Factor VII gene polymorphism, factor VII levels, and prevalent cardiovascular disease: the Framingham Heart Study

The Association of Different Genetic Variants with the Development of Hypoxic-Ischemic Encephalopathy

The aim of this study is to investigate the frequency of six tag SNPs (single nucleotide polymorphisms) within specific genes (F2, F5, F7, MTHFR, NOS2A, PAI 2-1, PAI 2-2, and PAI 3-3): F2 (rs1799963), F5 (rs6025), F7 (rs6046), NOS 2 (rs1137933), PAI 2 (SERPINB2) (rs6103), MTHFR (rs1801133). The study also investigates their association with the development and severity of HIE. The genes F2, F5, and F7 code for proteins involved in blood clotting. MTHFR is a gene that plays a significant role in processing amino acids, the fundamental building blocks of proteins. NOS2A, PAI 2-1, PAI 2-2, and PAI 3-3 are genes involved in the regulation of various physiological processes, such as the relaxation of smooth muscle, regulation of central blood pressure, vasodilatation, and synaptic plasticity. Changes in these genes may be associated with brain injury. This retrospective study included 279 participants, of which 132 participants had Hypoxic-Ischemic Encephalopathy (HIE) and 147 subjects were in the control group. Our study found that certain genetic variants in the rs61103 and rs1137933 polymorphisms were associated with hypoxic-ischemic encephalopathy (HIE) and the findings of the magnetic resonance imaging. There was a correlation between Apgar scores and the degree of damage according to the ultrasound findings. These results highlight the complex relationship between genetic factors, clinical parameters, and the severity of HIE.

Quantile-specific heritability of plasminogen activator inhibitor type-1 (PAI-1, aka SERPINE1) and other hemostatic factors

BACKGROUND

Plasminogen activator inhibitor type-1 (PAI-1, aka SERPINE1) is a moderately heritable glycoprotein that regulates fibrin clot dissolution (fibrinolysis).

OBJECTIVES

Test whether the heritabilities (h2 ) of PAI-1 and other hemostatic factors are constant throughout their distribution or whether they are quantile-specific (i.e., a larger or smaller h2 depending on whether their concentrations are high or low).

METHODS

Quantile regression was applied to 5606 parent-offspring pairs and 5310 full siblings of the Framingham Heart Study. Quantile-specific heritability was estimated from the parent-offspring regression slope (βPO , h2  = 2βPO /(1+rspouse )) and the full-sib regression slope (βFS , h2  = {(1+8rspouse βFS )0.5 -1}/(2rspouse )).

RESULTS

Heritability (h2  ± SE) increased significantly with increasing percentiles of the offspring's age- and sex-adjusted PAI-1 distribution when estimated from βPO (plinear trend  = 0.0001): 0.09 ± 0.02 at the 10th, 0.09 ± 0.02 at the 25th, 0.16 ± 0.02 at the 50th, 0.29 ± 0.04 at the 75th, and 0.26 ± 0.08 at the 90th percentile of the PAI-1 distribution, and when estimated from βFS (plinear trend  = 6.5x10-7 ). There was no significant evidence for quantile-specific heritability for factor VII (plinear trend  = 0.35), D-dimer (plinear trend  = 0.08), tPA (plinear trend  = 0.74), or von Willebrand factor (plinear trend  = 0.79).

CONCLUSION

Higher mean plasma PAI-1 antigen concentrations tend to accentuate genetic effects (quantile-dependent expressivity), which is consistent with the greater reported differences in PAI-1 concentrations between rs1799889 SERPINE1 (4G/5G) genotypes in patients with osteonecrosis, meningococcal sepsis, obesity, prior myocardial infarction, deep vein thrombosis, and polycystic ovarian syndrome than in healthy controls. It is also consistent with the greater increases in PAI-1 concentrations in 4G-allele carriers than 5G/5G homozygotes following fibrinolytic treatment, low-salt intake, and high saturated fat intake.

The impact of R353Q genetic polymorphism in coagulation factor VII on the initial anticoagulant effect exerted by warfarin

BACKGROUND

The initial rise in INR following warfarin is attributed to rapid decline in coagulation factor VII (F7). The R353Q polymorphism in F7 accounts for approximately 1/3 of the variability in F7 activity (FVIIc).

OBJECTIVE

Evaluate the role of R353Q in the initial response to warfarin.

METHODS

Twenty-eight healthy, males, carrying CYP2C9*1/*1 (n = 14), CYP2C9*1/*2 (n = 4) or CYP2C9*1/*3 (n = 10) genotypes, received single 20 mg warfarin. S&R-warfarin concentrations, INR, and FVIIc were monitored periodically for 7 days.

RESULTS

Baseline and maximal INR were 5.6% and 33.5% higher among carriers of the RQ (n = 12) as compared with those carrying the RR (n = 16) genotype (p = 0.032, p = 0.003, respectively). Baseline and nadir FVIIc were 21.6% and 42.0% lower among subjects carrying the RQ as compared with carriers of the RR genotype (p = 0.001, p = 0.007 respectively). In multiple regression analysis, R353Q predicted 36.6% of the variability in peak INR whereas 20.2%, 9.9%, and 5.9% were attributed to VKORC1 genetic polymorphism, cholesterol concentration, and S Warfarin concentration after 24 h, respectively.

CONCLUSIONS

R353Q genetic polymorphism plays a key role in determining the initial response to warfarin. The incorporation of this genetic variant into warfarin loading algorithm should be further investigated.

Factor VII deficiency - an enigma; clinicohematological profile in 12 cases

OBJECTIVE

Factor VII deficiency is the commonest of the rare bleeding disorders with limited knowledge on clinical profile. The objective of this study was to study the prevalence and clinico-hematological profile of factor VII-deficient patients.

METHODS

It is a retrospective observational study of probable inherited factor VII deficiency covering 18 months. Their clinical profile, family history, investigation and treatment records were studied in detail.

