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

Impact of Thrombophilic Polymorphisms in Antenatal Women on Perinatal Health: A Single-Center Prospective Study

BACKGROUND

Despite pregnancy's hypercoagulable state, the correlation between inherited thrombophilia and thrombotic adverse pregnancy outcomes remains uncertain. The objective of this study was to determine the prevalence of inherited thrombophilic polymorphisms among asymptomatic pregnant individuals and to examine their potential correlation with adverse perinatal outcomes.

METHODS

in this single-center prospective study, 105 healthy pregnant women were included. Genotyping was conducted for factor V Leiden (FVL), prothrombin gene mutation, methylenetetrahydrofolate reductase enzyme (MTHFR) C677T, MTHFR A1298C, and plasminogen activator inhibitor-1 (PAI-1), alongside the assessment of protein C (PC), protein S (PS), and antithrombin (AT) levels. The study analyzed the association between inherited thrombophilic polymorphisms and pregnancy complications linked to placental insufficiency, such as gestational hypertension (GH), preeclampsia (PE), intrauterine death (IUD), fetal growth restriction (FGR), and placental abruption.

RESULTS

The prevalence of identifiable thrombophilic polymorphism mutations was 61.9% (95% confidence interval-CI 52.4-70.8%), with the most common single mutation being PAI-1 4G/5G (12/105, 11.4%, 95% CI 6.4-18.5). The most frequent combined mutation was heterozygosity for MTHFR C677T and PAI-1 (12/105, 11.4%, 95% CI 6.4-18.5). Notably, no FVL homozygous carriers or single homozygous and heterozygous carriers for prothrombin polymorphisms were found. Additionally, no deficiencies in PC and AT were detected among participants. Except for homozygosity for PAI-1, none of the studied polymorphisms demonstrated a significant association with pregnancy complications linked to placental insufficiency.

CONCLUSIONS

The asymptomatic carriers of inherited thrombophilic polymorphisms do not have an increased risk of adverse perinatal outcomes.

A combination of strongly associated prothrombotic single nucleotide polymorphisms could efficiently predict venous thrombosis risk

Background

Venous thrombosis (VT) is multifactorial trait that contributes to the global burden of cardiovascular diseases. Although abundant single nucleotide polymorphisms (SNPs) provoke the susceptibility of an individual to VT, research has found that the five most strongly associated SNPs, namely, rs6025 (F5 Leiden), rs2066865 (FGG), rs2036914 (F11), rs8176719 (ABO), and rs1799963 (F2), play the greatest role. Association and risk prediction models are rarely established by using merely the five strongly associated SNPs. This study aims to explore the combined VT risk predictability of the five SNPs and well-known non-genetic VT risk factors such as aging and obesity in the Hungarian population.

Methods

SNPs were genotyped in the VT group (n = 298) and control group (n = 400). Associations were established using standard genetic models. Genetic risk scores (GRS) [unweighted GRS (unGRS), weighted GRS (wGRS)] were also computed. Correspondingly, the areas under the receiver operating characteristic curves (AUCs) for genetic and non-genetic risk factors were estimated to explore their VT risk predictability in the study population.

Results

rs6025 was the most prevalent VT risk allele in the Hungarian population. Its risk allele frequency was 3.52-fold higher in the VT group than that in the control group [adjusted odds ratio (AOR) = 3.52, 95% CI: 2.50-4.95]. Using all genetic models, we found that rs6025 and rs2036914 remained significantly associated with VT risk after multiple correction testing was performed. However, rs8176719 remained statistically significant only in the multiplicative (AOR = 1.33, 95% CI: 1.07-1.64) and genotypic models (AOR = 1.77, 95% CI: 1.14-2.73). In addition, rs2066865 lost its significant association with VT risk after multiple correction testing was performed. Conversely, the prothrombin mutation (rs1799963) did not show any significant association. The AUC of Leiden mutation (rs6025) showed better discriminative accuracy than that of other SNPs (AUC = 0.62, 95% CI: 0.57-0.66). The wGRS was a better predictor for VT than the unGRS (AUC = 0.67 vs. 0.65). Furthermore, combining genetic and non-genetic VT risk factors significantly increased the AUC to 0.89 with statistically significant differences (Z = 3.924, p < 0.0001).

