title: Translocations as a mechanism for homozygous deletion of 13q14 and loss of the ATM gene in a patient with B-cell chronic lymphocytic leukemia.
abstract: Chromosomal aberrations detected by fluorescence in situ hybridization (FISH) on interphase nuclei are important prognostic markers in chronic lymphocytic leukemia (CLL). Deletions in 13q14 and in 11q22.3 are two of the most frequent aberrations in this disease entity (55 and 18%, respectively) and are usually effected by interstitial deletions. Here, we report on the case of a 66-year-old woman with CLL who was analyzed by conventional metaphase cytogenetics as well as fluorescence in situ hybridization. Deletion-specific probes detected a homozygous loss of two anonymous loci in chromosomal band 13q14 in parallel with a heterozygous loss of the ATM gene located in chromosomal band 11q22.3. Karyotype analysis indicated reciprocal but unbalanced translocations involving chromosomes 3, 11, and 13. Deleted sites on 13q14 appeared to be located within the breakpoint regions of the translocations. We show that mechanisms other than interstitial deletions may lead to loss of critical chromosomal regions in CLL.
authors.affiliation: MLL Munich Leukemia Laboratory, Max-Lebsche-Platz 31, 81377 Munich, Germany. hannes.herholz@mll-online.com
authors.forename: Hannes
authors.initials: H
authors.lastname: Herholz
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kern
authors.forename: Susanne
authors.initials: S
authors.lastname: Schnittger
authors.forename: Torsten
authors.initials: T
authors.lastname: Haferlach
authors.forename: Frank
authors.initials: F
authors.lastname: Dicker
authors.forename: Claudia
authors.initials: C
authors.lastname: Haferlach
mesh_terms: D000368:Aged; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics*; D002871:Chromosome Banding; D002872:Chromosome Deletion; D020223:Chromosome Painting; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics*; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics*; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D006720:Homozygote; D006801:Humans; D007621:Karyotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D014178:Translocation, Genetic; D025521:Tumor Suppressor Proteins / Q000235:genetics*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D025521:Tumor Suppressor Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases