Inheritance: autosomal dominant
Gene affected: GP1BA = glycoprotein Ib (platelet), alpha polypeptide
Location: 17pter-p12
Features:
(1) bleeding disorder with mucocutaneous bleeding, especially after aspirin or other drug with antiplatelet activity
(2) prolonged bleeding time and fluctuating thrombocytopenia
(3) increased response to low dose ristocetin in platelet-rich plasma (PPP)
(4) bleeding not corrected by cryoprecipitate
(5) platelet hyperaggregability (due to increased affinity of the receptor for vWF)
(6) bleeding corrected by transfusion of a platelet concentrate
(7) absence of mutations in the von Willebrand Factor gene
Differential diagnosis: type 2B von Willebrand disease (a defect in vWF results in increased affinity with a normal GP1BA)
