Thrombophilia, polymorphisms, and vascular disease

Spontaneous miscarriage driven by maternal genetic mutation at position of PAI-1-844G/A: shed light on a race-specific genetic polymorphism

OBJECTIVE

Association between a genetic polymorphism and disease, either positively or negatively, within a population may not necessarily predict association in other race-ethnic populations. The aim of this study was to genotype well recognized thrombophilia associated polymorphisms as common risk factors for miscarriage and investigate their benefit to use as risk factors in southwest region of Iran females (Khuzestan) in the Arabs ethnic minority group with spontaneous miscarriage. We developed a Reverse Dot Blot Assay for the genotyping of four polymorphisms.

RESULTS

There were significant differences in the genotype distribution and allelic frequencies of the MTHFR 1298 A > C, MTHFR 677 C > T, Factor V Leiden 1691 G > A, PAI-1-844G > A polymorphisms between the case and control groups. The MTHFR 1298 A > C, MTHFR 677 C > T and Factor V Leiden 1691 G > A polymorphisms were significantly associated with spontaneous miscarriage risk. Unlike some other race-ethnic populations, PAI-1-844G > A polymorphism was associated with risk of developing unplanned miscarriage in Iranian Arabs ethnic minority group females.

Candidate genes related to acute cerebral circulatory disorders in Preeclampsia in the Kazakh Population

BACKGROUND

The purpose of this study is to conduct a comparative analysis of the population frequencies of alleles and genotypes of polymorphic variants of coagulation and fibrinolysis genes SERPINE1 rs1799889, ITGA2 rs1126643, THBD rs1042580, FII rs1799963, FV rs6025, FVII rs6046, angiogenesis and endothelial dysfunction PGF rs12411, FLT1 rs4769612, KDR rs2071559, ACE rs4340, GWAS associated with the development of acute cerebral circulatory disorders in preeclampsia, in an ethnically homogeneous population of Kazakhs with previously studied populations of the world.

METHODS

The genomic database was analysed based on the results of genotyping of 1800 conditionally healthy individuals of Kazakh nationality ∼2.5 million SNPs using OmniChip 2.5 M Illumina chips at the DECODE Iceland Genomic Center as part of the joint implementation of the project "Genetic Studies of Preeclampsia in Populations of Central Asia and Europe" (InterPregGen) within the 7th Framework Programme of the European Commission under Grant Agreement No. 282540.

RESULT

The study discovered a significantly higher population frequency of carrying the unfavorable rs1126643 allele of the ITGA2 gene polymorphism when compared with European populations. The population frequencies of carrying minor alleles of the SERPINE1 (rs179988) and KDR (rs2071559) genes in the Kazakh population were significantly lower when compared with the previously studied populations of Europe and Asia. An intermediate frequency of unfavorable minor alleles between European and Asian populations was found in Kazakhs for gene polymorphisms: FV rs6025, PGF rs12411, and ACE rs4340. The genomic analysis determined the choice of polymorphisms for their further replicative genotyping in patients with ACCD in PE in the Kazakh population.

CONCLUSION

The obtained results will serve as a basis for the development of effective methods of early diagnosis and treatment of PE in pregnant women, carriers of unfavorable genotypes.

Prevalence of rare F5 variants in general population from Bosnia and Herzegovina

Human gene F5, encoding coagulation factor V, was previously reported to be highly polymorphic. Apart from FV Leiden, several other rare variants have been detected in clinical practice and associated with thrombotic events, especially in cases when patient's phenotype and FV Leiden genotype were not in agreement. In this study, the prevalence of 17 rare F5 variants has been studied on a sample of 130 healthy adult individuals from the general Bosnian-Herzegovinian population. DNA was isolated from buccal swab samples, while genotyping was performed using MALDI-TOF MS method. The results have shown that Asp2194Gly and Met2120Thr are polymorphic in the study population with minor allele frequencies of 0.077 and 0.073, respectively. Additionally, these two variants were mutually exclusive with FV Leiden and none of them was positively associated with participants' family history of cardiovascular or cerebrovascular diseases. While the obtained results are in agreement with previously reported data for the general Caucasian populations, it is worth noting that only two rare F5 variants were detected in the study population, albeit at considerable frequencies. Still, scientific information on rare F5 variants is rather scarce and further studies aiming to assess functional importance of these variants, as well as their role as prothrombotic factors are necessary.

