von Willebrand disease: a clinical and laboratory study of sixty-five patients.

von Willebrand disease (VWD) is the commonest inherited bleeding disorder, yet it has not been well recognized in Southeast Asia. The aim of this prospective study was to report our experience of VWD diagnosis and to establish the clinical presentations of VWD in Taiwan. From October 2003 to April 2010, 863 patients with suspicion of having an inherited bleeding disorder underwent VWD screening tests. Those with positive tests were selected for further clinical and laboratory evaluation. A nested gender- and age-matched control cohort underwent similar investigation for comparison. VWD was diagnosed by comprehensive laboratory tests including factor VIII clotting activity, von Willebrand factor antigen assay, VWF:ristocetin cofactor activity (VWF:RCo) and platelet function analyzer (PFA)-100 closure times. VWF multimer analysis was performed by western blot for disease subtype identification. Sixty-five (7.5%) patients from 55 unrelated families were discovered to have VWD. Their median age was 27 years with a range of 4 to 69 years. The most common and specific bleeding symptom in male and female patients was bleeding after dental extraction and menorrhagia, respectively, as compared with control subjects. PFA-100 epinephrine closure time was the most sensitive laboratory test for VWD diagnosis with a sensitivity of 85%, followed by VWF:RCo assay (73%). Among 49 patients with VWF multimer analysis, 37(75.5%) were revealed to have type 1 VWD. Our study demonstrates that VWD and its clinical manifestations and subtypes in Taiwan are similar to those in the West and represents the first report of its kind in a Southeast Asian population.