RESULTS

The study group comprised of total 12 factor VII deficiency cases with mean age of 17.5 years of onset of symptoms. The commonest symptom was menorrhagia (41.6%) followed by epistaxis (25%) and easy bruisability (16.6%). These 12 patients when categorized according to bleeding severity: severe bleeding - 2, moderate bleeding - 3, mild bleeding - 6 and asymptomatic - 1. All cases had prolonged prothrombin time (PT) with mean PT of 35.4 seconds (range 18-50 seconds) and mean prolongation of PT from upper limit of normal - 19.4 seconds (range 2-34 seconds). Factor VII levels ranged from < 1-40% in these patients. Clinical symptoms were not in concordance with factor levels. Of 12 patients, required treatment other than local measures.

DISCUSSION AND CONCLUSION

Inherited factor VII deficiency is the commonest autosomally inherited factor deficiency with marked variation in the age of presentation and clinical symptoms. The laboratory results in form of PT and factor VII levels do not correlate with the severity of clinical presentation. A comprehensive evaluation to exclude acquired causes of factor VII deficiency, e.g. obesity, liver diseases, vitamin K deficiency and acquired inhibitors is required before labeling it as inherited in the absence of family history and molecular studies.

Factor VII levels, R353Q and -323P0/10 Factor VII variants, and the risk of acute coronary syndrome among Arab-African Tunisians

The importance of the extrinsic haemostatic system, of which factor VII/VIIa (FVII/FVIIa) is a key constituent, in acute coronary syndrome (ACS) is well recognized. The contribution of FVII gene variants R353Q and -323P0/10, and altered FVII plasma levels to the risk of ACS was investigated in a North African Tunisian Arab cohort consisting of 308 ACS cases and 312 age-, gender- and ethnically-matched control subjects; FVII antigen levels were determined by ELISA. Regression analysis was used in assessing the association of FVII variants and changes in FVII levels to the overall risk of ACS. Significantly higher FVII antigen levels were seen in ACS patients (P < 0.001), and were associated with ACS and with ACS severity, and this association was confirmed by multivariate regression analysis, after adjusting for a number of confounders (BMI, smoking, systolic blood pressure, hypertension, diabetes, and glucose, cholesterol, and triglycerides levels). While the carriage of 353Q allele, was associated with significant reduction in FVII plasma levels, the distribution of the R353Q genotypes was comparable between cases and control subjects, thereby indicating that altered FVII levels, independent of R353 variant, were associated with increased risk of ACS. In contrast, the -323Ins variant, while not associated with altered FVII plasma levels, was associated with ACS, following adjustment for BMI, smoking, systolic blood pressure, hypertension, diabetes, and glucose, cholesterol, triglycerides and FVII levels. In summary, elevated FVII levels, and the -323P0/10 but not R353Q polymorphism, constitute risk factors for ACS.

Linkage analysis identifies a locus for plasma von Willebrand factor undetected by genome-wide association

The plasma glycoprotein von Willebrand factor (VWF) exhibits fivefold antigen level variation across the normal human population determined by both genetic and environmental factors. Low levels of VWF are associated with bleeding and elevated levels with increased risk for thrombosis, myocardial infarction, and stroke. To identify additional genetic determinants of VWF antigen levels and to minimize the impact of age and illness-related environmental factors, we performed genome-wide association analysis in two young and healthy cohorts (n = 1,152 and n = 2,310) and identified signals at ABO (P < 7.9E-139) and VWF (P < 5.5E-16), consistent with previous reports. Additionally, linkage analysis based on sibling structure within the cohorts, identified significant signals at chromosome 2q12-2p13 (LOD score 5.3) and at the ABO locus on chromosome 9q34 (LOD score 2.9) that explained 19.2% and 24.5% of the variance in VWF levels, respectively. Given its strong effect, the linkage region on chromosome 2 could harbor a potentially important determinant of bleeding and thrombosis risk. The absence of a chromosome 2 association signal in this or previous association studies suggests a causative gene harboring many genetic variants that are individually rare, but in aggregate common. These results raise the possibility that similar loci could explain a significant portion of the "missing heritability" for other complex genetic traits.

Contribution of coagulation factor VII R353Q, -323P0/10 and HVR4 polymorphisms to coronary artery disease in Tunisians

We examined the contribution of two factor VII (FVII) bi-allelic (R353Q, -323P0/10) and one tandem repeat (HVR4) polymorphisms to the risk of coronary artery disease (CAD) in Tunisians. Study subjects comprised 308 CAD patients and 312 age-, gender- and ethnically-matched controls. Regression analysis was used in assessing the FVII association to CAD risk. While the distribution of -323P0/10 alleles and genotypes were comparable between cases and controls, marginal association of the R353Q variant was noted, with the Q allele (19.1 vs. 23.8%; P = 0.05) and Q allele-containing genotypes (R/Q + Q/Q; 33.8 vs. 48.0%) being slightly under-represented in cases than in controls. On the other hand, four alleles of FVII microsatellite HVR4 were detected at variable frequencies in Tunisians, and comprised H6 (63.2%), H7 (33.8%), and to lesser extents H5 (1.9%) and H8 (0.8%). Of these, the H7 variant was under-represented in patients [P = 0.038; OR (95%CI) = 0.75 (0.58-0.97)]. Of the major genotypes detected (H6/H6, H6/H7, H7/H7) only H6/H6 was positively associated with CAD [P = 0.047; OR (95%CI) = 1.39 (1.00-1.94)]. In conclusion, our study underscores the role of polymorphisms in the FVII gene in modulating the susceptibility to CAD in (North African) Tunisian Arabs.

Canalization effect in the coagulation cascade and the interindividual variability of oral anticoagulant response. A simulation study

Background

Increasing the predictability and reducing the rate of side effects of oral anticoagulant treatment (OAT) requires further clarification of the cause of about 50% of the interindividual variability of OAT response that is currently unaccounted for. We explore numerically the hypothesis that the effect of the interindividual expression variability of coagulation proteins, which does not usually result in a variability of the coagulation times in untreated subjects, is unmasked by OAT.

