scholarly journals Identification and characterisation of mutations associated with von Willebrand disease in a Turkish patient cohort

2013 ◽  
Vol 110 (08) ◽  
pp. 264-274 ◽  
Author(s):  
Adel Abuzenadah ◽  
Ashley Cartwright ◽  
Nawal Al-Shammari ◽  
Rachael Coyle ◽  
Michaela Eckert ◽  
...  
Keyword(s):  
Von Willebrand Disease ◽  
Compound Heterozygous ◽  
Missense Mutations ◽  
End Joining ◽  
Turkish Patient ◽  
Non Homologous End Joining ◽  
Type 3 ◽  
Von Willebrand ◽  
High Degree

SummarySeveral cohort studies have investigated the molecular basis of von Willebrand disease (VWD); however, these have mostly focused on European and North American populations. This study aimed to investigate mutation spectrum in 26 index cases (IC) from Turkey diagnosed with all three VWD types, the majority (73%) with parents who were knowingly related. IC were screened for mutations using multiplex ligation-dependent probe amplification and analysis of all von Willebrand factor gene (VWF) exons and exon/intron boundaries. Selected missense mutations were expressed in vitro. Candidate VWF mutations were identified in 25 of 26 IC and included propeptide missense mutations in four IC (two resulting in type 1 and two in recessive 2A), all influencing VWF expression in vitro. Four missense mutations, a nonsense mutation and a small in-frame insertion resulting in type 2A were also identified. Of 15 type 3 VWD IC, 13 were homozygous and two compound heterozygous for 14 candidate mutations predicted to result in lack of expression and two propeptide missense changes. Identification of intronic breakpoints of an exon 17–18 deletion suggested that the mutation resulted from non-homologous end joining. This study provides further insight into the pathogenesis of VWD in a population with a high degree of consanguineous partnerships.

A Novel Mutation Glyl672→Arg in Type 2A and a Homozygous Mutation in Type 2B von Willebrand Disease

1996 ◽  
Vol 76 (02) ◽  
pp. 253-257 ◽  
Author(s):  
Takeshi Hagiwara ◽  
Hiroshi Inaba ◽  
Shinichi Yoshida ◽  
Keiko Nagaizumi ◽  
Morio Arai ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Novel Mutation ◽  
Point Mutations ◽  
Japanese Patients ◽  
Von Willebrand Disease ◽  
Homozygous Mutation ◽  
Missense Mutations ◽  
Reaction Products ◽  
Type 3 ◽  
Von Willebrand

SummaryGenetic materials from 16 unrelated Japanese patients with von Willebrand disease (vWD) were analyzed for mutations. Exon 28 of the von Willebrand factor (vWF) gene, where point mutations have been found most frequent, was screened by various restriction-enzyme analyses. Six patients were observed to have abnormal restriction patterns. By sequence analyses of the polymerase chain-reaction products, we identified a homozygous R1308C missense mutation in a patient with type 2B vWD; R1597W, R1597Q, G1609R and G1672R missense mutations in five patients with type 2A; and a G1659ter nonsense mutation in a patient with type 3 vWD. The G1672R was a novel missense mutation of the carboxyl-terminal end of the A2 domain. In addition, we detected an A/C polymorphism at nucleotide 4915 with HaeIII. There was no particular linkage disequilibrium of the A/C polymorphism, either with the G/A polymorphism at nucleotide 4391 detected with Hphl or with the C/T at 4891 detected with BstEll.

scholarly journals Rare Occurrence of Inhibitors in Von Willebrand Disease: A Case Report

2022 ◽  
Vol 8 ◽  
Author(s):  
Bipin P. Kulkarni ◽  
Kirti Ghargi ◽  
Chandrakala Shanmukhaiah ◽  
Shrimati D. Shetty
Keyword(s):  
Correct Diagnosis ◽  
Severe Form ◽  
Von Willebrand Disease ◽  
Rare Occurrence ◽  
Standard Assay ◽  
Type 3 ◽  
Von Willebrand ◽  
High Degree ◽  
Willebrand Factor ◽  
Inhibitor Titer

