmental Origins of Health and Disease in human cohorts because they are routinely collected during clinical care. Samples were matched across different time conditions, as they were from the same cord blood samples obtained from the same individuals. Maintaining whole blood ex vivo up to 24 h (4°C) or dried blood spots up to 7 days (room temp.) had little effect on DNA methylation profiles. Minimal differences were detected between cord blood immediately frozen and dried blood spots. Our results indicate that DNA methylation profiles are resilient to ex vivo sample handling conditions prior to storage. These data will help guide future human studies focused toward determination of DNA methylation modifications in whole blood.

Prothrombogenic polymorphic variants of hemostatic and folate metabolism genes In patients with aseptic cerebral venous thrombosis

Cerebral venous sinus thrombosis (CVT) becomes the cause of stroke in less than 1% of patients. In 20-30% of patients, the cause of thrombosis remains unclear, and thrombosis is considered idiopathic. Inherited hypercoagulable conditions significantly increase the risk of CVT. The aim of the study was to evaluate the frequency of prothrombogenic polymorphic variants of hemostatic and methionine-homocysteine metabolism genes alleles and genotypes in patients with aseptic CVT. Fifty one patients aged 18–75 with aseptic CVT were examined. The control group included 36 healthy volunteers. Neuroimaging methods included brain MRI in standard modes (T1, T2, T2 d-f (FLAIR), DWI) and MR venosinusography. All patients were surveyed to identify carriers of prothrombogenic polymorphic variants of hemostatic and folate metabolism genes alleles and genotypes. Prothrombogenic polymorphic variants of hemostatic genes were detected in 94% of patients, and the variants of the methionine-homocysteine metabolism genes were observed in 86% of patients. The differences between distributions of alleles and genotypes 5G6754G of the PAI-1 gene, G103T of the FXIIIA1 gene, A66G of the MTRR gene, A2756G of the MTR gene in the group of patients with CVT and in the control group were significant. Allele 4G, genotypes 4G/4G and 5G/4G of 5G6754G polymorphism of the PAI-1 gene; allele T of G103Т polymorphism of the FXIIIA1 gene; allele G and genotype A/G of A66G polymorphism of the MTRR gene; allele G and genotype A/G of A2756G polymorphism of the MTR gene correlated with aseptic CVT. It was concluded that the gene polymorphisms 5G6754G (PAI-1), G103T (FXIIIA1), A66G (MTRR) and A2756G (MTR) carriage increased the risk of aseptic CVT and did not affect the thrombosis clinical manifestations.

Thrombin-Activatable Fibrinolysis Inhibitor Polymorphisms and Cerebral Venous Thrombosis in Mexican Mestizo Patients

Thrombin-activatable fibrinolysis inhibitor (TAFI) gene polymorphisms have been proposed as a predisposing factor for cerebral venous thrombosis (CVT). We analyzed the association between CVT and TAFI single-nucleotide polymorphisms (rs3742264, rs2146881, and rs1926447) compared to healthy controls. Mexico Mestizo confirmed cases with CVT and age- and sex-matched controls with no history of venous thrombotic events were recruited from July 2006 to July 2015. Demographic, clinical, and imaging information was included in the analysis. Genotyping single-nucleotide polymorphisms were performed by allele-specific polymerase chain reaction. Allelic univariate analysis, haplotype association, and Hardy-Weinberg equilibrium were assessed. A total of 113 CVT cases (94 females [83.2%]; median age 35 years [interquartile range 27-43 years]) and 134 age- and sex-matched controls were included. The main risk factors for CVT were pregnancy/puerperium (30.9%), oral contraceptive use (19.5%), and hereditary thrombophilia (7.1%). We found no significant association for heterozygous and homozygous models for rs3742264 ( P = .30 and P = .69, respectively), rs2146881 ( P = .90 and P = .17, respectively), or rs1926447 ( P = .40 and P = .52, respectively) compared to controls; these findings were consistent in subgroup and haplotype analyses. In conclusion, TAFI rs3742264, rs2146881, and rs1926447 polymorphisms do not increase the risk of CVT in comparison to healthy controls.

Sex-specific effect of CPB2 Ala147Thr but not Thr325Ile variants on the risk of venous thrombosis: A comprehensive meta-analysis

BACKGROUND

Thrombin activatable fibrinolysis inhibitor (TAFI), encoded by the Carboxypeptidase B2 gene (CPB2), is an inhibitor of fibrinolysis and plays a role in the pathogenesis of venous thrombosis. Experimental findings support a functional role of genetic variants in CPB2, while epidemiological studies have been unable to confirm associations with risk of venous thrombosis. Sex-specific effects could underlie the observed inconsistent associations between CPB2 genetic variants and venous thrombosis.

