[Upper extremity abnormalities, thrombopenia and thrombopathy. 3 cases].

Three cases of congenital radial aplasia and amegakaryocytic thrombopenia are discussed from clinical, genetic and hematological viewpoints. Electron microscope studies of the megakaryocytes in the first two patients revealed the presence of microcytic, immature and hypogranular cells. Platelet aggregability studies in the first patient demonstrated the presence of pathological intra-platelet nucleotide release as well as membrane abnormalities of the Willebrand factor binding site. The second case presented an isolated deficiency in platelet factor 3.