Von Willebrand disease pathophysiology: Difference between revisions

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Latest revision as of 14:10, 5 October 2018

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Prince Tano Djan, BSc, MBChB [2] Nazia Fuad M.D.

Overview

Von Willebrand factor is a glycoprotein present in blood and is involved in hemostasis. Its synthesis takes place in the endothelium (in the Weibel-Palade bodies), megakaryocytes (α-granules of platelets), and subendothelial connective tissue and are stored there too. The vWF monomer contains a number of specific domains which binds to factor VIII, platelet GPIb-receptor, Heparin, Collagen. Von Willebrand disease is due to an abnormality, either quantitative or qualitative, of the von Willebrand factor. Von Willebrand factor gene mutations results in problems with subunit or multimer formation, storage, secretion, proteolysis, and increased clearance. Von Willebrand's Disease can also be acquired secondary to another diseases. Acquired VWD is associated with other diseases resulting from different pathological processes. These pathological processes includes Antibody formation resulting in Impaired vWF function and Increased clearance of VWF. Other mechanisms are enhanced proteolysis and decreased synthesis of von Willebrand factor (vWF). Von Willebrand disease types 1 and 2 (except type 2N which is inherited recessively) are inherited as autosomal dominant traits and type 3 is inherited as autosomal recessive.

Pathophysiology

Physiology

Von Willebrand factor (vWF)

The normal physiology of von Willebrand’s factor can be understood as follows:^[1]

Structure

It is a glycoprotein present in blood and is involved in hemostasis.
Its synthesis takes place in the endothelium (in the Weibel-Palade bodies), megakaryocytes (α-granules of platelets), and subendothelial connective tissue.
The fundamental vWF monomer is a 2050-amino acid protein.

These monomer contains a number of specific domains with a distinguishing function.

D'/D3 domain, binds to factor VIII
A1 domain, which binds to:
- Platelet GPIb-receptor
- Heparin
- Collagen
the A2 domain unfolds and then attach to ADAMTS13 protease that inactivates vWF by making smaller multimers.
The partial unfolding is affected by shear flow in the blood, by calcium binding, and by the "vicinal disulfide" at the A2-domain C-terminus.
the A3 domain binds to collagen (Von Willebrand factor type A domain)
the C1 domain, in which the RGD motif binds to platelet integrin α_IIbβ₃ when this is activated (Von Willebrand factor type C domain)
Platelet integrin are the transmembrane receptors which facilitate extracellular matrix adhesion.
The "cystine knot" domain (at the C-terminal end of the protein), which vWF shares with platelet-derived growth factor(PDGF), transforming growth factor-β (TGFβ) and β-human chorionic gonadotropin (βHCG, of pregnancy test fame). (Von Willebrand factor type C domain)

Monomers are subsequently N-glycosylated, arranged into dimers in the endoplasmic reticulum and into multimers in the Golgi apparatus.
Multimers of vWF are usually very large, >20,000 kDa, and consist of almost 80 subunits.
Only the large multimers are functional.
Some cleavage products from vWF production that are also secreted but serve no function.

Function

Von Willebrand factor's main function is binding to other proteins, specially factor VIII.
It plays an important role in platelet adhesion to wound sites.
Von Willebrand factor binds to factor VIII while it is inactive in circulation
Von Willebrand factor protects FVIII from degradation and delivers it to the site of injury
Factor VIII degrades rapidly when not bound to vWF
Factor VIII is released from vWF by the action of thrombin.
In the absence of vWF, factor VIII has a half-life of 1-2 hours
When it is carried by intact vWF, factor VIII half-life becomes 8-12 hour
When vWF is exposed in endothelial cells due to damage occurring to the blood vessel, it binds to collagen.
Endothelium also releases vWF which forms additional links between the platelets' glycoprotein Ib/IX/V and the collagen fibrils
Von Willebrand factor attaches to platelets by its specific receptor to glycoprotein Ib on the platelet surface.
It acts as an adhesive bridge between the platelets and damaged subendothelium at the site of vascular injury
VWF binds to platelet glycoprotein Ib when it forms a complex with gpIX and gpV
This binding is most efficient under high shear stress
When coagulation has been stimulated vWF binds to other platelet receptors that are activated by thrombin.

