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 (IMW) 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