Switch in X-inactivation in a JAK2 V617F-negative case of polycythemia vera with two acquired X-autosome translocations.
We report a JAK2 V617F-negative case of polycythemia vera with two acquired balanced X-autosome translocations and no history of previous exposure to chemo/radiotherapy. The patient's first clone carried a novel translocation t(X;15)(q24;q13) as a sole abnormality. The second clone exhibited an additional translocation, t(X;20)(q13;q13.3), which is a rare recurrent abnormality in myeloid malignancies. This is the first report of a hematological disorder with both X chromosomes being translocated. Late replication studies revealed a switch in X-inactivation from the X chromosome involved in t(X;15) (first clone) to the X chromosome involved in the t(X;20)(q13;q13.3) (second clone). The inactivation of the translocated X chromosomes could provide potential for the inactivation of the adjacent autosomal regions, resulting in epigenetic gene silencing.
Manola
Kalliopi N
KN
Laboratory of Cytogenetics, National Center for Scientific Research (NCSR) "Demokritos", 15310 Aghia Paraskevi, Athens, Greece.
Stavropoulou
Chryssa
C
Georgakakos
Vasileios N
VN
Zoi
Katerina
K
Fisfis
Markos
M
Evmorfiadis
Ilias
I
Zoi
Christine
C
Pantelias
Gabriel E
GE
Stefanoudaki
Katy
K
Sambani
Constantina
C
D000368:Aged; D025063:Chromosome Disorders / Q000150:complications / Q000235:genetics*; D002895:Chromosomes, Human, Pair 5 / Q000235:genetics*; D041321:Chromosomes, Human, X / Q000235:genetics*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D053614:Janus Kinase 2 / Q000235:genetics*; D011087:Polycythemia Vera / Q000235:genetics*; D014178:Translocation, Genetic; D049951:X Chromosome Inactivation / Q000235:genetics*
C507924:JAK2 protein, human; D053614:Janus Kinase 2