METHODS

A comprehensive literature search was conducted for associations between Ala147Thr and Thr325Ile variants with venous thrombosis. Authors were contacted to provide sex-specific genotype counts from their studies. Combined and sex-specific random effects meta-analyses were used to estimate a pooled effect estimate for primary and secondary genetic models.

RESULTS

A total of 17 studies met the inclusion criteria. A sex-specific meta-analysis applying a dominant model supported a protective effect of Ala147Thr on venous thrombosis in females (OR = 0.81, 95%CI: 0.68,0.97; p = 0.018), but not in males (OR = 1.06, 95%CI:0.96-1.16; p = 0.263). The Thr325Ile did not show a sex-specific effect but showed variation in allele frequencies by geographic region. A subgroup analysis of studies in European countries showed decreased risk, with a recessive model (OR = 0.83, 95%CI:0.71-0.97, p = 0.021) for venous thrombosis.

CONCLUSIONS

A comprehensive literature review, including unpublished data, provided greater statistical power for the analyses and decreased the likelihood of publication bias influencing the results. Sex-specific analyses explained apparent discrepancies across genetic studies of Ala147Thr and venous thrombosis. While, careful selection of genetic models based on population genetics, evolutionary and biological knowledge can increase power by decreasing the need to adjust for testing multiple models.

Association between thrombin-activatable fibrinolysis inhibitor gene polymorphisms and venous thrombosis risk: a meta-analysis

Thrombin-activatable fibrinolysis inhibitor (TAFI) is an important antifibrinolytic factor that has been shown in increased concentrations to be associated with an increased risk for venous thrombosis. However, the effect of TAFI gene polymorphisms on the risk of venous thrombosis remains debatable. The aim of the current study was to evaluate the association of three single nucleotide polymorphisms: 505G>A (rs3742264), 1040 C>T (rs1926447) and -438G>A (rs2146881) with venous thrombosis risk using a meta-analysis. A systematic literature search for eligible studies published before 20 January 2015 was conducted in PubMed, EMBASE, Web of Science, WanFang database and Chinese National Knowledge Infrastructure. We assessed the possible association by pooled odds ratio and its 95% confidence interval. A total of 14 independent case-control studies including 2970 cases and 3049 controls were enrolled in the final meta-analysis. A significant reduction of venous thrombosis risk in the 505G>A polymorphism was observed under allele comparison, homozygote comparison and recessive models, but opposite results were seen in Asians. Likewise, there was a significant decreased susceptibility to venous thrombosis in the 1040C>T polymorphism in homozygote comparison and recessive models. In the subgroup analysis, the nonvenous thromboembolism disease group showed a significantly increased venous thrombosis risk. Pooled estimates did not show evidence of association between -438G>A and venous thrombosis risk in any genetic model. This meta-analysis suggested that although the -438G>T polymorphism is not correlated with venous thrombosis risk in all models, a trend toward reduced risk still could be observed. The A allele and AA genotype of 505G>A in whites and the TT genotype of 1040C>T were significantly associated with a decreased risk of venous thrombosis, except in the non-venous thromboembolism group.

Cerebral Venous Thrombosis: Current and Newer Anticoagulant Treatment Options

BACKGROUND

Cerebral venous thrombosis (CVT) is rare and involves thrombosis of the veins and sinuses of the brain, most commonly the superior sagittal sinus. Approximately 5 CVT cases occur per 1 million persons in western countries. CVT causes 0.5% of strokes. Early diagnosis is crucial to prevent such outcomes as hydrocephalus, intracranial hypertension, and further seizures. Standard medical treatment of CVT consists of low-molecular-weight heparin and endovascular thrombolysis. Small case reports have found that the newer oral anticoagulants can be used for CVT treatment; however, they are associated with increased risk of bleeding and other adverse effects.

REVIEW SUMMARY

CVT can be triggered by an imbalance of the body's homeostasis or reduced action of the intrinsic antithrombotic mechanism. Factors influencing this change include infection, brain tumor, inflammatory conditions, genetic thrombophilias, head trauma that causes intracranial bleeding, and certain medications. CVT may cause brain infarction and increased intracranial pressure. Sometimes, idiopathic intracranial hypertension presents as the only clinical manifestation. Confirmation of the diagnosis typically is through neuroimaging. Current CVT treatment depends on disease extent and severity.

CONCLUSIONS

CVT is a rare neurological disease with potentially serious implications and high neurological morbidity and mortality rates. Understanding the role of risk factors-such as genetic or acquired thrombophilia, pregnancy, use of oral contraceptives, and hyperhomocysteinemia-in CVT development is important. Although heparin and warfarin have been used for more than 50 years, newer oral anticoagulants (eg, dabigatran, rivaroxaban, apixaban) might offer an alternative to traditional therapy.

