What are the different types of von Willebrand disease?

Type

Description

1

Partial quantitative VWF deficiency
•    The most common form (50 to 70% of cases)
•    Several subtypes depending on intra-platelet VWF content
•    Difficult to diagnose: overlap between VWF levels in patients and the normal population
•    VWF levels between 10 and 50%
•    Corresponding reduction in VWF antigen (VWF:Ag) and in ristocetin cofactor activity (VWF:RCo)
Ratio of VWF:RCo/VWF:Ag > 0.7
•    Dominant transmission with varying expression and penetrance

2

Qualitative VWF deficiency
•    Abnormal interaction between VWF and platelets

2A

Deficient platelet adhesion dependent on VWF associated with selective deficiency of high molecular weight (HMW) multimers
•    Abnormal interaction of VWF with platelets; decreased affinity of VWF for platelets due to absence of high molecular weight and intermediate molecular weight multimers
•    Ratio of VWF:RCo/VWF:Ag < 0.7
•    Dominant transmission with varying expression and penetrance

2B

High affinity of VWF for platelet glycoprotein Ib
•    Adsorption of HMW multimers on platelets resulting in fluctuating thrombocytopenia
•    Dominant transmission with varying expression and penetrance

2M

Deficient VWF-dependent platelet adhesion with no selective deficiency in HMW multimers
•    Reduced affinity of VWF for platelets not associated with a multimerisation abnormality
•    Dominant transmission with varying expression and penetrance

2N

Marked deficiency in VWF binding to factor VIII
•    Diagnosis through study of VWF binding to FVIII
•    Normal levels of VWF (VWF:Ag and VWF:RCo)
•    Factor VIII deficit with ratio of FVIII:C/VWF:Ag < 0.5
•    Recessive autosomal transmission

3

Complete quantitative VWF deficiency
•    The rarest form: 1 to 3% of patients
•    Subjects homozygous or composite heterozygous
•    VWF undetectable
•    Extremely low levels of factor VIII (< 10%)
•    Autosomal recessive transmission

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