Nine kindreds of familial sticky platelet syndrome phenotype

A new decade awaits sticky platelet syndrome: where are we now, how do we manage and what are the complications?

INTRODUCTION

Sticky platelet syndrome is a less known platelet function disorder with a familiar occurrence and likely genetic background. Clinically, it is characterized by an increased risk of venous and arterial thromboembolic events and obstetric placenta-mediated complications. The increased aggregation after low-dose ADP and/or epinephrine is its distinctive laboratory feature. Though described for almost 40 years, several issues regarding its etiology, involved pathomechanisms, genetic background, optimal diagnostic and treatment approach remain controversial.

AREAS COVERED

The work aims to summarize published studies, the actual definition of the syndrome, and point out its drawbacks. A literature search on Medline, Embase, and archives from EHA congresses was performed (terms: 'sticky platelet syndrome' - 'platelet hyperreactivity' - 'platelet hyperaggregability'). The authors added in their unpublished data. The introductory overview of the present understanding is followed by the discussion of the pathophysiologic, diagnostic, and therapeutic problems.

EXPERT OPINION

Despite the growing evidence provided by case reports and series, the lack of robust studies limits the decision-making on diagnostics and management. The diagnostic issues, particularly the standardization of light transmission aggregometry, represent the crucial problem for the broader acceptance of the syndrome.

Primary Thrombophilia in Mexico XIII: Localization of the Thrombotic Events in Mexican Mestizos With the Sticky Platelet Syndrome

The sticky platelet syndrome (SPS) is a common cause of both arterial and venous thrombosis, being a dominant autosomal disease with qualitative platelet alterations and familial occurrence. It is characterized by platelet hyperreactivity with increased platelet aggregability in response to low concentrations of platelet agonists: epinephrine, adenosine diphosphate, or both. The clinical manifestations involve venous or arterial thrombosis, recurrent pregnancy loss, and fetal growth retardation. To analyze the localization of the thrombotic episodes in a cohort of Mexican mestizo patients with SPS. Between 1992 and 2016, 86 Mexican mestizo patients with SPS as the single thrombophilic condition were prospectively identified; all of them had a history of thrombosis. There were 15 males and 71 females. The thrombotic episodes were arterial in 26 cases and venous in 60 (70%). Arterial thrombosis was mainly pulmonary thromboembolism, whereas venous thromboses were identified most frequently in the lower limbs. Mexican mestizo population with SPS is mainly female; the type I of the condition is the most frequent; both arterial and venous thrombosis can occur, and they are mainly pulmonary embolism and lower limbs venous thrombosis, respectively.

GP6 Haplotype of Missense Variants is Associated with Sticky Platelet Syndrome Manifested by Fetal Loss

Disequilibrium of hemostasis is central to the pathogenesis of all thromboses, and platelets are essential for primary hemostasis. The platelet membrane glycoprotein receptor is involved in the clot formation in blood; therefore, the changes in related genes could impair platelet aggregation in patients with sticky platelet syndrome (SPS). Patients with SPS who experienced fetal loss were shown to harbor a risk haplotype at GP6 locus. The aim of the study was to examine the genetic linkage of this selected risk haplotype with single nucleotide variations (SNVs) in the coding sequence of the GP6 gene in order to identify possible functional SNVs in association with SPS and fetal loss. A total of 37 patients with SPS manifested fetal loss, and 42 healthy controls were enrolled in the study. The SPS was diagnosed with platelet aggregometry. The SNVs were determined by dideoxy sequencing and high-resolution melting analysis. The missense variations were detected in patients with risk haplotype only. The association analysis showed association of the minor alleles with the SPS manifested by fetal loss as follows-rs1671152 (odds ratio [OR]: 4.667, 95% confidence interval [CI]: 1.462-14.89, P = .006), rs2304167 (OR: 5.085, 95% CI: 1.605-16.10, P = .003), and rs1654416 (OR: 5.085, 95% CI: 1.605-16.10, P = .003). Using the Expectation-Maximization (EM) algorithm, the estimated minor haplotype with predicted protein residue PEAN was significantly associated with the given phenotype (OR: 4.746, 95% CI: 1.486-15.15, P = .005). We have shown that haplotype PEAN associated with SPS and manifested by fetal loss and suggest that the mechanism involved in the action of GPVI has significant effect on GPVI-mediated signal transduction through Syk-phosphorylation.

Sticky platelets syndrome in a young patient with massive pulmonary embolism

Patient:

Female, 51

Final Diagnosis:

Sticky platelets syndrome

Symptoms:

Pulmonary embolism

Medication:

—

Clinical Procedure:

Thrombolysis

Specialty:

Hematology

Objective:

Disease of unknown ethiology

Background:

Sticky platelets syndrome (SPS) is an inherited thrombophilia characterized by platelet hyperaggregability, which can lead to the higher risk of thrombosis. The etiology of SPS remains unclear, but several gene polymorphisms have been recently studied and autosomal dominant heredity is suspected. Although SPS is traditionally connected with arterial thrombosis, several cases of SPS as a cause of venous thromboembolism have been described.

Case Report:

We report the case of a 51-year-old apparently healthy woman with massive pulmonary embolism, who required thrombolytic therapy. In this patient SPS was identified as the only condition leading to higher risk of developing thromboembolic disease.

Conclusions:

Although at present few physicians have practical experience with SPS, this syndrome may lead to serious health problems or even death. The presented case points to the benefit of SPS diagnostics in standard screening of inherited thrombophilia for effective prophylaxis and treatment in patients with venous thromboembolism.