Results

We developed a stochastic variant of the Hockin-Mann model of the tissue factor coagulation pathway, using literature data for the variability of coagulation protein levels in the blood of normal subjects. We simulated in vitro coagulation and estimated the Prothrombin Time and the INR across a model population. In a model of untreated subjects a "canalization effect" can be observed in that a coefficient of variation of up to 33% of each protein level results in a simulated INR of 1 with a clinically irrelevant dispersion of 0.12. When the mean and the standard deviation of vitamin-K dependent protein levels were reduced by 80%, corresponding to the usual Warfarin treatment intensity, the simulated INR was 2.98 ± 0.48, a clinically relevant dispersion, corresponding to a reduction of the canalization effect.

Then we combined the Hockin-Mann stochastic model with our previously published model of population response to Warfarin, that takes into account the genetical and the phenotypical variability of Warfarin pharmacokinetics and pharmacodynamics. We used the combined model to evaluate the coagulation protein variability effect on the variability of the Warfarin dose required to reach an INR target of 2.5. The dose variance when removing the coagulation protein variability was 30% lower. The dose was mostly related to the pretreatment levels of factors VII, X, and the tissue factor pathway inhibitor (TFPI).

Conclusions

It may be worth exploring in experimental studies whether the pretreatment levels of coagulation proteins, in particular VII, X and TFPI, are predictors of the individual warfarin dose, even though, maybe due to a canalization-type effect, their effect on the INR variance in untreated subjects appears low.

Association between polymorphisms in the coagulation factor VII gene and coronary heart disease risk in different ethnicities: a meta-analysis

Background

Previous studies have examined the association between polymorphisms in the coagulation factor VII gene and the risk of coronary heart disease (CHD), but those studies have been inconclusive. This study was conducted to assess the associations between these polymorphisms and CHD and evaluated the associations in different ethnicities.

Methods

Literature-based searching was conducted to collect data and two methods, namely fixed-effects and random-effects, were performed to pool the odds ratio (OR), together with the 95% confidence interval (CI). Publication bias and between-study heterogeneity were also examined.

Results

Thirty-nine case-control studies of the three polymorphisms, R353Q (rs6046), HVR4 and -323Ins10 (rs36208070) in factor VII gene and CHD were enrolled in this meta-analysis, including 9,151 cases of CHD and 14,099 controls for R353Q, 2,863 cases and 2,727 controls for HVR4, and 2,862 cases and 4,240 controls for -323Ins10. Significant association was only found in Asian population for R353Q (Q vs R), with pooled OR of 0.70(95%CI: 0.55, 0.90). For the -323Ins10 polymorphism (10 vs 0), we found significant associations in both Asian and European populations, with pooled ORs of 0.74(95%CI: 0.61, 0.88) and 0.63(95%CI: 0.53, 0.74), respectively. Marginal significant association was found between HVR4 (H7 vs H5+H6) and CHD (OR = 0.88, 95% CI: 0.78, 1.00). There was no evidence of publication bias, but between-study heterogeneity was found in the analyses.

Conclusions

The -323Ins10 polymorphism in factor VII gene is significantly associated with CHD in both Asian and European populations, while R353Q polymorphism showed trend for association with CHD in Asians. Lack of association was found for HVR4 polymorphism. Further studies are needed to confirm the association, especially for -323Ins10 polymorphism.

Arterial thrombus formation in cardiovascular disease

The pathogenesis of arterial thrombosis is complex and dynamic. Unlike venous thrombi, arterial thrombi typically form under conditions of high blood flow and are mainly composed of platelet aggregates, giving them the appearance of 'white clots'. Strong evidence suggests that arterial thrombi originate as a consequence of an injured atherosclerotic plaque, and that their formation involves the release of prothrombotic material (such as tissue factor), platelet aggregation, and platelet adhesion to the vascular wall. The initially labile platelet plaque is then stabilized by insoluble fibrin produced upon activation of the coagulation cascade. Inherited genetic factors (gene polymorphisms) and acquired predisposing conditions (such as the concentration and activity of clotting factors) can influence both the composition and the size of an arterial thrombus. Further research is needed to elucidate the functions of blood coagulation proteins and cellular elements that are critical to the pathogenesis of arterial thrombosis. This Review explains mechanisms of pathological arterial thrombus formation and discusses genetic and acquired risk factors of atherothrombosis.

R353Q polymorphism in the factor VII gene and cardiovascular risk in Heterozygous Familial Hypercholesterolemia: a case-control study

Background

Heterozygous Familial Hypercholesterolemia (FH) is a genetic disorder characterized by a high risk of cardiovascular disease. Certain polymorphisms of the factor VII gene have been associated with the development of coronary artery disease and there is a known association between factor VII levels and polymorphic variants in this gene. To date, no study has evaluated the association between factor VII and coronary artery disease in patients with FH.

Results

This case-control study comprised 720 patients (546 with FH and 174 controls). We determined the prevalence and allele frequencies of the R353Q polymorphism of factor VII, the plasma levels of factor VII antigen (FVII Ag) and whether they could be predictive factors for cardiovascular risk. 75% (410) of the patients with FH were RR, 23% (127) RQ and 1.6% (9) QQ; in the control group 75.3% (131) were RR, 21.3% (37) RQ and 3.4% (6) QQ (p = 0.32). No statistically significant associations were observed in the distribution of genotypes and allele frequencies between case (FH) and control groups. Nor did we find differences when we evaluated the relationship between the R353Q polymorphism and cardiovascular risk (including coronary disease, ischemic stroke and peripheral arterial disease), either in the univariate analysis or after adjustment for sex, age, arterial hypertension, body mass index, xanthomas, diabetes, smoking, HDLc and LDLc and lipid-lowering treatment. The FVII Ag concentrations behaved in a similar fashion, with no differences for the interaction between controls and those with FH (RR vs. RQ/QQ; p = 0.96). In the subgroup of patients with FH no association was found among cardiovascular disease, genotype and FVII Ag levels (RR vs. RQ/QQ; p = 0.97).