Introduction: Type 3 Von Willebrand Disease (VWD) is the least common but the most severe form of a disease, with a prevalence of about 0. 5 to 1 per million in Western countries. The prevalence of type 3 VWD in the developing countries, with a high degree of consanguinity, is about 6 per million. Moreover, due to underdiagnosis of the milder cases, the prevalence of type 3 VWD is about 50% of the cases. Rarely, some patients develop the Von Willebrand Factor (VWF) inhibitors, which may subsequently develop severe anaphylactic reactions on further exposure to the VWF containing factor replacement therapy. The prevalence of inhibitor development in patients with type 3 VWD has been shown to be in the range of 5.8 to 9.5%. In the absence of a gold standard assay for the quantitation of VWF inhibitors, a correct diagnosis and management of these patients are often challenging.Objectives: The objective of this study is to standardize the Bethesda assay for the VWF inhibitors and to estimate the VWD inhibitor titer in two cases of congenital type 3 VWD, which developed the VWF inhibitors.Results and Conclusions: We could successfully standardize the Bethesda assay for the quantitation of VWF inhibitors in two patients with congenital type 3 VWD with inhibitors.

Clinical cases of using coagulation factor VIII with von Willebrand factor in parturient women with type III von Willebrand disease

2020 ◽  
Author(s):  
И.В. Куртов ◽  
Е.С. Фатенкова ◽  
Н.А. Юдина ◽  
А.М. Осадчук ◽  
И.Л. Давыдкин
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Coagulation Factor ◽  
Von Willebrand Disease ◽  
Coagulation Factor Viii ◽  
Vitro Fertilization ◽  
Type 3 ◽  
Von Willebrand ◽  
Willebrand Factor

Болезнь Виллебранда (БВ) может представлять определенные трудности у рожениц с данной патологией. Приведены 2 клинических примера использования у женщин с БВ фактора VIII свертывания крови с фактором Виллебранда, показана эффективность и безопасность их применения. У одной пациентки было также показано использование фактора свертывания крови VIII с фактором Виллебранда во время экстракорпорального оплодотворения. Von Willebrand disease presents a certain hemostatic problem among parturients. This article shows the effectiveness and safety of using coagulation factor VIII with von Willebrand factor for the prevention of bleeding in childbirth in 2 patients with type 3 von Willebrand disease. In one patient, the use of coagulation factor VIII with von Willebrand factor during in vitro fertilization was also shown.

Molecular Genetics Analysis of Von Williebrand Disease: Studies in Cohort Pakistani Patients

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4689-4689
Author(s):  
Shariq Ahmed ◽  
Arshi Naz ◽  
Hamideh Yadegari ◽  
Julia Driesen ◽  
Tahir Shamsi ◽  
...  
Keyword(s):  
Cohort Study ◽  
Molecular Genetics ◽  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
Compound Heterozygous ◽  
Missense Mutations ◽  
Type Iii ◽  
Children's Hospital ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Introduction: Von Willebrand disease (VWD) type III is the second most common inherited bleeding disorder in Pakistan. It is caused by severe quantitative deficiency of plasma Von Willebrand factor (VWF). Absence of VWF increases the severity of disease and is caused by homozygous/ compound heterozygous mutations in Von Willebrand factor gene. Objective: The aim of study is to characterize molecular genetics of Von Willebrand type III in Pakistani population. Setting: NIBD & BMT Karachi, Chughtais lab, Children's Hospital Lahore, PAEC Islamabad and HMC Peshawar. Material And Method: In this cohort study of Von Willebrand disease (VWD) type III, Blood samples of 48 unrelated patients of type III VWD were collected in National Institute Of Blood Disease & Bone Marrow Transplant (NIBD) Karachi, Chughtais lab, Children's Hospital Lahore, PAEC Islamabad and HMC Peshawar. Genomic DNA was extracted from peripheral blood by QIAamp DNA Blood mini kit (Qiagen) and Exon specific PCR was done for VWF gene and Direct gene sequenced on automated ABI-3130 Genetic Analyzer (Applied Biosystems). Sequence Variations in VWF were checked on ISTH-SSC VWD homepage (http://www.vwf.group.shef.ac.uk/), Ensemble genome browser (http://www.ensembl.org/), VWFdb hemobase and biobase biological database (http://www.hgmd.cf.ac.uk/ac/index.php). We have adopted the nomenclature for numbering amino acids of Human genome variation society (HGVS). Statistics analysis was done SPSSv17. Results: Sequence analysis detected mutations in 46 (95.83%) out of 48 samples. VWD type III has led to identification of 28 cases (60.8%) homozygous and 18 (39.1%) were compound heterozygous. We have indentified total 31 Mutations distributed as 17 missense mutations (54%), 7 nonsense mutations (22%) 2 small deletions (6%) , 2 insertion mutations (6%) and 3 splice site mutations (9%).19 of these were newly mutations in this cohort study.. Further method multiplex ligation dependent probe amplification (MLPA) is needed for detection of large deletions in two patients. Nonsense c.3931C>T, p.Q1311*was founder mutation in Pakistani patients. Conclusion: In cohort study, missense mutations are detected as common in among patients and most of the mutations identified in this cohort were homozygous due to Consanguinity in the family of the patients. Disclosures Oldenburg: SOBI: Consultancy.

