Cytogenetic analysis in patients with myelodysplastic syndrome.

Forty-six patients with myelodysplastic syndrome (MDS) were studied. Chromosomal abnormalities were observed in 20 of the 46 patients (43%). Abnormalities of chromosome No. 5 occurred in 6 patients (13%); four of them had a deletion of the long arm of this chromosome [del (5q)]. Four patients had monosomy 7 (8.6%), and six patients had trisomy 8 (13%). Our results suggest that chromosomal abnormalities, deletion (5q), monosomy 7 and trisomy 8, might play important roles in the pathogenesis of MDS.