Inherited platelet disorders

Inherited platelet disorders may be the cause of bleeding symptoms of varying severity as platelets fail to fulfil their haemostatic role after vessel injury. Platelet disorders may be difficult to diagnose (and are likely to be mis-diagnosed) and raise problems in therapy and management. This review explores the clinical and molecular genetic phenotype of several inherited disorders. Inherited platelet disorders can be classified according to their platelet defects: receptor defects (adhesion or aggregation), secretion disorder, and cytoskeleton defects. The best characterized platelet receptor defects are Glanzmann thrombasthenia (integrin alpha IIb beta 3 defect) and Bernard-Soulier syndrome (defect of GPIb/IX/V). Detailed case reports of patients suffering from Glanzmann thrombasthenia (GT) or Bernard-Soulier syndrome (BSS) showing the bleeding diathesis as well as investigation of platelet aggregation/agglutination and platelet receptor expression will complement this review. In addition, Hermansky-Pudlak syndrome (HPS) as an important defect of delta-granule secretion is extensively described together with a case report of a patient suffering from HPS type 1.