Abstract
83 patients with myelodysplastic syndromes were analyzed for the presence of three haematological features: (1) macrocytic anaemia, (2) normal or high platelet count and (3) megakaryocytic hypolobulation in most megakaryocytes. In 10 of the 83 patients, a 5q- chromosome was the only clonal aberration; 31 patients had other chromosomal aberrations (including 6 patients with 5q-chromosome and other abnormalities in the same clone) and 42 patients had a normal karyotype in their bone marrow cells. 9 patients displayed all three haematological features investigated. In 8 of these patients the 5q- chromosome was the only clonal aberration. The 9th patient had a karyotype of 47,XX,+8. None of the 6 patients with 5q- chromosome and additional abnormalities in the same clone fulfilled all criteria. The ''5q- syndrome'', a situation with the 5q- chromosome as a sole aberration, should be accepted as a diagnostic entity within the macrocytic anaemias. This syndrome can be suspected on the basis of the above haematological indicators and the diagnosis confirmed with bone marrow karyotype analysis.