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 syndrome (MDS) is a deletion of the long arm of chromosome 5, del(5q). The 5q- syndrome is a distinct entity, that presents with specific morphologic abnormalities of the megakaryocytic lineage. Thus, we evaluated the presence or absence of the del(5q) in these cells. We performed fluorescence in situ hybridization analysis using unique sequence probes (one for 5q31, the other for 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). Megakaryocytes were identified by nuclear morphology, size, and ploidy index. Our results demonstrate the presence of the del(5q) in the megakaryocytic lineage and, thus, the involvement of these cells in the disease process.