Phenotypic Parameters in Genotypically Selected Type 2B von Willebrand Disease Patients: A Large, Single-Center Experience Including a New Novel Mutation

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.

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A Novel Mutation in the D3 Domain of von Willebrand Factor Markedly Decreases Its Ability to Bind Factor VIII and Affects Its Multimerization

Blood ◽

10.1182/blood.v92.12.4663 ◽

1998 ◽

Vol 92 (12) ◽

pp. 4663-4670 ◽

Cited By ~ 28

Author(s):

S. Jorieux ◽

C. Gaucher ◽

J. Goudemand ◽

C. Mazurier

Keyword(s):

Factor Viii ◽

Von Willebrand Factor ◽

Stop Codon ◽

Novel Mutation ◽

Von Willebrand Disease ◽

Enzyme Linked Immunosorbent Assay ◽

Sequencing Analysis ◽

Normal Platelet ◽

Von Willebrand ◽

Willebrand Factor

Abstract In type 2N von Willebrand disease (vWD), von Willebrand factor (vWF) is characterized by normal multimeric pattern, normal platelet-dependent function, but a markedly decreased affinity for factor VIII (FVIII). In this report, we describe the case of a vWD patient who has an abnormal vWF multimers distribution associated with a markedly decreased vWF ability to bind FVIII. Sequencing analysis of patient’s vWF gene showed, at heterozygous state, a G→A transition resulting in the substitution of Asn for Asp at position 116 of the mature vWF subunit and a C→T transition, changing the codon for Arg 896 into a stop codon. His sister who has a subnormal vWF level, but a normal FVIII/vWF interaction, was found to be heterozygous for the Arg896ter mutation only. Recombinant vWF (rvWF) containing the candidate (Asn116) missense mutation was expressed in COS-7 cells. The expression level of Asn116rvWF was significantly decreased compared with wild-type rvWF. The multimeric pattern of Asn116rvWF was greatly impaired as shown by the decrease in high molecular weight forms. The FVIII binding ability of Asn116rvWF was dramatically decreased. These data show that the Asp116Asn substitution is the cause of both the defective FVIII/vWF interaction and the impaired multimeric pattern observed in the patient’s vWF. The monoclonal antibody 31H3 against D’ domain of vWF (epitope aa 66-76) that partially inhibits the FVIII binding and recognizes only nonreduced vWF, showed a decreased ability to bind Asn116rvWF when used as capture-antibody in enzyme-linked immunosorbent assay (ELISA). This result suggests that a potential conformation change in the D’ domain is induced by the Asp116Asn substitution, which is localized in the D3 domain.

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Identification of p.W246L As a Novel Mutation in the GP1BA Gene Responsible for Platelet-Type von Willebrand Disease

Seminars in Thrombosis and Hemostasis ◽

10.1055/s-0033-1364183 ◽

2014 ◽

Vol 40 (02) ◽

pp. 151-160 ◽

Cited By ~ 10

Author(s):

Adriana Woods ◽

Analia Sanchez-Luceros ◽

Emilse Bermejo ◽

Juvenal Paiva ◽

Maria Alberto ◽

...

Keyword(s):

