von Willebrand disease.

von Willebrand disease (VWD) is the most common inherited bleeding disorder. The disorder is characterized by excessive mucocutaneous bleeding. The most common bleeding manifestations of this condition include nosebleeds, bruising, bleeding from minor wounds, menorrhagia or postpartum bleeding in women as well as bleeding after surgery.

Emicizumab in Type 3 von Willebrand Disease: Report of a Case with an Alloantibody and Literature Review.

Type 3 von Willebrand disease (VWD), the most severe form of VWD, is an inherited recessive bleeding disorder caused by the complete deficiency of von Willebrand factor (VWF). The reported prevalence is 1 per million but varies worldwide according to the frequency of consanguineous marriages. The clinical phenotype is characterized not only by mucocutaneous bleedings, but also by hemarthroses and muscle hematoma, as in patients with moderate hemophilia.

Application of genetic testing for the diagnosis of von Willebrand disease.

von Willebrand disease (VWD) is the most frequent inherited bleeding disorder, with an estimated symptomatic prevalence of 1 per 1000 in the general population. VWD is characterized by defects in the quantity, quality, or multimeric structure of von Willebrand factor (VWF), a glycoprotein being hemostatically essential in circulation. VWD is classified into 3 principal types: low VWF/type 1 with partial quantitative deficiency of VWF, type 3 with virtual absence of VWF, and type 2 with functional abnormalities of VWF, being classified as 2A, 2B, 2M, and 2N.

Type 2M/2A von Willebrand disease: a shared phenotype between type 2M and 2A.

Four variants have been continuously subjected to debate and received different von Willebrand disease (VWD) classifications: p.R1315L, p.R1315C, p.

Population-based prevalence and mutational landscape of von Willebrand disease using large-scale genetic databases.

Von Willebrand disease (VWD) is a common bleeding disorder caused by mutations in the von Willebrand factor gene (VWF). The true global prevalence of VWD has not been accurately established. We estimated the worldwide and within-population prevalence of inherited VWD by analyzing exome and genome data of 141,456 individuals gathered by the genome Aggregation Database (gnomAD).

Clinical and Laboratory Presentation and Underlying Mechanism in Patients with Low VWF.

Background:  Low von Willebrand factor (VWF) refers to subjects with plasma levels of 30 to 50 IU/dL. The mechanism of low VWF is poorly understood. We chose to determine the clinical presentation, laboratory phenotype, and underlying mechanisms of low VWF.

Erratum to 'A comparative study in type 2 von Willebrand disease patients using four different platelet-dependent von Willebrand factor assays.' [Research and Practice in Thrombosis and Haemostasis Volume 7, Issue 3, March 2023, 100139].

[This corrects the article DOI: 10.1016/j.rpth.

A comparative study in patients with type 2 von Willebrand disease using 4 different platelet-dependent von Willebrand factor assays.

Background: Several assays are now available to evaluate platelet-dependent von Willebrand factor (VWF) activity.

Objective: To report the results obtained using 4 different assays in patients with von Willebrand disease (VWD) carrying variants mainly in the A1 domain, which is critical for VWF binding to glycoprotein Ib (GPIb) and ristocetin.

Methods: We evaluated 4 different assays, 2 gain-of-function mutant GPIb binding (VWF:GPIbM) and 2 ristocetin cofactor (VWF:RCo) assays, in 76 patients with type 2 VWD.

von Willebrand factor neutralizing and non-neutralizing alloantibodies in 213 subjects with type 3 von Willebrand disease enrolled in 3WINTERS-IPS.

Background: Type 3 von Willebrand disease (VWD) is the most severe form of this disease owing to the almost complete deficiency of von Willebrand factor (VWF). Replacement therapy with plasma-derived products containing VWF or recombinant VWF rarely cause the development of alloantibodies against VWF that may be accompanied by anaphylactic reactions.

Objective: The objective of this study was to assess the prevalence of anti-VWF alloantibodies in subjects with type 3 VWD enrolled in the 3WINTERS-IPS.

Genetic determinants of enhanced von Willebrand factor clearance from plasma.

Background: Enhanced von Willebrand factor (VWF) clearance from plasma is associated with von Willebrand disease (VWD). However, the genetic background of this disease mechanism is not well defined.

Objective: To determine VWF variants that are associated with reduced VWF survival.

Phenotypic and genetic characterizations of the Milan cohort of von Willebrand disease type 2.

von Willebrand disease (VWD) type 2 is caused by qualitative abnormalities of von Willebrand factor (VWF). This study aimed to determine the genotypic and phenotypic characterizations of a large VWD type 2 cohort from Milan. We included 321 patients (54% female) within 148 unrelated families from 1995 to 2021.

Von Willebrand factor propeptide and pathophysiological mechanisms in European and Iranian patients with type 3 von Willebrand disease enrolled in the 3WINTERS-IPS study.

Background: Type 3 von Willebrand disease (VWD) is a severe bleeding disorder caused by the virtually complete absence of von Willebrand factor (VWF). Pathophysiological mechanisms of VWD like defective synthesis, secretion, and clearance of VWF have previously been evaluated using ratios of VWF propeptide (VWFpp) over VWF antigen (VWF:Ag) and factor (F)VIII coagulant activity (FVIII:C) over VWF:Ag.