Pathogenesis

von Willebrand disease is due to an abnormality, either quantitative or qualitative, of the von Willebrand factor^[2]

Pathogenetic mechanisms of inherited VWD

VWD subtype	Pathogenetic mechanisms
Type 1 VWD	65% have VWF mutations	Partial quantitative deficiency of VWF
	70% of VWF variants are missense substitutions affecting VWF trafficking, storage, secretion, and clearance
	Transcription and splicing VWF mutations
Type 2A VWD	Mutations in D1/D2/D′D3 assemblies, A2 and CTCK domains	Loss of high-molecular-weight multimers (HMWMs)
	Interference with HMW multimer formation, storage, and secretion
	Increased ADAMTS13 proteolysis
Type 2B VWD	Mutations in A1 domain	The increase in binding of larger VWF multimers to platelet GP Ib results in sequestration of the platelets and VWF resulting in Thrombocytopenia
	Excessive binding to GPIb glycoprotein Ib
Type 2M VWD	Mutations in A1 and A3 domains	Qualitative variants with decreased binding of VWF to GP Ib, resulting in decreased platelet adhesion
	Diminished binding to GPIbα glycoprotein Ib (A1 domain) or collagen (A3 domain)
Type 2N VWD	Missense variants in D′D3 assembly	Qualitative variants with remarkably decreased affinity for FVIII
	Reduced FVIII binding
Type 3 VWD	VWF mutations found in 85%-90% of cases	Produces null phenotype or the VWF that is not secreted.
	VWF deletions, nonsense, splice site, and missense mutations	Produces null phenotype or the VWF that is not secreted.

Pathogenetic mechanisms of acquired VWD

Von Willebrand's Disease can also be acquired secondary to another disease.^[3]^[4]^[5]^[6]^[7]^[8]^[9]^[10]

Acquired VWD is associated with other diseases resulting from different pathological processes. These pathological processes include:

Antibody formation resulting in:^[11]^[12]
- Impaired vWF function
- Increased clearance of VWF
Enhanced proteolysis
Decreased synthesis

Genetics

Von Willebrand disease types 1 and 2 (except type 2N which is inherited recessively) are inherited as autosomal dominant traits and type 3 is inherited as autosomal recessive. The diagram below illustrates autosomal dominant inheritance.

**von Willebrand disease**

von Willebrand disease types I and II are inherited in an autosomal dominant pattern.

The vWF gene is located on chromosome twelve (12p13.2).
It has 52 exons spanning 178kbp. *
VWD Types 1 and 2 are inherited as autosomal dominant traits and type 3 is inherited as autosomal recessive. Occasionally type 2 also inherits recessively.

Associated conditions

Acquired conditions associated with Von Willebrand disease include the following:^[13]^[14]^[3]^[4]^[5]^[6]^[7]

Heart-related conditions

Malignant diseases

Monoclonal gammopathy of undetermined significance
chronic myeloid leukemia and chronic lymphocytic leukemia
Wilms tumor
Waldenström macroglobulinemia
Essential thrombocythemia
Multiple myeloma
Non-Hodgkin lymphoma
Polycythemia vera