Conclusions

Our study did not find a direct relationship between cardiovascular risk in patients with Heterozygous Familial Hypercholesterolemia, the R353Q polymorphism of factor VII and FVII Ag levels.

Haplotype and genotype effects of the F7 gene on circulating factor VII, coagulation activation markers and incident coronary heart disease in UK men

BACKGROUND

Evidence for the associations of single nucleotide polymorphisms (SNPs) in the F7 gene and factor (F)VII levels and with risk of coronary heart disease (CHD) is inconsistent. We examined whether F7 tagging SNPs (tSNPs) and haplotypes were associated with FVII levels, coagulation activation markers (CAMs) and CHD risk in two cohorts of UK men.

METHODS

Genotypes for eight SNPs and baseline levels of FVIIc, FVIIag and CAMs (including FVIIa) were determined in 2773 healthy men from the Second Northwick Park Heart Study (NPHS-II). A second cohort, Whitehall II study (WH-II, n = 4055), was used for replication analysis of FVIIc levels and CHD risk.

RESULTS

In NPHS-II the minor alleles of three SNPs (rs555212, rs762635 and rs510317; haplotype H2) were associated with higher levels of FVIIag, FVIIc and FVIIa, whereas the minor allele for two SNPs (I/D323 and rs6046; haplotype H5) was associated with lower levels. Adjusted for classic risk factors, H2 carriers had a CHD hazard ratio of 1.34 [95% confidence interval (CI): 1.12-1.59; independent of FVIIc], whereas H5 carriers had a CHD risk of 1.29 (95% CI: 1.01-1.56; not independent of FVIIc) and significantly lower CAMs. Effects of haplotypes on FVIIc levels were replicated in WH-II, as was the association of H5 with higher CHD risk [pooled-estimate odds ratio (OR) 1.16 (1.00-1.36), P = 0.05], but surprisingly, H2 exhibited a reduced risk for CHD.

CONCLUSION

 tSNPs in the F7 gene strongly influence FVII levels. The haplotype associated with low FVIIc level, with particularly reduced functional activity, was consistently associated with increased risk for CHD, whereas the haplotype associated with high FVIIc level was not.

MISS: a non-linear methodology based on mutual information for genetic association studies in both population and sib-pairs analysis

MOTIVATION

Finding association between genetic variants and phenotypes related to disease has become an important vehicle for the study of complex disorders. In this context, multi-loci genetic association might unravel additional information when compared with single loci search. The main goal of this work is to propose a non-linear methodology based on information theory for finding combinatorial association between multi-SNPs and a given phenotype.

RESULTS

The proposed methodology, called MISS (mutual information statistical significance), has been integrated jointly with a feature selection algorithm and has been tested on a synthetic dataset with a controlled phenotype and in the particular case of the F7 gene. The MISS methodology has been contrasted with a multiple linear regression (MLR) method used for genetic association in both, a population-based study and a sib-pairs analysis and with the maximum entropy conditional probability modelling (MECPM) method, which searches for predictive multi-locus interactions. Several sets of SNPs within the F7 gene region have been found to show a significant correlation with the FVII levels in blood. The proposed multi-site approach unveils combinations of SNPs that explain more significant information of the phenotype than their individual polymorphisms. MISS is able to find more correlations between SNPs and the phenotype than MLR and MECPM. Most of the marked SNPs appear in the literature as functional variants with real effect on the protein FVII levels in blood.

AVAILABILITY

The code is available at http://sisbio.recerca.upc.edu/R/MISS_0.2.tar.gz

Novel associations of multiple genetic loci with plasma levels of factor VII, factor VIII, and von Willebrand factor: The CHARGE (Cohorts for Heart and Aging Research in Genome Epidemiology) Consortium

BACKGROUND

Plasma levels of coagulation factors VII (FVII), VIII (FVIII), and von Willebrand factor (vWF) influence risk of hemorrhage and thrombosis. We conducted genome-wide association studies to identify new loci associated with plasma levels.

METHODS AND RESULTS

The setting of the study included 5 community-based studies for discovery comprising 23 608 European-ancestry participants: Atherosclerosis Risk In Communities Study, Cardiovascular Health Study, British 1958 Birth Cohort, Framingham Heart Study, and Rotterdam Study. All subjects had genome-wide single-nucleotide polymorphism (SNP) scans and at least 1 phenotype measured: FVII activity/antigen, FVIII activity, and vWF antigen. Each study used its genotype data to impute to HapMap SNPs and independently conducted association analyses of hemostasis measures using an additive genetic model. Study findings were combined by meta-analysis. Replication was conducted in 7604 participants not in the discovery cohort. For FVII, 305 SNPs exceeded the genome-wide significance threshold of 5.0x10(-8) and comprised 5 loci on 5 chromosomes: 2p23 (smallest P value 6.2x10(-24)), 4q25 (3.6x10(-12)), 11q12 (2.0x10(-10)), 13q34 (9.0x10(-259)), and 20q11.2 (5.7x10(-37)). Loci were within or near genes, including 4 new candidate genes and F7 (13q34). For vWF, 400 SNPs exceeded the threshold and marked 8 loci on 6 chromosomes: 6q24 (1.2x10(-22)), 8p21 (1.3x10(-16)), 9q34 (<5.0x10(-324)), 12p13 (1.7x10(-32)), 12q23 (7.3x10(-10)), 12q24.3 (3.8x10(-11)), 14q32 (2.3x10(-10)), and 19p13.2 (1.3x10(-9)). All loci were within genes, including 6 new candidate genes, as well as ABO (9q34) and VWF (12p13). For FVIII, 5 loci were identified and overlapped vWF findings. Nine of the 10 new findings were replicated.

