Clinical, laboratory and ultrastructural findings in patients with storage pool disease: A case series

Abstract

IntroductionPlatelet storage pool diseases (SPD) are a heterogeneous group of bleeding disorders associated with defects in the storage, secretion, or release of platelet granules. Patients with SPD present with a life-long mucocutaneous bleeding diathesis. Our goal was to study the clinical, laboratory, and ultrastructural changes in platelets of patients diagnosed with SPD using a transmission electron microscope (TEM). MethodsIn this retrospective, cross-sectional cohort study, medical records of all patients referred for evaluation of a platelet function disorder were screened for an underlying diagnosis of SPD during the period 2010–2020. ResultsSixty-eight patients were identified, among whom 62 (91.2%) had a platelet function assay (PFA) study, of whom 21 (33.9%) were abnormal. Clinical, laboratory, and light transmission aggregometry (LTA) suggested that 10 (14.7%) patients had SPD; five had gray platelet syndrome (GPS), three had Hermansky Pudlak syndrome (HPS), and two had Chedia-Higashi syndrome (CHS). Most of these cases presented with mucocutaneous bleeding diathesis, but a few had oculocutaneous albinism. They were associated with variable abnormalities in the PFA and LTA studies. However, EM studies using TEM showed a reduction/absence of alpha or delta granules in GPS and HPS patients, respectively, but no abnormality in the granules of CHS patients. ConclusionsAlthough patients with SPD presented with bleeding diathesis, PFA and platelet aggregation studies were inconclusive. Abnormalities in platelet ultrastructure on EM studies demonstrated corroborative evidence for SPD with absent/reduced alpha or delta granules.