Drugs and other agents

Autoimmune disorders

Systemic lupus erythematosus

Other disorders

References

↑ Peyvandi F, Garagiola I, Baronciani L (May 2011). "Role of von Willebrand factor in the haemostasis". Blood Transfus. 9 Suppl 2: s3–8. doi:10.2450/2011.002S. PMC 3159913. PMID 21839029.
↑ Lillicrap D (November 2013). "von Willebrand disease: advances in pathogenetic understanding, diagnosis, and therapy". Blood. 122 (23): 3735–40. doi:10.1182/blood-2013-06-498303. PMC 3952678. PMID 24065240.
↑ ^3.0 ^3.1 Franchini M, Lippi G (2007). "Acquired von Willebrand syndrome: an update". Am J Hematol. 82 (5): 368–75. doi:10.1002/ajh.20830. PMID 17133419.
↑ ^4.0 ^4.1 Tiede A, Rand JH, Budde U, Ganser A, Federici AB (2011). "How I treat the acquired von Willebrand syndrome". Blood. 117 (25): 6777–85. doi:10.1182/blood-2010-11-297580. PMID 21540459.
↑ ^5.0 ^5.1 Kumar S, Pruthi RK, Nichols WL (2002). "Acquired von Willebrand disease". Mayo Clin Proc. 77 (2): 181–7. doi:10.4065/77.2.181. PMID 11838652.
↑ ^6.0 ^6.1 Veyradier A, Jenkins CS, Fressinaud E, Meyer D (2000). "Acquired von Willebrand syndrome: from pathophysiology to management". Thromb Haemost. 84 (2): 175–82. PMID 10959686.
↑ ^7.0 ^7.1 Federici AB, Rand JH, Bucciarelli P, Budde U, van Genderen PJ, Mohri H; et al. (2000). "Acquired von Willebrand syndrome: data from an international registry". Thromb Haemost. 84 (2): 345–9. PMID 10959711.
↑ Ng et al. Diagnostic Approach to von Willebrand Disease. Blood 2015; 125(13): 2029-2037.
↑ Blomback et al. Von Willebrand Disease Biology Hemophilia 2012; 18: 141-147.
↑ Favarolo et al. Von Willebrand Disease and Platelet Disorders. Hemophilia 2014; 20: 59-64.
↑ van Genderen PJ, Vink T, Michiels JJ, van 't Veer MB, Sixma JJ, van Vliet HH (1994). "Acquired von Willebrand disease caused by an autoantibody selectively inhibiting the binding of von Willebrand factor to collagen". Blood. 84 (10): 3378–84. PMID 7949092.
↑ Handin RI, Martin V, Moloney WC (1976). "Antibody-induced von Willebrand's disease: a newly defined inhibitor syndrome". Blood. 48 (3): 393–405. PMID 1085186.
↑ Simone JV, Cornet JA, Abildgaard CF (1968). "Acquired von Willebrand's syndrome in systemic lupus erythematosus". Blood. 31 (6): 806–12. PMID 4172730.
↑ Wautier JL, Levy-Toledano S, Caen JP (1976). "Acquired von Willebrand's syndrome and thrombopathy in a patient with chronic lymphocytic leukaemia". Scand J Haematol. 16 (2): 128–34. PMID 1083062.

Template:WH Template:WS

[pmid21839029-1] Peyvandi F, Garagiola I, Baronciani L (May 2011). "Role of von Willebrand factor in the haemostasis". Blood Transfus. 9 Suppl 2: s3–8. doi:10.2450/2011.002S. PMC 3159913. PMID 21839029.

[pmid24065240-2] Lillicrap D (November 2013). "von Willebrand disease: advances in pathogenetic understanding, diagnosis, and therapy". Blood. 122 (23): 3735–40. doi:10.1182/blood-2013-06-498303. PMC 3952678. PMID 24065240.

[pmid17133419-3] 3.0 ^3.1 Franchini M, Lippi G (2007). "Acquired von Willebrand syndrome: an update". Am J Hematol. 82 (5): 368–75. doi:10.1002/ajh.20830. PMID 17133419.

[pmid21540459-4] 4.0 ^4.1 Tiede A, Rand JH, Budde U, Ganser A, Federici AB (2011). "How I treat the acquired von Willebrand syndrome". Blood. 117 (25): 6777–85. doi:10.1182/blood-2010-11-297580. PMID 21540459.

[pmid11838652-5] 5.0 ^5.1 Kumar S, Pruthi RK, Nichols WL (2002). "Acquired von Willebrand disease". Mayo Clin Proc. 77 (2): 181–7. doi:10.4065/77.2.181. PMID 11838652.

[pmid10959686-6] 6.0 ^6.1 Veyradier A, Jenkins CS, Fressinaud E, Meyer D (2000). "Acquired von Willebrand syndrome: from pathophysiology to management". Thromb Haemost. 84 (2): 175–82. PMID 10959686.

[pmid10959711-7] 7.0 ^7.1 Federici AB, Rand JH, Bucciarelli P, Budde U, van Genderen PJ, Mohri H; et al. (2000). "Acquired von Willebrand syndrome: data from an international registry". Thromb Haemost. 84 (2): 345–9. PMID 10959711.

[8] Ng et al. Diagnostic Approach to von Willebrand Disease. Blood 2015; 125(13): 2029-2037.

[9] Blomback et al. Von Willebrand Disease Biology Hemophilia 2012; 18: 141-147.

[10] Favarolo et al. Von Willebrand Disease and Platelet Disorders. Hemophilia 2014; 20: 59-64.

[pmid7949092-11] van Genderen PJ, Vink T, Michiels JJ, van 't Veer MB, Sixma JJ, van Vliet HH (1994). "Acquired von Willebrand disease caused by an autoantibody selectively inhibiting the binding of von Willebrand factor to collagen". Blood. 84 (10): 3378–84. PMID 7949092.

