EXAMINING VARIABILITY IN THE DIAGNOSIS AND MANAGEMENT OF PEOPLE WITH BLEEDING DISORDERS OF UNKNOWN CAUSE: COMMUNICATION FROM THE ISTH SSC SUBCOMMITTEE ON VON WILLEBRAND FACTOR.

BACKGROUND: Bleeding disorder of unknown cause (BDUC) is characterised by a bleeding phenotype in the setting of normal haemostatic testing. No standardised diagnostic criteria or treatment algorithms exist for people with BDUC. To address the unmet need, the International Society on Thrombosis and Haemostasis von Willebrand Factor Scientific Subcommittee (ISTH VWF SCC) performed a real-world survey, aimed at addressing knowledge gaps, developing consensus pathways and ultimately improving care. OBJECTIVES AND METHODS: We sought to determine current international clinical practices in the investigation, registration, and treatment of people with BDUC through an online structured survey of health care providers (HCPs) who managed patient with bleeding disorders. RESULTS: Two hundred and sixteen respondents from 39 countries were included in the final analysis. The clinical assessment of those with a possible bleeding disorder varied, with only 55% excluding hypermobility but high levels (80%) of bleeding assessment tools (BAT) usage. In haemostatic testing only the prothrombin time (PT) and activated partial thromboplastin time (APTT) tests gained universal support. Tranexamic acid (TXA) was favoured for prophylaxis for minor (71%)/major (59%) surgeries and pregnancy (58%) but advice on the treatment advised if bleeding occurred was heterogeneous. The management of heavy menstrual bleeding (HMB) in women despite combined oral contraceptive pill (COCP) use also proved challenging with HCPs selecting multiple alternative strategies. CONCLUSION: Significant variation exists in the recognition, registration and management of people with BDUC worldwide. This survey emphasises the need for consensus pathways to diagnose and treat BDUC to standardise and improve care for patients internationally.

2-years retrospective observational case-control study on survival and marginal bone loss of implants in patients with hereditary coagulopathies

Background: Evaluating 2-years implant loss and marginal bone loss in patients with hereditary coagulopathies, comparing with a healthy control group. Material and Methods: 37 implants in 13 patients (17 haemophilia A, 20 Von-Willebrand disease) versus 26 implants in 13 healthy patients. Data measured through Lagervall-Jansson index (after surgery, at prosthetic loading, at 2 years). Statistics: Chi-square, Haberman’s, ANOVA, Mann-Whitney-U. Significance p<0.05. Results: Haemorrhagic accidents in 2 coagulopathies patients (non-statistical differences). Hereditary coagulopathies patients suffered more hepatitis (p<0.05), HIV (p<0.05) and less previous periodontitis (p<0.01). Non-statistical differences in marginal bone loss among groups. 2 implants were lost in the hereditary coagulopathies and none in the control group (non-statistical differences). Hereditary coagulopathies patients had longer (p<0.001), and narrower implants (p<0.05) placed. 43.2% external prosthetic connection in hereditary coagulopathies patients (p<0.001); change of prosthetic platform more frequent in control group (p<0.05). 2 implants lost: external connection (p<0.05). Survival rate 96.8% (hereditary coagulopathies 94.6%, control group 100%). Conclusions: Implant and marginal bone loss at 2 years is similar in patients with hereditary coagulopathies and control group. Precautions should be taken on the treatment for hereditary coagulopathies patients, through prior haematological protocol. Implant loss only occurred in in a patient with Von-Willebrand´s disease. (AU)

Postmortem diagnosis of severe factor X deficiency in a fetus with intracranial hemorrhage resulting in intrauterine death.

In patients with severe congenital factor X deficiency, spontaneous intracranial hemorrhage (ICH) is particularly frequent in early childhood. We describe a case of fetal death at 26 weeks due to massive ICH. Gene panel analysis of postmortem samples revealed homozygosity for a pathologic F10 gene variant (c.1210T>C, p.Cys404Arg), which impedes correct folding of the catalytic serine protease domain and, therefore, causes a significant reduction in FX levels. The parents, not consanguineous but of the same ethnic community, were found to be heterozygous for this variant and did not have any personal or family history of abnormal bleeding. To the best of our knowledge, this is the first reported case of severe FX deficiency resulting in ICH diagnosed through postmortem genetic analysis. It illustrates the importance of exploring the etiology of fetal or neonatal ICH, which may impact future pregnancies, and the treatment of a potential coagulopathy in the child.

An updated interactive database for 1692 genetic variants in coagulation factor IX provides detailed insights into hemophilia B.

BACKGROUND: Genetic variants in coagulation factor IX (FIX) are associated with hemophilia B, a rare bleeding disease. F9 variants are widespread across the gene and were summarized in our FIX variant database introduced in 2013. OBJECTIVES: We aimed to rationalize the molecular basis for 598 new F9 variants and 1645 new clinical cases, totaling 1692 F9 variants and 5358 related patient cases. METHODS: New F9 variants were identified from publications and online resources, and compiled into a MySQL database for comparison with the human FIXa protein structure. RESULTS: The new total of 1692 F9 variants correspond to 406 (88%) of the 461 FIX residues and now include 70 additional residues. They comprise 945 unique point variants, 281 deletions, 352 polymorphisms, 63 insertions, and 51 others. Most FIX variants were point variants, although their proportion (56%) has reduced compared to 2013 (73%); at the same time, the proportion of polymorphisms has increased from 5% to 21%. The 764 unique mild severity variants in the mature protein with known phenotypes include 74 (9.7%) quantitative type I variants and 116 (15.2%) predominantly qualitative type II variants. The remaining 574 variants types are unspecified. Inhibitors are associated with 152 hemophilia B cases out of 5358 patients (2.8%), an increase of 93 from the previous database. CONCLUSION: The even distribution of the F9 variants revealed few mutational hotspots, and most variants were associated with small perturbations in the FIX protein structure. The updated database will assist clinicians and researchers in assessing treatments for patients with hemophilia B.

Invasive procedures in the oral cavity of individuals with Bernard-Soulier syndrome: An integrative review.

AIM: Bernard-Soulier syndrome (BSS) is an inherited bleeding disorder characterized by macroplatelets and thrombocytopenia, prolonged bleeding time, and a prevalence of less than 1 in 1,000,000. In view of the recognition of the risk of bleeding and the management of daily surgical practice in these patients, adequate strategies are necessary to provide the safest care. This article aims to perform an integrative review of the literature on the management of invasive procedures in the oral cavity of individuals with BSS. METHOD: The PubMed/Medline and LILACS databases were searched using Boolean operators related to BSS, bleeding disorders, and oral care. RESULTS: As a result, only five articles with the main theme were included: one letter to the editor and four case reports, described chronologically as to date of publication, classification of the article, and medical/odontological measures taken. CONCLUSION: We conclude with this review the need for adequate knowledge of surgeons regarding coagulation disorders and the need to discuss and plan procedures with the hematology team, as well as the importance of the notion of management of possible complications resulting from invasive treatments in the oral cavity of patients with BSS.

Major differences in clinical presentation, diagnosis and management of men and women with autosomal inherited bleeding disorders.

BACKGROUND: In recent years, more awareness is raised about sex-specific dilemmas in inherited bleeding disorders. However, no large studies have been performed to assess differences in diagnosis, bleeding phenotype and management of men and women with bleeding disorders. Therefore, we investigated sex differences in a large cohort of well-defined patients with autosomal inherited bleeding disorders (von Willebrand disease (VWD), rare bleeding disorders (RBDs) and congenital platelet defects (CPDs)). METHODS: We included patients from three nationwide cross-sectional studies on VWD, RBDs and CPDs in the Netherlands, respectively the WiN, RBiN and TiN study. In all studies a bleeding score (BS) was obtained, and patients filled in an extensive questionnaire on the management and burden of their disorder. FINDINGS: We included 1092 patients (834 VWD; 196 RBD; 62 CPD), of whom 665 (60.9%) were women. Women were more often referred because of a bleeding diathesis than men (47.9% vs 36.6%, p = 0.002). Age of first bleeding was similar between men and women, respectively 8.9 ± 13.6 (mean ±sd) years and 10.6 ± 11.3 years (p = 0.075). However, the diagnostic delay, which was defined as time from first bleeding to diagnosis, was longer in women (11.6 ± 16.4 years) than men (7.7 ± 16.6 years, p = 0.002). Similar results were found when patients referred for bleeding were analyzed separately. Of women aging 12 years or older, 469 (77.1%) had received treatment because of sex-specific bleeding. INTERPRETATION: Women with autosomal inherited bleeding disorders are more often referred for bleeding, have a longer diagnostic delay, and often require treatment because of sex-specific bleeding. FUNDING: The WiN study was supported (in part) by research funding from the Dutch Hemophilia Foundation (Stichting Haemophilia), Shire (Takeda), and CSL Behring (unrestricted grant).

