The most common coagulation disorders haemophilia A and Von Willebrand's disease are due to -

Hemophilia (Bleeder's disease or the disease of kings) is due to deficiency of Factory 8. Von Willebrand disease is due to an abnormality; either quantitative or qualitative, of the VWF, which is a large multimeric glycoprotein that functions as the carrier protein for factor 8. VWF also is required for normal platelet adhesion. It functions in both primary (involving platelet adhesion) and secondary (involving  factor VIII) hemostasis.