Prevalence and Geographical Variation of Prothrombin G20210A Mutation in Patients with Cerebral Vein Thrombosis: A Systematic Review and Meta-Analysis

Objectives

To compare the prevalence of prothrombin G20210A in patients with objectively confirmed cerebral vein or cortical vein thrombosis against healthy controls, and evaluate geographical variations.

Design

Systematic review and meta-analysis of case control studies.

Methods

We conducted a systematic review of electronic databases including MEDLINE and EMBASE. The main outcome was the prevalence of prothrombin G20210A in patients with objectively confirmed cerebral vein or cortical vein thrombosis; we also analyzed individual country variations in the prevalence. The random-effects model OR was used as the primary outcome measure.

Results

In total 19 studies evaluated 868 cases of cerebral venous thrombosis and 3981 controls. Prothrombin G20210A was found in 103/868 of the patients with cerebral venous thrombosis and 105/3999 of the healthy controls [random effects pooled OR 5.838, 95% CI 3.96 to 8.58; I²17.9%]. The prevalence of prothrombin G20210A was significantly elevated in Italian studies (OR 9.69), in Brazilian studies (OR 7.02), and in German studies (OR 3.77), but not in Iranian studies (OR 0.98).

Conclusion

Prothrombin G20210A is significantly associated with cerebral venous thrombosis when compared to healthy controls, although this association is highly dependent on the country of origin.

Factor V Leiden, factor V Cambridge, factor II GA20210, and methylenetetrahydrofolate reductase in cerebral venous and sinus thrombosis: A case-control study

Background:

Factor V G1691A (FV Leiden), FII GA20210, and methylenetetrahydrofolate reductase (MTHFR) C677T mutations are the most common genetic risk factors for thromboembolism in the Western countries. However, there is rare data in Iran about cerebral venous and sinus thrombosis (CVST) patients. The aim of this study was to evaluate the frequency of common genetic thrombophilic factors in CVST patients.

Materials and Methods:

Forty consequently CVST patients from two University Hospital in Isfahan University of Medical Sciences aged more than 15 years from January 2009 to January 2011 were recruited. In parallel, 51 healthy subjects with the same age and race from similar population selected as controls. FV Leiden, FII GA20210, MTHFR C677T, and FV Cambridge gene mutations by polymerase chain reaction technique were evaluated in case and control groups.

Results:

FV Leiden, FII GA20210, and FV Cambridge gene mutations had very low prevalence in both case (5%, 2%, 0%) and control (2.5%, 0%, 0%) and were not found any significant difference between groups. MTHFR C677T mutations was in 22 (55%) of patients in case group and 18 (35.5%) of control group (P = 0.09).

Conclusion:

This study showed that the prevalence of FV Leiden, FII GA20210, and FV Cambridge were low. Laboratory investigations of these mutations as a routine test for all patients with CVST may not be cost benefit.

Impact of genetic polymorphisms in thrombin activatable fibrinolysis inhibitor (TAFI) on venous thrombosis disease: A meta-analysis

BACKGROUND

Reported studies have showed that Thrombin Activatable Fibrinolysis Inhibitor (TAFI) may be associated with an increased risk of venous thromboembolism. But the relation of VT with TAFI gene SNPs could not be clearly demonstrated. Thus, we conducted a meta-analysis to analyze the associations between three TAFI variants -438G/A, 505G/A and 1040C/T and the risk of venous thrombosis.

METHODS

We carried out a systematic search to obtain all the eligible studies published before 30th October 2014. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were computed to assess the association.

RESULTS

13 eligible studies were enrolled including 2321 patients and 2464 controls. There was a significant association between 505G/A and the risk of VTD under all models except recessive model (G vs. A: OR=1.13, 95% CI: 1.02, 1.26; GG vs. AA:OR=1.47, 95% CI: 1.14, 1.88; GA vs. AA: OR=1.36, 95% CI: 1.06, 1.73; GG+GA vs. AA: OR=1.41, 95% CI: 1.12, 1.77). Similarly, obvious relationship was observed in subgroup analyses in light of type of disease and ethnicity. Likewise, for 1040C/T variant, significant associations were identified under homozygote, heterozygote and dominant models (CC vs. TT: OR=1.65, 95% CI: 1.06, 2.59; CT vs. TT: OR=1.55, 95% CI: 1.19, 2.03; CC+CT vs. TT: OR=1.55, 95% CI: 1.20, 2.00). Sub-analysis presented significant associations in non-CVT and non-Asian group under homozygote, heterozygote, and dominant models and CVT group in recessive model.

