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Hemophilias are bleeding disorders due to deficiency in one of the factors present in the clotting cascade.1 The most common factor abnormalities are of Factor VIII (hemophilia A) or Factor IX (hemophilia B). Historically, hemophilia A was known as “classic hemophilia” and hemophilia B as “Christmas disease,” but these terms are no longer in common use. von Willebrand disease (vWD) is a related hereditary deficiency of von Willebrand factor (vWF).

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These hereditary bleeding disorders typically appear early in life, and adult patients will usually be able to relate a history of a bleeding problem in themselves or their family. However, patients with mild forms of inherited disease may be unaware of a bleeding disorder until stressed by significant trauma or development of another hemostatic problem. Because of new mutations, patients with congenital coagulopathies may not have a family history of bleeding.

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Systemic bleeding disorders should be suspected in patients with severe bleeding related to trivial trauma or minor surgery, or spontaneous bleeding, particularly when the bleeding occurs in joints or muscle. Unusual bleeding or bruising at multiple areas should also raise concern about a coagulopathy. Medications can be responsible for unmasking a mild bleeding diathesis.

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The pattern of bleeding can suggest a likely etiology. For example, patients with easy bruising, gingival bleeding, epistaxis, hematuria, GI bleeding, or heavy menses are more likely to have a deficiency or dysfunction of the platelets. Conversely, patients with spontaneous deep bruises, hemarthrosis, retroperitoneal bleeding, or intracranial bleeding are more likely to have a coagulation factor deficiency. In factor-deficient patients, bleeding associated with trauma may be delayed. This is presumed to be due to the instability of the initial platelet thrombus that is inadequately stabilized by fibrin clot formation. Patients with vWD may present with features of both platelet and clotting factor problems.

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Hemophilia is a disorder of coagulation caused primarily by a deficiency in a circulating plasma protein.1,2 Hemophilia A is caused by a deficiency of Factor VIII and is the most common cause of hemophilia in the U.S., affecting 1 in 10,000 males. Hemophilia B is caused by a deficiency of Factor IX and is less common, affecting approximately 1 in 25,000 to 35,000 males. Together, these forms of hemophilia make up about 99% of patients with inherited coagulation factor deficiencies. Hemophilia A and B are clinically indistinguishable from each other, and specific factor testing must be done to identify the specific type of hemophilia.

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Both hemophilia A and B are X-linked disorders; therefore, this is overwhelmingly a disease of men, with women typically being asymptomatic carriers. Only rarely do women have severe disease. While these disorders are genetic and can be inherited, a family history of bleeding may be absent because approximately one third of new cases of hemophilia A and one fifth of new cases of hemophilia B arise from a spontaneous gene mutation.

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