CONGENITAL PLATELET DISORDERS

Hemostasis depends on a sufficient quantity of well-functioning platel ets. Platelets adhere to the damaged vessel wall via surface glycoprot eins that couple to collagen fibers and different adhesive proteins in the wound. The contact triggers activation cascades in the cell, lead ing to release and secretion of mediators that activate adjacent plate lets. Further activation results in exposure of binding sites for fibr inogen that couples one platelet to another and to alterations in the plasma membrane that generate a procoagulant surface thereby facilitat ing blood coagulation. A number of congenital abnormalities in these p athways have now been characterized, offering further insight in the r ole of platelets in the cessation of bleeding and providing a basis fo r future corrective therapy.