Christmas Disease
Clinical Manifestations
Christmas disease (hemophilia B), the hereditary functional deficiency of Christmas factor (factor IX), is clinically indistinguishable from classic hemophilia, and can be differentiated only by laboratory tests.
It is inherited in the same way as an X chromosome-linked disorder and is therefore virtually limited to males. As is true of classic hemophilia, the disorder varies in severity from family to family in proportion to the degree of the clotting factor deficiency. Christmas disease is heterogeneous in nature, for in some families the plasma is deficient in Christmas factor, whereas in others the plasma contains one or another of several nonfunctional variants of this clotting factor. Therapy for hemorrhagic episodes in Christmas disease is currently best carried out by transfusion of normal plasma, which contains the factor deficient in the patient’s plasma. An alternative therapy, infusion of concentrates of Christmas factor separated from normal plasma, may be needed in some situations, but its use may be complicated by the transmission of viral diseases as well as by other problems.Geography
Worldwide, Christmas disease is perhaps one-eighth to one-fifth as prevalent as classic hemophilia. Most reported cases have been in individuals of European origin, but in South Africa and in the United States, as reflected by Ohio data, Christmas disease is relatively as common in blacks as in whites. Christmas disease of moderate severity is particularly prevalent among inhabitants of the village of Tenna, in Switzerland, and among Ohio Amish. This disorder is said to be rare in Japan.
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