CONCLUSION

This meta-analysis showed that -438G/A variant was not associated with the incidence of venous thrombosis. But in non-Asian populations, G allele and GG genotype of 505G/A may increase the risk of venous thrombosis diseases. GG genotype of 505G/A and one C carrier (CC and CT) of 1040C/T gave rise to the development of venous thrombosis diseases except CVT. Additionally, the heterozygote CT may be a potential contributing factor of gene effect in venous thrombosis.

Allele frequency distribution of 1691G >A F5 (which confers Factor V Leiden) across Europe, including Slavic populations

The allele 1691A F5, conferring Factor V Leiden, is a common risk factor in venous thromboembolism. The frequency distribution for this allele in Western Europe has been well documented; but here data from Central, Eastern and South-Eastern Europe has been included. In order to assess the significance of the collated data, a chi-squared test was applied, and Tukey tests and z-tests with Bonferroni correction were compared. Results: A distribution with a North-Southeast band of high frequency of the 1691A F5 allele was discovered with a pocket including some Southern Slavic populations with low frequency. European countries/regions can be arbitrarily delimited into low (group 1, <2.8 %, mean 1.9 % 1691A F5 allele) or high (group 2, ≥2.8 %, mean 4.0 %) frequency groups, with many significant differences between groups, but only one intra-group difference (the Tukey test is suggested to be superior to the z-tests). Conclusion: In Europe a North-Southeast band of 1691A F5 high frequency has been found, clarified by inclusion of data from Central, Eastern and South-Eastern Europe, which surrounds a pocket of low frequency in the Balkans which could possibly be explained by Slavic migration. There seem to be no indications of variation in environmental selection due to geographical location.

Protein Z G79A polymorphism and puerperal cerebral venous thrombosis

Protein Z (PZ), a cofactor for PZ-dependent protease inhibitor, is known to play an important role in inhibiting the coagulation cascade. The aim of the study was to investigate whether PZ G79A polymorphism is a risk factor for puerperal cerebral venous thrombosis (CVT). A total of 71 patients with puerperal CVT and 98 healthy controls were genotyped for PZ 79GA polymorphism by polymerase chain reaction-restriction fragment length polymorphism method. In patients, the genotype distribution for GG, GA, and AA genotypes was 22.5%, 43.7%, and 33.8%, and in controls, 25.5%, 40.8%, and 33.7%, respectively. The risk associated with carrying the mutant genotype (GA and AA) versus the wild GG genotype was found to be 1.11 (95% confidence interval: 0.52-2.35; P = .909). There was no significant difference in the clinical features of the patients with and without the polymorphism. We therefore conclude that PZ G79A polymorphism is not a risk factor for puerperal CVT in Indian women.

Haplotypes of TAFI gene and the risk of cerebral venous thrombosis--a case-control study

INTRODUCTION

Cerebral venous thrombosis (CVT) is an uncommon disease with some differences compared to other-site thrombosis, including a higher frequency in young people, female sex and oral contraceptive users. Thrombin-activatable fibrinolysis inhibitor (TAFI) is a regulator of fibrinolysis, whose levels are genetically controlled and its increase is associated to thrombosis. Our objective was to investigate in a case-control study the association between CVT and TAFI single nucleotide polymorphisms (SNPs) and its haplotypes in comparison to other-site venous thrombosis and controls.

MATERIALS AND METHODS

Seventy two patients with CVT were compared to 143 individuals with no history of thromboembolic events (control group) and to 128 patients with deep vein thrombosis in the limbs and/or pulmonary embolism (venous thromboembolism-VTE group). SNPs were genotyped by restriction fragment length polymorphism or allele-specific PCR for F2 20210G>A, F5 1691G>A, TAFI (-1053C>T, -438G>A, 505G>A, 1040C>T and +1542C>G).

RESULTS

The GTC haplotype for TAFI 505G>A/1040C>T/+1542C>G SNPs was associated with an increased risk of CVT compared to controls [odds ratio (OR) 2.67, 95% confidence interval (CI): 1.13 - 6.34) and VTE group (OR 2.51, 95%CI: 1.07 - 8.06). The CVT risk became even more pronounced when evaluating unprovoked or hormone-related thrombosis cases: CVT compared to controls (OR 3.24, 95%CI: 1.19 - 8.82) and VTE group (OR 4.32, 95%CI: 1.27 - 14.63).

CONCLUSIONS

Our data indicate that the GTC haplotype for TAFI 505G>A/1040C>T/+1542C>G SNPs increased the risk of CVT in comparison to controls and VTE cases. Further studies are required to confirm our findings.