Conclusions

Our study revealed that the five strongly associated SNPs combined with non-genetic factors could efficiently predict individual VT risk susceptibility. The combined model was the best predictor of VT risk, so stratifying high-risk individuals based on their genetic profiling and well-known non-modifiable VT risk factors was important for the effective and efficient utilization of VT risk preventive and control measures. Furthermore, we urged further study that compares the VT risk predictability in the Hungarian population using the formerly discovered VT SNPs with the novel strongly associated VT SNPs.

Predictive Ability of a Clinical-Genetic Risk Score for Venous Thromboembolism in Northern and Southern European Populations

Venous thromboembolism (VTE) is a complex, multifactorial problem, the development of which depends on a combination of genetic and acqfiguired risk factors. In a Spanish population, the Thrombo inCode score (or TiC score), which combines clinical and genetic risk components, was recently proven better at determining the risk of VTE than the commonly used model involving the analysis of two genetic variants associated with thrombophilia: the Factor V Leiden (F5 rs6025) and the G20210A prothrombin (F2 rs1799963). The aim of the present case-control study was to validate the VTE risk predictive capacity of the TiC score in a Northern European population (from Sweden). The study included 173 subjects with VTE and 196 controls. All were analyzed for the genetic risk variants included in the TiC gene panel. Standard measures -receiver operating characteristic (ROC) area under the curve (AUC), sensitivity, specificity, and odds ratio (OR)-were calculated. The TiC score returned an AUC value of 0.673, a sensitivity of 72.25%, a specificity of 60.62%, and an OR of 4.11. These AUC, sensitivity, and OR values are all greater than those associated with the currently used combination of genetic variants. A TiC version adjusted for the allelic frequencies of the Swedish population significantly improved its AUC value (0.783). In summary, the TiC score returned more reliable risk estimates for the studied Northern European population than did the analysis of the Factor V Leiden and the G20210A genetic variations in combination. Thus, the TiC score can be reliably used with European populations, despite differences in allelic frequencies.

Age and Origin of the Founder Antithrombin Budapest 3 (p.Leu131Phe) Mutation; Its High Prevalence in the Roma Population and Its Association With Cardiovascular Diseases

Background: Antithrombin (AT) is one of the most important regulator of hemostasis. AT Budapest 3 (ATBp3) is a prevalent type II heparin-binding site (IIHBS) deficiency due to founder effect. Thrombosis is a complex disease including arterial (ATE) and venous thrombotic events (VTE) and the Roma population, the largest ethnic minority in Europe has increased susceptibility to these diseases partly due to their unfavorable genetic load. We aimed to calculate the age and origin of ATBp3 and to explore whether the frequency of it is higher in the Roma population as compared with the general population from the corresponding geographical area. We investigated the association of ATBp3 with thrombotic events in well-defined patients' populations in order to refine the recommendation when testing for ATBp3 is useful.

Methods and Results: Prevalence of ATBp3, investigated in large samples (n = 1,000 and 1,185 for general Hungarian and Roma populations, respectively) was considerably high, almost 3%, among Roma and the founder effect was confirmed in their samples, while it was absent in the Hungarian general population. Age of ATBp3—as calculated by analysis of 8 short tandem repeat sequences surrounding SERPINC1—was dated back to XVII Century, when Roma migration in Central and Eastern Europe occurred. In our IIHBS cohort (n = 230), VTE was registered in almost all ATBp3 homozygotes (93%) and in 44% of heterozygotes. ATE occurred with lower frequency in ATBp3 (around 6%); it was rather associated with AT Basel (44%). All patients with ATE were young at the time of diagnosis. Upon investigating consecutive young (<40 years) patients with ATE (n = 92) and VTE (n = 110), the presence of ATBp3 was remarkable.

Conclusions: ATBp3, a 400-year-old founder mutation is prevalent in Roma population and its Roma origin can reasonably be assumed. By the demonstration of the presence of ATBp3 in ATE patients, we draw the attention to consider type IIHBS AT deficiency in the background of not only VTE but also ATE, especially in selected populations as young patients without advanced atherosclerosis. We recommend including the investigation of ATBp3 as part of thrombosis risk assessment and stratification in Roma individuals.

