Characterization by chromosome painting of balanced and unbalanced X chromosome translocations in myelodysplastic syndromes.
Structural anomalies of the X chromosome, especially translocations, are rare events in myelodysplastic syndromes (MDS). In a series of 2270 MDS patients analyzed between 1983 and 1994 (Center for Human Genetics, Leuven), 9 cases were found with translocations involving the X chromosome. These aberrations were not restricted to specific FAB subtypes and were the sole anomalies in 3 cases. In the remaining 6 patients, they were associated with other abnormalities, including 5q-, observed in three cases. Fluorescence in situ hybridization (FISH) was retrospectively performed on 8 patients and was shown to be a useful complement for the characterization of the translocations involving the X chromosome. In 3 cases, we could identify translocation partners and breakpoint regions only by using chromosome painting. No recurrent chromosome partners were observed. The breakpoints could be localized along the whole X chromosome. There was, however, a cluster in the Xq13 region involved in 4 of the 9 patients. The previously reported association of Xq13 anomalies with refractory anemia with ringed sideroblasts (RARS) was found in only one case. Despite the lack of characteristic translocations involving the X chromosome, the occurrence of such changes as the sole karyotypic anomaly suggests that they could play a role in the pathogenesis of some myelodysplastic syndromes.
Michaux
L
L
Center for Human Genetics, University of Leuven, Belgium.
Wlodarska
I
I
Mecucci
C
C
Hernandez
J M
JM
Van Orshoven
A
A
Michaux
J L
JL
Van den Berghe
H
H
D000368:Aged; D002871:Chromosome Banding; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000473:pathology*; D012189:Retrospective Studies; D014178:Translocation, Genetic; D014960:X Chromosome / Q000648:ultrastructure*