Genotype associations of factor VII gene with plasma factor VII coagulant activity and antigen levels in healthy Chinese

Decanucleotide insertion polymorphism of F7 significantly influences the risk of thrombosis in patients with essential thrombocythemia

OBJECTIVE

There is strong evidence that certain thrombophilic single nucleotide polymorphisms (SNPs) account for an increased risk of thrombosis. The additive impact of inherited thrombotic risk factors to a certain disease- immanent thrombotic risk is vastly unknown. Therefore, we aimed to investigate the influence of three novel, preselected SNPs on the risk of thrombosis in patients diagnosed with myeloproliferative neoplasm (MPN).

METHOD

In 167 patients with a diagnosis of essential thrombocythemia (ET) or prefibrotic primary myelofibrosis (PMF) thrombophilic SNPs in the genes of factor VII (F7), nitric oxide synthase 3 (NOS3) and FcɣRIIa (FCGR2A) were determined. Subsequently, the polymorphic variants were correlated with the incidence of major thrombosis after diagnosis.

RESULTS

Decanucleotide insertion polymorphism of F7 emerged as an independent, significant risk factor for total thrombosis and arterial thrombosis in particular in the whole group of patients (P = 0.0007) as well as in the separate analysis of patients with ET (P = 0.0002).

CONCLUSION

Our results illustrate that the risk of thrombosis in MPN is significantly multiplied by inherited thrombophilic SNPs. This result points to the importance of a combined consideration of the inherited and the acquired hypercoagulable state in patients with MPN. Larger studies are needed to confirm and extend these important findings.

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.

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.

Association analysis of genetic polymorphisms of factor V, factor VII and fibrinogen β chain genes with human abdominal aortic aneurysm

Increased activity of the coagulation system is associated with the increased risk of many arterial thrombotic diseases and atherosclerosis. The purpose of this study was to evaluate the influence of selected polymorphisms in genes coding for coagulation factor V (1691 G/A, the so-called Leiden mutation), factor VII (−323 0/10 bp insertion/deletion) and fibrinogen β chain (−455 G/A) on the risk of abdominal aortic aneurysm, a particular form of atherothrombosis. We conducted a case-control study of 153 Polish patients hospitalized due to abdominal aortic aneurysm (AAA) and compared the results to those obtained from matched healthy control subjects. The polymorphisms were ascertained through genotyping by polymerase chain reaction and restriction digestion of amplified fragments. The study revealed that individuals carrying heterozygous genotype GA for the fibrinogen β chain −455 G/A mutation had at least a 2-fold greater likelihood of AAA development compared to control subjects (OR=3.01; 95% CI 1.83–4.96). The cases possessing homozygous mutant genotype (AA) had no significant risk of developing AAA compared to the control subjects (OR=1.12; 95% CI 0.33–2.44; p=0.83). Concerning factor V 1691 G/A and factor VII −323 0/10 bp mutations, we did not find any statistically significant correlation between them and AAA occurrence. In conclusion, we suggest that the −455G/A polymorphism of the fibrinogen β chain gene is a potential genetic marker to identify the risk of AAA.

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.

The Effects of Three Factor VII Polymorphisms on Factor VII Coagulant Levels in Healthy Singaporean Chinese, Malay and Indian Newborns

Factor VII (FVII) is an independent risk factor for coronary artery disease. Three polymorphisms of the factor VII gene (F7) were studied in a group of healthy newborns comprising 561 Chinese, 398 Malays and 226 Asian Indians from Singapore. The allele frequencies of 3 polymorphisms (R353Q, Promoter 0/10bp Del/Ins and Intron 7) in the FVII gene were ascertained through genotyping by polymerase chain reaction and restriction digestion of amplified fragments. In Chinese the minor allele frequencies are Q: 0.04, Ins: 0.03, R7: 0.44; Malays, Q: 0.06, Ins: 0.10, R7: 0.41; and Indians, Q: 0.25, Ins: 0.23, R7: 0.43. Strong linkage disequilibrium (Delta > 0.7) is observed between the 0/10 bp and the R353Q sites in all ethnic groups. We conclude that: (i) the prevalence of the minor Q and Ins alleles of the R353Q and 0/10 bp polymorphisms are significantly higher in the Indian newborns than the Chinese and Malays; (ii) the Q allele is significantly associated (p = 0.01) with a lower plasma FVII coagulant level in the Indian and Malay neonates; and this polymorphism explains up to 3.8% of the variance in FVII coagulant levels; (iii) there is no significant difference in allele frequencies of the three polymorphisms between neonates with and without family histories of CAD.

