Patients with Classic Von Willebrands disease have:
**Core Concept**
Von Willebrand disease (VWD) is a genetic disorder characterized by a deficiency or dysfunction of von Willebrand factor (VWF), a crucial protein involved in blood coagulation. VWF serves as a carrier protein for factor VIII and facilitates platelet adhesion to the site of injury.
**Why the Correct Answer is Right**
Patients with Classic Von Willebrand disease have a deficiency of VWF, leading to impaired platelet adhesion and aggregation, resulting in prolonged bleeding. This deficiency is usually due to a mutation in the VWF gene, leading to reduced or absent VWF production. The absence of VWF also results in the degradation of factor VIII, further contributing to the bleeding diathesis.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not accurately describe the pathophysiology of Classic Von Willebrand disease.
* **Option B:** This option is incorrect as it is associated with a different bleeding disorder, Hemophilia A, which is caused by a deficiency of factor VIII.
* **Option C:** This option is incorrect as it is associated with a different bleeding disorder, Hemophilia B, which is caused by a deficiency of factor IX.
**Clinical Pearl / High-Yield Fact**
Classic Von Willebrand disease is the most common inherited bleeding disorder, and it is often misdiagnosed as a milder form of Hemophilia A due to the overlapping symptoms. It is essential to perform specific VWF tests, such as the VWF antigen and activity assays, to confirm the diagnosis.
**Correct Answer: A. Deficiency of von Willebrand factor (VWF) leading to impaired platelet adhesion and aggregation.**