scholarly journals Profile of Mutations Identified in the 3WINTERS-IPS Project on European & Iranian Patients with Previously Diagnosed Type 3 Von Willebrand Disease.

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1184-1184
Author(s):  
Luciano Baronciani ◽  
Flora Peyvandi ◽  
Anne Goodeve ◽  
Reinhard Schneppenheim ◽  
Zahra Badiee ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Research Funding ◽  
Advisory Board ◽  
Von Willebrand Disease ◽  
Compound Heterozygous ◽  
Advisory Committees ◽  
Type 3 ◽  
Von Willebrand ◽  
Two Populations ◽  
Iranian Patients

Abstract Background: The type 3 Von Willebrand International RegistrieSInhibitor Prospective Study (3WINTERS-IPS) is a no-profit, investigator initiated, multicenter, European-Iranian observational, retrospective and prospective study on patients with diagnosis of type 3 VWD. Patients with type 3 von Willebrand Disease (VWD3) have markedly reduced levels of von Willebrand factor (VWF) and very severe bleeding phenotype. Due to the recessive inheritance pattern, VWD3 is by definition a rare bleeding disorder (1:Million) but its prevalence may increase in countries like Iran with consanguineous marriages. Aim: To identify the VWF genetic defects in a cohort of European and Iranian patients with previously diagnosed VWD3 enrolled into the 3WINTERS-IPS project. Methods: Patients classified locally as VWD3 were enrolled in the study following informed consent. 141 patients were from 9 different European countries and 119 patients were from the Islamic Republic of Iran. Plasma/buffy-coat samples were sent to expert labs to confirm patient's laboratory phenotype and to perform molecular analysis. PCR and Sanger sequencing/ next generation sequencing and multiplex-ligation dependent probe amplification were used in Hamburg, Sheffield and Milan to confirm previously identified variants or to seek previously unidentified variants. Results: DNA samples from 122 patients from Europe and 114 patients from Iran were analyzed at the molecular level. Of the 236 VWD3 patients under evaluation 24 are still in progress. Of the 212 fully evaluated patients 139 were homozygous (EU/IR=46/93) and 43 were compound heterozygous (EU/IR=36/7). In the remaining 30 patients no variants were identified in 19 samples (EU/IR=6/13) and only one variant was found in the remaining 11 cases (EU/IR=10/1). 135 (EU/IR=82/53) different gene defects were identified among the 375 (EU/IR=174/201) alleles found in this study. Of these 135 variants identified 51(EU/IR=22/29) were not reported on the www.ensembl.org database. The distribution of the different type of variants identified in the two populations is shown in the Figure. The two charts are showing quite similar percentages of the variants identified, with a main exception for the Small deletions and Small insertions. Only five variants are shared among the two populations. Three of these are the "hotspot" variants at the Arg codon, p.Arg1659* (EU/IR=9/8), p.Arg1853* (EU/IR=2/3) and p.Arg2535* (EU/IR=1/2). However, a missense variant , p.Cys275Ser (EU/IR=1/2) and a large deletion, delEx1_Ex5 (EU/IR=1/2) were also found in both populations. Fifteen variants were recurrent and were found in 154 alleles, whereas 49 variants were found only once in the heterozygous state (EU/IR=40/9) and 50 variants were found only twice, mainly in the homozygous state (EU/IR=25/25). Six large deletions were identified (delEx1_Ex3, delEx1_Ex5, delEx14_Ex15, delEx17, delEx35_Ex52 and delEx1_Ex52) and a duplication (dupEx1_Ex28), nevertheless 52 alleles with missense variants were identified (EU/IR=20/32). Discussion: As expected, the majority of the Iranian patients were found to be homozygous (Homozygous/Compound Heterozygous=93/7) reflecting a high rate of consanguinity, nevertheless half of the European patients were found to be homozygous (Homozygous/Compound Heterozygous=46/36). The European populations demonstrated a higher heterogeneity of variants with 82 different variants among the 175 mutated alleles vs 53 different variants among the 201 mutated alleles identified in the Iranian population. Nevertheless, a higher number of previously unreported variants was found in the Iranian population (29) vs the European one (22), probably due to bias of previous investigations performed in European patients. Figure Figure. Disclosures Peyvandi: Ablynx: Other: Member of Advisory Board, Speakers Bureau; Shire: Speakers Bureau; Roche: Speakers Bureau; Grifols: Speakers Bureau; Grifols: Speakers Bureau; Novo Nordisk: Speakers Bureau; Sobi: Speakers Bureau; Sobi: Speakers Bureau; Novo Nordisk: Speakers Bureau; Kedrion: Consultancy; Novo Nordisk: Speakers Bureau; Octapharma US: Honoraria; Novo Nordisk: Speakers Bureau; Sobi: Speakers Bureau; Ablynx: Other: Member of Advisory Board, Speakers Bureau; Kedrion: Consultancy; Novo Nordisk: Speakers Bureau; Kedrion: Consultancy; Ablynx: Other: Member of Advisory Board, Speakers Bureau; Octapharma US: Honoraria; Shire: Speakers Bureau; Roche: Speakers Bureau; Kedrion: Consultancy; Kedrion: Consultancy; Ablynx: Other: Member of Advisory Board, Speakers Bureau; Octapharma US: Honoraria; Octapharma US: Honoraria; Sobi: Speakers Bureau; Roche: Speakers Bureau; Octapharma US: Honoraria; Shire: Speakers Bureau; Sobi: Speakers Bureau; Roche: Speakers Bureau; Roche: Speakers Bureau; Shire: Speakers Bureau; Ablynx: Other: Member of Advisory Board, Speakers Bureau; Grifols: Speakers Bureau; Grifols: Speakers Bureau; Grifols: Speakers Bureau; Shire: Speakers Bureau. Schneppenheim:CSL Behring: Consultancy; SHIRE: Consultancy. Berntorp:Octapharma: Consultancy; CSL Behring: Consultancy; Shire: Consultancy, Other: honoraria for lecturing . Eikenboom:CSL: Research Funding. Mannucci:Bayer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kedrion: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Grifols: Speakers Bureau; Alexion: Speakers Bureau; Baxalta/Shire: Speakers Bureau; Novo Nordisk: Speakers Bureau. Mazzucconi:Baxalta-Shire: Consultancy, Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Novartis,: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Novo Nordisk: Consultancy, Speakers Bureau; CSL Behring: Consultancy, Speakers Bureau. Oldenburg:Swedish Orphan Biovitrum: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Grifols: Honoraria, Membership on an entity's Board of Directors or advisory committees; Biogen Idec: Honoraria, Membership on an entity's Board of Directors or advisory committees; Chugai: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Biotest: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Mutation distribution in the von Willebrand factor gene related to the different von Willebrand disease (VWD) types in a cohort of VWD patients

