title: [Thrombopenia and radial aplasia: 2 cases with platelet function and ultrastructural studies of megakaryocytes and platelets (author's transl)].
abstract: The authors report on two cases of congenital thrombopenia with radial aplasia. Both children display several birth defects and a mild thrombopenia; hemorragic manifestations occured in the first case only. Megakaryoblastic to platelets series, as studied with electronic microscopy, show small-sized, "microcytic" and hypogranular megakaryocytes, displaying a maturative disorder (dysmegakaryocytopoiesis). In functional studies, platelets of the first patient show an imperfect nucleotidic release and do not agregate normally with ristocetin. The second case exhibits mostly a PF3 reduction. The variety of expression of the megakaryocytic-platelets disorders appears likewise in the skeletal and visceral malformations. The whole disorder could be ascribed to a pleiotropic abnormal gene with a variable expressivity.
mesh_terms: D001792:Blood Platelets / Q000378:metabolism / Q000648:ultrastructure*; D002675:Child, Preschool; D005260:Female; D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D007223:Infant; D008533:Megakaryocytes / Q000378:metabolism / Q000648:ultrastructure*; D010974:Platelet Aggregation; D011884:Radius / Q000002:abnormalities*; D013921:Thrombocytopenia / Q000151:congenital* / Q000378:metabolism / Q000473:pathology
vernacular_title: Thrombopénie et aplasie radiale: deux cas avec étude ultrastructurale et fonctionnelle de la lignée mégacaryocytoplaquettaire.