What clinical sign is characteristic of Bernard-Soulier syndrome?

Bernard-Soulier syndrome is a rare inherited bleeding disorder characterized primarily by a defect in the platelet glycoprotein complex, particularly GPIb-IX-V. This defect impairs the platelets' ability to adhere to the blood vessel wall, which is crucial for forming clots.

A notable clinical sign of Bernard-Soulier syndrome is the presence of large platelets—also referred to as "giant platelets"—which can be observed during a blood smear. These larger-than-normal platelets result from a developmental abnormality that occurs in the megakaryocytes, the precursor cells in the bone marrow that produce platelets. While the condition may lead to thrombocytopenia (a low platelet count), the platelets that are produced tend to be larger in size and are often not as effective in their function when it comes to hemostasis.

In terms of the other options, thrombocythemia (an abnormally high platelet count) does not apply as Bernard-Soulier syndrome is characterized by a reduced platelet count due to impaired production and effectiveness. Small platelets are also not indicative of this syndrome; instead, the presence of giant platelets is the defining feature. Increased clotting times are not specifically tied