Protein S Deficiency and Arterial Thromboembolism: A Case Report and Review of the Literature.

Protein S (PS) deficiency is associated with a well documented risk of venous thromboembolism. However, the relation between PS deficiency itself to arterial thrombotic events (ATEs) is not clearly established. In our case, we report an ATE in a patient with a documented novel PROS1 mutation and a family history of PS deficiency. Other etiologies for arterial thrombosis were excluded. The role of precise diagnosis with levels of PS and documentation for mutational analysis are discussed. We highlight the problems with diagnosis in previously reported cases with arterial thrombotic events and discuss the potential for treatment with antiplatelet therapy in a subset of patients with PS deficiency. Copyright 2019, Fearon et al.