In platelet aggregation studies, which result is most likely associated with Bernard-Soulier syndrome?

The result most commonly associated with Bernard-Soulier syndrome is characterized by normal platelet aggregation to collagen and ADP, while showing decreased aggregation to ristocetin. This condition is a genetic disorder that leads to a deficiency in the glycoprotein Ib-IX-V complex on the surface of platelets, which is crucial for the interaction between platelets and von Willebrand factor (vWF).

In platelet aggregation tests, ristocetin requires the presence of vWF to mediate the binding of platelets; thus, with the deficiency seen in Bernard-Soulier syndrome, the aggregation response to ristocetin will be impaired. On the other hand, the aggregation responses to collagen and ADP do not typically involve vWF in the same way, so these responses remain intact in individuals with this syndrome.

This pattern of aggregation helps clinicians differentiate Bernard-Soulier syndrome from other platelet disorders that may exhibit different aggregation responses, making it a critical aspect of diagnosing the disease.