The inheritance pattern described by several generations in a family with von Willebrand disease is best called what?

The inheritance pattern described by several generations in a family with von Willebrand disease is best called what?

• A. Mosaic
• B. Autosomal recessive
• C. Autosomal dominant (correct)
• D. X-linked

Answer: (C)

Seeing the trait appear across several generations and in both males and females points to an autosomal dominant pattern. In autosomal dominant conditions, the trait is transmitted from affected individuals to their children across generations (vertical transmission), and about half of the offspring from an affected parent will show the trait. Von Willebrand disease most commonly behaves this way for types 1 and 2, so multiple generations with both sexes affected fits autosomal dominant inheritance. Type 3 is autosomal recessive, which often shows affected individuals without a consistent vertical pattern and can require both parents to be carriers, so it wouldn’t match the described family pattern as neatly. X-linked inheritance would more typically show affected males with carrier or unaffected females, which isn’t implied by the multigenerational, mixed-sex presentation. Mosaic inheritance is not the typical explanation for a straightforward multigenerational pattern.

Seeing the trait appear across several generations and in both males and females points to an autosomal dominant pattern. In autosomal dominant conditions, the trait is transmitted from affected individuals to their children across generations (vertical transmission), and about half of the offspring from an affected parent will show the trait. Von Willebrand disease most commonly behaves this way for types 1 and 2, so multiple generations with both sexes affected fits autosomal dominant inheritance. Type 3 is autosomal recessive, which often shows affected individuals without a consistent vertical pattern and can require both parents to be carriers, so it wouldn’t match the described family pattern as neatly. X-linked inheritance would more typically show affected males with carrier or unaffected females, which isn’t implied by the multigenerational, mixed-sex presentation. Mosaic inheritance is not the typical explanation for a straightforward multigenerational pattern.