Frequency of thrombophilia associated genes variants: population-based study

BACKGROUND

Thrombophilia is a hypercoagulable state that may have a genetic basis (inherited) or can be acquired. It is a multifactorial condition and only the mutual interactions between the environment and genes may lead to the development of clinical manifestation. This state is the main factor promoting venous (rarely arterial) thromboembolism (VTE). Inherited thrombophilia is mainly associated with two pathogenic variants in the V coagulation factor (FV) and the prothrombin (FII) genes. The aim of our study was to evaluate the frequency of two pathogenic variants in FII and FV genes as inherited thrombophilia factors in a group within the Polish population in comparison with other described populations.

METHODS

All studied groups consisted of 633 unrelated patients aged between 18 and 70. Individuals in the research group come from the Podlasie region of Poland. Genotyping of FII and FV variants was performed using the 7900HT Fast Real-Time PCR System and were genotyped by TaqMan assay.

RESULTS

The pathogenic allele frequency for A allele was 0.03 (3%) and 0.07 (7%) for FII and FV genes, respectively. The GA/AA genotypes (c.*97G > A variant) were observed in only 33 (5.03%) individuals in the studied group. Additionally, the frequency of GA/AA genotypes was over 17.4% in the coagulation factor V. Co-incidence of heterozygous genotype GA of variants FII and FV genes was observed in only 4 subjects.

CONCLUSION

The FII gene variant shown in our study is less frequent than in other European countries (about 6%). In contrast, the A allele of the FV gene occurs with a frequency similar to that of Northern, Central and South Central Europe (about 5%).

Genetic profiling revealed an increased risk of venous thrombosis in the Hungarian Roma population

BACKGROUND

Besides modifiable risk factors, genetic susceptibility may also explain the high cardiovascular disease burden of the Roma population.

OBJECTIVES

Aim of this study was to define the genetic susceptibility of Hungarian Roma to venous thrombosis (VT) and comparing it to that of the general population.

METHODS

Fifty-two SNPs associated with VT (in F2, F5, F9, F11, F15, FGA, FGB, FGG, CYP4V2, KLKB1 and vWF) were selected and analyzed in the group of Roma (N = 962) and general (N = 1492) subjects collected by cross-sectional studies. Allele frequencies and genetic risk scores (GRS, unweighted and weighted) were computed for the study groups and compared to estimate the joint effects of SNPs.

RESULTS

The majority of the susceptible alleles were more prevalent in the Roma population, and both GRS and wGRS were found to be significantly higher in Roma than in the general population (GRS: 41.83 ± 5.78 vs. 41.04 ± 6.04; wGRS: 7.78 ± 1.28 vs. 7.46 ± 1.33, p = .001). Only 2.39% of subjects in the Roma population were in the bottom fifth of the wGRS (wGRS≤0.19) compared with 3.62% of those in the general population (p = .080); 2.88% of the general subjects were in the top fifth of the wGRS (wGRS≥10.02), while 4.26% of the Roma population were (p = .066).

CONCLUSION

In conclusion, the Roma population seems to have increased genetic susceptibility to VT. This might have important implications in the future in identifying possible new opportunities for targeted prevention and treatment for those subgroups in the populations who are at greater risk for VT development.

Sensitized mutagenesis screen in Factor V Leiden mice identifies thrombosis suppressor loci

