No abstract

Congenital fibrinogen disorders are caused by mutations in one of the three fibrinogen genes that affect the synthesis, assembly, intracellular processing, stability or secretion of fibrinogen. Functional studies of mutant Bβ-chains revealed the importance of individual residues as well as three-dimensional structures for fibrinogen assembly and secretion. This study describes two novel homozygous fibrinogen Bβ chain mutations in two Slovak families with afibrinogenemia and hypofibrinogenemia. Peripheral blood samples were collected from all subjects with the aim of identifying the causative mutation. Coagulation-related tests and rotational thromboelastometry were performed. All exons and exon–intron boundaries of the fibrinogen genes (FGA, FGB and FGG) were amplified by PCR followed by direct sequencing. Sequence analysis of the three fibrinogen genes allowed us to identify two novel homozygous mutations in the FGB gene. A novel Bβ chain truncation (BβGln180Stop) was detected in a 28-year-old afibrinogenemic man with bleeding episodes including repeated haemorrhaging into muscles, joints, and soft tissues, and mucocutaneous bleeding and a novel Bβ missense mutation (BβTyr368His) was found in a 62-year-old hypofibrinogenemic man with recurrent deep and superficial venous thromboses of the lower extremities. The novel missense mutation was confirmed by molecular modelling. Both studying the molecular anomalies and the modelling of fibrinogenic mutants help us to understand the extremely complex machinery of fibrinogen biosynthesis and finally better assess its correlation with the patient’s clinical course.

Background Mild antithrombin deficiency (previously defined as antithrombin activity below 70% or 80%) has been associated with a 2.4-3.5-fold increased risk of recurrent venous thromboembolism (VTE). This finding may have implications for duration of antithrombotic therapy in VTE patients with mild antithrombin deficiency. Objectives To externally validate whether mild antithrombin deficiency is a risk factor for recurrent VTE. Methods In a population-based cohort study, patients with a first VTE (n = 2357) were stratified according to percentile cut-off antithrombin levels (< 5th [< 87%], 5-10th [87-92%], > 10th percentile [> 92%]) and functional antithrombin levels (< 70%, 70-80%, > 80%). Results During a median follow-up of 7.4 years, 361 recurrent events occurred (incidence rate, 2.5/100 patient-years). We observed an increased risk of recurrent VTE in the lowest antithrombin activity category (< 5th percentile; < 87%) as compared with antithrombin activity that was > 10th percentile (> 92%), with an adjusted hazard ratio (HR) of 1.5 (95%CI, 1.0-2.3). When analyses were stratified to antithrombin cut-off criteria of< 70% vs. patients with antithrombin activity > 80%, the adjusted HR for venous recurrence was 3.7 (95% CI, 1.4-9.9). Mild antithrombin deficiency was able to predict recurrent VTE over at least 8 years of follow-up and the association remained present when the population was stratified to the presence or absence of thrombosis risk factors. Restriction analyses, where patients who used anticoagulation at time of blood draw and those who reported drinking ≥ 5 glasses alcohol daily were excluded, did not materially affect these outcomes. Conclusion This study confirms that mild antithrombin deficiency is a risk factor for recurrent VTE.

The aim of this study was to evaluate the genetic variability of the selected single nucleotide polymorphisms (SNPs) and examine the association between these SNPs and risk for deep vein thrombosis (DVT) in patients with sticky platelet syndrome (SPS). We examined 84 patients with SPS and history of DVT and 101 healthy individuals. We were interested in 2 SNPs within platelet endothelial aggregation receptor 1 (PEAR1) gene (rs12041331 and rs12566888), 2 SNPs within mkurine retrovirus integration site 1 gene (rs7940646 and rs1874445), 1 SNP within Janus kinase 2 gene (rs2230722), 1 SNP within FCER1G gene (rs3557), 1 SNP within pro-platelet basic protein (rs442155), 4 SNPs within alpha2A adrenergic receptor 2A (ADRA2A; rs1800545, rs4311994, rs11195419, and rs553668), and 1 SNP within sonic hedgehog gene (rs2363910). We identified 2 protective SNPs within PEAR1 gene and 1 risk SNP within ADRA2A gene (PEAR1: rs12041331 and rs12566888; ADRA2A: rs1800545). A haplotype analysis of 4 SNPs within ADRA2A gene identified a risk haplotype aagc ( P = .003). Moreover, we identified 1 protective haplotype within PEAR1 gene (AT, P = .004). Our results support the idea that genetic variability of PEAR1 and ADRA2A genes is associated with platelet hyperaggregability manifested as venous thromboembolism. The study also suggests a possible polygenic type of SPS heredity.

