Background: Protein S is a vitamin K-dependent serum protein that has a pivotal role in the anticoagulant system. The major function of protein S is as a cofactor to facilitate the action of activated protein C on its substrates, activated factor V (FVa) and activated factor VIII (FVIIIa). Deficiency of protein S is associated with increased risk of deep vein thrombosis (DVT).

Aims: To describe a case report of deficiency protein S presenting as DVT.

Methods: A 45 year male had unilateral swelling of left lower limb with sudden onset painful for last five days. There was history of diabetes mellitus in the past. Venous Doppler showed hypoechoic thrombus within the lumen of left greater saphenous veins, common femoral, superficial femoral, popliteal and tibialis anterior signifying occlusion. Investigations revealed high D-dimer levels ( 28.87 µg/mL ), protein S levels 35 %, and HbA1c levels 7.3 %. Antithrombin III and protein C levels were normal. The patient was admitted and started on fondaparinux 2.5 mg subcutaneous injection once daily for 2 months along with oral anti diabetes theraphy.

Results: The present case asserted to the evidence that protein S deficiency is associated with thrombosis. Inheritable forms are rare, usually due to large deletions in the PS gene (PROS1). Without molecular analysis, it is difficult to decided whether PS deficiency is acquired or hereditary. Hereditary forms usually associated with DVT rather than arterial thrombosis. In our case patient had DVT in left leg revealed by Doppler ultrasound examination. Theraphy is mainly antithrombotics and long term anticoagulants. During the initial phase, heparin as intravenous unfractioned heparin or as subcutaneous low molecular weight heparin (LMWH) should be continued for a minimum of five days.

Conclusions: Fondaparinux treatment 2,5 mg subcutaneous injection once daily for 2 months giving a good response in patient DVT associated with Protein S deficiency.

« Back to ISTH 2020 Congress

ISTH Congress Abstracts - https://abstracts.isth.org/abstract/deep-vein-thrombosis-associated-with-protein-s-deficiency/