C1272S: A new candidate mutation in type 2A von Willebrand disease that disrupts the disulfide loop responsible for the interaction of VWF with platelet GP lb‐IX

Penas, Norma; Pérez, Almudena; González-Boullosa, Rosario; Batlle, J.

doi:10.1002/ajh.10455

Cited by 6 publications

(13 citation statements)

References 15 publications

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“…Similar results were obtained from a patient with a C1272F mutation reported by Woods et al with low basal VWF:Ag = 32 U/dl, VWF:RCo/VWF:Ag ratio < 0.15 and absent RIPA at >1.5 mg/mL ristocetin [15]. A DDAVP trial previously performed on a patient with a C1272S mutation reported by Penas et al in which platelet counts dropped from 200*10 9 L −1 to 157*10 9 L −1 at 30 min post-DDAVP treatment even though VWF:Ag, VWF:RCo, RIPA and presence of high molecular weight multimers were deficient relative to normal throughout the trial [15]. Relative to the patients reported here, DDAVP treatment of the C1272S patient only modestly reduced the platelet count indicating that perhaps the expression of the mutation was variable as has been observed with other type 2M/2A VWD patients with the same genotype within the same family [27].…”

Section: Resultssupporting

confidence: 88%

“…In agreement with our clinical data at "basal" times, the patient with a C1272R mutation reported by Lavergne et al also had low VWF:Ag = 30 U/dl, a VWF:RCo activity < 5, and absent RIPA, but a DDAVP trial was not performed [14]. Similar results were obtained from a patient with a C1272F mutation reported by Woods et al with low basal VWF:Ag = 32 U/dl, VWF:RCo/VWF:Ag ratio < 0.15 and absent RIPA at >1.5 mg/mL ristocetin [15]. A DDAVP trial previously performed on a patient with a C1272S mutation reported by Penas et al in which platelet counts dropped from 200*10 9 L −1 to 157*10 9 L −1 at 30 min post-DDAVP treatment even though VWF:Ag, VWF:RCo, RIPA and presence of high molecular weight multimers were deficient relative to normal throughout the trial [15].…”

Section: Resultsmentioning

confidence: 54%

“…DDAVP-induced thrombocytopenia has previously been observed in other noncysteine type 2B gain-of-function mutations [26], but other reported cysteine mutations [14, 16] have not demonstrated gain-of-function in patients [15]. In agreement with our clinical data at "basal" times, the patient with a C1272R mutation reported by Lavergne et al also had low VWF:Ag = 30 U/dl, a VWF:RCo activity < 5, and absent RIPA, but a DDAVP trial was not performed [14].…”

Section: Resultsmentioning

confidence: 99%

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Enhanced Local Disorder in a Clinically Elusive von Willebrand Factor Provokes High-Affinity Platelet Clumping

Tischer

Machha

Frontroth

et al. 2017

Journal of Molecular Biology

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Mutation of the cysteines forming the disulfide loop of the platelet GPIbα adhesive A1 domain of von Willebrand factor causes quantitative VWF deficiencies in the blood and von Willebrand disease. We report two cases of transient severe thrombocytopenia induced by DDAVP-treatment. Cys1272Trp and Cys1458Tyr mutations identified by genetic sequencing implicate an abnormal gain-of-function phenotype, evidenced by thrombocytopenia, that quickly relapses back to normal platelet counts and deficient plasma VWF. Using surface plasmon resonance, analytical rheology, and hydrogen-deuterium exchange mass spectrometry (HXMS), we decipher mechanisms of A1-GPIbα mediated platelet adhesion and resolve dynamic secondary structure elements that regulate the binding pathway. Constrained by the disulfide, conformational selection between weak and tight binding states of A1 takes precedence and drives normal platelet adhesion to VWF. Less restrained through mutation, loss of the disulfide preferentially diverts binding through an induced-fit disease pathway enabling high-affinity GPIbα binding and firm platelet adhesion to a partially disordered A1 domain. HXMS reveals a dynamic asymmetry of flexible and ordered regions common to both variants indicating that the partially disordered A1 lacking the disulfide retains native-like structural dynamics. Both binding mechanisms share common structural and thermodynamic properties, but the enhanced local disorder in the disease state perpetuates high-affinity platelet agglutination, characteristic of type 2B VWD, upon DDAVP-stimulated secretion of VWF leading to transient thrombocytopenia and a subsequent deficiency of plasma VWF, characteristic of type 2A VWD.

