The 9p24.3 breakpoint of a constitutional t(6;9)(p12;p24) in a patient with chronic lymphocytic leukemia maps close to the putative promoter region of the DMRT2 gene.
B-cell chronic lymphocytic leukemia (B-CLL) is a very common hematological malignancy. Although several alterations in different loci have been identified and established as prognostic factors the pathogenetic cascade remains obscure. Here we give an account on a 71-year-old man with B-CLL and a translocation t(6;9) in his diagnostic bone marrow. Subsequent chromosome analysis of his blood lymphocytes revealed a constitutional karyotype 46,XY,t(6;9) (p12;p24) that has not been previously reported. Seeking for gene disruption correlated with the B-CLL we precisely mapped both breakpoints by fluorescence in situ hybridization (FISH) analysis with chromosome-specific bacterial artificial chromosome (BAC) clones and their long-range polymerase chain reaction (LRPCR) subfragments. An 11-kb LRPCR subfragment derived from RP11-399A15 was found to span the breakpoint at 6p12.1. FISH analysis with a 12-kb LRPCR fragment derived from RP11-147I11 which overlaps with RP11-110M16 as well as with a cDNA for DMRT2 (doublesex and mab-3 related transcription factor 2) maps the 9p24.3 breakpoint maximum 10 kb upstream from DMRT2. In silico analysis of the transcripts within the vicinity of the breakpoints revealed that the translocation does not disrupt any known genes but could affect the putative DMRT2 promoter. Long range effects on gene expression cannot be excluded so far.
Rüssel
J
J
Institut für Humangenetik und Medizinische Biologie, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, Germany.
Dutta
U
U
Wand
D
D
Schlote
D
D
Hansmann
I
I
D000368:Aged; D022202:Chromosomes, Artificial, Bacterial; D002896:Chromosomes, Human, Pair 6; D002899:Chromosomes, Human, Pair 9; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D030561:Databases, Nucleic Acid; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics*; D008297:Male; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D016615:Telomere; D014157:Transcription Factors / Q000235:genetics*
C119852:DMRT2 protein, human; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D014157:Transcription Factors