In Willebrand disease, there is currently no test available to identify non-invasively patients with a high risk of bleeding from angiodysplasias The study propose to use a sublingual capillary bed analysis by video-microscopy, a sensitive, reproducible and non-invasive technique, to assess whether sublingual capillary density is predictive of hemorrhagic risk for patients with von Willebrand disease.

Inclusion Criteria:

• Adult patient with a significant form of von Willebrand disease (according to the inclusion criteria of the Willebrand Disease French Reference Center), a Glanzmann Thrombasthenia, a moderate to severe Haemophilia A or a woman carrying the hemophilia gene
• Social insured patient

Exclusion Criteria:

• Minor patient
• Refusal of consent
• Person benefiting from a system of legal protection
• Pregnant patient