grey platelet syndrome
Definition An autosomal dominant (OMIM:139090) condition in which the platelets lack alpha and dense granules and by extension, certain platelet proteins–e.g., von Willebrand factor, fibrinogen, fibrin, fibronectin, platelet factor 4–PF4, beta-thromboglobulin, PDGF, thrombospondin, and contact-promoting proteins.
Clinical findings Lifelong bleeding diatheses with epistaxis, bruisability, petechiae
Lab Thrombocytopenia, enlarged platelets with a gray hue on Wright-Giemsa stained peripheral blood smears, increased bleeding time
Molecular pathology Defects of NBEAL2, which is involved in thrombopoiesis and plays a role in alpha-granule production or secretion, cause grey platelet syndrome.
Management DDAVP–desmopressin acetate
Synonyms Bleeding disorder—platelet type 4, platelet alpha granule deficiency