Deletion of 5q31 is observed in megakaryocytic cells in patients with myelodysplastic syndromes and a del(5q), including the 5q-syndrome

One of the most common structural rearrangements in myelodysplastic syndrom e (MDS) is a deletion of the long arm of chromosome 5, del(5q). The 5q- syn drome is a distinct entity, that presents with specific morphologic abnorma lities of the megakaryocytic lineage. Thus, we evaluated the presence or ab sence of the del(5q) in these cells. We performed fluorescence in situ hybr idization analysis using unique sequence probes (one for 5q31, the other fo r the 5p telomeric band), and tested bone marrow specimens from 10 patients with MDS (including 6 patients with the 5q- syndrome) and a del(5q). Megak aryocytes were identified by nuclear morphology, size, and ploidy index. Ou r results demonstrate the presence of the del(5q) in the megakaryocytic lin eage and, thus, the involvement of these cells in the disease process. (C) 2000 Wiley-Liss, Inc.