CONCLUSIONS

New genetic associations were discovered outside previously known biological pathways and may point to novel prevention and treatment targets of hemostasis disorders.

Factor VII, blood lipids and fat intake: gene-nutrient interaction and risk of coronary heart disease with the factor VII R353Q polymorphism

BACKGROUND

The relation between dietary fat, blood lipids, plasma factor VII coagulant activity (FVIIc) and risk of coronary heart disease (CHD) according to the R353Q polymorphism in the factor VII gene was assessed.

METHODS

Cross-sectional study of 15,073 individuals participating in the European Prospective Investigation of Cancer (EPIC) Norfolk, 7433 of which had FVIIc available. Nested case-control study of 985 CHD cases and 2009 matched controls.

RESULTS

FVIIc was significantly associated with total fat intake in females, especially in the RR homozygotes (standardized beta=0.24; 95% confidence interval (95% CI) 0.08-0.40; P<0.01), but there were no associations with intakes of saturated, monounsaturated or polyunsaturated fatty acids according to genotype and no associations in males. FVIIc was significantly positively associated with total cholesterol (P<0.01) and with triacylglycerol (P<0.001) in both genders, with an interaction according to genotype for triacylglycerol in males: beta Q allele carriers 0.26 (95% CI 0.18-0.34), beta RR homozygotes 0.16 (95% CI 0.12-0.20) (Z interaction=-2.24; P<0.05). There was no effect of genotype on the odds ratio (OR) for incident CHD: OR 0.89 for Q allele carriers compared with RR homozygotes (95% CI 0.77-1.02) in 985 cases and 2009 matched controls.

CONCLUSION

These results show a strong association between dietary fat intake and FVIIc in women, and between serum triacylglycerol and cholesterol and FVIIc levels in both genders. The R353Q genotype only marginally affected modulation of FVIIc by dietary fat. The association between triacylglycerol and FVIIc was significantly stronger in males carrying the Q allele than in those with the RR genotype.

Human F7 sequence is split into three deep clades that are related to FVII plasma levels

It is widely accepted that FVII levels are strongly, consistently, and independently related to cardiovascular risk. These levels are influenced by genetic and environmental factors. Among the genetic factors, only a limited number of polymorphisms in the F7 gene have been reported, and they explain only a small proportion of the genetic variability. Recently, we have accomplished the complete dissection of the F7 quantitative trait locus responsible for all of the genetic variability observed in FVII levels. Now, we present the thorough study of the haplotype organization of F7 DNA sequence variation among individuals and the evolutionary processes that produced this variation, by sequencing 15 kb of genomic DNA sequence from the F7 locus in 40 unrelated individual (80 chromosomes) from the genetic analysis of idiopathic thrombophilia (GAIT) project as well as four non-human primate species. Our study revealed 49 polymorphisms, of which 39 SNPs were further considered. Genotyping of these DNA variations in the whole family-based GAIT sample helped resolve linkage phases, and a total of 37 distinct haplotypes were identified.Tajima's D was significantly positive in this sample, suggesting balancing selection. This parameter was a reflection of the phylogenetic structure of F7 haplotype, which was deeply split into three well-supported clades or haplogroups, suggesting that functional differences among F7 variants do not depend on a few single-site variations. Moreover, haplogroup 2 was associated with high FVII levels and haplogroup 3 with low levels. In this study, we have for the first time established a clear relation between genotypic variability structure and phenotypic variability of a particular quantitative trait involved in a complex disease.

A protective contribution of the Q allele of the R353Q polymorphism of the Factor VII gene in individuals with chronic stable angina?

BACKGROUND

Factor VII polymorphisms have been suggested in some studies to show an association with some aspects of coronary disease, and there is a known association between FVII levels and polymorphic variants in the gene. The aim of the study was to assess whether Factor VII polymorphism R353Q is associated with the extent of coronary artery disease in patients with chronic stable angina.

METHODS AND RESULTS

There is evidence that Factor VII polymorphisms are markers of susceptibility to coronary artery disease (CAD), but two studies have suggested that there is no association between the degree of vessel disease and these polymorphisms. One of these studies did not exclude patients with unstable angina or MI. We therefore set up a prospective cohort study to determine Factor VIIa, VIIc and VIIAg levels, genotype for R353Q, lipid status, smoking history and the degree of vessel disease, in patients attending the hospital for routine day case angiography over a 20 month period. From 519 cases, 400 had no previous MI or revascularisation, including 153 with zero vessel disease, and were successfully genotyped: 9 (2%) QQ, 78 (20%) RQ and 313 (78%) RR. Compared with RR subjects, heterozygotes were 2.7 years older (95% CI: 0.3, 5.0; p=0.027), but were not significantly different regarding gender, cholesterol, extent of vessel disease or smoking history. If those with vessel disease were considered, then the heterozygotes were 3.5 years older than the RR homozygotes (95% CI: 0.6-6.4, p=0.016). There was a significant association between all measures of Factor VII and the R353Q polymorphism, with the Q allele associating with lower levels. There was no significant association between the degree of vessel disease and genotype.

CONCLUSIONS

The degree of vessel disease as seen at day case angiography is independent of polymorphism status, but there appears nonetheless to be a moderate protective effect of the Q allele against stable angina, in that angiographic investigation occurs a few years later for RQ heterozygotes than RR homozygotes. The effect may be mediated by reduced levels of Factor VII.

Prevalence in a Tunisian Arabic population of factor VII DNA variants and relation to factor VII plasma levels

BACKGROUND

A raised plasma factor VII (FVII) level is a risk factor for coronary heart disease. DNA variants have been described to be associated with alteration in FVII levels. The prevalence of FVII polymorphisms is unknown in the Tunisian Arab population.

METHODS

In a group of 240 healthy Tunisians, we examined the relationship between levels of FVII coagulant activity (FVIIc) and two polymorphisms in the FVII gene. One polymorphism alters arginine at position 353 to glutamine (R/Q) and the other is a 10 base pair insertion (0/10 bp).