Platelet Aggregation ◽

Novel Mutation ◽

In Silico Analysis ◽

Von Willebrand Disease ◽

Severe Bleeding ◽

Low Concentrations ◽

Healthy Control ◽

Spontaneous Platelet Aggregation ◽

Von Willebrand ◽

Willebrand Factor

Platelet-type von Willebrand disease (PT-VWD) and type 2B von Willebrand disease (2B-VWD) are rare bleeding disorders characterized by increased ristocetin-induced platelet aggregation (RIPA) at low concentrations of ristocetin. Diagnosis of either condition is not easy and the differential diagnosis between the two entities is especially challenging as evidenced by high levels of misdiagnosis of both conditions, but particularly PT-VWD. Five mutations in the GP1BA gene related to PT-VWD and less than 50 patients are currently reported worldwide. We herein describe a patient with severe bleeding symptoms, macrothrombocytopenia, mild spontaneous platelet aggregation, positive RIPA at 0.3 and 0.4 mg/mL, von Willebrand factor ristocetin cofactor (VWF:RCo) to antigen (VWF:Ag) < 0.2, normal VWF propeptide/VWF:Ag ratio, and RIPA mixing tests and cryoprecipitate challenge positive for PT-VWD. GP1BA gene was studied in the patient, in his mother, and in 100 healthy control subjects. We identified a heterozygous substitution G > T located at nucleotide 3805 in the g.DNA of the patient's GP1BA gene, resulting in a Trp to Leu amino acid change at residue 246 (p.W246L). This mutation was absent in his unaffected mother and also in the 100 controls, and was predicted as damaging by in silico analysis. The residue W246 is located within the VWF-binding region and exists in a strongly conserved position in the phylogenetic tree, which is expected to be unable to tolerate substitutions without changing its functional characteristics. These findings argue strongly in favor of the view that this substitution does not represent a polymorphism and is therefore responsible for the PT-VWD phenotype of the patient.

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Characterization of a novel mutation in the von Willebrand factor propeptide in a distinct subtype of recessive von Willebrand disease

Thrombosis and Haemostasis ◽

10.1160/th08-03-0187 ◽

2008 ◽

Vol 100 (08) ◽

pp. 211-216 ◽

Cited By ~ 7

Author(s):

Elsa Lanke ◽

Ann-Charlotte Kristoffersson ◽

Malou Philips ◽

Lars Holmberg ◽

Stefan Lethagen

Keyword(s):

Novel Mutation ◽

Critical Role ◽

Von Willebrand Disease ◽

In Vitro Mutagenesis ◽

Correct Orientation ◽

Gene Coding ◽

Dimeric Form ◽

Von Willebrand ◽

Distinct Subtype

SummaryvonWillebrand factor (VWF) is a plasma protein that consists of a series of multimers of which the high-molecular-weight VWF multimers are the most potent in platelet adhesion and aggre-gation. The propeptide of theVWF (VWFpp) is known to be essential in the process of multimer assembly. Genetic studies were performed in a patient with a phenotype of vonWillebrand disease (VWD) characterized by very low plasma factorVIII and VWF levels and a VWF consisting of only a dimeric band and total absence of all multimers in plasma. The patient was found to be homozygous for the novel C570S mutation, caused by a 1709G>C transition in exon 14 of theVWF gene coding for the propeptide. Three asymptomatic relatives were found to be heterozygous. In-vitro mutagenesis and expression in COS-7 cells confirmed the detrimental effect of the mutation on VWF multimerization. Our findings show that the C570S mutation in the VWFpp abolishes multimerization of VWF. The mutation probably disrupts the normal configuration of the VWFpp, which is essential for correct orientation of the protomers and ultimately multimerization. The mutant amino acid is located in a region that is highly conserved across several species which underlines its critical role. This variant constitutes a distinct subtype of recessive 2AVWD with the exclusive presence of the dimeric form of VWF in plasma.

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A Novel Mutation in the D3 Domain of von Willebrand Factor Markedly Decreases Its Ability to Bind Factor VIII and Affects Its Multimerization

Blood ◽

10.1182/blood.v92.12.4663.424k06_4663_4670 ◽

1998 ◽

Vol 92 (12) ◽

pp. 4663-4670 ◽

Cited By ~ 1

Author(s):

S. Jorieux ◽

C. Gaucher ◽

J. Goudemand ◽

C. Mazurier

Keyword(s):