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Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 54%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Enhanced Local Disorder in a Clinically Elusive von Willebrand Factor Provokes High-Affinity Platelet Clumping

Tischer

Machha

Frontroth

et al. 2017

Journal of Molecular Biology

View full text Add to dashboard Cite

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“…In the case reported for the patient with C1272F, plasma VWF multimer gel analysis showed an absence of high and intermediate molecular weight multimers [1]. However, only high molecular weight multimers were absent in a patient with a C1272S substitution, indicating that VWF can be secreted into the blood as low molecular weight forms [2]. Multimer studies on recombinant VWF containing C1272R and C1272G show an absence of high molecular weight multimers and an absence of both high and intermediate molecular weight species in C1458G VWF [9].…”

Section: Discussionmentioning

confidence: 99%

A molten globule intermediate of the Von Willebrand factor A1 domain firmly tethers platelets under shear flow

et al. 2013

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Clinical mutations in patients diagnosed with Type 2A von Willebrand disease (vWD) have been identified that break the single disulfide bond linking N- and C-termini in the vWF A1 domain. We have modeled the effect of these mutations on the disulfide-bonded structure of A1 by reducing and carboxy-amidating these cysteines. Solution biophysical studies show that loss of this disulfide bond induces a molten globule conformational state lacking global tertiary structure but retaining residual secondary structure. The conformational dependence of platelet adhesion to these native and molten globule states of A1 is quantitatively compared using real-time high-speed video microscopy analysis of platelet translocation dynamics under shear flow in a parallel plate micro-fluidic flow chamber. While normal platelets translocating on surface-captured native A1 domain retain the catch-bond character of pause times that increase as a function of shear rate at low shear and decrease as a function of shear rate at high shear, platelets that interact with A1 lacking the disulfide bond remain stably attached and do not translocate. Based on these findings, we propose that the shear stress-sensitive regulation of the A1-GPIb interaction is due to folding the tertiary structure of this domain. Removal of the tertiary structure by disrupting the disulfide bond destroys this regulatory mechanism resulting in high-strength interactions between platelets and vWF A1 that are dependent only on residual secondary structure elements present in the molten globule conformation.

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“…In patients with type 2A VWD, mutations in VWF A1 and A2 domains often resulted in the loss of HMW, and sometimes intermediate MW, multimers [7], [23]. It is proposed that type 2A VWD may be divided into groups I and II, based on different molecular defects [7], [11], [21], [24].…”

Section: Discussionmentioning

confidence: 99%

Identification and Functional Analysis of a Novel von Willebrand Factor Mutation in a Family with Type 2A von Willebrand Disease

et al. 2012

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von Willebrand factor (VWF) is essential for normal hemostasis. VWF gene mutations cause the hemorrhagic von Willebrand disease (VWD). In this study, a 9-year-old boy was diagnosed as type 2A VWD, based on a history of abnormal bleeding, low plasma VWF antigen and activity, low plasma factor VIII activity, and lack of plasma high-molecular-weight (HMW) VWF multimers. Sequencing analysis detected a 6-bp deletion in exon 28 of his VWF gene, which created a mutant lacking D1529V1530 residues in VWF A2 domain. This mutation also existed in his family members with abnormal bleedings but not in >60 normal controls. In transfected HEK293 cells, recombinant VWF ΔD1529V1530 protein had markedly reduced levels in the conditioned medium (42±4% of wild-type (WT) VWF, p <0.01). The mutant VWF in the medium had less HMW multimers. In contrast, the intracellular levels of the mutant VWF in the transfected cells were significantly higher than that of WT (174±29%, p <0.05), indicating intracellular retention of the mutant VWF. In co-transfection experiments, the mutant reduced WT VWF secretion from the cells. By immunofluorescence staining, the retention of the mutant VWF was identified within the endoplasmic reticulum (ER). Together, we identified a unique VWF mutation responsible for the bleeding phenotype in a patient family with type 2A VWD. The mutation impaired VWF trafficking through the ER, thereby preventing VWF secretion from the cells. Our results illustrate the diversity of VWF gene mutations, which contributes to the wide spectrum of VWD.

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C1272S: A new candidate mutation in type 2A von Willebrand disease that disrupts the disulfide loop responsible for the interaction of VWF with platelet GP lb‐IX

Cited by 6 publications

References 15 publications

Enhanced Local Disorder in a Clinically Elusive von Willebrand Factor Provokes High-Affinity Platelet Clumping

Enhanced Local Disorder in a Clinically Elusive von Willebrand Factor Provokes High-Affinity Platelet Clumping

A molten globule intermediate of the Von Willebrand factor A1 domain firmly tethers platelets under shear flow

Identification and Functional Analysis of a Novel von Willebrand Factor Mutation in a Family with Type 2A von Willebrand Disease

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