2012 ◽  
Vol 108 (10) ◽  
pp. 662-671 ◽  
Author(s):  
Hamideh Yadegari ◽  
Julia Driesen ◽  
Anna Pavlova ◽  
Arijit Biswas ◽  
Hans-Jörg Hertfelder ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Splice Site ◽  
Von Willebrand Disease ◽  
Missense Mutations ◽  
Large Deletions ◽  
Type 3 ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryVon Willebrand disease (VWD) is the most common inherited bleeding disorder caused by quantitative or qualitative defects of the von Willebrand factor (VWF). VWD is classified into three types – type 1 (partial quantitative deficiencies), type 2 (qualitative defects) and type 3 (complete deficiency of VWF). In this study we explored genotype and phenotype characteristics of patients with VWD with the aim of dissecting the distribution of mutations in different types of VWD. One hundred fourteen patients belonging to 78 families diagnosed to have VWD were studied. Mutation analysis was performed by direct sequencing of the VWF. Large deletions were investigated by multiplex ligation-dependent probe amplification (MLPA) analysis. The impact of novel candidate missense mutations and potential splice site mutations was predicted by in silico assessments. We identified mutations in 66 index patients (IPs) (84.6%). Mutation detection rate was 68%, 94% and 94% for VWD type 1, 2 and 3, respectively. In total, 68 different putative mutations were detected comprising 37 missense mutations (54.4%), 10 small deletions (14.7%), two small insertions (2.9%), seven nonsense mutations (10.3%), five splice-site mutations (7.4%), six large deletions (8.8%) and one silent mutation (1.5%). Twenty-six of these mutations were novel. Furthermore, in type 1 and type 2 VWD, the majority of identified mutations (74% vs. 88.1%) were missense substitutions while mutations in type 3 VWD mostly caused null alleles (82%). Genotyping in VWD is a helpful tool to further elucidate the pathogenesis of VWD and to establish the relationship between genotype and phenotype.

scholarly journals Characterization of Type 2N Von Willebrand Disease Mutations Using Ιn Vitro and Ιn Vivo Mouse Models

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 471-471
Author(s):  
Laura L Swystun ◽  
Ilinca Georgescu ◽  
Meghan Deforest ◽  
Mia Golder ◽  
Kate Sponagle ◽  
...  
Keyword(s):  
Plasma Levels ◽  
Fold Increase ◽  
Von Willebrand Disease ◽  
Compound Heterozygous ◽  
Wild Type ◽  
Binding Ability ◽  
Von Willebrand ◽  
Deficient Mice

Abstract Introduction: Von Willebrand factor (VWF) is a multimeric glycoprotein that serves as the carrier for the essential coagulation cofactor, factor VIII (FVIII). Both plasma levels of VWF and its FVIII-binding ability can influence plasma levels of FVIII. Type 2N von Willebrand disease (VWD) is associated with a reduced binding affinity of VWF for FVIII, resulting in accelerated proteolysis and clearance of FVIII (plasma levels 5 – 30% of normal). Type 2N VWD is a recessive trait and patients are either homozygous or compound heterozygous for 2N alleles. We hypothesize that type 2N VWD mutations can alter the expression and FVIII-binding ability of VWF. In these studies, we characterize three type 2N VWD mutations in vitro and in a murine model. R854Q (20-30% FVIII) is the most common 2N allele and is associated with a mild phenotype, while R816W (<10% FVIII) is associated with a severe phenotype. The