TAFI gene polymorphisms in patients with cerebral venous thrombosis

Gene polymorphisms of thrombin activatable fibrinolysis inhibition (TAFI) factor have been investigated in various studies in terms of etiology (recurrence) and treatment (fibrinolytic effect) of thrombus formation. Cerebral venous thrombosis (CVT) is a life-threatening disease observed in young persons. Fifty-nine patients with CVT and 100 healthy control subjects were enrolled in the case/control study. The association between TAFI gene polymorphisms -438G>A, +505A>G and +1040C>T and cerebral venous thrombosis was investigated. It was found that frequencies of polymorphic genotype and allele were not different in patients than in control group and that they were not significant for cerebral venous thrombosis.

Risk of venous thromboembolism associated with single and combined effects of Factor V Leiden, Prothrombin 20210A and Methylenetethraydrofolate reductase C677T: a meta-analysis involving over 11,000 cases and 21,000 controls

Genetic and environmental factors interact in determining the risk of venous thromboembolism (VTE). The risk associated with the polymorphic variants G1691A of factor V (Factor V Leiden, FVL), G20210A of prothrombin (PT20210A) and C677T of methylentetrahydrofolate reductase (C677T MTHFR) genes has been investigated in many studies. We performed a pooled analysis of case-control and cohort studies investigating in adults the association between each variant and VTE, published on Pubmed, Embase or Google through January 2010. Authors of eligible papers, were invited to provide all available individual data for the pooling. The Odds Ratio (OR) for first VTE associated with each variant, individually and combined with the others, were calculated with a random effect model, in heterozygotes and homozygotes (dominant model for FVL and PT20210A; recessive for C677T MTHFR). We analysed 31 databases, including 11,239 cases and 21,521 controls. No significant association with VTE was found for homozygous C677T MTHFR (OR: 1.38; 95 % confidence intervals [CI]: 0.98-1.93), whereas the risk was increased in carriers of either heterozygous FVL or PT20210 (OR = 4.22; 95 % CI: 3.35-5.32; and OR = 2.79;95 % CI: 2.25-3.46, respectively), in double heterozygotes (OR = 3.42; 95 %CI 1.64-7.13), and in homozygous FVL or PT20210A (OR = 11.45; 95 %CI: 6.79-19.29; and OR: 6.74 (CI 95 % 2.19-20.72), respectively). The stratified analyses showed a stronger effect of FVL on individuals ≤ 45 years (p value for interaction = 0.036) and of PT20210A in women using oral contraceptives (p-value for interaction = 0.045). In this large pooled analysis, inclusive of large studies like MEGA, no effect was found for C677T MTHFR on VTE; FVL and PT20210A were confirmed to be moderate risk factors. Notably, double carriers of the two genetic variants produced an impact on VTE risk significantly increased but weaker than previously thought.

Participation of protein Z-dependent protease inhibitor and protein Z system in the pathomechanism of thrombotic complications

Thrombotic complications of unknown etiology remain a serious diagnostic and therapeutic problem. Occurrence of the inherited polymorphisms of genes encoding proteins involved in the coagulation cascade is one of the possible causes of these complications. In recent years, protein Z (PZ) and PZ-dependent protease inhibitor (ZPI) have been added to the list of prothrombotic factors. PZ is a glycoprotein serving as a cofactor of ZPI, which is responsible for the inhibition of prothrombinase. Expression of the PZ gene is under the control of many transcriptional factors; several polymorphisms alternate the rate of gene expression. The present article describes the significance of the ZPI-PZ system in venous and arterial thrombosis, adverse pregnancy outcomes and antiphospholipid syndrome complications.

The risk of occurrence of venous thrombosis: focus on protein Z

Protein Z (PZ) is a vitamin K-dependent factor identified in human plasma in 1984 characterized by an homology with other vitamin K-dependent factors. PZ acts as the cofactor of the PZ dependent inhibitor (ZPI), in the inhibition of activated factor X bound on phospholipid surface. In humans, PZ is characterized by an unusual wide distribution in plasma partly explained by a genetic control. Several PZ gene polymorphisms influencing plasma concentration have been described. In mice, the disruption of PZ gene is asymptomatic, but in association with homozygous FV Leiden produced a severe prothrombotic phenotype. This review analyzes the results obtained from different studies so far published in order to understand whether PZ deficiency could be considered as a risk factor for venous thrombosis. The roles of PZ plasma level and PZ gene polymorphisms remain debated with conflicting results. Many of these studies reported low PZ levels in association with an increased risk of venous thrombosis. On the other side, some studies did not observe an association between low levels of PZ and thrombotic events. A relationship between PZ deficiency and pregnancy complications was also described but not confirmed by all studies. These discrepancies can be explained by the heterogeneity of populations chosen as control, by the PZ interindividual variability and by the small size of the cohorts in mainly retrospective studies. Large prospective studies remain to be done to investigate its possible role in thrombosis.