Factor Viii ◽

Von Willebrand Factor ◽

Stop Codon ◽

Novel Mutation ◽

Von Willebrand Disease ◽

Enzyme Linked Immunosorbent Assay ◽

Sequencing Analysis ◽

Normal Platelet ◽

Von Willebrand ◽

Willebrand Factor

In type 2N von Willebrand disease (vWD), von Willebrand factor (vWF) is characterized by normal multimeric pattern, normal platelet-dependent function, but a markedly decreased affinity for factor VIII (FVIII). In this report, we describe the case of a vWD patient who has an abnormal vWF multimers distribution associated with a markedly decreased vWF ability to bind FVIII. Sequencing analysis of patient’s vWF gene showed, at heterozygous state, a G→A transition resulting in the substitution of Asn for Asp at position 116 of the mature vWF subunit and a C→T transition, changing the codon for Arg 896 into a stop codon. His sister who has a subnormal vWF level, but a normal FVIII/vWF interaction, was found to be heterozygous for the Arg896ter mutation only. Recombinant vWF (rvWF) containing the candidate (Asn116) missense mutation was expressed in COS-7 cells. The expression level of Asn116rvWF was significantly decreased compared with wild-type rvWF. The multimeric pattern of Asn116rvWF was greatly impaired as shown by the decrease in high molecular weight forms. The FVIII binding ability of Asn116rvWF was dramatically decreased. These data show that the Asp116Asn substitution is the cause of both the defective FVIII/vWF interaction and the impaired multimeric pattern observed in the patient’s vWF. The monoclonal antibody 31H3 against D’ domain of vWF (epitope aa 66-76) that partially inhibits the FVIII binding and recognizes only nonreduced vWF, showed a decreased ability to bind Asn116rvWF when used as capture-antibody in enzyme-linked immunosorbent assay (ELISA). This result suggests that a potential conformation change in the D’ domain is induced by the Asp116Asn substitution, which is localized in the D3 domain.

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Congenital Factor Deficiencies in Children: A Report of a Single-Center Experience

Clinical and Applied Thrombosis/Hemostasis ◽

10.1177/1076029617731596 ◽

2017 ◽

Vol 24 (6) ◽

pp. 901-907 ◽

Cited By ~ 2

Author(s):

Zafer Şalcıoğlu ◽

Cengiz Bayram ◽

Hülya Şen ◽

Gizem Ersoy ◽

Gönül Aydoğan ◽

...

Keyword(s):

Hemophilia A ◽

Coagulation Factors ◽

Von Willebrand Disease ◽

Hemophilia B ◽

Pediatric Hematology ◽

Single Center Experience ◽

Von Willebrand ◽

Collaborative Efforts ◽

Congenital Factor

Congenital factor deficiencies (CFDs) refer to inherited deficiency of coagulation factors in the blood. A total of 481 patients with CFDs, who were diagnosed and followed at our Pediatric Hematology and Oncology Clinic between 1990 and 2015, were retrospectively evaluated. Of the 481 cases, 134 (27.8%) were hemophilia A, 38 (7.9%) were hemophilia B, 57 (11.8%) were von Willebrand disease (vWD), and 252 (52.3%) were rare bleeding disorders (RBDs). The median age of the patients at the time of diagnosis and at the time of the study was 4.1 years (range: 2 months to 20.4 years) and 13.4 years (range: 7 months to 31.3 years), respectively. The median duration of the follow-up time was 6.8 years (range: 2.5 months to 24.8 years). One hundred nineteen (47.2%) of 252 patients with RBDs were asymptomatic, 49 (41.1%) of whom diagnosed by family histories, 65 (54.6%) through preoperative laboratory studies, and 5 (4.2%) after prolonged bleeding during surgeries. Consanguinity rate for the RBDs was 47.2%. Prophylactic treatment was initiated in 80 patients, 58 of whom were hemophilia A, 7 were hemophilia B, 13 were RBDs, and 2 were vWD. Significant advances have been achieved during the past 2 decades in the treatment of patients with CFDs, particularly in patients with hemophilias. The rarity and clinical heterogeneity of RBDs lead to significant diagnostic challenges and improper management. In this regard, multinational collaborative efforts are needed with the hope that can improve the management of patients with RBDs.

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