An Identical Translocation between Chromosome 1 and 7 in Three Patients with Myelofibrosis and Myeloid Metaplasia

Abstract

An identical chromosome abnormality was observed in 3 unrelated patients with myelofibrosis and myeloid metaplasia, 2 of the patients showing a history of polycythemia vera (PV) before development of the myelofibrosis. Unstimulated peripheral blood cultures showed a translocation between chromosomes 1 and 7 replacing a homolog of pair 7. It was identified by G[Giemsa]- and C[constitutive heterochromatin]-banding as t(1;7)(7pter .fwdarw. 7p11::1p1? .fwdarw. 1qter). While the 1st patient also showed trisomy 21 and the 3rd patient had some extra material on the short arm of chromosome 17, all 3 had trisomy 1q and monosomy 7q. Although each of these abnormalities is frequently observed separately in various hematological disorders, the combination of the 2 in the form of an identical translocation in 3 patients is an example of induced nonrandom cytogenetic change in myelofibrosis.