[pmid1085186-12] Handin RI, Martin V, Moloney WC (1976). "Antibody-induced von Willebrand's disease: a newly defined inhibitor syndrome". Blood. 48 (3): 393–405. PMID 1085186.

[pmid4172730-13] Simone JV, Cornet JA, Abildgaard CF (1968). "Acquired von Willebrand's syndrome in systemic lupus erythematosus". Blood. 31 (6): 806–12. PMID 4172730.

[pmid1083062-14] Wautier JL, Levy-Toledano S, Caen JP (1976). "Acquired von Willebrand's syndrome and thrombopathy in a patient with chronic lymphocytic leukaemia". Scand J Haematol. 16 (2): 128–34. PMID 1083062.

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@@ Line 2: / Line 2: @@
 {{Von Willebrand disease}}
-{{CMG}}
+{{CMG}}    {{AE}} {{PTD}} {{N.F}}
 ==Overview==
+Von Willebrand factor is a [[glycoprotein]] present in blood and is involved in [[hemostasis]]. Its [[synthesis]] takes place in the [[endothelium]] (in the Weibel-Palade bodies), [[Megakaryocyte|megakaryocytes]] (α-granules of [[platelets]]), and subendothelial connective tissue and are stored there too. The vWF [[monomer]] contains a number of specific [[Protein domains|domains]] which binds to [[factor VIII]], platelet GPIb-receptor, [[Heparin]], [[Collagen]]. Von Willebrand disease is due to an abnormality, either [[quantitative]] or [[qualitative]], of the von Willebrand factor. Von Willebrand factor gene [[Mutation|mutations]] results in problems with subunit or multimer formation, storage, secretion, [[proteolysis]], and increased clearance. Von Willebrand's Disease can also be [[Acquired disorder|acquired]] secondary to another diseases. [[Acquired disorder|Acquired]] [[VWD]] is associated with other diseases resulting from different pathological processes. These pathological processes includes [[Antibody]] formation resulting in Impaired vWF function and Increased clearance of [[VWF]]. Other mechanisms are enhanced [[proteolysis]] and decreased [[synthesis]] of von Willebrand factor (vWF). [[Von Willebrand disease]] types 1 and 2 (except type 2N which is inherited recessively) are inherited as [[autosomal dominant]] traits and type 3 is inherited as [[autosomal recessive]].
 ==Pathophysiology==
-In healthy individuals, VWF circulates as high-molecular-weight multimers carrying factor VIII. Some persons have mildly reduced [[VWF]] levels, which may contribute to a bleeding phenotype but are not necessarily caused by defects in the VWF gene. Persons with low VWF levels and a bleeding tendency are classified as having low VWF, rather than [[von Willebrand’s disease]] (VWD). There is a partial deficiency of functionally normal [[VWF]] in type 1 [[VWD]] and a complete deficiency in type 3 disease. This deficiency can result from a reduction in protein synthesis, which is often caused by null alleles (large gene deletions, stop codons, [[frame-shift mutations]], or [[splice-site mutations]]) but may also be due to [[mutations]] in the [[promotor]] regions. Homozygosity or compound heterozygosity for these defects results in type 3 VWD. Some heterozygous carriers have mild symptoms and receive a diagnosis of type 1 disease. However, most cases of type 1 [[VWD]] are caused by heterozygous [[missense]] mutations that exert a dominant-negative effect because the mutant subunits are incorporated into the multimer together with the normal subunits, resulting in a abnormality of the entire multimer.
+=== Physiology ===
+==== '''Von Willebrand factor''' ('''vWF''') ====
+The normal [[physiology]] of [[von Willebrand’s disease|von Willebrand’s factor]] can be understood as follows:<ref name="pmid21839029">{{cite journal |vauthors=Peyvandi F, Garagiola I, Baronciani L |title=Role of von Willebrand factor in the haemostasis |journal=Blood Transfus |volume=9 Suppl 2 |issue= |pages=s3–8 |date=May 2011 |pmid=21839029 |pmc=3159913 |doi=10.2450/2011.002S |url=}}</ref>
+'''Structure'''