Prothrombotic Factors Have Significant Association with Arterial and Venous Strokes in Indian Tamilians

BACKGROUND

Prothrombotic factors have been correlated with vascular events in young patients, with recurrent strokes, and with venous thromboembolisms. However, their prevalence in adult strokes, in healthy populations, and in specific ethnic groups is not well defined. We investigated the association of prothrombotic factors with strokes in a South Indian Tamil population.

METHODS

In this hospital-based cross-sectional study, plasma homocysteine (Hcys), protein C and protein S activity levels, activated protein C resistance (APCR) as a surrogate for factor V Leiden (FVL), fibrinogen, and antithrombin III (ATIII) were determined from 75 consecutive patients with ischemic stroke (IS), 25 with cortical venous thrombosis (CVT), and 75 healthy control participants. The Student t test or Mann-Whitney U test was used for comparing prothrombotic factor levels between the stroke and control groups. The χ2 or Fisher exact test was used for comparisons of proportions of thrombophilia and estimation of odds ratios. Mid-P correction was done for multiple estimations.

RESULTS

Hcys levels in patients with IS were significantly higher compared with those in healthy control participants (P = 0.02). Proportions of ATIII deficiency and hyperfibrinogenemia were significantly higher in the IS group, and no healthy control participants had hyperfibrinogenemia. Protein C deficiency was more frequent in those with IS (17%; P < 8 × 10-5) and CVT (P < 10-7) compared with healthy control participants, and protein C activity levels (P = 0.016) were also significantly lower in patients with CVT. Other parameters had no significant associations with IS and CVT. The frequency of protein S deficiency was high in healthy control participants (60%) and in both patients with IS (45%; P = 0.1) and patients with CVT (48%; P = 0.4). No patients or control participants had abnormal APCR.

CONCLUSIONS

In Tamilian participants, several prothrombotic factors were associated with IS. Protein C deficiency alone was associated with CVT. Replication of the pattern in genetically linked populations around the world may affect management of stroke in those populations.

Population study of thrombophilic markers and pharmacogenetic markers of warfarin prevalence in Bosnia and Herzegovina

AIM

To investigate the prevalence of common genetic variants that can serve as markers of thrombophilia and warfarin pharmacogenetics in Bosnia and Herzegovina.

METHODS

The study was performed between August and October 2017 on 130 healthy unrelated adult volunteers from Bosnian-Herzegovinian population sample. The prevalence of the following genetic variants was determined: F5 c.1601G>A (factor V Leiden), F2 c.*97G>A (factor II or prothrombin mutation), F13A1 (factor XIII) c.103G>T, MTHFR (methylenetetrahydrofolate reductase) c.665C>T and c.1286A>C, as well as PAI-1 (plasminogen activator inhibitor 1) c.-816A>G and c.-844G>A as markers of thrombophilia risk, and *2 and *3 alleles of CYP2C9 (cytochrome P450 2C9) and five variants of VKORC1 (vitamin K epoxide reductase complex subunit 1) as markers of warfarin pharmacogenetics. DNA was isolated from buccal swabs using salting out method, while genotyping was performed using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry.

RESULTS

Minor allele frequencies for two main thrombophilia risk factors, F5 c.1601G>A and F2 c.*97G>A were 0.023 and 0.008, respectively. Combined data for the markers of warfarin pharmacogenetics imply that 57.4% study participants can be expected to metabolize warfarin at an extensive, 40.3% at intermediate, and 2.3% at a poor rate.

CONCLUSION

This study reports the first extensive population genetic data for thrombophilia and warfarin pharmacogenetic markers in Bosnia and Herzegovina. Allele frequencies of genetic variants are within the general average for European populations, and their presence implies the necessity of introduction of personalized medicine in warfarin-mediated antithrombotic therapy.

[The association of hemostasis system genes with the development of ischemic stroke in patients under the age of 50 years]

AIM

To study an influence of polymorphic variants of hemostasis system genes on the risk of ischemic stroke (IS) in patients of the Slavic population under the age of 50 years.

MATERIAL AND METHODS

Ninety-two patients (19 women and 73 men), aged 18-50 years, were examined. The diagnosis of stroke was confirmed by neuroimaging (CT or MRI) in all patients. Polymorphic alleles of GP1BA, F2, F5 were studied by a real-time polymerase chain reaction using the TaqMan technology.

RESULTS AND CONCLUSION

An analysis of the GP1BA -5T/C polymorphism showed that it was associated with IS in young men, lacunar stroke and stroke due to thrombosis of the brachiocephalic arteries. This association was not found in young women. The F5 G1691A polymorphism was associated with lacunar stroke. The F2 G20210A polymorphism was associated with stroke due to thrombosis of the brachiocephalic arteries.

