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Congenital protein C or S deficiency
DefinitionThese inherited disorders of blood coagulation are caused by deficiency of the Vitamin K-dependent plasma proteins C or S that are naturally occurring anticoagulants. The disorder results in an increased tendency for intravascular blood clot formation.
Causes, incidence, and risk factors
Congenital protein C or S deficiency is an inherited disorder that causes abnormal blood clotting. Normal blood coagulation is a complex process involving as many as 20 different plasma proteins which are known as blood coagulation factors.
A series of complex chemical reactions using these factors takes place very rapidly to form an insoluble protein called fibrin that stops bleeding . Other plasma proteins, such as proteins C and S, inhibit or reverse the cascade to prevent excessive clotting.
When certain coagulation factors are deficient or missing, the chain reaction does not take place normally. In this disorder, an increased risk of blood clot formation called thrombosis is present. Risk factors are an individual or family history of recurrent blood clots in the veins.
Mutations in protein C can cause a syndrome of activated protein C resistance similar to factor V Leiden (a mutation in factor V ).
There are different types of genetic transmission of this disease. Heterozygous (one normal gene and one defective) protein C deficiency occurs in approximately 1 in 300 members of the general population. Protein S deficiency occurs in about 1 in 20,000 people.
Signs and tests
TreatmentTreatment for deep venous thrombosis includes therapy with heparin and warfarin. Warfarin is usually given preventatively after a first clotting episode in patients identified to have this disorder.
Expectations (prognosis)The outcome is usually good with treatment, but recurrences can occur.
In rare cases, initial anticoagulation with warfarin can cause transient increased coagulation with severe skin lesions. Patients are at risk if not adequately anticoagulated with heparin prior to taking warfarin.
Calling your health care providerCall your health care provider if symptoms develop that are suggestive of intravenous clotting (i.e., swelling and redness of the leg).
PreventionIf the disorder is diagnosed, precautions may be taken to avoid thrombus formation in high-risk situations that promote slow movement of the blood in the veins. This occurs with prolonged bed rest usually as a result of an illness, surgery, or hospitalization.
Update Date: 8/18/2003Corey Cutler, M.D., M.P.H., F.R.C.P.C, Department of Medical Oncology, Dana-Farber Cancer Institute; Instructor in Medicine, Harvard University, Boston, MA. Review provided by VeriMed Healthcare Network.
Last updated: Tue, 06 Jan 2009 00:20:03 GMT