Hereditary protein S deficiency leads to ischemic stroke

Hereditary Protein S Deficiency With an Extensive Femoral Artery Thrombosis

Protein S (PS) deficiency is widely recognized for its connection to venous thromboembolism risk. However, the relation between PS deficiency and arterial thrombotic events (ATEs) remains uncertain. Here, we report a patient who experienced an ATE with a family history of PS deficiency. We highlight an attention to the issues related to the management of arterial thrombotic events and discuss the potential use of antiplatelet therapy as a treatment option for a specific group of patients diagnosed with PS deficiency.

Origin and timing of de novo variants implicated in type 2 von Willebrand disease

Very few studies have shown the real origin and timing of de novo variants (DNV) implicated in von Willebrand disease (VWD). We investigated four families with type 2 VWD. First, we conducted linkage analysis using single nucleotide variant genotyping to recognize the possible provenance of DNV. Second, we performed amplification refractory mutation system‐quantitative polymerase chain reaction to confirm the real origin of variant (~0% mutant cells) or presence of a genetic mosaic variant (0%–50% mutant cells) in three embryonic germ layer‐derived tissues and sperm cells. Then, three possible timings of DNV were categorized based on the relative likelihood of occurrence according to the number of cell divisions during embryogenesis. Two each with type 2B VWD (proband 1 p.Arg1308Cys, proband 4 p.Arg1306Trp) and type 2A VWD (proband 2 p.Leu1276Arg, proband 3 p.Ser1506Leu) were identified. Variant origins were identified for families 1, 2 and 3 and confirmed to originate from the mother, father and father, respectively. However, the father of family 4 was confirmed to have isolated germline mosaicism with 2.2% mutant sperm cells. Further investigation confirmed the paternal grandfather to be the origin of variant. Thus, we proposed that DNV originating from the two fathers most likely occurred at the single sperm cell, the one originating from the mother occurred at the zygote during the first few cellular divisions; alternatively, in family 4, the DNV most likely occurred at the early postzygotic development in the father. Our findings are essential for understanding genetic pathogenesis and providing accurate genetic counselling.

Midbrain infarction in inherited protein S deficiency: a rare association

Inherited thrombophilic disorders are well-established predisposing factors for venous thromboembolism, but their role in arterial ischaemic stroke is uncertain. The exact mechanism of arterial thrombosis in thrombophilias remains elusive. Herein, we report a case of a 30-year-old woman who was admitted to our facility with sudden-onset right-sided ptosis and ophthalmoplegia. Detailed clinical features, neuroimaging and laboratory evaluation clinched the diagnosis of ischaemic stroke in midbrain due to microvascular obstruction associated with isolated protein S deficiency. She was treated with oral anticoagulant (warfarin) and physiotherapy; without any improvement of her symptoms at 2 months of follow-up. A high index of clinical suspicion is needed in any case of young ischaemic stroke in absence of common cardiac and vascular risk factors, to recognise the presence of inherited thrombophilia.

Rivaroxaban in Recurrent Ischemic Stroke Due to Protein S Deficiency: A Case Report

Protein S deficiency is a thrombophilia associated with an increased risk of thromboembolism. Previous studies have shown its role as a predisposing factor for venous thromboembolism, but its role in recurrent arterial ischemic stroke remains uncertain. Here we report a patient with recurrent ischemic stroke due to protein S deficiency. Oral anticoagulant treatment with vitamin K antagonist (VKA) drugs is used to treat and prevent thromboembolic events caused by thrombophilia, but it has many limitations, especially in the case of recurrent thromboembolic events. Direct oral anticoagulants (DOACs) have many advantages over VKA. Previous studies have shown that they are safe in cases of thrombophilia, but they are not well studied in recurrent ischemic stroke due to protein S deficiency. In this study our patient was treated with rivaroxaban. Protein S deficiency may be a predisposing factor in recurrent ischemic stroke, and rivaroxaban can be a safe and effective treatment option. Further studies are needed to confirm our findings.

Proteomics-Based Identification of Diagnostic Biomarkers Related to Risk Factors and Pathogenesis of Ischemic Stroke

Ischemic stroke is caused by blood clot formation and consequent vessel blockage. Proteomic approaches provide a cost-effective alternative to current diagnostic methods, including computerized tomography (CT) scans and magnetic resonance imaging (MRI). To identify diagnostic biomarkers associated with ischemic stroke risk factors, we performed individual proteomic analysis of serum taken from 20 healthy controls and 20 ischemic stroke patients. We then performed SWATH analysis, a data-independent method, to assess quantitative changes in protein expression between the two experimental conditions. Our analysis identified several candidate protein biomarkers, 11 of which were validated by multiple reaction monitoring (MRM) analysis as novel diagnostic biomarkers associated with ischemic stroke risk factors. Our study identifies new biomarkers associated with the risk factors and pathogenesis of ischemic stroke which, to the best of our knowledge, were previously unknown. These markers may be effective in not only the diagnosis but also the prevention and management of ischemic stroke.

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.

The Journey of Protein S from an Anticoagulant to a Signaling Molecule

Protein S (PS), a γ-carboxyglutamate-containing serum protein, was unexpectedly discovered in 1977. Soon after its discovery, PS gained the attention of researchers because of its physiological importance, acting as a multifunctional protein at the intersection of blood coagulation, inflammation, and other cellular processes. Protein S functions as an anticoagulant by directly inhibiting procoagulants, such as Factor Xa (FXa), FVa, and FIXa, while also serving as a cofactor for anticoagulants such as Activated Protein C and Tissue Factor Pathway Inhibitor. By associating with C4b binding protein (C4BP), PS has also been shown to minimize the effect of inflammation. Finally, PS promotes efferocytosis through TAM family protein kinase receptors. Mutations in the PS gene cause pathological conditions such as deep vein thrombosis and hereditary ischemia. In this review, we summarize studies regarding the multiple functions of PS.