RESULTS

The FVII distribution was in accordance with the Hardy-Weinberg equilibrium. The allele frequencies of Q and 10 bp were 0.212 and 0.235, respectively. There were significant differences in these allelic frequencies between Tunisian and other populations (p<0.001). We observed lower FVIIc levels among subjects with the Q allele compared to RR subjects (RR: 98.17%, RQ/QQ: 57.41%, p<0.0001). For the 0/10 polymorphism, no statistically difference was observed.

CONCLUSION

The prevalence of the Q allele which was found to be associated with lower plasma FVIIc levels is high in Tunisian population. Further analyses should yield information on the protective role of carrying the Q allele for coronary heart disease.

Role of thrombotic and fibrinolytic factors in acute coronary syndromes

There is a growing body of literature concerning the contribution of hemostatic factors to the development of cardiovascular disease. The mechanisms of the coagulation/fibrinolytic system are complicated and one factor is intimately interrelated with another; thus the contribution of each factor cannot be clearly understood, unless hemostatic factors are considered in accordance with endothelial function and vessel morphology. Although there are many clinical studies about the correlation between hemostatic factors and cardiovascular risk, the results are inconsistent and conflicting at times. Fibrinogen and D-dimer are associated with atherosclerosis or coronary events across multiple studies, even after multivariate adjustment. But the hemostatic factors are intimately correlated, so it can be said that focusing on one to the exclusion of others is inappropriate. The clinical trials with statins or angiotensin converting enzyme inhibitors have shown favorable effects on the prognosis of cardiovascular disease. The study of hemostatic factors in relation to these drugs has provided insights into understanding how these drugs produce beneficial effects.

R353Q Polymorphism, Activated Factor VII, and Risk of Premature Myocardial Infarction in Japanese Men

BACKGROUND

The association between myocardial infarction (MI) and the R353Q polymorphism of the Factor VII (FVII) gene, which reportedly influences FVII concentrations, activated Factor VII (FVIIa), or FVII antigen (FVIIag), remains controversial.

METHODS AND RESULTS

The present case - control study in 127 Japanese men with their first MI at or before 45 years of age and 150 matched healthy controls was designed to clarify this association in premature MI. R353Q polymorphism was determined by polymerase chain reaction, and plasma concentrations of FVIIa and FVIIag were assayed. The distribution of the RR, RQ, and QQ genotypes with respect to R353Q polymorphism was 117, 10, and 0 in the patients, and 131, 17, and 2 in the controls. The Q allele was negatively associated with premature MI (odds ratio =0.41, p=0.038). The plasma concentration of FVIIa was slightly higher in patients (55.1+/-40.9 U/L) than in controls (44.8+/-20.2 U/L), but not significantly (p=0.078); the plasma concentration of FVIIag did not differ between patients (88.7+/-15.7%) and controls (87.0+/-9.0%) (p=0.557). Plasma FVIIa concentrations were influenced by R353Q polymorphism (p<0.001).

CONCLUSIONS

The Q allele may be protective against premature MI.

Coagulation factor VII, R353Q polymorphism, and serum choline-containing phospholipids in males at high risk for coronary heart disease

INTRODUCTION

Elevated levels of coagulation factor VII (FVII) have been associated with increased risk for myocardial infarction (MI). The R353Q polymorphism of the FVII gene has been shown to modify plasma levels of FVII, and has in some studies also been associated with reduced risk for MI.

OBJECTIVES

To examine the R353Q polymorphism of the FVII gene and the relation to myocardial infarction (MI), cardiovascular disease (CVD), and diabetes, and furthermore, to elucidate the association between the polymorphism and plasma levels of FVII coagulant activity (FVIIc), FVII antigen (FVIIag), activated FVII (FVIIa), and serum choline-containing phospholipids (PC).

METHODS

In 560 elderly men characterised as hypercholesterolemic in 1972, we examined the R353Q polymorphism by melting curve analysis after real-time PCR. In a subgroup of 205 individuals, FVIIc, FVIIag, FVIIa, and PC were analysed.

RESULTS

There were no significant associations between genotype and the disease states, although we observed a lower number of MI cases among subjects with the Q allele, compared to the RR individuals (14% vs. 19%). FVIIag and FVIIc levels were lower in RQ compared to RR subjects, whereas for FVIIa the opposite was observed (p<0.001 for all). PC correlated positively with FVIIag (r=0.24, p<0.001), but negatively with FVIIa (r=-0.25, p<0.001). No genotype specific interactions were found for the association between FVII and PC.

CONCLUSION

No significant associations between the R353Q polymorphism and MI, CVD, or diabetes were observed, although the polymorphism strongly influenced plasma levels of FVII. Serum PC correlated significantly with FVIIag and inversely with FVIIa, independently of genotype.

Clinical significance of gene-diagnosis for defects in coagulation factors and inhibitors

cDNA sequences of all known coagulation factors and inhibitors of coagulation have been described and an enormous number of disease generating mutations in these factors has been found by genetic analysis of affected families. The vast majority of these defects have severe clinical consequences such as spontaneous bleeding or predisposition to venous thrombosis and pulmonary embolism. While all the genetic defects described so far cause disease, or at least represent a risk factor for diseases such as bleeding or thrombosis, only a minority of these conditions actually need DNA analysis to be detected and/or treated properly. The purpose of this review is therefore to describe clinical situations in which the knowledge of the underlying genetic defect is important for decision making in patients with inherited hemophilia or thrombophilia.

