Tiling resolution array CGH of dic(7;9)(p11 approximately 13;p11 approximately 13) in B-cell precursor acute lymphoblastic leukemia reveals clustered breakpoints at 7p11.2 approximately 12.1 and 9p13.1.
The dic(7;9)(p11 approximately 13;p11 approximately 13) is a recurrent chromosomal abnormality in acute lymphoblastic leukemia (ALL), mainly of B-lineage. Although more than 20 dic(7;9)-positive ALLs have been reported to date, the molecular genetic consequences of this aberration are unknown. We performed tiling resolution (32K) genome-wide array-based comparative genomic hybridization (array CGH) analysis of three cases with dic(7;9) in order to characterize the breakpoints on 7p and 9p. The analysis showed a clustering of breakpoints within 9p13.1 in all three cases and within 7p11.2 in two cases; the array CGH revealed two different breakpoints - 7p12.1 and 7p14.1 - in the remaining case. Based on these findings the abnormality should hence be designated dic(7;9)(p11.2 approximately 12.1;p13.1). Locus-specific fluorescence in situhybridization analysis of one of the cases narrowed down the 7p11.2 breakpoint to a <500-kb segment in this sub-band, a region containing three known genes. Unfortunately, lack of material precluded further molecular genetic studies, and it thus remains unknown whether the pathogenetically important outcome of the dic(7;9) is formation of a chimeric gene or loss of 7p and/or 9p material.
Lundin
C
C
Department of Clinical Genetics, Lund University Hospital, Lund, Sweden. Catarina.Lundin@med.lu.se
Heidenblad
M
M
Strombeck
B
B
Borg
A
A
Hovland
R
R
Heim
S
S
Johansson
B
B
D000293:Adolescent; D000328:Adult; D000368:Aged; D002051:Burkitt Lymphoma / Q000235:genetics*; D002648:Child; D002877:Chromosomes, Human; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D009693:Nucleic Acid Hybridization