title: Detection of cryptic chromosomal lesions including acquired segmental uniparental disomy in advanced and low-risk myelodysplastic syndromes.
abstract: OBJECTIVE
  Using metaphase cytogenetics (MC), chromosomal defects can be detected in 40% to 60% of patients with myelodysplastic syndromes (MDS); cytogenetic results have a major impact on prognosis. We hypothesize that more precise methods of chromosomal analysis will detect new/additional cryptic lesions in a higher proportion of MDS patients.
  
  
  METHODS
  We have applied single nucleotide polymorphism microarrays (SNP-A) to perform high-resolution karyotyping in MDS to determine gene copy number and detect loss of heterozygosity (LOH).
  
  
  RESULTS
  Using this method, chromosomal defects were found in 82% of MDS patients vs 50% as measured by MC; lesions were present in 68% of patients with normal MC, while in 81% of those with abnormal MC, new aberrations were found. In addition to gains or losses of chromosomal material, areas of LOH due to segmental uniparental disomy were found in 33% of patients.
  
  
  CONCLUSIONS
  SNP-A findings demonstrate that chromosomal lesions are present in a much higher proportion of patients than predicted by traditional cytogenetics. These lesions may reflect an underlying generalized chromosomal instability in MDS. Additional previously cryptic defects may explain the clinical variability of MDS. New lesions may have important prognostic implications, suggesting that, in the future, SNP-A-based karyotyping may complement MC in laboratory evaluation of MDS.
authors.affiliation: Experimental Hematology and Hematopoiesis Section, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH 44195, USA.
authors.forename: Lukasz P
authors.initials: LP
authors.lastname: Gondek
authors.forename: Abdo S
authors.initials: AS
authors.lastname: Haddad
authors.forename: Christine L
authors.initials: CL
authors.lastname: O'Keefe
authors.forename: Ramon
authors.initials: R
authors.lastname: Tiu
authors.forename: Marcin W
authors.initials: MW
authors.lastname: Wlodarski
authors.forename: Mikkael A
authors.initials: MA
authors.lastname: Sekeres
authors.forename: Karl S
authors.initials: KS
authors.lastname: Theil
authors.forename: Jaroslaw P
authors.initials: JP
authors.lastname: Maciejewski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002869:Chromosome Aberrations; D018628:Gene Dosage; D006801:Humans; D007621:Karyotyping / Q000379:methods*; D019656:Loss of Heterozygosity; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D020641:Polymorphism, Single Nucleotide; D024182:Uniparental Disomy