Objective: To investigate whether the VWFpp/VWF:Ag and FVIII:C/VWF:Ag ratios may also be applied to understand the pathophysiological mechanism underlying type 3 VWD and whether VWFpp is associated with bleeding severity.

The dominant p.Thr274Pro mutation in the von Willebrand factor propeptide causes the von Willebrand disease type 1 phenotype in two unrelated patients.

Background: von Willebrand factor propeptide (VWFpp) plays an important role in VWF multimerization and storage. VWFpp mutations have been previously associated with types 1, 3 and 2A/IIC von Willebrand disease (VWD).

Aims: To characterize the novel p.

Genotypes of European and Iranian patients with type 3 von Willebrand disease enrolled in 3WINTERS-IPS.

Type 3 von Willebrand disease (VWD3) is a rare and severe bleeding disorder characterized by often undetectable von Willebrand factor (VWF) plasma levels, a recessive inheritance pattern, and heterogeneous genotype. The objective of this study was to identify the VWF defects in 265 European and Iranian patients with VWD3 enrolled in 3WINTERS-IPS (Type 3 Von Willebrand International Registries Inhibitor Prospective Study). All analyses were performed in centralized laboratories.

Pro-coagulant imbalance in patients with community acquired pneumonia assessed on admission and one month after hospital discharge.

Objectives: Patients hospitalized because of community-acquired-pneumonia (CAP) are at risk of cardiovascular diseases. Although plasma procoagulant imbalance play a role, mechanisms are not completely understood. We aimed to investigate whether there is a measurable state of procoagulant imbalance following inflammation determined by CAP.

The ADAMTS13-von Willebrand factor axis in COVID-19 patients.

Background: Severe coronavirus disease 2019 (COVID-19) is characterized by an increased risk of thromboembolic events, with evidence of microthrombosis in the lungs of deceased patients.

Objectives: To investigate the mechanism of microthrombosis in COVID-19 progression.

Patients/methods: We assessed von Willebrand factor (VWF) antigen (VWF:Ag), VWF ristocetin-cofactor (VWF:RCo), VWF multimers, VWF propeptide (VWFpp), and ADAMTS13 activity in a cross-sectional study of 50 patients stratified according to their admission to three different intensity of care units: low (requiring high-flow nasal cannula oxygenation, n = 14), intermediate (requiring continuous positive airway pressure devices, n = 17), and high (requiring mechanical ventilation, n = 19).

Increasing levels of von Willebrand factor and factor VIII with age in patients affected by von Willebrand disease.

Essentials VWF and FVIII increase with age in patients affected by VWD. VWF and FVIII increase in type 1 and in low levels of VWF patients. VWF and FVIII do not increase in type 1 Vicenza.

Comparison of von Willebrand factor platelet-binding activity assays: ELISA overreads type 2B with loss of HMW multimers.

Background: A number of new assays with different measuring principles are available to measure von Willebrand factor (VWF) glycoprotein Ib (GPIb)-binding activity, but little is known about how these assays might behave differently for subtypes of von Willebrand disease (VWD).

Objectives: The Comparison of Assays to Measure VWF Activity (COMPASS-VWF) study was designed to compare all available VWF GPIb-binding activity assays for VWF. We specifically searched for particular assay behavior differences.

Bleeding symptoms in patients diagnosed as type 3 von Willebrand disease: Results from 3WINTERS-IPS, an international and collaborative cross-sectional study.

Background: Type 3 von Willebrand's disease (VWD) patients present markedly reduced levels of von Willebrand factor and factor VIII. Because of its rarity, the bleeding phenotype of type 3 VWD is poorly described, as compared to type 1 VWD.

Aims: To evaluate the frequency and the severity of bleeding symptoms across age and sex groups in type 3 patients and to compare these with those observed in type 1 VWD patients to investigate any possible clustering of bleeding symptoms within type 3 patients.

Evaluation of a fully automated von Willebrand factor assay panel for the diagnosis of von Willebrand disease.

Introduction: von Willebrand disease (VWD) diagnosis starts with first level tests: factor VIII coagulant activity, VWF antigen (VWF:Ag) and platelet-dependent VWF activity (VWF:RCo, VWF:Ab, VWF:GPIbR or VWF:GPIbM). The VWF collagen binding (VWF:CB) assay measures the binding capacity of von Willebrand factor (VWF) to collagen.

Aim: To assess, in previously diagnosed VWD patients, the performance of a fully automated chemiluminescent test panel including VWF:Ag, VWF:GPIbR and VWF:CB assays.

How we make an accurate diagnosis of von Willebrand disease.

von Willebrand disease (VWD) is a common autosomally inherited hemorrhagic disorder mainly associated with mucocutaneous bleeding. VWD is due to quantitative (type 1 and 3) or qualitative (type 2) defects of von Willebrand factor (VWF), a large multimeric plasma glycoprotein that plays a relevant role in hemostasis. VWF is essential to mediate platelet adhesion and aggregation at the sites of vascular injury under high shear stress conditions.