The study aims to study the expression of numerous proteins involved in angiogenesis in 70 patients with von Willebrand disease in order to try to identify markers of interest. Secondly, the investigators plan to investigate whether there is a relationship between the proteins tested, the distribution of multimers and the clinical phenotype of the patients, in particular by looking for the presence of bleeding linked to the presence of angiodysplasias.

Inclusion Criteria:

For patients:

• Patient with von Willebrand disease proven by genetic analysis of the VWF gene.
• Lack of treatment that could interfere with angiogenesis.
• Patient informed by an information note sent to his home, with the possibility of objecting to the use of his blood samples in the context of research.

For the control:

• Patient with a normal coagulation report
• Absence of abnormal hemorrhagic symptoms
• Lack of notion of angiodysplasia.
• Lack of treatment that could interfere with angiogenesis.
• Patient informed by an information note sent to his home, with the possibility of objecting to the use of his blood samples in the context of research.

Exclusion Criteria:

• Patient under guardianship or curatorship.
• Pregnant and lactating women.
• Blood transfusion or treatment with von Willebrand factor concentrates less than 7 days old.
• Treatment which may interfere with angiogenesis.

The studied population will be composed of:

• 70 patients with von Willebrand disease: 10 type 1 patients, 10 type 2A (IIA) patients, 10 type 2A (IIE) patients, 10 type 2B patients, 10 type 2M patients, 10 type 2M patients (2A-like) and 10 type 3 patients.
• 20 healthy volunteers