+* It is a [[glycoprotein]] present in blood and is involved in [[hemostasis]].
+* Its [[synthesis]] takes place in the [[endothelium]] (in the Weibel-Palade bodies), [[Megakaryocyte|megakaryocytes]] (α-granules of [[platelets]]), and [[subendothelial]] [[connective tissue]].
+* The fundamental vWF [[monomer]] is a 2050-[[Amino acid|amino acid protein]].
+These [[monomer]] contains a number of specific [[Protein domains|domains]] with a distinguishing function.
+* D'/D3 [[Protein domains|domain]], binds to factor VIII
+* A1 [[Protein domains|domain]], which binds to:
+** Platelet GPIb-receptor
+** [[Heparin]]
+** [[Collagen]]
+* the A2 [[Domain (biology)|domain]] unfolds and then attach to ADAMTS13 protease that inactivates vWF by making smaller [[Multimeric protein|multimers]].
+* The partial unfolding is affected by shear flow in the blood, by [[calcium]] binding, and by the "vicinal disulfide" at the A2-domain C-terminus.
+* the A3 [[Protein domains|domain]] binds to [[collagen]] (Von Willebrand factor type A domain)
+* the C1 [[Protein domains|domain]], in which the RGD motif binds to [[platelet]] integrin α<sub>IIb</sub>β<sub>3</sub> when this is activated (Von Willebrand factor type C domain)
+* Platelet integrin are the [[Transmembrane receptor|transmembrane receptors]] which facilitate [[extracellular matrix]] adhesion.
+* The "cystine knot" [[Domain (biology)|domain]] (at the C-terminal end of the protein), which vWF shares with [[platelet-derived growth factor]](PDGF), [[Transforming growth factor-β|transforming growth factor]]-β (TGFβ) and [[Human chorionic gonadotropin|β-human chorionic gonadotropin]] (βHCG, of pregnancy test fame). (Von Willebrand factor type C domain)
+* [[Monomer|Monomers]] are subsequently N-glycosylated, arranged into [[Dimer|dimers]] in the [[endoplasmic reticulum]] and into [[Multimeric protein|multimers]] in the [[Golgi apparatus]].
+* [[Multimeric protein|Multimers]] of vWF are usually very large, >20,000 kDa, and consist of almost 80 subunits.
+* Only the large [[Multimeric protein|multimers]] are functional.
+* Some cleavage products from vWF production that are also secreted but serve no function.
+'''Function'''
+* Von Willebrand factor's main function is binding to other [[Protein|proteins]], specially [[factor VIII]].
+* It plays an important role in [[platelet]] adhesion to wound sites.
+* Von Willebrand factor binds to [[factor VIII]] while it is inactive in circulation
+* Von Willebrand factor protects [[Factor VIII|FVIII]] from [[degradation]] and delivers it to the site of injury
+* [[Factor VIII]] degrades rapidly when not bound to vWF
+* [[Factor VIII]] is released from vWF by the action of [[thrombin]].
+* In the absence of vWF, [[factor VIII]] has a [[half-life]] of 1-2 hours
+* When it is carried by intact vWF, [[factor VIII]] [[half-life]] becomes 8-12 hour
+* When vWF is exposed in [[endothelial cells]] due to damage occurring to the blood vessel, it binds to [[collagen]].
+* [[Endothelium]] also releases vWF which forms additional links between the [[Glycoprotein Ib|platelets' glycoprotein Ib]]/IX/V and the [[Collagen|collagen fibrils]]
+* Von Willebrand factor attaches to [[Platelet|platelets]] by its specific receptor to [[glycoprotein Ib]] on the [[platelet]] surface.
+* It acts as an adhesive bridge between the [[Platelet|platelets]] and damaged [[subendothelium]] at the site o[[Vascular|f vascular]] injury
+* VWF binds to [[Platelet gp 1 b|platelet]] [[glycoprotein Ib]]  when it forms a complex with gpIX and gpV
+* This binding is most efficient under high shear stress
+* When [[coagulation]] has been stimulated vWF binds to other [[platelet]] receptors that are activated by [[thrombin]].
+=== Pathogenesis ===
