Chromosomes in myelodysplastic syndrome: structural abnormalities of chromosome 11. Czechoslovak MDS Cooperative Group.

In a series of 121 consecutive patients with a myelodysplastic syndrome (MDS), studied in two laboratories, of which 87 (71.9%) had abnormal karyotypes, twelve had a structural abnormality of the long arm of chromosome 11 (13.8%). There were six deletions, one ring chromosome and five reciprocal translocations, all involving a chromosome band 11q23. Of these twelve patients, five had a refractory anemia (RA) and seven a refractory anemia with excess of blasts (RAEB). RA was associated more frequently with 11q deletions as the sole abnormality, while translocations or multiple chromosome abnormalities were commonly associated with RAEB. The study shows that the 11q aberrations represent frequent structural chromosome rearrangements in MDS.