Hematological features of patients with myelodysplastic syndromes associated with a chromosome 5q deletion.

The hematological and clinical features of 26 patients with myelodysplasia and a chromosome 5q deletion in the bone marrow are presented. We have examined the relationship of French-American-British Co-operative Group (FAB) 1982 classification and bone marrow karyotype at diagnosis with patient outcome and the presence or absence of the classical features of the 5q-syndrome. Those patients classified as refractory anemia (RA) with no additional karyotypic abnormalities have the typical features of the 5q-syndrome and a good prognosis. None of the patients in this group transformed to acute leukemia during the period of follow-up. Patients with either refractory anemia and excess blasts (RAEB) or additional karyotypic abnormalities show many of the hematologic features of the 5q-syndrome but do not share the good prognosis. We conclude that the 5q-syndrome may be best defined as primary MDS of the FAB type RA with a 5q deletion as the sole karyotypic abnormality. This simple definition will distinguish patients with a good prognosis and all the classical features of the 5q-syndrome.