Bone marrow cytogenetic studies were performed on 93 patients with primary myelodysplastic syndrome (MDS) diagnosed at the Clinical Hospital of the Federal University of Paraná, Brazil. Chromosomal alterations were observed in 69% of the patients. Monosomy of chromosome 7, deletions of 7q, 5q, 12p and 20q, rearrangements of 11q23 and trisomies of chromosomes 8 and 21 were the most frequent abnormalities observed. Among adult patients the most frequent aberrations were rearrangements of 11q23 and 12p deletions. In the pediatric group, 5q deletions and monosomy of chromosome 7 were the most common alterations.
hematological disorders; myelodysplasias; cancer cytogenetics
