protein S deficiency

Last reviewed 01/2018

Protein S deficiency results in a primary hypercoagulable state.

Both quantitative and qualitative abnormalities of protein S have been identified.

In the normal individual, 60% of protein S in the plasma is inactive, being bound to the C4b-binding protein. Excessive binding of protein S to C4b-binding protein may result in a deficiency of active protein S in the plasma.

Protein S deficiency is associated with (1):

• 10x increased risk of thrombosis
• 3% prevalence in patients with venous thromboembolism
• 2% prevalence in normal population

Reference:

(1) British Heart Foundation (Factfile 2/2002). Thrombophilia.