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Diseases of White Blood Cells and Platelets and Disorders of Coagulation
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There are more than 300 mutations in the VWF gene that can cause von Willebrand disease, in which reduced or delayed clot formation results in prolonged bleeding following vascular injury. Some mutations are associated with only slightly reduced levels or activity of VWF, whereas others are associated with drastic reductions leading to severe disease. In contrast, mutations that affect ADAMTS13 cause diseases characterized by excess clotting and have been associated with familial thrombotic thrombocytopenic purpura, a rare disorder involving abnormal blood coagulation.
Thrombocytopathy Thrombocytopathies are any of several blood disorders characterized by dysfunctional platelets (thrombocytes), which result in prolonged bleeding time, defective clot formation, and a tendency to hemorrhage. Inherited thrombocytopathies include von Willebrand disease; thrombasthenia, characterized by abnormal clot retraction and defective platelet aggregation; and BernardSoulier syndrome, characterized by unusually large platelets. In addition, thrombocytopathy is sometimes seen in cases of Down syndrome and Wiskott-Aldrich syndrome (an immune disorder). Acquired thrombocytopathy has been known to be associated with several disorders, including cirrhosis, leukemia, pernicious anemia, scurvy, and uremia. Temporary platelet dysfunction is sometimes induced by such drugs as antihistamines, aspirin, indomethacin, phenothiazines, phenylbutazone, and tricyclic antidepressants. Treatment for congenital thrombocytopathy is platelet transfusion to control bleeding. For acquired thrombocytopathies, cure of the underlying disease usually results in improved platelet function.
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