PRECISE DIAGNOSIS BY GENE ANALYSIS AND SUCCESSFUL MANAGEMENT OF DELIVERY IN 3 PATIENTS WITH TYPE-IIB VON-WILLEBRAND DISEASE

Type IIB is a rare variant of von Willebrand disease (vWD). An affecte d individual's bleeding tendency and thrombocytopenia are exacerbated with pregnancy, and the proper management of these patients during del ivery has not been well established. Since it is important to distingu ish this disease from the platelet type vWD in order to administer the appropriate therapy, gene analysis is necessary to make the precise d iagnosis. We now report the successful management of delivery in three patients, who were diagnosed as having type IIB vWD by the detection of missense mutations in the von Willebrand factor (vWF) gene (C3916 - -> T and C3922 --> T). These changes cause Arg543 --> Trp and Arg545 - ->Cys substitutions in the A1 domain of vWF. We were able to manage th e bleeding tendency of these patients at delivery mainly with vWF conc entrates to supply normal vWF.