Following admission to the emergency department, a 26-year-old woman with severe menorrhagia states that both her father and sister have a bleeding disorder. The hemostatic disorder transmitted by autosomal-dominant mode is which of the following?
## **Core Concept**
The question tests knowledge of bleeding disorders, specifically those with an autosomal dominant mode of inheritance. Menorrhagia, or heavy menstrual bleeding, is a common presentation of various bleeding disorders. Understanding the genetic transmission of these disorders is crucial for diagnosis and management.
## **Why the Correct Answer is Right**
The correct answer, **von Willebrand disease (VWD)**, is the most common inherited bleeding disorder and is transmitted in an autosomal dominant pattern. VWD results from a deficiency or dysfunction of von Willebrand factor (VWF), a protein critical for platelet adhesion to damaged endothelium and serving as a carrier for factor VIII. This disorder can cause menorrhagia, easy bruising, and bleeding after trauma or surgery. The autosomal dominant inheritance means a single copy of the mutated gene is enough to cause the condition, which aligns with the family history provided.
## **Why Each Wrong Option is Incorrect**
- **Option A:** Hemophilia A and B are X-linked recessive disorders, primarily affecting males, which does not match the autosomal dominant pattern or the family history provided.
- **Option B:** While some forms of thrombocytopenia can have a genetic component, the question seems to focus on disorders specifically known for autosomal dominant inheritance and association with menorrhagia and a clear familial bleeding tendency.
- **Option C:** This option is not provided, but typically, disorders like platelet function disorders can have various inheritance patterns.
- **Option D:** If not von Willebrand disease, another less likely option could be a different bleeding disorder, but given the context, **von Willebrand disease** fits best.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that von Willebrand disease is the most common inherited bleeding disorder and often presents with mucocutaneous bleeding symptoms such as menorrhagia, easy bruising, and nosebleeds. It is inherited in an autosomal dominant manner, which means there is a 50% chance of passing the mutated gene to each offspring.
## **Correct Answer:** . von Willebrand disease