title: Leukemic recombinations involving heterochromatin in myeloproliferative disorders with t(1;9).
abstract: The unbalanced t(1;9) is a rare, recurrent rearrangement in polycythemia vera (PV) resulting in trisomy of both 1q and 9p arms, whereas a balanced t(1;9)(q12;q12), to our knowledge, has never been reported before. We studied two patients with PV and one with idiopathic myelofibrosis bearing an unbalanced t(1;9) and one patient with essential thrombocythemia with a balanced t(1;9). In all cases fluorescence in situ hybridization showed that the breakpoints were located within the satellite II family of heterochromatin of chromosome 1 and the satellite III of chromosome 9. Heterochromatin breakage and reunion produce the unbalanced t(1;9) and may contribute to a gene dosage effect due to gains of 1q and 9p. Case 4 with the balanced t(1;9), however, suggests that translocation of heterochromatin close to critical genes could interfere with their function. The molecular event underlying juxtaposition of satellite II of chromosome 1 and the satellite III of chromosome 9 remains to be elucidated.
authors.affiliation: Laboratory of Health Physics & Environmental Hygiene, NCSR Demokritos, 15310 Aghia Paraskevi, Athens, Greece. csambani@ipta.demokritos.gr
authors.forename: Constantina
authors.initials: C
authors.lastname: Sambani
authors.forename: Roberta
authors.initials: R
authors.lastname: La Starza
authors.forename: Valentina
authors.initials: V
authors.lastname: Pierini
authors.forename: Peter
authors.initials: P
authors.lastname: Vandenberghe
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Gonzales-Aguilera
authors.forename: Helen
authors.initials: H
authors.lastname: Rigana
authors.forename: Daphne
authors.initials: D
authors.lastname: Koumbi
authors.forename: Kalliopi N
authors.initials: KN
authors.lastname: Manola
authors.forename: Chryssa
authors.initials: C
authors.lastname: Stavropoulou
authors.forename: Vasileios N
authors.initials: VN
authors.lastname: Georgakakos
authors.forename: Maria
authors.initials: M
authors.lastname: Pagoni
authors.forename: Iwona
authors.initials: I
authors.lastname: Wlodarska
authors.forename: Cristina
authors.initials: C
authors.lastname: Mecucci
mesh_terms: D000368:Aged; D002878:Chromosomes, Human, Pair 1; D002899:Chromosomes, Human, Pair 9; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D009196:Myeloproliferative Disorders / Q000235:genetics*; D014178:Translocation, Genetic