[Protein Z, polymorphisms in the protein Z gene and thrombosis]

Protein Z (PZ) is a vitamin K dependent protein acting as the cofactor of the protein Z dependent inhibitor (ZPI), in the inhibition of activated factor X bound on the phospholipids. Normal plasma protein Z concentrations have wide variations among individuals, partly explained by a genetic control. Several protein Z gene polymorphisms influence plasma concentration, separately and in combination. The role of PZ in blood coagulation regulation has been demonstrated in vitro. The responsibility of low PZ level in the occurrence of thrombosis has been questioned. However, the roles of PZ plasma level and PZ gene polymorphisms remain debated with conflicting results in arterial, venous, or placental thrombosis. These discrepancies can be explained by the heterogeneity of populations chosen as control, by the PZ interindividual variability, by the small size of the cohorts in mainly retrospective studies and perhaps by the lack of real important influence of this protein on coagulation. PZ measurement is not actually considered as a biological marker of thrombophilia. Large prospective studies remain to be done to investigate its possible role in thrombosis.

Cerebral vein thrombosis

Advances in neuroimaging have modified our knowledge on cerebral vein thrombosis (CVT). This disease is now diagnosed more frequently, and increasing evidence as to what are the most common risk factors and on the natural history of the disease is becoming available. Most patients with CVT have a benign prognosis: only a minority of patients die during the acute phase or in the following months. Most patients surviving CVT recover completely, or have only mild functional or cognitive deficits. Unfractionated or low-molecular weight heparin is widely used as a first-line therapy of CVT, despite the absence of conclusive evidence about the safety and efficacy in this setting. Vitamin K antagonists are usually prescribed for secondary prevention, but the optimal duration of treatment remains unknown. Because most patients with CVT have partial or complete recanalization of the vessels within the first few months after the index event, and because recurrences of CVT after a first episode appear to be uncommon, routine use of long-term therapy or event life-long secondary prevention seem to be unnecessary.

Cerebral venous and sinus thrombosis and thrombophilic mutations in Western Iran: association with factor V Leiden

The present study aimed at investigating the prevalence of factor V Leiden G1691A, prothrombin G20210A, and MTHFR C677T in cerebral venous and sinus thrombosis (CVST) patients and their possible association with CVST in Western Iran. A total of 24 CVST patients with the mean age of 37.1 +/- 11.7 years and 100 sex- and age-matched healthy individuals from Kermanshah Province of Iran with ethnic background of Kurd were studied for factor V Leiden G1691A, prothrombin G20210A and MTHFR C677T by PCR-RFLP method using Mnl I, Hind III, and Hinf I restriction enzymes, respectively. Prevalence of factor V Leiden was 16.7% in patients and 2% in control group. A significant association was found between factor V Leiden mutation and CVST with odds ratio (OR) of 9.8 (95% confidence intervals [CI] 1.68-57.2, P = .01). No prothrombin G20210A was found among patients. In patients, MTHFR C677T tended to be higher (58.3%) compared to control (44%), OR of 1.8 (95% CI 0.73-4.5, P = .2). Our study for the first time has determined the prevalence of inherited thrombophilia in a homogenous ethnic group of CVST patients and suggests that factor V Leiden, and not the prothrombin gene mutation is a risk factor for CVST in Western Iran.

Protein Z G79A polymorphism in patients with severe sepsis

The aim of the study is to investigate whether the presence of a protein Z polymorphism is a risk factor for the development and outcome of sepsis. Sepsis is a clinical syndrome characterized by the presence of systemic signs and symptoms of inflammation. When sepsis leads to organ failure, the term severe sepsis and septic shock is used. The genetic causes of severe sepsis are not fully explained. Protein Z is a vitamin K- dependent glycoprotein and a member of the coagulation cascade. The study included 53 patients with severe sepsis and 70 control healthy volunteers without a familial history of thrombosis. The G79A polymorphism of intron F of the protein Z gene was analyzed by the method of polymerase chain reaction-based DNA analysis. The protein Z intron F G79A polymorphism frequencies of the patients and controls were 43.4% and 40%, respectively. Carrying 79 AA genotype could be a risk factor for severe sepsis and septic shock (OR = 4.5, 95% CI: 0.45-46.1), but it could not find any difference between survivor and nonsurvivor groups. They concluded that the frequency of intron F G79A polymorphism of protein Z gene was higher in patients than controls, and carrying 79 AA genotype could be a risk factor for severe sepsis and septic shock.

How I treat rare venous thromboses

Venous thromboembolism may involve venous sites other than the lower limbs, such as cerebral, splanchnic, and upper limb veins. Although uncommon, these thromboses may be clinically severe and challenging for caregivers. In this review, the main pathogenic, clinical, and therapeutic features of thromboses in rare venous sites are discussed. Even though there was a lot of recent progress in understanding the mechanistic role of inherited and acquired thrombophilia and of the interactions between different risk factors, the optimal management of these patients is still unsettled, being currently based on the consensus of experts due to the lack of randomized trials. The implementation of large interdisciplinary registries is a necessary weapon to optimize the treatment of rare venous diseases.