The exact pathogenesis of SPS is not sufficiently explained. Our findings seem to support the idea that SPS might have an autosomal dominant hereditary fashion.

The patient database at the First Department of Internal Medicine in Martin, the Central Slovak Institute for Cardiac and Vascular Diseases in Banska Bystrica, and the National Slovak Institute of Cardiovascular Diseases in Bratislava was searched to identify patients with benign tumors of the heart seen during the 5-year period between 2011 and 2016. Forty-one patients with primary cardiac myxomas were identified and their medical records were reviewed for details pertaining to presenting symptoms, staging modalities, treatment approaches, and outcomes. Most of the studied patients were diagnosed with echocardiography (n = 35, 85%). The occurrence of the tumor was higher in the female population (n = 25, 61%). The most common presenting symptoms were dyspnoea (n = 17, 42%), chest pain (n = 3, 7%), or pain and paraesthesia of the limbs (n = 2, 5%). Acute embolic event due to embolization of tumor fragments resulted in cerebral stroke (n = 5, 12%). All patients were treated by resection. Only one comorbid patient died due to multiple-organ dysfunction syndrome two weeks after the resection. The most common postoperative complication was bleeding (n = 2, 5%) and infection (n = 2, 5%). The early diagnosis and appropriate treatment are often curative, with very low risk of recurrence. Postoperative survival is high.

Sequencing of the gene encoding for von Willebrand factor (VWF) has brought new insight into the physiology of VWF as well as its pathophysiology in the context of von Willebrand disease (VWD). Molecular testing in VWD patients has shown high variability in the overall genetic background of this condition. Almost 600 mutations and many disease-causing mechanisms have been described in the 35 years since the VWF gene was identified. Genetic testing in VWD patients is now available in many centers as a part of the VWD diagnostic algorithm. Molecular mechanisms leading to types 2 and 3 VWD are well characterized; thus, information from genetic analysis in these VWD types may be beneficial for their correct classification. However, the molecular basis of type 1 VWD is still not fully elucidated and most likely represents a multifactorial disorder reflecting a combined impact of environmental and genetic factors within and outside of VWF. Regarding sequencing methods, the previous gold-standard Sanger sequencing is gradually being replaced with next-generation sequencing methods that are more cost- and time-effective. Instead of gene-by-gene approaches, gene panels of genes for coagulation factors and related proteins have recently become a center of attention in patients with inherited bleeding disorders, especially because a high proportion of VWD patients, mainly those with low VWF plasma levels (type 1), appear to be free of mutations in VWF. Whole-exome sequencing (WES) and whole-genome sequencing (WGS) are accessible in a very limited number of laboratories. Results from these studies have presented several genes other than VWF or ABO possibly affecting VWF levels, and such findings will need further validation studies.

Background: Rotational thrombelastometry (ROTEM) is a real-time clotting test that provides insight into clotting factors, the fibrinolytic system and platelet function. We obtained the longitudinal values on ROTEM in normal pregnancy and in puerperium. Material and Methods: After ethics committee approval and subject informed consent, citrated blood was sampled from healthy pregnants four times during pregnancy and one time postpartum. As controls we used nonpregnant women undergoing voluntary blood donation. Extem and Intem tests and basic coagulation test were carried out. Results: We included 112 women in our study, 55 non-pregnant women (controls) and 57 healthy pregnants with 5 samplings. The values of maximum clot firmness (MCF - in EXTEM and INTEM) were significantly higher up to 34th-36th week of pregnancy than those in non-pregnant subjects. MCF in 6th-7th week after delivery was significantly higher in both tests. Clotting time (CT) in pregnant women was significantly shorter (EXTEM) compared to non-pregnant subjects. We also found a very strong correlation between MCF and platelet count in all gestational weeks.' Conclusions: Rotation thromboelastometry clearly demonstrates the hypercoagulability in pregnancy and can reflect the higher risk of venous thromboembolism in both pregnancy and puerperium. Strong correlation between MCF and platelet count can suggest role of platelets in hypercoagulability in pregnant women. This study provides a better knowledge about physiological changes in ROTEM measurement during pregnancy and postpartum.