Bernard-Soulier syndrome is characterised by large platelets, thrombocytopenia, and absent platelet agglutination with ristocetin. The deficient platelet surface glycoprotein is:

• A GPIIb/IIIa (αIIbβ3 integrin)
• B GPVI (collagen receptor)
• C GPIb-IX-V complex ✓
• D Thromboxane A2 receptor

Explanation

Bernard-Soulier syndrome (BSS) is an autosomal recessive disorder caused by deficiency of the GPIb-IX-V glycoprotein complex on platelet surfaces, which is the receptor for von Willebrand factor (vWF). Without GPIb, platelets cannot adhere to subendothelial collagen via vWF bridges (primary haemostasis defect), explaining the ristocetin non-agglutination (ristocetin requires GPIb-vWF interaction). Large platelets (giant platelets) and mild thrombocytopenia are characteristic. GPIIb/IIIa deficiency causes Glanzmann thrombasthenia (absent aggregation, normal ristocetin); GPVI is the collagen signalling receptor.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.