Von Willebrand disease, also known as Von Willebrand syndrome (VWD for short). The Von Willebrand factor (VWF for short) in the plasma of patients with this disease is deficient or has an abnormal molecular structure. The manifestations of typical cases are: ① Prolonged bleeding time. ② Reduced platelet adhesion to glass beads and weakened or no aggregation of ristocetin. ③ Reduced plasma factor VIII-related antigen (VIIIR: Ag) and coagulation activity (VIII: C) or reduced VWF activity (VIIIR: VWF). VWD is a common hereditary bleeding disease that can affect both men and women. Most patients have autosomal dominant inheritance, and a few have autosomal recessive inheritance. The VWF gene is located on chromosome 12.