Which bleeding disorder is characterized by decreased platelet function primarily due to a deficiency of a specific factor?

• A. Von Willebrand disease
• B. Thrombocytopenia
• C. Factor V Leiden
• D. Hemophilia A

Answer: (A)

Von Willebrand disease is characterized by decreased platelet function primarily due to a deficiency of von Willebrand factor (vWF). This factor plays a crucial role in the aggregation of platelets and facilitates their adhesion to the damaged endothelium at the site of a vascular injury. In individuals with this disorder, the deficiency or dysfunction of vWF leads to impaired platelet function, which results in symptoms such as easy bruising, excessive bleeding from small cuts, and prolonged bleeding after surgery or trauma.

The importance of von Willebrand factor extends to its role in stabilizing factor VIII, a clotting factor essential for the coagulation cascade. A deficiency in vWF therefore not only affects platelet function but also can lead to low levels of circulating factor VIII, contributing to bleeding tendencies.

Other bleeding disorders mentioned involve different mechanisms. Thrombocytopenia refers to a reduced number of platelets in the blood, which can lead to bleeding but does not necessarily involve a functional deficiency in the platelets themselves. Factor V Leiden is a genetic mutation that leads to an increased risk of thrombosis rather than bleeding. Hemophilia A is a deficiency in factor VIII itself but does not primarily involve platelet function as von Willebrand disease does. Thus, the distinctive feature of von Wille