Bernard-Soulier syndrome is a rare platelet disorder presenting with severe thrombocytopenia (with giant platelets) and mucocutaneous bleeding. The defective glycoprotein complex in Bernard-Soulier syndrome is:

• A Glycoprotein IIb-IIIa complex (fibrinogen receptor/integrin αIIbβ3)
• B Glycoprotein VI (collagen receptor)
• C Glycoprotein Ib-IX-V complex (vWF receptor) ✓
• D Glycoprotein Ia-IIa (collagen receptor, integrin α2β1)

Explanation

Bernard-Soulier syndrome results from deficiency or dysfunction of the GPIb-IX-V complex (also called CD42), which is the primary receptor for von Willebrand factor and mediates initial platelet adhesion to subendothelial vWF at high shear rates. The GPIb-IX-V complex also anchors the platelet cytoskeleton and influences platelet size — its absence causes giant platelets (macro-thrombocytopenia) because normal platelet budding from megakaryocytes is impaired. Glanzmann thrombasthenia is characterised by defective GPIIb-IIIa (fibrinogen receptor) — aggregation is impaired but platelet count and size are normal.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.