Explain the inheritance pattern of the following disorder and how it contributes to the clinical manifestations of each of the following disorders:

a. Hemophilia A
b. Hemophilia B
c. von Willebrand's disease
d. Bernard-Soulier syndrome

What will be an ideal response?

Answer: Hemophilia A results from an inherited deficiency of factor VIII coagulation protein. This inheritance pattern is sex linked. Women are carriers of the aberrant gene and often are asymptomatic because they have the XX genotype. The normal X chromosome present masks the effects of the aberrant gene. A male child of a carrier mother has a 25% chance of having hemophilia A. If so, the child will suffer the full-blown illness because he lacks another X chromosome to mask him from the effects of the genetic anomaly.
b. Hemophilia B
Answer: Hemophilia B results from an inherited deficiency of factor IX coagulation protein. It is similar in inheritance to hemophilia A and produces very similar results.
c. von Willebrand's disease
Answer: von Willebrand's disease results from an inherited deficiency in VWF. The mode of inheritance is autosomal dominant and can be seen equally in both sexes. It is the most common coagulopathy afflicting women.
d. Bernard-Soulier syndrome
Answer: Bernard-Soulier syndrome results from an inherited deficiency of platelet glycoprotein Ib/IX. The mode of inheritance is autosomal recessive and occurs equally in both sexes.