Susceptibility to pre-eclampsia in Finnish women is associated with R485K polymorphism in the factor V gene, not with Leiden mutation

Factor V Leiden-independent activated protein C resistance: Communication from the plasma coagulation inhibitors subcommittee of the International Society on Thrombosis and Haemostasis Scientific and Standardisation Committee

Activated protein C resistance (APC-R) due to the single-nucleotide polymorphism factor V Leiden (FVL) is the most common cause of hereditary thrombophilia. It is found predominantly in Caucasians and is uncommon or absent in other populations. Although FVL is responsible for >90% of cases of hereditary APC-R, a number of other F5 variants that also confer various degrees of APC-R and thrombotic risk have been described. Acquired APC-R due to increased levels of coagulation factors, reduced levels of inhibitors, or the presence of autoantibodies occurs in a variety of conditions and is an independent risk factor for thrombosis. It is common for thrombophilia screening protocols to restrict assessment for APC-R to demonstrating the presence or absence of FVL. The aim of this Scientific and Standardisation Committee communication is to detail the causes of FVL-independent APC-R to widen the diagnostic net, particularly in situations in which in vitro APC-R is encountered in the absence of FVL. Predilution clotting assays are not FVL specific and are used to detect clinically significant F5 variants conferring APC-R, whereas different forms of acquired APC-R are preferentially detected using the classical activated partial thromboplastin time-based APC-R assay without predilution and/or endogenous thrombin potential APC-R assays. Resource-specific recommendations are given to guide the detection of FVL-independent APC-R.

A novel mutation (Ser951LeufsTer8) in F5 gene leads to hereditary coagulation factor V deficiency

The current study aims to explore the phenotype and genotype of a novel mutation (Ser951LeufsTer8) of F5 gene combined with polymorphism (R485K) in a family of hereditary coagulation factor V deficiency. The factor V activity and antigen were tested with clotting assay and ELISA. The F5 gene was amplified by PCR with direct sequencing and TA-clone-sequenced. The protein structure and harmfulness of the mutation were studied by Swiss-PdbViewer and bioinformatics software. The prothrombin time and activated partial thromboplastin time of proband were significantly prolonged, factor V activity and factor V antigen both were reduced to less than 20%. Sequencing analysis detected proband with Ser951LeufsTer8 and R485K (Arg513Lys), four family members with novel mutation and their factor V activity and factor V antigen were all decreased about 50%. The Ser951LeufsTer8 is associated with decrease in the factor V level of the family, and it is the first mutation report in the position (Ser951LeufsTer8) with factor V deficiency.

Association of hypertensive disorders of pregnancy risk and factor V Leiden mutation: A meta-analysis

AIM

To date, the conclusions of studies on a possible association between factor V Leiden (FVL, FV G1691A, rs6025) and hypertensive disorders of pregnancy (HDP) are conflicting. Here, we aimed to estimate the relationship between the risk of HDP and FVL.

METHODS

Eligible studies focused on FVL and HDP were searched from the PubMed and the Web of Science databases up to March 31, 2018. We used random effects model for the meta-analysis, and I² statistic to assess the degree of heterogeneity between all included studies. To evaluate the association between FVL and the risk of HDP, we calculated the odds ratio (OR) and 95% confidence intervals (CI) comparing cases and controls of all samples and each subgroup based on different regions.

RESULTS

Fifty citations on FVL and HDP were identified through the literature search, and a meta-analysis on the GA + AA genotype between 6041 cases and 8364 controls was conducted. The holistic analysis found that pregnant women with GA or AA genotype of FVL have a 1.97-fold (95% CI: 1.64-2.35, P < 0.00001) increased risk of HDP compared with GG carriers. While the OR are 2.23 (95% CI: 1.76-2.84, P < 0.00001) and 1.90 (95% CI: 1.12-3.23, P = 0.02) in Europe and the Middle East subgroups, respectively.

CONCLUSION

Factor V Leiden mutation is associated with an increased risk of HDP, and is particularly associated with preeclampsia and eclampsia in European women. However, further high-quality studies are warranted to confirm the possible effectiveness of FVL in HDP patients.

Association between thrombophilia gene polymorphisms and preeclampsia: a meta-analysis

OBJECTIVE

To estimate the relationship between the risk of preeclampsia and two thrombophilia gene single-nucleotide polymorphisms (SNPs), the factor V G1691A SNP and the prothrombin G20210A SNP.

DATE SOURCES

A systematic search of the English-language literature up to November 2012 was performed using Medline and EMBASE. Search terms included "preeclampsia," "thrombophilia," "factor V Leiden," "prothrombin gene 20210," and their combinations.