Genetics of ischaemic stroke in young adults

Background

Stroke may be a clinical expression of several inherited disorders in humans. Recognition of the underlined genetic disorders causing stroke is important for a correct diagnosis, for genetic counselling and, even if rarely, for a correct therapeutic management. Moreover, the genetics of complex diseases such the stroke, in which multiple genes interact with environmental risk factors to increase risk, has been revolutionized by the Genome-Wide Association Study (GWAS) approach.

Scope of review

Here we review the single-gene causes of ischemic stroke, bringing the reader from the candidate gene method toward the exciting new horizons of genetic technology.

Major conclusions

The aetiological diagnosis of ischemic stroke in young adults is more complex than in the elderly. The identification of a genetic cause is important to provide appropriate counseling and to start a correct therapy, when available. The advent of GWAS technology, such as for other complex pathological conditions, has contributed enormously to the understanding of many of these genetic bases. For success large, well phenotyped case cohorts are required, and international collaborations are essential.

General significance

This review focuses on the main causes of genetically-based ischemic stroke in young adults, often classified as indeterminate, investigating also the recent findings of the GWAS, in order to improve diagnostic and therapeutic management.

•

The aetiological diagnosis of stroke in young adults needs a different and more complex diagnostic work up than in older adults.

•

Stroke may be a clinical expression of several inherited disorders in humans.

•

The most common genetic causes of stroke are CADASIL, Fabry and mitochondrial diseases.

•

Recognition of the underlined genetic disorders causing stroke is important for the correct management of the patient.

Polymorphisms in thrombophilic genes are associated with deep venous thromboembolism in an Iranian population

It has been revealed that the inherited thrombophilia increases the risk of thrombosis in the venous system. To study the association of factor V G1691A, factor V HR2 (4070A/G), prothrombin G20210A, and PAI-1 (- 675 I/D, 5G/4G) polymorphisms with deep venous thromboembolism (DVT), these polymorphisms were investigated. A total of 193 patients who presented clinical symptoms of deep venous thromboembolism including 103 men and 90 women, and 500 healthy individuals without both personal and family histories of thromboembolic disorders including 275 men and 225 women were recruited into the study. Genotyping was carried out using the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) technique. Our results showed that the genotype distribution for FV (G1691A and A4070G) and PAI-1 4G/5G polymorphisms in DVT patients were significantly higher than healthy control (P < 0.05). Also, the mutant allele frequencies for all studied polymorphisms differed significantly between the case and control groups (P < 0.05). We concluded that the prevalence of FV (G1691A and A4070G) and PAI-1 4G/5G polymorphisms increased the risk of DVT occurrence in subjects. These findings provide additional evidence to support the hypothesis that thrombophilic gene polymorphisms are involved in vascular thromboembolism.

Residual vein thrombosis and onset of post-thrombotic syndrome: influence of the 4G/5G polymorphism of plasminogen activator inhibitor-1 gene

BACKGROUND

Plasminogen activator inhibitor-1 (PAI-1) is the most important inhibitor of plasminogen activator. The functional 4G/5G polymorphism of the gene coding for PAI-1 may affect PAI-1 plasmatic activity, influencing the imbalance between coagulation and fibrinolysis cascades. In this prospective cohort analytic study, we investigated the role of this single nucleotide polymorphism in the persistence of thrombotic lesion and the occurrence of post-thrombotic syndrome.

PATIENTS/METHODS

In a group of 168 patients with post-surgical deep vein thrombosis of the legs, we analyzed the 4G/5G polymorphism in the promoter of PAI-1 gene and plasmatic PAI-1 activity. Enrolled patients were divided in two groups: patients with 4G/5G polymorphism and increased PAI-1 activity (n=85) and patients without 4G/5G polymorphism and normal PAI-1 activity (n=83). All patients were treated according to current protocols and re-examined after 3, 12 and 36 months in order to evaluate the persistence of thrombotic lesion and the occurrence of post-thrombotic syndrome.

RESULTS

We found a significantly increased PAI activity in carrier of the 4G allele, who experienced much more frequently a persistence of thrombosis after 3, 12 and 36 months and/or the development of post-thrombosis syndrome, in spite of the anticoagulant treatment.

