SEVERE VON WILLEBRAND'S DISEASE WITH ABNORMAL PLATELET AGGREGATION

Abstract

A 17-year-old boy with a life long history of easy bruising, epistaxis, subcutaneous hematoma and prolonged bleeding time from minor injuries, was initially diagnosed as having von Willebrand's disese, when he presented epistaxis at 2 years of age. Since his initial diagnosis, he has been treated with cryoprecipitate on many occasions to correct his bleeding tendency. The laboratory findings in the patient and his family are summarized in the table. The patient's mother, father and one brother have not complained any bleeding tendency.Multimeric analysis of vWF using SDS agarose gels showed absence of large multimer in the patient's plasma, decreased large multimer in mother's and brother's plasma. When the patient's PRP was tested for aggregation and release of ATP by ADP, epinephrine and collagen, using lumi aggregometer, platelet aggregation was abnormal as shown by disaggregation and almost no ATP activity was detectable in the supernatant. ATP contents of patient's and father's platelet was about 50% of normal platelets. Washed platelets of the patient in normal plasma did not aggregate normally, but washed normal platelets in the patient's plasma aggregate normally. No inhibitor of vWF could be demonstrated in the patient's plasma. Clot retraction was normal. These findings suggest that our patient has inherited vWD from materal side and the platelet aggregation defect, probably a kind of storage pool disease, from the paternal side of the family.