Hypofibrinogenemia and the α-Fibrinogen Thr312Ala Polymorphism may be Risk Factors for Early Pregnancy Loss

Factor VII R353Q (rs6046), FGA A6534G (rs6050), and FGG C10034T (rs2066865) Gene Polymorphisms and Risk of Recurrent Pregnancy Loss in Iranian Women

Recurrent pregnancy loss is a multi factorial and heterogeneous disorder defined as two or more consecutive pregnancy losses before 20 weeks' gestation. Gene polymorphisms including factor VII R353Q (rs6046), fibrinogen alpha chain A6534G (rs6050) and fibrinogen gamma chain C10034T (rs2066865) have potential role in thrombophilia and the relation between these three polymorphisms and an increased risk of venous thrombosis have been reported. As thrombophilia is associated with a considerable proportion of pregnancy loss and the association between these gene polymorphisms and recurrent pregnancy loss remains controversial, the aim of the present study was to evaluate the relation of these polymorphisms and recurrent pregnancy loss in Iranian women. A total of 144 women with a history of two or more consecutive miscarriages as the patient group and 150 healthy women with two live births and no history of pregnancy loss as the control group were included in the study. Polymerase chain reaction and restriction fragment length polymorphism were used for genotyping. The results were validated by DNA sequencing. The SPSS, SNPStats and Finch TV were used to analyze the results. Factor VII R353Q (rs6046) gene polymorphism showed a significant difference between RPL patients and the control group according to multiple logistic regression models [codominant (OR=0.38; 95% CI=0.23-0.63, P≤0.0001), dominant (OR=0.32; 95% CI=0.20-0.52, P≤0.0001), over dominant (OR=0.46; 95% CI=0.29-0.75, P=0.0017) and log-additive (OR=0.35; 95% CI=0.23-0.53, P≤0.0001)]. Fibrinogen alpha chain A6534G (rs6050) and fibrinogen gamma chain C10034T (rs2066865) gene polymorphisms showed no correlation with recurrent pregnancy loss. Factor VII R353Q (rs6046) gene polymorphism can be considered a risk factor for recurrent pregnancy loss. Further studies in larger populations are needed to confirm the findings.

Methylenetetrahydrofolate Reductase 677T Allele Is a Risk Factor for Arterial Thrombosis in Chinese Han Patients with Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by the persistent presence of antiphospholipid antibodies (aPL) and thrombotic or obstetric events. Given the heterogeneity of the clinical manifestations, it is likely that genetic and acquired factors are involved in the pathogenesis of APS. The inherited polymorphisms of the thrombophilic gene, including methylenetetrahydrofolate reductase (MTHFR) C677T, type 1 plasminogen activator inhibitor (PAI-1) 4G/5G, factor V Leiden (FVL) G1691A, prothrombin (PT) G20210A, antithrombin (AT), and fibrinogen (Fg) polymorphisms, were analyzed in 67 aPL(+) patients from the Chinese Han population, including 41 APS patients and 26 persistent aPL carriers. The MTHFR C677T genotypes of 105 healthy controls, and the PAI-1 4G/5G polymorphism of 120 healthy controls, from the Chinese Han population were acquired for this study. Both the MTHFR C677T genotype (χ² = 10.67, p = 0.004) and C/T allele distribution (χ² = 5.92, p = 0.019) between the aPL(+) patients and healthy controls were found to be significantly different. Furthermore, we observed that the patients with at least one T allele had a higher risk of arterial thrombosis (CT vs. CC, OR 11.00, p= 0.025; CT + TT vs. CC, OR 10.27, p = 0.018). The C677T mutation of MTHFR is a risk factor for arterial thrombosis in Chinese Han patients with APS.

Hypofibrinogenemia and miscarriage: report of a first successful pregnancy under fibrinogen substitution and short review of the literature

Disorders of fibrinogen have been reported to be associated not only with bleeding and thrombosis but also with miscarriage. Here, we report the case of a woman with genetically determined hypofibrinogenemia and recurrent miscarriages who had a first successful pregnancy under fibrinogen substitution. Current knowledge on fibrinogen disorders and recurrent miscarriages is briefly summarized and discussed.