Factor V Leiden (F5L ) is a common genetic risk factor for venous thromboembolism in humans. We conducted a sensitized N-ethyl-N-nitrosourea (ENU) mutagenesis screen for dominant thrombosuppressor genes based on perinatal lethal thrombosis in mice homozygous for F5L (F5L/L ) and haploinsufficient for tissue factor pathway inhibitor (Tfpi+/- ). F8 deficiency enhanced the survival of F5L/LTfpi+/- mice, demonstrating that F5L/LTfpi+/- lethality is genetically suppressible. ENU-mutagenized F5L/L males and F5L/+Tfpi+/- females were crossed to generate 6,729 progeny, with 98 F5L/LTfpi+/- offspring surviving until weaning. Sixteen lines, referred to as "modifier of Factor 5 Leiden (MF5L1-16)," exhibited transmission of a putative thrombosuppressor to subsequent generations. Linkage analysis in MF5L6 identified a chromosome 3 locus containing the tissue factor gene (F3). Although no ENU-induced F3 mutation was identified, haploinsufficiency for F3 (F3+/- ) suppressed F5L/LTfpi+/- lethality. Whole-exome sequencing in MF5L12 identified an Actr2 gene point mutation (p.R258G) as the sole candidate. Inheritance of this variant is associated with suppression of F5L/LTfpi+/- lethality (P = 1.7 × 10-6), suggesting that Actr2p.R258G is thrombosuppressive. CRISPR/Cas9 experiments to generate an independent Actr2 knockin/knockout demonstrated that Actr2 haploinsufficiency is lethal, supporting a hypomorphic or gain-of-function mechanism of action for Actr2p.R258G Our findings identify F8 and the Tfpi/F3 axis as key regulators in determining thrombosis balance in the setting of F5L and also suggest a role for Actr2 in this process.

Vascular Genetic Variants and Ischemic Stroke Susceptibility in Albanians from the Republic of Macedonia

BACKGROUND

Acute first-ever ischemic stroke (FIS) is a heterogeneous, polygenic disorder. The contribution of vascular genetic variants as inherited causes of ischemic stroke has remained controversial.

AIM

To examine the association of genetic variants in vascular factors with the occurrence of FIS.

MATERIAL AND METHODS

The current research was performed in a group of 39 patients with FIS (study group) and 102 healthy volunteers (control group). We analyzed the prevalence of vascular genetic variants in following genes: factor V, prothrombin, methylenetetrahydrofolate reductase (MTHFR), factor XIII, plasminogen activator 1, endothelial protein C receptor (EPCR), apolipoprotein B, apolipoprotein E, β-fibrinogen, human platelet antigen 1, angiotensin-converting enzyme (ACE), endothelial nitric oxide synthase (eNOS) and lymphotoxin alpha.

RESULTS

It was found that heterozygous LTA 804C>A and FXIII V34L Leu/Leu were significantly more frequent in patients with FIS than in control group (p = 0.036 and p = 0.017, respectively). The frequency of FXIII V34L Val/Val was significantly lower in patients with FIS than in control group (p = 0.020). Other frequencies of vascular gene variants in patients with FIS and in control group were not significantly different.

CONCLUSIONS

This is the first comprehensive study to present data indicating that polymorphism of vascular genes in the prevalence of acute FIS exists in the Albanian population from the Republic of Macedonia. Variations in these genes have been detected in patients with acute FIS, suggesting that their combination might act in a susceptible or protective manner in this Albanian population.

The prevalence of Factor V Leiden, prothrombin G20210A, MTHFR C677T and MTHFR A1298C mutations in healthy Turkish population

BACKGROUND

Factor V Leiden (FVL), prothrombin gene (PT G20210A) and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms are the main biomarkers used in the evaluation of tendency to venous thromboembolism. Our study aimed to investigate the distribution frequencies of these polymorphisms in healthy Turks living in the urban Yozgat region. 

MATERIAL AND METHODS

This study included 90 blood donor candidates. All the donors were apparently healthy, and there was no family relationship between them. Mutations including FVL, PT G20210A, and MTHFR (C677T, A1298C) were investigated in all participants. Screening of polymorphisms was carried out using the SNaPshot® multiplex system.

RESULTS

There were 42 male and 48 female individuals with age range 17-78 years and mean age 47.5 ± 13.6 years. The heterozygous FVL mutation was noted in 17 (10 male and seven female) donors (19%). FVL mutation was more frequently encountered in males than in females (23.8% vs. 12.5%). The heterozygous PT G20210A mutation was observed in five (5.5%) of the 90 (three male, two female) donors. The prevalence of homozygous polymorphisms of MTHFR C677T was 8.8% and of MTHFR A1298C 13.3%. On the other hand, four of the 90 participants (4.4%) carried none of these polymorphisms.