Analysis of 272 Genetic Variants in the Upgraded Interactive FXI Web Database Reveals New Insights into FXI Deficiency.

Coagulation Factor XI (FXI) is a plasma glycoprotein composed of four apple (Ap) domains and a serine protease (SP) domain. FXI circulates as a dimer and activates Factor IX (FIX), promoting thrombin production and preventing excess blood loss. Genetic variants that degrade FXI structure and function often lead to bleeding diatheses, commonly termed FXI deficiency. The first interactive FXI variant database underwent initial development in 2003 at https://www.factorxi.org . Here, based on a much improved FXI crystal structure, the upgraded FXI database contains information regarding 272 FXI variants (including 154 missense variants) found in 657 patients, this being a significant increase from the 183 variants identified in the 2009 update. Type I variants involve the simultaneous reduction of FXI coagulant activity (FXI:C) and FXI antigen levels (FXI:Ag), whereas Type II variants result in decreased FXI:C yet normal FXI:Ag. The database updates now highlight the predominance of Type I variants in FXI. Analysis in terms of a consensus Ap domain revealed the near-uniform distribution of 81 missense variants across the Ap domains. A further 66 missense variants were identified in the SP domain, showing that all regions of the FXI protein were important for function. The variants clarified the critical importance of changes in surface solvent accessibility, as well as those of cysteine residues and the dimer interface. Guidelines are provided below for clinicians who wish to use the database for diagnostic purposes. In conclusion, the updated database provides an easy-to-use web resource on FXI deficiency for clinicians.

Analysis of 180 Genetic Variants in a New Interactive FX Variant Database Reveals Novel Insights into FX Deficiency.

Coagulation factor X (FX), often termed as Stuart-Prower factor, is a plasma glycoprotein composed of the γ-carboxyglutamic acid (GLA) domain, two epidermal growth factor domains (EGF-1 and EGF-2), and the serine protease (SP) domain. FX plays a pivotal role in the coagulation cascade, activating thrombin to promote platelet plug formation and prevent excess blood loss. Genetic variants in FX disrupt coagulation and lead to FX or Stuart-Prower factor deficiency. To better understand the relationship between FX deficiency and disease severity, an interactive FX variant database has been set up at https://www.factorx-db.org , based on earlier web sites for the factor-XI and -IX coagulation proteins. To date (April 2021), we report 427 case reports on FX deficiency corresponding to 180 distinct F10 genetic variants. Of these, 149 are point variants (of which 128 are missense), 22 are deletions, 3 are insertions, and 6 are polymorphisms. FX variants are phenotypically classified as being type I or II. Type-I variants involve the simultaneous reduction of FX coagulant activity (FX:C) and FX antigen levels (FX:Ag), whereas type-II variants involve a reduction in FX:C with normal FX:Ag plasma levels. Both types of variants were distributed throughout the FXa protein structure. Analyses based on residue surface accessibilities showed the most damaging variants to occur at residues with low accessibilities. The interactive FX web database provides a novel easy-to-use resource for clinicians and scientists to improve the understanding of FX deficiency. Guidelines are provided for clinicians who wish to use the database for diagnostic purposes.

Inherited Bleeding Disorders in North Indian Children: 14 years' Experience from a Tertiary Care Center.

Inherited bleeding disorders are not uncommon in pediatric practice: most of them being chronic, require lifelong replacement therapy. To frame a management policy, it is essential to assess the load and pattern of bleeding disorders in the local population. However, there is paucity of data reporting the clinical spectrum of coagulation and platelet function disorders in Indian children. Hence to find out the exact burden and clinico-investigational profile of these patients we conducted this study. In this retrospective case review, detailed clinical information was extracted from case records in 426 children with a suspected diagnosis of hereditary bleeding disorder registered in the Pediatric Hematology clinic of a tertiary referral centre over a period of 14 years (1998-2011) and pooled for analysis. In our cohort prevalence of hemophilia A, hemophilia B, platelet function disorders, von Willebrand disease and other rare factor deficiencies were 72%, 11%, 7%, 4% and 4% respectively. Common clinical spectrum included skin bleeds, arthropathy, mucosal bleeds. 10% had deeper tissue bleeding and 16% received replacement therapy at the first visit. Nearly 3/4th of cases were lost for follow up after the initial visit. Hemophilia A was the commonest inherited bleeding disorder in our population. Skin bleeds and arthropathy were common clinical presentations. Factor replacement therapy was restricted to a minority. There is an urgent need for establishing centres of excellence with administrative commitment for factor replacement therapy for comprehensive management of such children in resource-limited countries.