Genetic polymorphisms of hemostasis genes and primary outcome of very low birth weight infants

BACKGROUND

Recent investigations have reported an influence of thrombophilic mutations and antithrombotic risk factors with development of intraventricular hemorrhage. It was our objective for this study to investigate the impact of genetic polymorphisms of hemostasis genes on the primary outcome measures of sepsis, bronchopulmonary dysplasia, intraventricular hemorrhage, and periventricular leukomalacia in a large cohort of very low birth weight infants.

METHODS

There were 586 very low birth weight infants enrolled prospectively in a multicenter trial between September 2003 and July 2005, and an additional 595 very low birth weight infants, who had been recruited in a previous prospective trial, were studied. DNA samples were taken by buccal swab, and genotypes of factor V Leiden mutation, prothrombin G20210A mutation, the factor VII-323 del/ins polymorphism, and the factor XIII-Val34Leu polymorphisms were determined by polymerase chain reaction and restriction enzyme digestion.

RESULTS

In contrast to data published previously, the frequency of intraventricular hemorrhage or periventricular leukomalacia was not significantly influenced by any of the genetic variants tested. Carriers of the factor XIII-Val34Leu polymorphism, however, had a higher sepsis rate and a longer period of hospital care compared with noncarriers. The factor VII-323 del/ins polymorphism was found to be a potential protective factor against bronchopulmonary dysplasia.

CONCLUSIONS

We could not confirm previously reported associations of hemostasis gene variants and development of intraventricular hemorrhage in very low birth weight infants. To better understand gene-disease associations in very low birth weight infants, the prospective development of large-scale cohorts with well-defined phenotypes and corresponding DNA samples is essential.

Cross-laboratory audit of normal reference ranges and assessment of ABO blood group, gender and age on detected levels of plasma coagulation factors

We have assessed the influence of the ABO blood group, gender and age on plasma levels of the coagulation factors II, V, VII, VIII, IX, X, XI and XII as part of a quality audit of laboratory activities. There was no statistically significant difference in gender donor age (total normal donors: n = 406, mean/median age = 46.0/47.0 years, range = 16-77 years; females: n = 177, mean/median age = 44.7/46.0 years, range = 16-75 years; males: n = 229, mean/median age = 47.0/48.0 years, range = 17-77 years). With increasing age, we observed small but statistically significant rises (linear correlation; P < 0.01 for all parameters) in factors V, VII, VIII, IX and XI. With gender, we observed higher levels (P < 0.05) in females for factors II, VII, X, IX, XI and XII. With the ABO group, we observed lower levels in the O group (versus non-O group; P < 0.05) for factors VIII, IX and XII. We could therefore define differing normal reference ranges based on the differing study data. Study findings are compared with previously published literature, and this has identified a wide diversity in normal reference ranges both between different factors and between different studies. Finally, we also performed a cross-laboratory audit of peer laboratory practice and similarly show a wide diversity in normal reference ranges used between different laboratories.

Reduction in coagulation factor VII plasma levels by R353Q but not the -323P0/10 promoter polymorphism in healthy Tunisians

The association between the R353Q and -323P0/10 (10-bp insertion in the promoter region at position -323) factor VII mutations and plasma factor VII levels was investigated in a group of 214 healthy Tunisians. The frequency for the Q allele was 0.253 and that for the 10-bp allele was 0.206, and their distribution was variable, with a high prevalence of the 10-bp allele (0.306) seen in North Tunisia and a high prevalence of the Q allele (0.288) see in the Sahel region. No significant linkage disequilibrium was observed between the two mutations, and the most prevalent haplotype was -323P0/353R (0.589 +/- 0.054). Carriers of the R353Q (P < 0.001), but not -323P0/10 (P = 0.088), factor VII mutations had lower mean factor VII serum concentrations. This reduction in mean serum factor VII was more pronounced among homozygous (Q/Q) carriers and among males (49.9%) compared to females (32.7%). Adjusting for all other variables in the linear regression analysis (sex, age, region, smoking, and R353Q and -323P0/10 mutations), heterozygous carriers of the -323P0/10 and R353Q mutation had on average reductions of 10 units (P = 0.005) and 30 units (P < 0.001) in plasma factor VII, respectively, compared to noncarriers, while homozygote carriers of the R353Q (-43.3, P < 0.001), but not carriers of the -323P0/10 (-6.30, P = 0.356), had significantly lower levels of mean plasma factor VII. These data suggest that part of the previously described effects on FVIIc levels associated with the R/Q polymorphism may be explained by genetic variation in the promoter region of the FVII gene.

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.

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.