Coagulation disorders are disorders which affect the coagulation cascade and can either cause excessive or inadequate clotting. Coagulation disorders usually involve a deficiency in at least one clotting factor, and the most common disorders include von Willebrand disease, hemophilia, and vitamin k deficiency.  Von Willebrand disease is the most common bleeding disorder and is characterized by a deficiency in von Willebrand factor due to an autosomal dominant genetic mutation. The von Willebrand factor is mostly involved in primary hemostasis where it helps platelets stick together. The factor also plays a role in secondary hemostasis by helping stabilize factor VIII.   There are three types of hemophilia that are caused by genetic mutations in clotting factor genes and can be passed on from parent to child. Hemophilia A is a deficiency in factor VIII, hemophilia B is a deficiency in factor IX, and hemophilia C is a deficiency in factor XI. All types of hemophilia affect the intrinsic pathway.  A vitamin K deficiency may occur when a sufficient amount of vitamin K is not absorbed from foods or when not enough foods with vitamin K are consumed (e.g., leafy dark green vegetables like spinach). Vitamin K is a cofactor required to make factors II, VII, IX, and X functional. Therefore, vitamin K deficiency affects all three pathways.