+von Willebrand disease is due to an abnormality, either [[quantitative]] or [[qualitative]], of the von Willebrand factor<ref name="pmid24065240">{{cite journal |vauthors=Lillicrap D |title=von Willebrand disease: advances in pathogenetic understanding, diagnosis, and therapy |journal=Blood |volume=122 |issue=23 |pages=3735–40 |date=November 2013 |pmid=24065240 |pmc=3952678 |doi=10.1182/blood-2013-06-498303 |url=}}</ref>
+'''Pathogenetic mechanisms of  inherited VWD'''
+{| class="wikitable"
+! colspan="1" rowspan="1" |VWD subtype
+! colspan="1" rowspan="1" |Pathogenetic mechanisms
+!
+|-
+| colspan="1" rowspan="1" |Type 1 VWD
+| colspan="1" rowspan="1" |65% have ''VWF'' [[Mutation|mutations]]
+| rowspan="3" |Partial [[Quantitative|quantitative deficiency]] of VWF
+|-
+| colspan="1" rowspan="1" |
+| colspan="1" rowspan="1" |70% of ''VWF'' variants are [[Missense mutation|missense]] substitutions affecting VWF trafficking, storage, [[secretion]], and clearance
+|-
+| colspan="1" rowspan="1" |
+| colspan="1" rowspan="1" |[[Transcription (genetics)|Transcription]] and [[Splicing (genetics)|splicing]] ''VWF'' [[Mutation|mutations]]
+|-
+| colspan="1" rowspan="1" |Type 2A VWD
+| colspan="1" rowspan="1" |[[Mutation|Mutations]] in D1/D2/D′D3 assemblies, A2 and CTCK [[Protein domains|domains]]
+| rowspan="3" |Loss of high-molecular-weight multimers (HMWMs)
+|-
+| colspan="1" rowspan="1" |
+| colspan="1" rowspan="1" |Interference with [[Multimeric protein|HMW multimer]] formation, storage, and [[secretion]]
+|-
+| colspan="1" rowspan="1" |
+| colspan="1" rowspan="1" |Increased ADAMTS13 [[proteolysis]]
+|-
+| colspan="1" rowspan="1" |Type 2B VWD
+| colspan="1" rowspan="1" |[[Mutation|Mutations]] in A1 [[Protein domains|domain]]
+| rowspan="2" |The increase in binding of larger VWF multimers to [[platelet]] GP Ib results in sequestration of the [[platelets]] and VWF resulting in [[Thrombocytopenia]]
+|-
+| colspan="1" rowspan="1" |
+| colspan="1" rowspan="1" |Excessive binding to GPIb [[Glycoprotein Ib|''glycoprotein Ib'']]
+|-
+| colspan="1" rowspan="1" |Type 2M VWD
+| colspan="1" rowspan="1" |[[Mutation|Mutations]] in A1 and A3 [[Protein domains|domains]]
+| rowspan="2" |[[Qualitative]] variants with decreased binding of VWF to GP Ib, resulting in decreased platelet adhesion
+|-
+| colspan="1" rowspan="1" |
+| colspan="1" rowspan="1" |Diminished binding to GPIb''α [[glycoprotein Ib]]''  (A1 domain) or [[collagen]] (A3 domain)
+|-
+| colspan="1" rowspan="1" |Type 2N VWD
+| colspan="1" rowspan="1" |Missense variants in D′D3 assembly
+| rowspan="2" |[[Qualitative]] variants with remarkably decreased [[affinity]] for [[Factor VIII|FVIII]]
+|-
+| colspan="1" rowspan="1" |
+| colspan="1" rowspan="1" |Reduced [[Factor VIII|FVIII]] binding
+|-
+| colspan="1" rowspan="1" |Type 3 VWD
+| colspan="1" rowspan="1" |''VWF'' [[Mutation|mutations]] found in 85%-90%  of cases
+| rowspan="2" |Produces  [[Phenotype|null phenotype]] or the VWF that is not secreted.
+|-
+| colspan="1" rowspan="1" |
+| colspan="1" rowspan="1" |''VWF'' [[Deletion (genetics)|deletions]], nonsense, [[Splice site|splice site,]] and [[Missense mutation|missense mutations]]
+|}
+'''Pathogenetic mechanisms of acquired VWD'''
+* Von Willebrand's Disease can also be acquired secondary to another disease.<ref name="pmid17133419">{{cite journal| author=Franchini M, Lippi G| title=Acquired von Willebrand syndrome: an update. | journal=Am J Hematol | year= 2007 | volume= 82 | issue= 5 | pages= 368-75 | pmid=17133419 | doi=10.1002/ajh.20830 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17133419  }} </ref><ref name="pmid21540459">{{cite journal| author=Tiede A, Rand JH, Budde U, Ganser A, Federici AB| title=How I treat the acquired von Willebrand syndrome. | journal=Blood | year= 2011 | volume= 117 | issue= 25 | pages= 6777-85 | pmid=21540459 | doi=10.1182/blood-2010-11-297580 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21540459  }} </ref><ref