CONCLUSION

This study showed that the prevalence of FVL, PT G20210A, MTHFR C677T and MTHFR A1298C polymorphisms is quite high, and the coexistence of FVL with other genotypes is not rare in a healthy Turkish population living in the Yozgat region. Of course, further detailed studies should be performed to support these findings. Hippokratia 2015; 19 (4): 309-313.

Ethnic diversity in the genetics of venous thromboembolism

Genetic susceptibility is considered as a crucial factor for the development of venous thromboembolism (VTE). Epidemiologic and genetic studies have revealed clear disparities in the incidence of VTE and the distribution of genetic factors for VTE in populations stratified by ethnicity worldwide. While gain-of-function polymorphisms in the procoagulant genes are common inherited factors in European-origin populations, the most prevalent molecular basis for venous thrombosis in Asians is confirmed to be dysfunctional variants in the anticoagulant genes. With the breakthrough of genomic technologies, a set of novel common alleles and rare mutations associated with VTE have also been identified, in different ethnic groups. Several putative pathways contributing to the pathogenesis of thrombophilia in populations of African-ancestry are largely unknown, as current knowledge of hereditary and acquired risk factors do not fully explain the highest risk of VTE in Black groups. In-depth studies across diverse ethnic populations are needed to unravel the whole genetics of VTE, which will help developing individual risk prediction models and strategies to minimise VTE in all populations.

Resilience to orthostasis and haemorrhage: A pilot study of common genetic and conditioning mechanisms

A major challenge presently is not only to identify the genetic polymorphisms increasing risk to diseases, but to also find out factors and mechanisms, which can counteract a risk genotype by developing a resilient phenotype. The objective of this study was to examine acquired and innate vagal mechanisms that protect against physical challenges and haemorrhages in 19 athletes and 61 non-athletes. These include examining change in heart rate variability (HF-HRV; an indicator of vagus activity) in response to orthostatic challenge, platelet count (PLT), mean platelet volume (MPV), and single-nucleotide polymorphisms in genes that encode several coagulation factors, PAI-1, and MTHFR. Individual differences in PLT and MPV were significant predictors, with opposite effects, of the profiles of the HF-HRV changes in response to orthostasis. Regular physical training of athletes indirectly (through MPV) modifies the genetic predisposing effects of some haemostatic factors (PAI-1 and MTHFR) on vagal tone and reactivity. Individual differences in vagal tone were also associated with relationships between Factor 12 C46T and Factor 11 C22771T genes polymorphisms. This study showed that genetic predispositions for coagulation are modifiable. Its potential significance is promoting advanced protection against haemorrhages in a variety of traumas and injuries, especially in individuals with coagulation deficits.

Risk of Budd-Chiari syndrome associated with factor V Leiden and G20210A prothrombin mutation: a meta-analysis

Background

Various studies have demonstrated that factor V Leiden (FVL) and G20210A prothrombin mutation contribute to the risk of Budd-Chiari syndrome (BCS), while other studies provided conflicting findings. In order to derive more precise estimations of the relationships, a meta-analysis was performed.

Methods

Eligible articles were identified through search of databases including Pubmed, Chinese Biomedical Database (CBM, Chinese), and Chinese National Knowledge Infrastructure (CNKI, Chinese). Odd ratios (ORs) with 95% confidence intervals (CIs) were calculated using random- or fixed- model.

Results

Finally, twelve studies were included for FVL and nine studies were included for G20210A prothrombin mutation. With respect to FVL, significantly increased BCS risk was found in the overall population (OR = 6.29, 95%CI = 4.23–9.36). Subgroup analyses suggested that FVL was associated with an increased risk of BCS in the population with high background mutation prevalence (>1% in the normal population). No significant association was found between BCS and G20210A prothrombin mutation (OR = 1.78, 95%CI = 0.77–4.11).

Conclusion

The presence of FVL should be evaluated in patients with BCS. Conversely, G20210A prothrombin mutation is not significantly associated with risk of BCS. Large-scale well designed studies are necessary to be conducted to further confirm or refute the observed association.