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 formative abnormalities and a mild thrombopenia; hemorragic manifestations occurred in the first case only. Megacryoblastic to platelets series, as studied with electronic microscopy, show small-sized, "microcytic" and hypogranular megacaryocytes, displaying a maturative disorder (dysmegacaryocytopoiesis). 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 megacaryocytic-platelets disorders appears likewise in the squelettal and visceral malformations. The whole disorder could be ascribed to a pleiotropic abnormal gene with a variable expressivity.
mesh_terms: D001792:Blood Platelets / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D007223:Infant; D008533:Megakaryocytes / Q000648:ultrastructure*; D010974:Platelet Aggregation; D011884:Radius / Q000002:abnormalities*; D013921:Thrombocytopenia / Q000097:blood / Q000150:complications / Q000151:congenital*
vernacular_title: Thrombopénie et aplasie radiale:deux cas avec étude ultrastructurale et fonctionnelle de la lignée mégacaryocytoplaquettaire.