name="pmid11838652">{{cite journal| author=Kumar S, Pruthi RK, Nichols WL| title=Acquired von Willebrand disease. | journal=Mayo Clin Proc | year= 2002 | volume= 77 | issue= 2 | pages= 181-7 | pmid=11838652 | doi=10.4065/77.2.181 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11838652  }} </ref><ref name="pmid10959686">{{cite journal| author=Veyradier A, Jenkins CS, Fressinaud E, Meyer D| title=Acquired von Willebrand syndrome: from pathophysiology to management. | journal=Thromb Haemost | year= 2000 | volume= 84 | issue= 2 | pages= 175-82 | pmid=10959686 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10959686  }} </ref><ref name="pmid10959711">{{cite journal| author=Federici AB, Rand JH, Bucciarelli P, Budde U, van Genderen PJ, Mohri H et al.| title=Acquired von Willebrand syndrome: data from an international registry. | journal=Thromb Haemost | year= 2000 | volume= 84 | issue= 2 | pages= 345-9 | pmid=10959711 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10959711  }} </ref><ref>Ng et al. Diagnostic Approach to von Willebrand Disease.  Blood 2015; 125(13): 2029-2037.</ref><ref>Blomback et al. Von Willebrand Disease Biology Hemophilia 2012; 18: 141-147.</ref><ref>Favarolo et al. Von Willebrand Disease and Platelet Disorders.  Hemophilia 2014; 20: 59-64.</ref>
+* [[Acquired disorder|Acquired]] [[VWD]] is associated with other diseases resulting from different pathological processes. These pathological processes include:
+*[[Antibody]] formation resulting in:<ref name="pmid7949092">{{cite journal| author=van Genderen PJ, Vink T, Michiels JJ, van 't Veer MB, Sixma JJ, van Vliet HH| title=Acquired von Willebrand disease caused by an autoantibody selectively inhibiting the binding of von Willebrand factor to collagen. | journal=Blood | year= 1994 | volume= 84 | issue= 10 | pages= 3378-84 | pmid=7949092 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=7949092  }} </ref><ref name="pmid1085186">{{cite journal| author=Handin RI, Martin V, Moloney WC| title=Antibody-induced von Willebrand's disease: a newly defined inhibitor syndrome. | journal=Blood | year= 1976 | volume= 48 | issue= 3 | pages= 393-405 | pmid=1085186 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1085186  }} </ref>
+**Impaired vWF function
+**Increased clearance of [[VWF]]
+*Enhanced [[proteolysis]]
+*Decreased [[synthesis]]
-Deficiency of [[vWF]] shows primarily in organs with extensive small vessels, such as the skin, the [[gastrointestinal tract]] and the [[uterus]].
-In more severe cases of type 1 [[vWD]], genetic changes are common within the [[vWF]] gene and are highly [[Penetrance|penetrant]]. In milder cases of type 1 [[vWD]] there may be a complex spectrum of molecular [[pathology]] in addition to [[Polymorphism (biology)|polymorphism]]s of the vWF gene alone.<ref>{{cite journal | author = James P, Notley C, Hegadorn C, Leggo J, Tuttle A, Tinlin S, Brown C, Andrews C, Labelle A, Chirinian Y, O'Brien L, Othman M, Rivard G, Rapson D, Hough C, Lillicrap D | title = The mutational spectrum of type 1 von Willebrand disease: Results from a Canadian cohort study | journal = Blood | volume = 109 | issue = 1 | pages = 145–54 | year = 2007 | pmid = 17190853 | doi = 10.1182/blood-2006-05-021105}}</ref> The individual's [[ABO blood group system|ABO blood group]] can influence presentation and pathology of vWD. Those individuals with blood group O have a lower mean level than individuals with other blood groups. Unless ABO group–specific vWF:antigen reference ranges are used, normal group O individuals can be diagnosed as type I vWD, and some individuals of blood group AB with a genetic defect of vWF may have the diagnosis overlooked because vWF levels are elevated due to blood group.<ref>{{cite journal | last = Gill | first = JC | coauthors = Endres-Brooks J, Bauer PJ, Marks WJ, Montgomery RR | title = The effect of ABO blood group on the diagnosis of von Willebrand disease | journal = Blood | volume = 69 | issue = 6 | pages = 1691–5 | publisher = | date = 1987 | url = http://www.bloodjournal.org/cgi/content/abstract/69/6/1691 | doi = | pmid = 3495304 | accessdate =  }}</ref>
