PB1390 - Gray platelet syndrome- novel NBEAL2 pathogenic variants and hemostasis evaluation by global coagulation assays.

Tuesday, June 27, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

Assaf Barg, MD

Pediatric Hematologist
The National Hemophilia Center, and Amalia Biron Research Institute of Thrombosis and Hemostasis, Sheba Medical Center, Ramat Gan, Israel
Tel Aviv, HaMerkaz, Israel

Co-Author(s)

EA

Einat Avishai

Research Assistant, Molecular Biology Unit, Coagulation Laboratory, National Hemophilia Center and T
Tel Aviv University
Tel Aviv, HaMerkaz, Israel
RD

Rima Dardik

Head, Molecular Biology Unit, Coagulation Laboratory, National Hemophilia Center and Thrombosis Unit
Tel Aviv University
Tel Aviv, HaMerkaz, Israel
Sarina Levy-Mendelovich, MD

Senior Pediatric Hemato-oncologist
The National Hemophilia Center, and Amalia Biron Research Institute of Thrombosis and Hemostasis, Sheba Medical Center, Ramat Gan, Israel
Tel Aviv, HaMerkaz, Israel
Omri Cohen, MD

Senior physician
Sheba medical center, Tel Aviv University
Holon, HaMerkaz, Israel
BR

Batia Roth Jelinek

Hematologist
Hadassa Medical Center
Jerusalem, Yerushalayim, Israel
OB

Ortal Barel

Head, Sheba clinical genomic unit
Tel Aviv University
Tel Aviv, HaMerkaz, Israel
Tami Livnat, Prof. (she/her/hers)

Head - Basic Research Laboratory, Amalia Biron Research Institute of Thrombosis and Hemostasis, Sheb
Tel Aviv University
Tel Aviv, Tel Aviv, Israel
Gili Kenet, MD

Director
The National Hemophilia Center, and Amalia Biron Research Institute of Thrombosis and Hemostasis, Sheba Medical Center, Tel Hashomer, Tel Aviv University, Tel Aviv, Israel
Yehud-Monosson, HaMerkaz, Israel

Background: Gray platelet syndrome (GPS) is a rare autosomal recessive disorder caused by pathogenic variants in NBEAL2. GPS is characterized by macrothrombocytopenia and a mild bleeding tendency. Platelets appear gray due to lack of α-granules.

Aims: To evaluate clinical characteristics and bleeding complications of GPS followed at a tertiary center. To investigate the role of global coagulation essays in assessing bleeding tendency of patients with GPS.

Methods: Data from medical files of patients diagnosed with GPS at our center were screened. Clinical bleeding tendency was evaluated by the ISTH bleeding assessment tool (BAT). Global coagulation essays including thrombin generation (TG) and rotational thromboelastometry (ROTEM) in patients with GPS were performed.

Results: The cohort included 3 GPS patients, whose data are presented in Table 1. Patients were born with a normal platelet count but developed thrombocytopenia at infancy. All had an abnormal bleeding assessment tool score. Two Female patients experienced life threatening abnormal uterine bleeding requiring recurrent red packed cells transfusion. One patient underwent surgery that was managed successfully with platelet transfusion and tranexamic acid. One patient developed additional autoimmune phenomena compatible with systemic lupus erythematosus. In all patients TG parameters in platelet rich plasma (PRP) were significantly lower as compared to controls (Figure 1). When spiking studies of PRP with rFVIIa were performed shortening of lag was noted.

Conclusion(s): Although GPS is considered a mild bleeding tendency, our female patients have experienced life threatening uterine bleeds. TG with PRP may serve as an ancillary test to asses bleeding tendency in patients with GPS. The role of rFVIIa in treating bleeding episodes in patients with GPS deserves further studies.