SYNERGISTIC EFFECT OF STORAGE POOL DEFICIENT PLATELETS AND LOW PLASMAVON-WILLEBRAND-FACTOR ON THE SEVERITY OF THE HEMORRHAGIC DIATHESIS INHERMANSKY-PUDLAK SYNDROME

A study of 565 Puerto Rican patients with storage pool deficient (SPD) Hermansky-Pudlak syndrome (HPS) demonstrated that most HPS patients h ad minor bleeding episodes while others had repeated, severe hemorrhag ic episodes requiring transfusion. The severity of bleeding in these l atter patients could not be attributed to their SPD alone. As swine wi th SPD platelets and low von Willebrand factor antigen (vWF:Ag) have m ore severe hemorrhages than pigs with either defect alone, 146 albino patients and 46 normally pigmented patients were examined for their le vel of vWF:Ag. The risk of SPD HPS patients having severe, repeated bl eeding episodes increased when vWF:Ag fell below 70 U/dL. Family studi es indicated that low vWF:Ag levels were more frequently associated wi th O blood group than from a gene suppressing production or release of vWF1. HPS patients should be tested for vWF:Ag levels. (C) 1993 Wiley -Liss, Inc.