PB1387 - Frequency of Inherited platelet secretion disorders in patients referred to the special coagulation laboratory of the Iranian blood transfusion organization (IBTO).

Background: Inherited platelet secretion disorders (IPSDs) are subtypes of inherited platelet function disorders (IPFDs) with mild to moderate bleeding manifestations due to the impairment in the content or release of platelet granules. This group of patients presents bleeding symptoms, especially mucocutaneous bleeding from mild to moderate and they are challenging to diagnose.

Aims: The purpose of our study was to evaluate the frequency of IPSDs among Iranian patients who had been referred to the special coagulation laboratory of IBTO.

Methods: For six months, patients who had been referred to our center for laboratory investigations of bleeding disorders were recruited in our study if they met the following criteria: request at least platelet aggregation and VWD diagnostic panel tests and if they had normal PT and aPTT tests. They were excluded from our study if they have diagnosed as: 1) Glanzmann thrombasthenia (GT), 2- Bernard-Soulier syndrome (BSS), 3-Platelet count less than 100×109 /µL(except in the syndromic forms), 4-Von Willebrand disease (VWD), 5- medication use which may affect the platelet function. Their platelet function was evaluated by light transmission aggregometry (LTA), ATP-releasing assay (by Lummi aggregometry), and CD62P expression (flow cytometry). In a few cases, dense granule number was checked by whole-mount electron microscopy (WM-EM). According to our diagnostic approach (image1), patients were subclassified as IPSDs, unknown bleeding disorders (UBDs) and other IPFDs.

Results: 37 patients were included in our study; seven patients were diagnosed as IPSDs, and eight patients were classified as unknown bleeding disorders (UBDs) and one patient as other types of IPFDs (image 2).

Conclusion(s): The frequency of IPSDs among patients referred to our reference coagulation laboratory seems to be high and evaluation of suspected patients with IPFDs for IPSDs seems a necessity for diagnosis of these patients in our country with the high number of consanguinity marriages.