R763A mutation inhibits propeptide cleavage that likely sterically interferes with the FVIII-binding ability of VWF. Methods: Type 2N VWD mutations were generated in the murine VWF cDNA. Heterologous VWF synthesis/secretion was characterized in vitro using HEK 293T cells and in vivo using hydrodynamic gene transfer of the murine VWF cDNA into VWF deficient mice. Binding of FVIII to type 2N variants was assessed in vitro using a solid phase binding assay and in vivo in VWF deficient mice by a FVIII chromogenic activity assay. Results: In HEK 293 T cells, biosynthesis of type 2N VWD variants was not significantly different from wild type VWF while secretion of all type 2N VWD variants was decreased relative to wild type: R763A (66%, p=0.0043), R816W (53%, p=0.0004), R854Q (4%, p<0.0001). Immunofluorescent staining of transfected HEK 293 cells demonstrated impaired pseudo-Weibel Palade body formation for the R854Q variant. Western blot analysis under denaturing conditions demonstrated that approximately 50% of the secreted R763A protein remained attached to the propeptide. Multimeric profiles of plasma-derived type 2N VWD mutants were normal. In vitro binding of plasma-derived murine type 2N VWD mutants to recombinant human FVIII was reduced relative to wild type VWF: R763A (56%, p=0.0009), R816W (10%, p<0.0001), R854Q (46%, p=0.0002). Type 2N VWD mutants were expressed alone or in a compound heterozygous state (R816W/R854Q) in VWF deficient mice. A trend of lower VWF:Ag levels were observed for type 2N VWD mutants relative to wild type (average 4.8 U/mL) after 14 days: R763A (35.7%), R816W (53.1%), R854Q (21.3%), except for compound heterozygous condition R816W/R854Q (103%). Plasma levels of FVIII:C are significantly reduced in VWF deficient mice (15-20% of normal). We measured the ability of hydrodynamically expressed type 2N VWD mutants to stabilize endogenous FVIII:C in VWF deficient mice. Hepatic expression of wild type VWF stabilized endogenous plasma FVIII:C, resulting in a significant increase in FVIII:C after 14 days (7.7-fold increase above baseline, p=0.0002). For the type 2N VWD mutants, variable partial stabilization of endogenous FVIII:C was observed relative to baseline: R763A (4.7-fold increase, p=0.01), R816W (1.2-fold decrease, p=0.04), R816W/R854Q (4.8-fold increase, p<0.0001), R854Q (2.1-fold increase, p=0.06). The correlation coefficient between VWF:Ag and FVIII:C was assessed for samples with VWF:Ag between 0.5-10 U/mL. Correlation between wild type VWF expression and FVIII:C was highly positive (r2=0.85, slope=189.5 ± 15.7, p<0.0001). Correlation between VWF:Ag and FVIII:C for mice expressing type 2N VWD mutants was variable: R763A (r2=0.89, slope=235.3 ± 18.15, p<0.0001), R816W (r2=0.591, slope=0.96 ± 2.8, p=0.7433), R816W/854Q (r2=0.72, slope=91.32 ± 10.64, p<0.0001) and R854Q (r2=0.705, slope=156.7 ± 24.4, p=0.0002). The slopes for R816W (p<0.0001) and R816W/R854Q (p=0.009) mutants were significantly different from wild type, suggesting impaired FVIII-stabilization in vivo. Conclusion: Expression of the type 2N VWD severe mutant R816W or the compound heterozygous R816W/R854Q mutant can recapitulate type 2N VWD in a murine model. Type 2N VWD mutations are associated with impaired secretion of VWF and/or decreased binding and stabilization of endogenous FVIII. Disclosures No relevant conflicts of interest to declare.

