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.

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 1 out of 20,000 people.

• Pain or tenderness in extremity or affected area
• Redness or swelling in affected area

• Deficient protein C
• Deficient protein S
• Normal thrombin time
• Normal prothrombin time
• Normal partial thromboplastin time
• Normal bleeding time

• Pulmonary embolism.
• Recurrent venous clots.
• Childhood stroke.
• 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.