 ===Genetics===
@@ Line 21: / Line 131: @@
 |+ '''von Willebrand disease'''
 !
-|-valign="top"
+|- valign="top"
 |[[Image:autodominant.jpg|thumb|von Willebrand disease types I and II are inherited in an [[autosomal dominant]] pattern.]]
 |}
@@ Line 30: / Line 140: @@
 ==Associated conditions==
-Acquired conditions associated with Von Willebrand disease include the following:
+Acquired conditions associated with Von Willebrand disease include the following:<ref name="pmid4172730">{{cite journal| author=Simone JV, Cornet JA, Abildgaard CF| title=Acquired von Willebrand's syndrome in systemic lupus erythematosus. | journal=Blood | year= 1968 | volume= 31 | issue= 6 | pages= 806-12 | pmid=4172730 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=4172730  }} </ref><ref name="pmid1083062">{{cite journal| author=Wautier JL, Levy-Toledano S, Caen JP| title=Acquired von Willebrand's syndrome and thrombopathy in a patient with chronic lymphocytic leukaemia. | journal=Scand J Haematol | year= 1976 | volume= 16 | issue= 2 | pages= 128-34 | pmid=1083062 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1083062  }} </ref><ref name="pmid17133419">{{cite journal| author=Franchini M, Lippi G| title=Acquired von Willebrand syndrome: an update. | journal=Am J Hematol | year= 2007 | volume= 82 | issue= 5 | pages= 368-75 | pmid=17133419 | doi=10.1002/ajh.20830 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17133419  }} </ref><ref name="pmid21540459">{{cite journal| author=Tiede A, Rand JH, Budde U, Ganser A, Federici AB| title=How I treat the acquired von Willebrand syndrome. | journal=Blood | year= 2011 | volume= 117 | issue= 25 | pages= 6777-85 | pmid=21540459 | doi=10.1182/blood-2010-11-297580 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21540459  }} </ref><ref name="pmid11838652">{{cite journal| author=Kumar S, Pruthi RK, Nichols WL| title=Acquired von Willebrand disease. | journal=Mayo Clin Proc | year= 2002 | volume= 77 | issue= 2 | pages= 181-7 | pmid=11838652 | doi=10.4065/77.2.181 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11838652  }} </ref><ref name="pmid10959686">{{cite journal| author=Veyradier A, Jenkins CS, Fressinaud E, Meyer D| title=Acquired von Willebrand syndrome: from pathophysiology to management. | journal=Thromb Haemost | year= 2000 | volume= 84 | issue= 2 | pages= 175-82 | pmid=10959686 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10959686  }} </ref><ref name="pmid10959711">{{cite journal| author=Federici AB, Rand JH, Bucciarelli P, Budde U, van Genderen PJ, Mohri H et al.| title=Acquired von Willebrand syndrome: data from an international registry. | journal=Thromb Haemost | year= 2000 | volume= 84 | issue= 2 | pages= 345-9 | pmid=10959711 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10959711  }} </ref>
 ====Heart-related conditions====
 *[[Mitral valve prolapse]]
 *Ventricular assist device
 *[[Ventricular septal defect]]
 *[[Aortic stenosis]]
 ====Malignant diseases====
-*Monoclonal gammopathy of undetermined significance
+*[[Monoclonal gammopathy]] of undetermined significance
+*[[chronic myeloid leukemia]] and [[chronic lymphocytic leukemia]]
-*Leukemia example [[chronic myeloid leukemia]] and [[chronic lymphocytic leukemia]]
 *[[Wilms tumor]]
 *[[Waldenström macroglobulinemia]]
@@ Line 49: / Line 158: @@
 *[[Non-Hodgkin lymphoma]]
 *[[Polycythemia vera]]
 ====Drugs and other agents====
@@ Line 55: / Line 163: @@
 * [[Ciprofloxacin]]
 *[[Griseofulvin]]
 ====Autoimmune disorders====
@@ Line 65: / Line 172: @@
 *[[Hemoglobinopathies]]
 *[[Angiodysplasia]]
 ==References==