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?: (A) Factor X deficiency, (B) von Willebrand's disease, (C) Factor VIII deficiency (true hemophilia), (D) Factor IX deficiency (Christmas disease)
Answer is B. von Willebrand disease is the most common hemostatic disorder transmitted by autosomal- dominant mode. Other disorders transmitted by this mode are hereditary hemorrhagic telangiectasia and factor XI deficiency. Diseases transmitted by an autosomal-recessive mode are factor X, factor V, factor VII, and factor I deficiencies. Factor VIII (true hemophilia) and factor IX (Christmas disease) deficiencies are sex-liked recessive.