CONCLUSIONS

These data not only confirm the role played by PAI-1 activity and by the 4G/5G SNP of the PAI-1 gene, but also suggest that current therapeutic protocols, recommending the administration of low weight molecular heparin and oral anticoagulant for the treatment of deep vein thrombosis, could be non sufficient for patients genetically predisposed to a less efficient clot lysis.

Genetic polymorphisms for the study of multifactorial stroke

Single-gene disorders explain only a minority of stroke cases. Stroke represents a complex trait, which is usually assumed to be polygenic. On this topic, the role of a wide number of candidate genes has been investigated in stroke through association studies, with controversial results. Therefore, it is difficult for the clinician to establish the validity and the level of clinical applicability of the previously reported associations between genetic factors and stroke. This review is an update and an extensive analysis of the more recent association studies conducted in stroke. We evaluated a number of studies on several candidate genes (including F5, F2, FGA/FGB/FGG, F7, F13A1, vWF, F12, SERPINE1, ITGB3/PLA1/PLA2/ITGA2B, ITGA2, GP1BA, ACE, AGT, NOS3, APOE, LPL, PON1, PDE4D, ALOX5AP, MTHFR, MTR, and CBS), providing a final panel of genes and molecular variants. We categorized this panel in relation to the degree of association with stroke, supported by the results of meta-analyses and case-control studies. Our findings could represent a useful tool to address further molecular investigations and to realize more detailed meta-analyses.

Inherited Thrombophilia in Arterial Disease: A Selective Review

Thrombophilia may be defined as an acquired or congenital abnormality of hemostasis predisposing to thrombosis. Because arterial thrombosis is usually linked with classical risk factors such as smoking, hypertension, dyslipidemia, or diabetes, a thrombophilia workup is usually not considered in case of arterial thrombosis. The most accepted inherited hemostatic abnormalities associated with venous thromboembolism are factor V Leiden (FVL) and factor II (FII) G20210A mutations, as well as deficiencies in antithrombin (AT), protein C (PC), and protein S (PS). This review focuses on the link between these abnormalities and arterial thrombosis. Overall, the association between these genetic disorders and the three main arterial complications (myocardial infarction [MI], ischemic stroke [IS], and peripheral arterial disease [PAD]) is modest. Routine screening for these disorders is therefore not warranted in most cases of arterial complications. However, when such an arterial event occurs in a young person, inherited abnormalities of hemostasis seem to play a role, particularly when associated with smoking or oral contraceptive use. These abnormalities also seem to play a role in the risk of premature occlusion after revascularization procedures. Therefore thrombophilia tests may be informative in a very restricted population with arterial events. Anticoagulants rather than antiplatelet therapy may be preferable for these patients, although this remains to be proven.

Comparative aspects of blood coagulation

Blood coagulation is a basic physiological defense mechanism that occurs in all vertebrates to prevent blood loss following vascular injury. In all species the basic mechanism of clot formation is similar; when endothelium is damaged a complex sequence of enzymatic reactions occurs that is localized to the site of trauma and involves both activated cells and plasma proteins. The reaction sequence is initiated by the expression of tissue factor on the surface of activated cells and results in the generation of thrombin, the most important enzyme in blood clot formation. Thrombin converts soluble fibrinogen, via soluble fibrin monomers, into the insoluble fibrin that forms the matrix of a blood clot as well as exerting positive-feedback regulation that effectively promotes additional thrombin generation that facilitates the rapid development of a thrombus. Both spontaneous and trauma-induced haemorrhagic episodes can develop in all mammals with inherited or acquired abnormalities in one or more of the coagulant proteins. Experimental studies with plasma from a wide range of species have led to the conclusion that there are extensive differences in the rates of thrombin generation and fibrin formation among species. However, current evidence suggests that at least some of these quantitative differences are likely due to the use of non-species specific laboratory reagents. Although the individual proteins involved in the procoagulant pathways exhibit similar functions in all animals, differences in amino acid sequence cause incomplete homology and varying degrees of immunological cross-reactivity for the same protein across species.