Molecular Characterization of a Multiethnic Group of 21 Patients with Type 3 von Willebrand Disease

2000 ◽  
Vol 84 (10) ◽  
pp. 536-540 ◽  
Author(s):  
Giovanna Cozzi ◽  
Maria Canciani ◽  
Flora Peyvandi ◽  
Alok Srivastava ◽  
Augusto Federici ◽  
...  
Keyword(s):  
Ethnic Origin ◽  
Von Willebrand Disease ◽  
Null Alleles ◽  
Missense Mutations ◽  
Nonsense Mutations ◽  
Molecular Defects ◽  
Large Gene ◽  
Type 3 ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryType 3 von Willebrand disease is a rare autosomal disorder characterized by unmeasurable levels of von Willebrand factor and severe hemorrhagic symptoms. We studied a multiethnic group of 37 patients, from Italy (n = 14), Iran (n = 10) and India (n = 13) to identify the molecular defects and to evaluate genetic heterogeneity among these populations. Twenty-one patients (6 Italians, 9 Iranians and 6 Indians) were fully characterized at the molecular level. Twenty-four different gene alterations were identified, 20 of which have not been described previously. The majority of the mutations caused null alleles, 11 being nonsense mutations (Q218*, W222*, R365*, R373*, E644*, Q706*, S1338*, Q1346*, Y1542*, R1659*, E2129*), 4 small deletions (437delG, 2680delC, 6431delT, del 8491-8499), 3 possible splice site mutations [IVS9(-1)g→a, IVS29(+10)c→t, IVS40(-1)g → c], 3 candidate missense mutations (C275S, C2174G, C2804Y), 2 small insertions (7375insC, 7921insC) and 1 large gene deletion. The latter mutation was associated with the development of alloantibodies to VWF, but this complication was also found in a patient homozygous for a nonsense mutation (Q1346*). Due to the ethnic origin of the patients most of them were the offspring of consanguineous marriages and so were homozygous for the mutations found (18/21). Our results indicate that molecular defects responsible for type 3 VWD are scattered throughout the entire VWF gene (from exon 3 to 52), and that there is no prevalent and common gene defect in the three populations studied by us.

