A Case of Bernard-Soulier Syndrome associated with von Willebrand Factor Antigen Abnormality

Abstract

Bernard-Soulier syndrome (BSS), a function disorder of platelet with autosomal recessive inheritance, is characterized by relatively severe bleeding tendency, giant platelets accompanied by the deficiency of membrane glycoprotein Ib (GPIb) and thrombocytopenia. GPIb is thougt to play an important role in the process of thrombus formation through its adhesive activity to subendothelial tissue, interacting with von Willebrand factor (vWF). BSS platelets fail to aggregate in response to ristocetin despite normal content of factor VIII/vWF in plasma. In this paper, we report clinical and hematological data of a 5 year old homozygous female BSS case and her heterozygous parents. Laboratory examinations revealed moderately decreased amount of vWF antigen and molecular abnormality examined by the crossed immunoelectrophoresis and the SDS agarose gel electrophoresis in proband and her mother. The results of SDS polyacrylamide gel electrophoresis/PAS stain and immunomagnetic platelet separation with monoclonal antibody to GPIb/GPIIbIIIa showed a lack of GPIb in proband and complicated abnormalities of GPIIb/IIIa complex in her parents. Intracellular Ca2+ mobilization under the stimulation of thrombin showed markedly decreased levels in proband and about half amount of normal in her parents.