The G79A polymorphism of protein Z gene is an independent risk factor for cerebral venous thrombosis

BACKGROUND AND PURPOSE

Protein Z (PZ), a vitamin Kdependent protein, plays a role in inhibiting coagulation. Its plasma level or PZ gene polymorphisms have been discussed as risk factors for stroke with conflicting results reported between various studies. Only one of these polymorphisms was studied in a cohort of patients suffering from cerebral venous thrombosis (CVT).

METHODS

We performed a retrospective genetic study comparing 100 healthy controls to 54 patients referred to our hemostasis unit after CVT occurrence. We compared the distribution of three PZ gene polymorphisms that may influence PZ plasma levels: A-13G in the promoter and G79A in intron F were tested using previously described techniques, and we developed a technique to evaluate the G-103A in intron A.

RESULTS

The G79A polymorphism was significantly more frequent in patients than in controls (p = 0.012): the presence of at least one A allele led to an odds ratio of 2.57 with a 95 % confidence interval of 1.23-5.34. The A-13G polymorphism also showed a nonsignificant trend towards a higher prevalence in patients.

CONCLUSION

The G79A polymorphism of the PZ gene was shown to be a new independent risk factor for cerebral venous thrombosis. Nevertheless, these results have to be confirmed by a prospective study including plasma PZ evaluation.

Association of the protein Z intron F G79A gene polymorphism with recurrent pregnancy loss

OBJECTIVE

To investigate the association of the common protein Z (PZ) intron F G79A gene polymorphism with recurrent early pregnancy loss (RPL) and its gene-gene interaction with known thrombophilic risk factors for RPL.

DESIGN

Case control study.

SETTING

University clinic.

PATIENT(S)

We enrolled 49 women with a history of two consecutive or three to six nonconsecutive pregnancy losses between the 8th and 12th weeks of gestation and 48 age-matched parous controls without a history of pregnancy complications.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Allele frequencies of the PZ intron F G79A polymorphism and its gene-gene interaction with known risk factors for RPL.

RESULT(S)

Fourteen case subjects (28.6%) and 24 control subjects (50.0%) carried at least one A allele. This was associated with a significant reduction of the relative risk for recurrent pregnancy loss (odds ratio [OR] 0.4, 95% confidence interval [CI] 0.2-0.9; adjusted OR 0.3, 95% CI 0.1-0.8). Coexistence of any thrombophilic risk factor studied with the 79A allele resulted in a clear reduction of the primal relative risk for recurrent pregnancy loss.

CONCLUSION(S)

The isolated presence of the PZ intron F 79A allele as well as the combination with known thrombophilic risk factors was protective against RPL between the 8th and 12th weeks of gestation.

Advances in the Genetic Basis of Ischemic Stroke

As one of the leading causes of death within both the developed and developing world, stroke is a world-wide problem. About 80% of strokes are ischemic. It is caused by multiple genetic factors, environmental factors, and interactions among these factors. There is a long list of candidate genes that have been studied for a possible association with ischemic stroke. Among the most widely investigated genes are those involved in haemostasis, inflammation, nitric oxide production, homocysteine and lipid metabolism, renin-angiotensin-aldosterone system. Combined link-age/association studies have demonstrated that genes encoding PDE4D and ALOX5AP confer risk for stroke. We review the studies of these genes which may have potential application on the early diagnosis, prevention and treatment ischemic stroke patients.

Thrombosis of sinus sagitalis during puerperium caused by thrombophilic gene mutation

Cerebral veno-sinus thrombosis (CVT) during puerperium may have fatal consequences. A nonspecific clinical picture must be complete with computed tomography of the brain and digital substract angiography of the brain blood vessels, and, once the clinical diagnosis is confirmed, coagulation tests and genetic analysis of the coagulation factor are to be made as well. Genetic polymorphisms associated with thrombophilia such as factor V Leiden, prothrombin G20210A, MTHFR C677T, ACE and PIA1/A2 may be the cause of the hypercoagulability that results in CVT.