Inherited coagulation disorders in Turkish children: A retrospective, single-center cohort study.

OBJECTIVE: This study aims to investigate the distribution, clinical characteristics and outcome of inherited coagulation disorders (ICD) in Turkish children. SUBJECTS AND METHODS: Data from all children (age<18 years) with ICD examined in our center were retrospectively reviewed. RESULTS: There were 403 children with ICD (233 males and 170 females) with a median age of four years at diagnosis. The percentages of von Willebrand disease (vWd), hemophilia and rare bleeding disorders (RBD) were 40 %, 34 % and 26 %, type-1, type-2 and type-3 vWd were 63 % 17 % and 20 %, hemophilia A and B were 84 % and 16 %, and severe, moderate and mild hemophilia were 48 %, 30 % and 22 %, respectively. Factor VII and FXI deficiencies were the most prevalent, comprising 56 % and 22 % of all children with RBD, respectively. Parental consanguinity rates were 72 % in type-3 vWd and 61 % in severe RBD. The overall prevalence of gastrointestinal bleedings was 4.5 % (18/403), intracranial bleeding (ICB) was 4.96 % (20/403), mortality from ICB was 30 % (6/20) and the overall mortality rate was 1.49 % (6/403). No life-threatening bleeding was seen during regular prophylaxis. Chronic arthropathy prevalence in severe hemophilia was 8 % with primary prophylaxis and 53 % with demand therap. Inhibitor prevalence was 14 % in hemophilia-A and 5 % in hemophilia-B. CONCLUSIONS: These data show that vWd is the most common ICD, type-3 vWd and RBD are prevalent due to frequent consanguineous marriages and diagnosis of ICD is substantially delayed in Turkish children. Prophylactic replacement therapy prevents occurrence of life-threatening bleedings and reduces the development of hemophilic arthropathy.

Diagnostic challenges of inherited mild bleeding disorders: a bait for poorly explored clinical and basic research.

The best-known inherited mild bleeding disorders (MBDs), i.e. type 1 von Willebrand disease (VWD), platelet function disorders (PFDs), and mild to moderate clotting factor deficiencies, are characterized clinically by mucocutaneous bleeding, and, although they are highly prevalent, still pose difficult diagnostic problems. These include establishing the pathological nature of bleeding, and the uncertainties surrounding the clinical relevance of laboratory results. Furthermore, the high frequency of bleeding symptoms in the normal population and the subjective appraisal of symptoms by patients or parents makes elucidating the pathological nature of bleeding difficult. Standardized bleeding assessment tools and semiquantitative bleeding scores (BSs) help to discriminate normal from abnormal bleeding. However, as most MBDs have similar bleeding patterns, for example, bleeding sites, frequency, and severity, BSs are of little help for diagnosing specific diseases. Global tests of primary hemostasis (bleeding time; PFA-100/200) lack sensitivity and, like BSs, are not disease-specific. Problems with the diagnosis of type 1 VWD and PFD include assay standardization, uncertain definition of von Willebrand factor cut-off levels, and the lack of universal diagnostic criteria for PFD. Regarding clotting factor deficiencies, the bleeding thresholds of some coagulation factors, such as factor VII and FXI, are highly variable, and may lead to misinterpretation of the clinical relevance of mild to moderate deficiencies. Remarkably, a large proportion of MBDs remain undiagnosed even after comprehensive and repeated laboratory testing. These are tentatively considered to represent bleeding of undefined cause, with clinical features indistinguishable from those of classical MBD; the pathogenesis of this is probably multifactorial, and unveiling these mechanisms should constitute a fertile source of translational research.

The role of rotational thromboelastometry in assessment of haemostasis during pregnancy in women with factor XI deficiency.