Genetic evaluation for coronary artery disease

There is substantial evidence that genetic factors contribute to coronary artery disease (CAD). Currently, family history collection and interpretation is the best method for identifying individuals with genetic susceptibility to CAD. Family history reflects not only genetic susceptibility, but also interactions between genetic, environmental, cultural, and behavioral factors. Stratification of familial risk into different risk categories (e.g., average, moderate, or high) is possible by considering the number of relatives affected with CAD and their degree of relationship, the ages of CAD onset, the occurrence of associated conditions, and the gender of affected relatives. Familial risk stratification should improve standard CAD risk assessment methods and treatment guidelines (e.g., Framingham CAD risk prediction score and Adult Treatment Panel III guidelines). Individuals with an increased familial risk for CAD should be targeted for aggressive risk factor modification. Individuals with a high familial risk might also benefit from early detection strategies and biochemical and DNA-based testing, which can further refine risk for CAD. In addition, individuals with the highest familial risk might have mendelian disorders associated with a large magnitude of risk for premature CAD. In these cases, referral for genetic evaluation should be considered, including pedigree analysis, risk assessment, genetic counseling and education, discussion of available genetic tests, and recommendations for risk-appropriate screening and preventive interventions. Research is needed to assess the feasibility, clinical validity, clinical utility, and ethical, legal, and social issues of an approach that uses familial risk stratification and genetic evaluation to enhance CAD prevention efforts.

On the use of population attributable fraction to determine sample size for case-control studies of gene-environment interaction

Most methods for calculating the sample size needed to detect gene-environment interactions use odds ratios to measure the effect size. We show that for any combination of susceptible genotype prevalence and exposure prevalence and their associated risks, the odds ratio measuring strength of interaction corresponds to a population attributable fraction (PAF) because of interaction and vice versa. Simultaneous consideration of odds ratio for interaction and the associated PAF attributable to interaction provides additional insight to investigators evaluating the feasibility and public health relevance of a proposed study. We considered gene-environment interactions on a multiplicative scale, and assumed a dichotomous environmental exposure variable and a single two-allele disease-susceptibility locus. Our results show, for example, that for studies of exposures and genotypes that are common in a population (30%-50%), the PAF for interaction is large (>27%) even if the odds ratio for interaction is only moderate (approximately 2). If simultaneous estimates of interaction odds ratio and PAF indicate that the PAF is so large as to be implausible, the investigator may decide to reevaluate the study design based on detecting a more reasonable PAF. In this case, the associated odds ratio for interaction will be weaker and a considerably larger sample size may be needed.

Boron supplementation and activated factor VII in healthy men

OBJECTIVE

The aim of the present study was to determine whether postprandial concentrations of the active component of serine protease coagulation factor VII (VIIa) were lowered by acute boron supplementation in vivo.

DESIGN

An acute, randomized, placebo-controlled, double blind, cross-over study.

SETTING

Free-living population.

SUBJECTS

Fifteen apparently healthy men, aged 45-65 y.

INTERVENTIONS

Subjects visited the centre on two occasions, with the study days separated by a minimum of 2 weeks. Following collection of a fasting blood sample, subjects received either placebo or acute bolus of 11.6 mg boron (given as 102.6 mg sodium tetraborate decahydrate) together with a standard fat-rich meal. Blood samples were obtained at 1, 2, 4 and 6 h after the administration of the test meal, during which time subjects were at liberty to consume deionized water only. Blood samples were assayed for concentrations of insulin, glucose, lipids and boron. Measurement of the concentration of activated factor VIIa and of factor VII antigen, and of the activity of coagulation factors VII, IX and X was also carried out.

RESULTS

Plasma boron concentrations were significantly higher following consumption of the boron supplement compared with placebo (0.124+/-0.02 vs 0.008+/-0.01 mg/l; P< or =0.001). There was no significant effect of acute boron supplementation on plasma insulin and glucose concentration or on blood lipid or coagulation factor profile. Factor VIIa rose significantly following consumption of the high fat meal (1.05+/-0.07 vs 1.26+/-0.07; P< or =0.001), but this increase was not altered by boron supplementation.

CONCLUSIONS

Results from this study suggest that acute boron supplementation (at 11.6 mg boron) does not alter the activity of factor VIIa following consumption of a high-fat meal.

SPONSORSHIP

This work was funded by Borax Europe Ltd.

Polymorphisms of genes affecting thrombosis and risk of myocardial infarction

BACKGROUND

As thrombosis is an essential factor in the pathogenesis of acute myocardial infarction (AMI), the genes of proteins affecting haemostasis are good candidate genes for AMI.

DESIGN

Associations of the known polymorphisms of the coagulation factor VII (FVII) gene (R353Q), the coagulation factor XIII (FXIII) gene (V34L) and the glycoprotein Ia (Gp1a) gene (C807T) with the occurrence of AMI were studied in 142 AMI survivors and 142 age- and sex-matched control subjects.

RESULTS

Among those who smoked, the L34 allele of the amino acid FXIII polymorphism was less common in the AMI patients (16%) than in the controls (27%) (P = 0.06), suggesting a possible interaction of AMI risk between the FXIII genotype and smoking status. No differences in the allele or genotype frequencies of the studied polymorphisms were seen between the whole study groups. Logistic regression analysis showed the carriers of the L34 allele of the FXIII amino acid polymorphism to have a significantly (P = 0.03) lower AMI risk compared with those homozygous for the V34 allele (odds ratio = 0.54, 95% confidence interval 0.31-0.93).

CONCLUSION

The L34 allele of the amino acid polymorphism of the FXIII gene is associated with a decreased risk of AMI, and this protecting association seems to be more pronounced in smokers.

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

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

Candidate genes as potential links between periodontal and cardiovascular diseases

Recent epidemiological associations between periodontal disease and cardiovascular disease have led to a search for biological mechanisms that explain the associations. Genetic factors that influence biological processes involved in both diseases represent one of the potential mechanisms that may link periodontitis and cardiovascular disease. At present, several candidate genes have been investigated in one of the diseases but not the other. Although there are limited data to support a specific candidate gene as the explanation for observed associations between the 2 diseases, a few candidates look promising. One candidate that influences inflammation, interleukin-1 gene polymorphisms, has been associated with periodontal disease and cardiovascular disease. This review will consider biological mechanisms and genes that may be reasonable candidates for an etiological mechanism that influences the clinical characteristics of both periodontal disease and cardiovascular disease.

