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Protein C Deficiency


Protein C deficiency is a disorder characterized by an increased tendency to form blood clots.


Protein C is a vitamin-K-dependent anticoagulant protein manufactured in the liver and circulated in the plasma. Protein C inhibits coagulation (clotting) by inactivating at least two proteins, Factors V and VIII. When there is a deficiency of protein C, coagulation may take place lending to possible thrombosis.

Defects can occur for a wide variety of reasons in the clotting or anticlotting mechanisms, and thus present a condition of bleeding problems (such as hemophilia) or clotting problems (such as thrombosis).

Decreased values of protein C are associated with:

  • Thrombosis
  • Deep vein thrombosis
  • Pulmonary embolism
  • Thrombophlebitis
  • Neonatal purpura fulminans (homozygote based)
  • Disseminated intravascular coagulation (DIC)


Protein C deficiency is a prethrombotic (a thrombus is a clot) disorder which may be a result of congenital biochemical defects or associated with other thrombotic disorders.

Congenital biochemical defects account for 35 to 60 percent of the cases and may result in conditions such as deep vein thrombosis, pulmonary embolism, and thrombophlebitis. The remaining cases of protein C deficiency are disorders such as cirrhosis, use of warfarin (coumadin), and vitamin K deficiency.

The risk factors include obesity, oral contraceptive use, varicose veins, infection, trauma, surgery, pregnancy, immobility, and congestive heart failure.

Family members of protein C deficiency patients should be screened for the presence of the genetic defect. Their increased risk of thrombosis can be noted and monitored accordingly.


There are no symptoms of protein C deficiency, however the results of this deficiency can emerge in such conditions as deep vein thrombosis, pulmonary embolism, thrombophlebitis, neonatal purpura fulminans, cirrhosis and warfarin-induced skin necrosis. The symptoms of those conditions are as follows:

Deep Vein Thrombosis. If the thrombosis is not in a leg, there are often no symptoms. Clots in the leg veins may cause symptoms such as pain, tenderness, swelling, discoloration and ulceration of the skin depending on the site of the clots and how extensive they are.

Pulmonary embolism. Shortness of breath, rapid pulse, chest pain, coughing, slight fever, dizziness and chest tenderness.

Thrombophlebitis. Redness along the affected segment of the vein.

Neonatal purpura fulminans. Generalized microvascular thrombosis.

Cirrhosis. Jaundice, edema (fluid collection in the tissue), mental confusion and vomiting of blood.

Warfarin-induced skin necrosis. Infarction in an area of tissue that undergoes necrosis (death) following cessation of blood supply. This rare thrombotic complication occurs in some patients within the first few days of initiating warfarin.


The diagnosis of a prethrombotic patient includes a medical and family history, a physical examination and laboratory tests. The medical and family history may reveal repeated episodes of thromboembolism, a family history of thrombosis and early onset of thromboembolism in childhood and teenage years.


Conditions in which there is a tendency for clot formation are often treated with anticoagulants such as heparin (injected) or warfarin (oral).

Anticoagulants decrease the clotting ability of the blood and therefore help prevent harmful clots from forming in the blood vessels. These medicines are sometimes called "blood thinners," although they do not actually thin the blood. They will not dissolve clots that have already formed. However, they may prevent existing clots from becoming larger and causing serious problems.


Should children of protein C deficiency patients be screened early to see if they are predisposed to this problem?

What type of drug treatment are you recommending?

What are the short and long term side effects of this medication?

Will taking this medication alleviate the possibility of blood-clotting conditions?

Will taking this medicine lead to other health problems?

Is this curable?