Primary thrombophilia in Mexico. V. A comprehensive prospective study indicates that most cases are multifactorial

Over a 36-month period, 46 consecutive Mexican mestizos with a clinical marker associated with a primary hypercoagulable state were prospectively assessed by searching for the sticky platelet syndrome (SPS), the activated protein C resistance (aPCR) phenotype, coagulation protein C activity and antigen, coagulation protein S, antithrombin III, plasminogen, tissue-type plasminogen activator activity, plasminogen activator inhibitor activity, plasminogen activator inhibitor type 1, IgG and IgM isotypes of antiphospholipid antibodies, homocysteine levels, the factor V gene Leiden, Cambridge, Hong Kong, and Liverpool mutations, the 677 C-->T mutation in the 5,10-methylenetetrahydrofolatereductase (MTHFR), and the G20210A polymorphism in the 3'-untranslated region of the prothrombin gene. Of the 46 consecutive patients prospectively accrued in the study, only 12 (26%) were males, the median age being 38 years (range 10-63 years). In only four individuals (8%) could we not record any abnormality. In 5/42 patients with abnormal results (12%), a single abnormality was recorded, whereas in the remaining 37, two to five co-existing abnormalities were identified. We found 22 (48%) patients with the SPS, 11 (24%) with the aPCR phenotype, 5 (11%) with the factor V Leiden mutation, 7 (15%) with the prothrombin gene mutation, 29 (63%) with the MTHFR gene mutation, 11 (24%) with the factor V HR2 haplotype, 11 (24%) with antiphospholipid antibodies, 4 (9%) with PS deficiency, 6 (13%) with PC deficiency, one with the FV Hong Kong mutation, and one with AT-III deficiency. The results are consonant with the idea that most cases of thrombophilia in Mexico are multifactorial.

Genetic thrombophilia

The genetic thrombophilias are an important cause of venous thrombotic events. Much has been learned about the natural history of these disorders, their genetics, and, to a lesser degree, their treatment. This article provides an overview of the genetics of thrombophilia. Specific information on the factor V Leiden mutation;the prothrombin G20210A mutation; and protein C, proteinS, and antithrombin deficiency is reviewed. Current testing and treatment options for the genetic thrombophilias also are discussed.

Polymorphisms in the 5'-UTR of the tissue factor gene are associated with altered expression in human endothelial cells

BACKGROUND

Enhanced tissue factor (TF) expression mediates many disease processes. Recently, four completely concordant polymorphisms were detected in the 5'-UTR of the TF gene. Three were single base changes and one was an 18-bp insertion/deletion at -1208.

OBJECTIVES

This study was undertaken to determine if the I-allele or the D-allele would associate with elevated TF expression in human umbilical vein endothelial cells (HUVEC).

METHODS

HUVEC were genotyped by polymerase chain reaction for 18-bp insert status. TF expression was induced by interleukin (IL)-1 or phorbol 12-myristate 13-acetate (PMA). Total TF activity was determined by a one-stage clotting assay and surface TF activity by a chromogenic assay. Protein binding differences between the I- and D-alleles were examined by gel shift assays.

RESULTS

IL-1- or PMA-induced total TF activity in D-allele HUVEC was increased 2.0-2.5-fold above that seen in II HUVEC. Surface clotting activity in D-allele cells was 1.3-1.7-fold greater than in II-allele cultures. Experiments with consensus site mutation oligos suggested that the 18-bp insert creates GATA and CCAAT-enhancer binding protein (C/EBP) transcription factor recognition sites.

CONCLUSIONS

The D-allele is associated with enhanced TF activity in HUVEC. The differences in TF expression between the alleles may be due to variant transcription factor binding in the -1208 region. Further studies are warranted to investigate whether the D-allele is associated with increased incidence of pathological processes that involve TF.

The coagulation system

Congenital and acquired hypercoagulable states arise from an imbalance between procoagulant and anticoagulant activity. Although these imbalances are present throughout the entire vascular tree, thrombotic lesions are usually localized in discrete segments of the veins or arteries and in certain organ systems. Thus, hypercoagulable states are likely to be associated with focal defects in the vascular wall to produce thrombosis. Many recently described factors are associated with hypercoagulability. Because thrombosis is a disease in which genetic and acquired risk factors interact dynamically, a thorough history, family history, and physical examination should be performed before ordering an extensive and costly coagulation panel.

Thrombophilia and chronic venous ulceration

It is known that thrombophilia (TP) is a risk factor for deep venous thrombosis (DVT), and that DVT predisposes to chronic venous ulceration (CVU). However, the relationship between TP and CVU has not been well studied. Review of the literature reveals that the prevalence of TP in CVU patients is high--similar to the prevalence found in patients with a history of DVT. This is despite many patients with CVU having no clear history, or duplex evidence of previous DVT. TP may predispose to CVU by leading to macro- or micro-vascular thrombosis. This association raises several issues regarding the investigation, prevention and management of patients with venous disease.