Myelodysplastic syndromes and 5q deletion Volume 1, issue 1, Janvier - Février 1995


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Laboratoire d'hématologie A, CHU Lille. P. Fenaux : Service des maladies du sang, CHU, 1, place de Verdun, 59037 Lille, France.

The authors review morphological, cytogenetic, molecular characteristics and therapy of myelodysplastic syndromes (MDS) with 5q deletion (del 5q). One can schematically individualize MDS with isolated del 5q and refractory anemia (without excess of blasts), characterized by female predominance, macrocytic anemia, normal WBC count, frequent thrombocytosis, typical dysmegakaryopoiesis, rare progression to AML and prolonged survival, which constitute the « 5q­ syndrome ». MDS with del 5q associated to other chromosome abnormalities have less characteristic hematological features, are often therapy related, are usually associated to an excess of marrow blasts, and have a poorer prognosis. Del 5q is also reported in AML. Cytogenetically, del 5q is an interstitial deletion with variable proximal and distal breakpoints, but a « common deleted segment » in 5q31 band is deleted in all cases. This strongly suggests the presence of gene(s) in 5q31 band whose inactivation may be involved in the pathogenesis of MDS (or AML) with del 5q. The nature of this or these genes (IRF1 gene ? EGR1 gene ? gene situated in D5S89 locus ?) is still uncertain in spite of intensive work on the subject. Finally, no currently, available treatment can improve the usually repetitive anemia associated to MDS with del 5q, and clinicians' efforts should aim at preventing the complications of regular and long term transfusions, mainly iron overload. This can be achieved by the prolonged subcutaneous administration of desferroxamine.