RESULT(S)

Thirty-seven studies with 5048 preeclampsia patients and 6796 controls were included in the meta-analysis. We found that the prothrombin G20210A polymorphism was associated with an increased risk of all preeclampsia (pooled odds ratio (OR) = 1.81, 95% confidence interval (CI) 1.25-2.63) and severe preeclampsia (pooled OR = 3.02, 95%CI 2.06-4.45). Meanwhile, the pooled OR for the association between factor V Leiden and all preeclampsia was 1.60 (95%CI 1.28-2.00) and 2.45 (95%CI 1.63-3.69) for the cases of severe preeclampsia.

CONCLUSION(S)

This meta-analysis supports that the factor V G1691A SNP and the prothrombin G20210A SNP are associated with an increased risk for both preeclampsia overall and severe preeclampsia.

Pathogenesis of preeclampsia: the genetic component

Preeclampsia (PE) is one of the main causes of maternal and fetal morbidity and mortality in the world, causing nearly 40% of births delivered before 35 weeks of gestation. PE begins with inadequate trophoblast invasion early in pregnancy, which produces an increase in oxidative stress contributing to the development of systemic endothelial dysfunction in the later phases of the disease, leading to the characteristic clinical manifestation of PE. Numerous methods have been used to predict the onset of PE with different degrees of efficiency. These methods have used fetal/placental and maternal markers in different stages of pregnancy. From an epidemiological point of view, many studies have shown that PE is a disease with a strong familiar predisposition, which also varies according to geographical, socioeconomic, and racial features, and this information can be used in the prediction process. Large amounts of research have shown a genetic association with a multifactorial polygenic inheritance in the development of this disease. Many biological candidate genes and polymorphisms have been examined in their relation with PE. We will discuss the most important of them, grouped by the different pathogenic mechanisms involved in PE.

CDKN1C mutations in HELLP/preeclamptic mothers of Beckwith-Wiedemann Syndrome (BWS) patients

Preeclampsia is the development of new-onset hypertension with proteinuria after 20 weeks of gestation. HELLP syndrome (haemolysis, elevated liver enzymes, and low platelet count) is a severe form of preeclampsia with high rates of neonatal and maternal morbidity. In recent years, loss of function of cdkn1c (a tight-binding inhibitor of G1 cyclin/cyclin-dependent kinase complexes and a negative regulator of cell proliferation) has been observed in several mouse models of preeclampsia. In this paper, we report on three women with HELLP/preeclampsia who had children with Beckwith Wiedemann syndrome, a complex genetic disorder characterised, among other findings, by overgrowth, omphalocele and macroglossia. All three children displayed mutations in CDKN1C predicted to generate truncated proteins. Two of the mutations were maternally inherited while the third was de novo. This finding suggests a fetal contribution to the maternal disease. To the best of our knowledge this is the first report of CDKN1C mutations in children born to women with preeclampsia/HELLP syndrome, thus suggesting the involvement of an imprinted gene in the pathophysiology of preeclampsia.

Inherited defects of coagulation Factor V: the thrombotic side

DNA variations in the Factor V gene have played a major role in thrombosis research ever since the discovery of Factor V Leiden. Here, all relatively common DNA variations in the coding regions of the Factor V gene are discussed. Many of them have been associated with venous thrombosis or related diseases. However, most variations have been studied separately, without taking the presence of other variations in the same gene into account. This means that their association with disease should be interpreted with caution, as it may reflect linkage with another variation. An approach in which a haplotype-based analysis of the Factor V gene is combined with in vitro assays of recombinant proteins is advocated. Finally, a possible reason for the relatively polymorphic nature of the Factor V protein is discussed.

M385T polymorphism in the factor V gene, but not Leiden mutation, is associated with placental abruption in Finnish women

This study determines whether genetic variability in the gene encoding factor V contributes to differences in susceptibility to placental abruption. Allele and genotype frequencies of three single nucleotide polymorphisms (SNPs) in the factor V gene leading to nonsynonymous changes (M385T in exon 8, and R485K and R506Q [Leiden mutation] in exon 10) were studied in 116 Caucasian women with placental abruption and 112 healthy controls. Single-point analysis was expanded to haplotype analysis and haplotype frequencies were estimated using an expectation-maximisation (EM) algorithm. Comparison of single-point allele and genotype distributions of SNPs in exon 8 and exon 10 of the factor V gene revealed statistically significant differences in M385T allele (P = 0.021) and genotype ( P = 0.013) frequencies between the patients and the control subjects. The C allele of SNP M385T was significantly less frequent among the patients (7%) vs. the control subjects (13%), at an odds ratio of 0.48 (95% CI 0.25-0.91). Allele and genotype differences between the patients and control subjects as regards R485K and Leiden mutation were not significant. In haplotype estimation analysis, there was a significantly lower frequency of haplotype T-R-R encoding the T385-R485-R506 variant in the group with placental abruption vs. the control group (P = 0.038) at an odds ratio of 0.519 (95% CI 0.272-0.987). We conclude that T385 is less frequent among the patient group than in the control group. The M385T variant in the factor V gene other than the Leiden mutation may play a role in disease susceptibility.