Protein C Deficiency

What is protein C deficiency?

Protein C deficiency is an inherited disorder that increases the risk of developing abnormal blood clots, some of which are life threatening. Protein C in the blood helps prevent clotting, and patients with a protein C deficiency have a defect in the gene that regulates blood clotting. These patients are at greater risk for deep vein thrombosis, a life-threatening blood clot that forms in the deep veins of the arms or legs and ends up stuck in the lungs. Protein C deficiency is also responsible for purpura fulminas, another severe clotting disorder that primarily affects infants. While serious, protein C deficiency can be managed. It is thought that as many as 1 in 500 people have a mild form of protein C deficiency, whereas severe protein C deficiency only affects 1 in 4 million infants.

How is protein C deficiency diagnosed?

A protein C deficiency diagnosis depends on identifying clotting symptoms such as pain, tenderness, redness, or swelling. Once identified, doctors look for a family history of clotting and run blood tests to examine protein C levels. Doctors also look at the activity of certain enzymes in the blood to determine the severity of the deficiency.

What are the symptoms of protein C deficiency?

Some of the most significant protein C deficiency symptoms include pain, tenderness, redness, or swelling (which could indicate a blood clot). Infants with purpura fulminans will have abnormal bleeding, bruising, and discolored skin with large purple patches or spots. Patients with deep vein thrombosis might feel pain and notice swelling in their legs—though there may be no pain or other signs to indicate a clot. Some people with protein C deficiency may never even have symptoms.

What treatments are available for protein C deficiency?

There is no one treatment specifically for protein C deficiency. Patients with mild forms may need treatment only during surgery, pregnancy, or other scenarios where they are at higher risk of a clot forming. Protein C deficiency treatment involves anti-coagulant or blood thinning drugs such as Warfarin to help break up and prevents clots. Because prevention is so critical, patients should always take all their treatments exactly as prescribed. They should also try to avoid situations that can cause blood clots, such as sitting or lying down for extended periods of time (e.g. long car rides).

Where can I find more information about protein C deficiency?

• U.S. National Library of Medicine
• National Organization for Rare Disorders (NORD)