A Case of Protein S Deficiency with Cerebral Infarction / 대한소아혈액종양학회지

ABSTRACT

Certain natural anticoagulants are known to play critical roles on the control of hemostasis in addition to the physiologic role of fibrinolysis. Major antiproteases of this group include antithrombin III, protein C, protein S, alpha-2-antiplasmin, alpha-2-macroglobulin, etc. There has been increasing recognition of the importance of the control of coagulation and fibrinolysis, both by certain physiologic processes and by natural inhibitors. Especially, activated protein C (protein Ca) and its cofactor, protein S, now are recognized as significant modulators of fibrinolysis, thrombosis and hemostasis. Children and adults with decreased levels of either protein are at increased risk from thrombosis. We experienced a 5 year-old girl patient with cerebral infarction who initially presented with abnormal movement of left extremities. She had lacunar infarction in the posterior limb of the right internal capsule and hypoplastic left carotid artery on brain MRI and MR angiography. She was diagnosed to have protein S deficiency with the level of 43% in the screening test of hypercoagulable state. She remains clinically well after heparin and warfarin treatment with regular follow-up of prothrombin time. A brief review of the literature ensues with the case report.