Variations of cardiovascular disease associated genes exhibit sex-dependent influence on human longevity

This article investigates the relationship between the polymorphic variations in genes associated with cardiovascular disease and longevity in the Danish population. A new procedure that combines both demographic and the individual genetic information in determining the relative risks of the observed genetic variations is applied. The sex-dependent influences can be found by introducing sex-specific population survival and incorporating the risk of gene-sex interaction. Three genetic polymorphisms, angiotensinogen M/T235, blood coagulation factor VII (FVII) R/Q353 and FVII-323ins10, manifest significant influences on survival in males, with reduced hazards of death for carriers of the angiotensinogen M235 allele, the F VII Q353 allele, and the FVII-323P10 allele. The results show that some of these genotypes associated with lower risk of CVD could also reduce the carrier's death rate and contribute to longevity. However, the presence of sex-dependent effects and the fact that major CVD-associated genes failed to impose detrimental influence on longevity lead us to concur that the aging process is highly complicated.

Genetic predisposition to coronary artery disease

Understanding the genetic basis of coronary artery disease (CAD) can improve management and prevention. Family and twin studies, animal models and gene association studies support a genetic basis for CAD. Genes contribute to CAD development and progression, and response to risk factor modification and lifestyle choices. Family history is the best indicator of a predisposition to CAD and further refinement is possible with biochemical and DNA testing. Many inherited cardiovascular risk factors can be modified, such as LDL cholesterol, homocysteine and lipoprotein(a). Early detection of CAD might lead to earlier intervention for genetically susceptible individuals. However, data are lacking regarding the efficacy of this approach in preventing clinical events. Despite this lack of evidence, knowledge of genetic CAD susceptibility has value in providing risk information and guiding decision making. Further research that investigates outcomes regarding genetic risk assessment for CAD is necessary.

Complementary effects of Mediterranean diet and moderate red wine intake on haemostatic cardiovascular risk factors

OBJECTIVES

To compare the effect of alcohol-free Mediterranean-type diet (MD) and high-fat diet (HFD) on plasma concentration of emergent haemostatic cardiovascular risk factors (HCVRF). Also, to test if red wine supplementation modifies HCVRF, independent of diet.

DESIGN, SUBJECTS AND INTERVENTION

Controlled prospective intervention study. Two groups, each of 21 healthy male university students (22+/-3.4 y), received either MD or HFD for 90 days. Between days 30 and 60, both diets were supplemented with 240 ml/day of red wine. Baseline and T30, T60 and T90-day samples were drawn. No drop out from the study was observed.

SETTING

University campus and outpatient nutrition clinic.

RESULTS

Volunteers on HFD at T30 had increases in pro-coagulants fibrinogen (22%), factor VIIc (9%), and factor VIIIc (4%), and decreases in natural anticoagulants antithrombin III (3%), protein C (11%) and protein S (6%) and of 20% in plasminogen activator inhibitor-1. At the same time, individuals on MD had increases in fibrinogen (4%), antithrombin III (5%), protein C (3%), protein S (2.7%), and decreases in factor VIIIc (9%), and plasminogen activator inhibitor-1 (21%). After adjusting by baseline values, MD was associated with lower plasma fibrinogen (P=0.03), factor VIIc (P=0.034) and factor VIIIc (P=0.0057) and with higher levels of protein S (P=0.013). Red wine supplementation, in both diets, resulted in decreased plasma fibrinogen (P=0.001) and factor VIIc (P=0.05), and increased tissue plasminogen activator antigen (P=0.01) and plasminogen activator inhibitor-1 antigen (P=0.0003). Wine consumption was also associated with significantly (P=0.01) divergent effects on antithrombin III: it decreased by 10% in individuals on HFD but increased slightly in those on MD. No effects of diet or wine were detected in plasma protein C and C-reactive protein.

CONCLUSION

MD and moderate consumption of red wine have complementary, mostly beneficial effects on HCVRF.

Reduced procedural risk for coronary catheter interventions in carriers of the coagulation factor VII-Gln353 gene

OBJECTIVES

We have focused on the role of coagulation factor VII (FVII) Arg353Gln polymorphism as a risk predictor of complications following percutaneous transluminal coronary angioplasty (PTCA), directional coronary atherectomy (DCA), and stenting.

BACKGROUND

The FVII Arg353Gln mutation decreases FVII activity, and presence of the Gln353 allele could be protective against thrombus formation during catheter interventions.

METHODS

A total of 666 consecutive patients with coronary artery disease who had undergone PTCA (n = 280), DCA (n = 104), or stenting (n = 282) were followed up for a 30-day composite end point, which included need for target vessel revascularization, myocardial infarction, and death. The Arg353Gln polymorphism of FVII was determined by PCR/RFLP assay.

RESULTS

Carriers of the Gln353 allele had significantly lower levels of total FVII activity (FVIIc, -20.7%, p < 0.001) and of activated circulating FVII (FVIIa, -32.7%, p = 0.03) compared with Arg353/Arg353. The composite end point occurred in 43 patients: 4 were heterozygous Arg353/Gln353, and 39 were homozygous Arg353/Arg353. The incidence of the composite end point was 2.5% in carriers of the Gln353 allele and 7.7% in Arg353/Arg353 homozygotes (p = 0.013). This corresponds to a 72% risk reduction in carriers of the Gln353 allele (relative risk: 0.28; 95% confidence interval: 0.09-0.81; p = 0.02).

CONCLUSIONS

The Gln353 allele of FVII is associated with substantial risk reduction in adverse events that complicate coronary catheter interventions. With the perspective of active site-blocked activated FVII (FVIIai) as conjunctive medication, the results suggest that the FVII genotype should be taken into due consideration in assessment of FVIIai medication and of its dosage.