INTRODUCTION: Women with factor XI (FXI) deficiency are at an increased risk of bleeding complications at delivery. Obstetric management is complicated by a lack of correlation between FXI level and bleeding risk. AIM: The aims of this study were to assess the difference in rotational thromboelastometry (ROTEM® ) in parturient women with FXI deficiency compared to parturient and non-parturient controls and to evaluate the usefulness of ROTEM® in assessing bleeding risk at delivery in women with FXI deficiency. METHODS: ROTEM® was performed on 60 women: 27 with FXI deficiency, 20 age-matched parturient controls and 12 non-parturient controls. Pregnancy outcomes and haemostatic cover was reviewed in 57 deliveries of women with FXI deficiency. RESULTS: Women with FXI deficiency had a longer clotting time (CT) and clot formation time (CFT) (P < 0.001), reduced alpha angle (P < 0.001) but no difference in MCF (P = 0.054) compared to parturient controls. Compared to non-parturient controls, they had a longer CT (P < 0.001), but shorter CFT (P < 0.001), increased alpha angle (P < 0.001) and increased MCF (P = 0.005). ROTEM® was an additional helpful parameter in managing parturient women with FXI deficiency, reducing the need for factor administration. CONCLUSION: ROTEM® demonstrated hypercoagulable changes during pregnancy in women with FXI deficiency. However, they took longer to clot compared to parturient controls, but had increased clot consolidation and clot strength compared to non-parturient controls. ROTEM® is an additional test that is helpful to assess bleeding risk and provision of appropriate haemostatic cover at delivery.

Introduction to the analysis of next generation sequencing data and its application to venous thromboembolism.

Despite knowledge of various inherited risk factors associated with venous thromboembolism (VTE), no definite cause can be found in about 50% of patients. The application of data-driven searches such as GWAS has not been able to identify genetic variants with implications for clinical care, and unexplained heritability remains. In the past years, the development of several so-called next generation sequencing (NGS) platforms is offering the possibility of generating fast, inexpensive and accurate genomic information. However, so far their application to VTE has been very limited. Here we review basic concepts of NGS data analysis and explore the application of NGS technology to VTE. We provide both computational and biological viewpoints to discuss potentials and challenges of NGS-based studies.

Thromboelastography identifies children with rare bleeding disorders and predicts bleeding phenotype.

Rare bleeding disorders (RBDs) comprise 3-5% of all congenital bleeding disorders. They can evade typical coagulation screening tests and there is a poor correlation between laboratory results and bleeding phenotype. Thromboelastography (TEG) measures coagulation globally in whole blood samples. The aims of this study were to evaluate the utility of TEG as an adjunct to the routine screening tests employed for the diagnosis of RBDs and to correlate TEG results with the bleeding phenotype in RBDs. TEG parameters and clot kinetics were compared to bleeding phenotypes (asymptomatic, mild, moderate and severe) in 26 RBD patients and 30 normal controls. Clot kinetics correlated strongly with RBDs and with the severity of bleeding phenotype with mean maximum rate of thrombus generation (MRTG) 15.4 mm min(-1) in controls vs. 6.0 in RBDs (P < 0.0001, Wilcoxin). The mean MRTG was 7.7 in mildly symptomatic, 5.5 in moderately symptomatic and 4.1 in severely symptomatic patients (P < 0.0001, Kruskal-Wallis). Disorders that are often missed by conventional screening tests, dysfibrinogenaemia and platelet disorders displayed a distinctive TEG curve with markedly decreased maximum amplitude (MA) and low MRTG values. Factor XIII and PAI deficient patients displayed increased fibrinolysis in addition to low MRTGs. All patients with RBDs, but none of the normal controls, had abnormal clot kinetics suggesting that TEG may be an effective screening test for RBDs.

Benign FGB (148Lys→Asn, and 448Arg→Lys), and novel causative γ211Tyr→His mutation distinguished by time of flight mass spectrometry in a family with hypofibrinogenaemia.

We describe a novel procedure for the direct analysis of plasma fibrinogen by HPLC time of flight (TOF) mass spectrometry and apply it to the investigation of a family with hypofibrinogenaemia. Electrospray TOF analysis provided much higher resolution than was possible with our previous quadrupole analyser and revealed three different mass changes within the fibrinogen Bß and γ chains of the family. It also demonstrated the actual hypofibrinogenaemia phenotype was caused by an aberrantγ chain (-23 Da) which was expressed at a diminished ratio of 0.2:1 relative to γ(A) and co-inherited with a second coequally expressed Bß variant (Bß(M) /Bß(A), 1:1). Co-segregation was confirmed by gene analysis that showed the affected father and son had a very rare Bß148Lys→Arg mutation (-14 Da) inherited together with a unique new γ211Tyr→His mutation (-26 Da). This latter causative substitution occurs at a site that is absolutely conserved across all fibrinogen chains and preserved across all species. TOF analysis also identified a variant Bß chain (54,186 Da) that was coequally expressed with normal Bß chains (54,213 Da) in the unaffected mother.