The prothrombin gene G20210A variant and puerperal cerebral venous and sinus thrombosis in South Indian women

Pregnancy and puerperium raise the risk of thrombotic events, and these risks are likely to be increased in women who are carriers of thrombophilic gene polymorphisms. Prothrombin G20210A variant is reported to be the second most frequent prothrombotic polymorphism in Caucasians. Our aim was to determine the prevalence of this variant in south Indian women and examine its association with cerebral venous and sinus thrombosis occurring during puerperium. We investigated 96 women with puerperal cerebral veno-sinus thrombosis (CVT) and 103 age-matched women with no post-partum complications. We used restriction fragment length polymorphism analysis to identify their genotypes. The prothrombin G20210A variant was not detected in either the CVT patients or the healthy control subjects. Our study on a large series of patients with puerperal CVT shows that the prothrombin G20210A variant is not present in south Indian women and is not associated with puerperal CVT. This study also highlights the fact that there are racial differences in the risk factors for thrombosis, which should be considered when investigating these patients.

Genetics of coagulation: considerations for cardiac surgery

Genetic variants in the coagulation system have been known since antiquity. Today, because of modern improvements in diagnosis and medical management, the clinician is likely to encounter a spectrum of coagulation factor deficiencies and identified polymorphic variants in the surgical population. Because perioperative hemorrhagic and thrombotic complications are potentially serious, it is important to understand the role that these defects and variants may play in predicting risk and optimizing patient management. The implications of coagulation genetics on the perioperative management of the cardiac surgery patient are reviewed.

Cerebral venous thrombosis: an update

Cerebral venous thrombosis (CVT) is a rare type of cerebrovascular disease that can occur at any age, including in neonates, and it accounts for 0.5% of all stroke. The widespread use of neuroimaging now allows for early diagnosis and has completely modified our knowledge on this disorder. CVT is more common than previously thought and it is recognised as a non-septic disorder with a wide spectrum of clinical presentations, numerous causes, and usually a favourable outcome with a low mortality rate. MRI with T1, T2, fluid-attenuated inversion recovery, and T2* sequences combined with magnetic resonance angiography are the best diagnostic methods. D-dimer concentrations are raised in most patients but normal D-dimers do not rule out CVT, particularly in patients who present with isolated headache. Heparin is the first-line treatment, but in a few cases more aggressive treatments, such as local intravenous thrombolysis, mechanical thrombectomy, and decompressive hemicraniectomy, may be required.

Curiouser and curiouser: recent advances in measurement of thrombin-activatable fibrinolysis inhibitor (TAFI) and in understanding its molecular genetics, gene regulation, and biological roles

The thrombin-activatable fibrinolysis inhibitor (TAFI) pathway defines a novel molecular connection between blood coagulation and both fibrinolysis and inflammation. TAFI is a plasma zymogen that can be activated by thrombin, the thrombin-thrombomodulin complex, or plasmin. The activated form of TAFI (TAFIa) attenuates fibrinolysis by removing the carboxyl-terminal lysine residues from partially degraded fibrin that mediate positive feedback in the fibrinolytic cascade. A role for TAFIa in modulating inflammation is suggested by the ability of this enzyme to down-regulate pericellular plasminogen activation and to inactivate the inflammatory peptides bradykinin and the anaphylatoxins C3a and C5a. The focus of this review is on recent advances in the clinical measurement of the TAFI pathway in human subjects and what this has revealed in terms of the molecular genetics of TAFI, the biological variation in plasma TAFI antigen levels, potential regulators of expression of the gene encoding TAFI, and the TAFI pathway as a risk factor for the development of vascular diseases. Although this field is in its infancy, much recent progress has been made and the available data suggest that the TAFI pathway is an intriguing new player in a variety of physiological and pathophysiological contexts.

Thrombophilic gene polymorphisms in puerperal cerebral veno-sinus thrombosis

Puerperal cerebral veno-sinus thrombosis (PCVT) is a common form of stroke in young women in India, which is associated with high morbidity and mortality. The frequency of PCVT in India is 10 to 12 times more compared to western population. As yet, the etiology of this condition is unclear. Our aim was to study the prevalence and the role of the common genetic polymorphisms associated with thrombophilia such as factor V Leiden, prothrombin G20210A and methylene tetrahydrofolate reductase (MTHFR) C677T, in aseptic PCVT. We investigated 86 women with PCVT and 86 age-matched women with no post-partum complications. Polymerase chain reaction (PCR)/restriction fragment length polymorphism analysis was used to identify their genotypes. The frequency of the three polymorphisms in cases and controls were: factor V Leiden, 2.3% versus 1.2% (OR 0.49, 95% CI=0.02-7.12, p=1.000) and MTHFR C677T, 16.3% versus 17.4% (OR 0.92, 95% CI=0.39-2.19, p=0.838). The prothrombin G20210A variant was not detected in either patients or controls. The clinical characteristics of the PCVT patients with the polymorphisms did not differ significantly from those without them. In our series of PCVT patients, the risk associated with the established thrombophilic risk factors is insignificant. Exploration of these gene polymorphisms seems to be of limited value in the investigation of PCVT in south Indian women.