Question

Bernard-Soulier syndrome is due to deficiency of

• A. Gp 2b/3a
• B. Gp 1b
• C. vWf
• D. TNF

Hint:

Bernard-Soulier is an adhesion defect; identify the platelet receptor for von Willebrand factor.

Answer 1

The Correct Option is B

Step 1: Bernard-Soulier syndrome (BSS) is a rare autosomal recessive bleeding disorder of platelet adhesion.
Step 2: The defect is a deficiency or dysfunction of platelet glycoprotein Gp1b (part of the Gp1b-IX-V complex), which is the receptor for von Willebrand factor (vWF). Without functional Gp1b, platelets cannot adhere to subendothelial vWF, so primary haemostasis fails. The answer is Gp 1b.
Step 3: Why the distractors are wrong: Gp2b/3a deficiency causes Glanzmann thrombasthenia, a defect of platelet aggregation, not adhesion. vWF deficiency is von Willebrand disease, a problem with the ligand itself rather than the platelet receptor. TNF is a cytokine and has no role in this platelet adhesion defect.