Bernard–Soulier syndrome and von Willebrand disease
Bernard–Soulier syndrome is an inherited platelet adhesion receptor disorder caused by defects of the GPIb-IX-V complex on platelets. [1] Von Willebrand disease is an inherited or acquired von Willebrand factor (VWF) disorder caused by quantitative or qualitative defects of VWF. [2]
Primary hemostatic defect
Bernard–Soulier syndrome involves impaired platelet adhesion to VWF because of defective GPIb-IX-V function or expression. [1] Von Willebrand disease involves impaired platelet adhesion because of defective VWF concentration, structure, or function. [2]
Typical clinical presentation
Bernard–Soulier syndrome commonly presents with mucocutaneous bleeding features such as epistaxis and gingival bleeding, with bleeding severity out of proportion to platelet count in some reports. [1] Von Willebrand disease commonly presents with mucocutaneous bleeding such as epistaxis, easy bruising, and menorrhagia, with bleeding pattern driven by VWD type and severity. [2]
Key laboratory patterns
Bernard–Soulier syndrome is characterized by thrombocytopenia and large (giant) platelets on peripheral blood smear. [3] Von Willebrand disease typically does not feature giant platelets or prominent thrombocytopenia as the primary diagnostic pattern. [2]
Diagnostic testing differences
Bernard–Soulier syndrome is evaluated by demonstrating abnormalities of the platelet GPIb-IX-V receptor complex, consistent with platelet-type adhesion failure. [1] Von Willebrand disease is diagnosed using a combination of assays that measure VWF levels and VWF activity, along with factor VIII activity as appropriate. [4] Ristocetin-based assays are used in VWD evaluation because VWF mediates platelet agglutination under ristocetin conditions. [2] In VWD, repeat testing may be required before an accurate diagnosis is established. [4]
Inheritance and genetic basis
Bernard–Soulier syndrome is caused by inherited variants affecting components of the platelet GPIb-IX-V complex. [1] Von Willebrand disease can be inherited or acquired, with genetic inheritance patterns varying by VWD type, and acquired VWD arising from non-genetic causes that alter VWF quantity or function. [2]
Practical differentiation points
Bernard–Soulier syndrome should be prioritized when giant platelets plus thrombocytopenia are present with a bleeding tendency. [3] Von Willebrand disease should be prioritized when bleeding is accompanied by abnormal VWF antigen/activity and/or factor VIII activity with otherwise typical platelet morphology. [2]
Management approach implications (mechanistic)
Bernard–Soulier syndrome management targets platelet adhesion failure due to GPIb-IX-V dysfunction. [1] Von Willebrand disease management targets normalization of deficient or dysfunctional VWF activity, with choice driven by VWD type and baseline laboratory profile. [2]
Summary of distinguishing features
Bernard–Soulier syndrome involves a platelet receptor defect (GPIb-IX-V) with thrombocytopenia and giant platelets. [1] Von Willebrand disease involves a VWF defect with diagnosis relying on VWF antigen/activity assays and bleeding phenotypes that vary by type. [2]