Von Willebrand Factor-Glycoprotein Ib-Alpha Interactions Play a Role in Generating Platelet Microparticles: Data from Ex Vivo and in Vitro Studies

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3920-3920
Author(s):  
Andrea Artoni ◽  
Anna Lecchi ◽  
MariaElisa Mancuso ◽  
Elena Santagostino ◽  
Augusto Federici ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Shear Stress ◽  
Tissue Factor ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Von Willebrand Disease ◽  
Type 3 ◽  
Von Willebrand ◽  
Normal Controls

Abstract Microparticles (MP) are circulating submicroscopic cell fragments expressing procoagulant phospholipids and haemostatic proteins such as tissue factor. Several evidences support a pro-haemostatic role of MP and suggest that the axis VWF-platelet GpIb might be critical in their generation. The aim of this study was to measure the levels of platelet-derived MP (PMP) and tissue factor-expressing MP (TFMP) in relationship with VWF levels and multimeric composition as well as shear stress exploiting ex vivo and in vitro natural models. PMP and TFMP were analyzed by flow cytometry and defined as Annexin V and GpIIb/IIIa or Tissue Factor positive events falling in a gate defined by 1 μm beads. MP were enumerated adding a known number of 7 μm beads to each test tube. In the first set of experiments, levels of PMP and TFMP were measured before and after DDAVP administration in 9 patients with mild hemophilia A. FVIII:C, VWF:Ag, PMP and TFMP were measured in plasma at baseline and 30 min, 1, 2, 4, 8 and 24 h after DDAVP 0.3 μg/kg, subcutaneously. A significant increase in the levels of PMP and TFMP (p<0.05 at all time points vs baseline) was observed after DDAVP; peak levels were achieved after 2–8 h. Correlation was found between the increase of VWF:Ag and FVIII:C levels and the peak levels of MP (r=0.62 and r=0.7, respectively). We then studied 27 patients with different types of von Willebrand disease (VWD) and 15 normal controls: citrated platelet rich plasma was exposed to increasing shear stress (from 0 to 90 dyne) for 45 seconds in a cone and plate viscometer and generated PMP were then enumerated by flow cytometry. In normal controls the number of MP at 25 dyne was significantly higher than the number at 0 dyne (p<0.05). In patients with type 1 VWD and type 2B PMP significantly increased as in normal controls (p<0.05 at 25 dyne), while in type 3 patients no PMP increase was observed (p n.s. till 90 dyne). Interestingly, in type 2M patients PMP started to increased significantly at 50 dyne (p<0.05), while type 2A patients had the same behaviour of type 3 patients. This study support the hypothesis that ultralarge VWF multimers released by the endothelium interact with platelets and trigger MP generation, both in vivo and in vitro.

Characterization of the Genetic Defects in Recessive Type 1 and Type 3 von Willebrand Disease Patients of Italian Origin

1998 ◽  
Vol 79 (04) ◽  
pp. 709-717 ◽  
Author(s):  
Giancarlo Castaman ◽  
Hans Vos ◽  
Rogier Bertina ◽  
Francesco Rodeghiero ◽  
Jeroen Eikenboom
Keyword(s):  
Stop Codon ◽  
Von Willebrand Disease ◽  
Genetic Defects ◽  
Missense Mutations ◽  
Molecular Defects ◽  
Recessive Type ◽  
Italian Origin ◽  
Type 3 ◽  
Von Willebrand

SummaryThe genetic defects causing recessive type 1 and type 3 von Wille-brand disease (VWD) in eight families from the northern part of Italy have been investigated. Mutations were identified in 14 of the 16 disease-associated von Willebrand factor (VWF) genes. Only one mutation, a stop codon in exon 45, was previously reported. Several new mutations were identified: one cytosine insertion in exon 42, one guanine deletion in exon 28, one probably complete VWF gene deletion, one substitution in the 3’ splice site of intron 13, one possible gene conversion, and three candidate missense mutations. One missense mutation, the substitution of a cysteine in exon 42, was identified in all type 3 VWD patients that were previously characterized as a subgroup with significant increase of factor VIII procoagulant activity after desmopressin infusion. This paper demonstrates again that the molecular defects of quantitative VWD are diverse and located throughout the entire VWF gene.

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