Extension of the Human Fibrinogen Database with Detailed Clinical Information—The αC-Connector Segment

Fibrinogen, an abundant plasma glycoprotein, is involved in the final stage of blood coagulation. Decreased fibrinogen levels, which may be caused by mutations, are manifested mainly in bleeding and thrombotic disorders. Clinically relevant mutations of fibrinogen are listed in the Human Fibrinogen Database. For the αC-connector (amino acids Aα240–410, nascent chain numbering), we have extended this database, with detailed descriptions of the clinical manifestations among members of reported families. This includes the specification of bleeding and thrombotic events and results of coagulation assays. Where available, the impact of a mutation on clotting and fibrinolysis is reported. The collected data show that the Human Fibrinogen Database reports considerably fewer missense and synonymous mutations than the general COSMIC and dbSNP databases. Homozygous nonsense or frameshift mutations in the αC-connector are responsible for most clinically relevant symptoms, while heterozygous mutations are often asymptomatic. Symptomatic subjects suffer from bleeding and, less frequently, from thrombotic events. Miscarriages within the first trimester and prolonged wound healing were reported in a few subjects. All mutations inducing thrombotic phenotypes are located at the identical positions within the consensus sequence of the tandem repeats.

Association of fibrinogen and plasmin inhibitor, but not coagulation factor XIII gene polymorphisms with coronary artery disease

BACKGROUND

In the final phase of clot formation, fibrinogen constitutes frame, whereas factor XIII (FXIII) active form is responsible for the covalent cross-linking of fibrin fibres and plasmin inhibitor (PI), thus contributing to clot stability. It could be expected that any change of coagulation factors' structure affects the clot formation and modulates the atherothrombotic risk. The aim was to determine the frequency of four single nucleotide polymorphisms: (i) A > G in codon 312 of the fibrinogen α-chain gene (rs6050, Thr312AlaFGA), (ii) C > T at position 10034 of the 3 - untranslated region in the fibrinogen γ-chain gene (rs2066865, 10034C > T FGG), (iii) C > T in codon 564 of the FXIII-A subunit gene (rs5982, Pro564LeuFXIII-A), and (iv) C > T in codon 6 of the plasmin inhibitor gene (rs2070863, Arg6TrpPI) in Croatian patients and their association with coronary artery disease (CAD).

METHODS

We performed the unrelated case-control association study on the consecutive sample of patients 18 years old, who had undergone coronary angiography for investigation of chest pain and suspected CAD. The cases were patients with confirmed CAD (N=201), and the controls were the subjects with no CAD (N=119). Samples were genotyped using PCR-RFLP analysis.

RESULTS

Observed frequencies of the rare alleles of Thr312Ala FGA, 10034C > T FGG, Leu564Pro FXIII-A and Arg6Trp PI polymorphisms were 21%, 17%, 14%, 20%, respectively. Patients with 10034C > T FGG CC genotype had 3.5 times (95% CI 1.02-12.03) higher adjusted odds for CAD than patients with 10034C > T FGG TT genotype. Patients with Arg6Trp PI CC genotype had 3.86 times (95% CI 1.23-12.12) higher odds for CAD than patients with Arg6Trp PI TT genotype. It seems that those genotype-related higher odds are also male-gender related. No difference was observed regarding any other investigated polymorphism.

CONCLUSIONS

Our finding suggests that 10034C > T FGG and Arg6Trp PI are associated with CAD.

Retrospective study of pregnancies in women with Thr331Ala fibrinogen polymorphisms

Background: We aimed to retrospectively review data of pregnant women with the α-fibrinogen Thr331Ala polymorphism; evaluate the relationship between this polymorphism and spontaneous abortion (SA), fetal growth restriction (FGR), and intrauterine fetal death (IUFD); and assess the effects of aspirin and/or heparin.Materials and methods: We examined the outcomes of 29 pregnancies (nine women) in women with the α-fibrinogen Thr331Ala polymorphism. Of these, 16 were untreated, whereas 13 were treated with heparin and/or aspirin.Results: The live birth rate was significantly higher in the treated group than in the nontreated group (69.2 versus 6.2%; p = .0004). In addition, the prophylactic use of a low dose of aspirin and/or heparin during early pregnancy in women with Thr331Ala may be an effective method for reducing fetal loss in these patients.Conclusions: This polymorphism interacts with pregnancy to result in poor obstetrical outcomes, but these effects can be mitigated with medical intervention. This study is the first to report outcomes of pregnancies complicated by the Thr331Ala polymorphism, which we believe may cause thrombophilia, SA, and IUFD. This study highlights the need for further research on this polymorphism in pregnancy.