Platelet-type von Willebrand disease

A bleeding disorder caused by a variation in the GP1BA gene that increases the affinity of platelet GPIbα for von Willebrand factor (vWF), characterized by mild to moderate mucocutaneous bleeding, which becomes more pronounced during pregnancy or following ingestion of drugs that have anti-platelet activity. PT-VWD is due to hyperresponsive platelets, resulting in thrombocytopenia. Diagnostic laboratory findings include enhanced ristocetin‑induced agglutination and features that mimic type 2B VWD despite a primary platelet defect. Functional studies in human platelets demonstrate abnormally increased vWF binding and hyperresponsiveness, consistent with enhanced GPIbα‑vWF interactions described in patient cells.