Molecular defects in haemophilia A and von Willebrand's disease.

A model is proposed for the synthesis of the factor VII/von Willebrand factor protein. The defect(s) in von Willebrand's disease are related to abnormalities of the protein subunit and/or its carbohydrate content, while in haemophilia the abnormality is related to a deficiency or abnormality of the X-dependent enzyme or protein which is involved in the generation of procoagulant activity of the factor VII/von Willebrand factor multimer.