In von Willebrand disease, which is either autosomal recessive or autosomal dominant, clotting time slows and the person bruises and bleeds easily. Not everyone who inherits the disease genotype actually develops the phenotype. Affected individuals have differing degrees of difficulty in clotting of blood. This condition is
A) completely penetrant, variably expressive, and not genetically heterogeneic.
B) incompletely penetrant, variably expressive, and genetically heterogeneic.
C) completely penetrant, invariably expressive, and not genetically heterogeneic.
D) pleiotropic and genetically heterogeneic

Question

Quizplus · Accepted Answer

The phenotype in von Willebrand disease is incompletely penetrant, meaning not all individuals who inherit the disease genotype will develop the phenotype. The disease is also variably expressive, meaning affected individuals can have differing degrees of difficulty in clotting blood. Finally, von Willebrand disease is genetically heterogeneic, meaning there are multiple genes that can cause the same phenotype.

In Von Willebrand Disease, Which Is Either Autosomal Recessive or Autosomal