Which statement is true about von Willebrand disease subtypes in terms of prevalence?

Which statement is true about von Willebrand disease subtypes in terms of prevalence?

• A. Type 1 is the most common
• B. Type 2A is the most common
• C. Type 2B is the most common
• D. Type 3 is the most common

Answer: (A)

In von Willebrand disease, the form with a mild, partial deficiency of von Willebrand factor is the most common. This Type 1 pattern is typically inherited in an autosomal dominant manner and tends to produce mild to moderate bleeding that runs in families, so it accounts for roughly two-thirds to three-quarters of VWD cases in many populations. The other groups comprise more specific qualitative defects (Type 2 subtypes: 2A, 2B, 2M, 2N) and the near-complete deficiency seen in Type 3, which are much less common due to the particular genetic changes required. Type 3 is especially rare because it usually involves a more severe, often recessive genetic defect, leading to very low or absent VWF levels. So, the statement that Type 1 is the most common reflects the usual distribution of VWD subtypes.

In von Willebrand disease, the form with a mild, partial deficiency of von Willebrand factor is the most common. This Type 1 pattern is typically inherited in an autosomal dominant manner and tends to produce mild to moderate bleeding that runs in families, so it accounts for roughly two-thirds to three-quarters of VWD cases in many populations. The other groups comprise more specific qualitative defects (Type 2 subtypes: 2A, 2B, 2M, 2N) and the near-complete deficiency seen in Type 3, which are much less common due to the particular genetic changes required. Type 3 is especially rare because it usually involves a more severe, often recessive genetic defect, leading to very low or absent VWF levels. So, the statement that Type 1 is the most common reflects the usual distribution of VWD subtypes.