title: [Clinical and experimental study of two cases of myelodysplastic syndromes with double isochromosome 20q- anomaly].
abstract: OBJECTIVE
  To explore the clinical and laboratory characteristics of two myelodysplastic syndromes (MDS) patients with double isochromosome 20q- anomaly.
  
  
  METHODS
  Bone marrow cell chromosome preparations were made with both direct method and short-term culture. Karyotype analysis was performed by R-banding technique, and dual-color FISH (fluorescence in situ hybridization) by using a 20q telomeric probe and a sequence-specific probe for 20q12.
  
  
  RESULTS
  The clinical and hematological findings were comparable with diagnosis of MDS. Karyotype analysis showed that both patients had double isochromosome 20q- anomaly: case 1 is 46, XX, der(20)? i(20q-) [6]/46, idem, der (6) i (6p) [1]/47, idem, +der (20)? i (20q-) [3]/47, idem, der(6)i (6p), +der(20)? i (20q-) [20]; case 2 is 45, XY, -7, der (20)? i (20q-) [17]/46, idem, +der(20) ? i(20q-) [3]. Two derivative chromosomes 20 were proved 20q isochromosomes with interstitial deletions by dual-color FISH in one patient.
  
  
  CONCLUSIONS
  Double isochromosome 20q- anomaly is a rare recurrent karyotype abnormality in MDS, and signals a poor prognosis.
authors.affiliation: Department of Hematology, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.
authors.forename: Sheng-lan
authors.initials: SL
authors.lastname: Gong
authors.forename: Yong-quan
authors.initials: YQ
authors.lastname: Xue
authors.forename: Jian-min
authors.initials: JM
authors.lastname: Wang
authors.forename: Feng-lai
authors.initials: FL
authors.lastname: Han
authors.forename: Yan-qun
authors.initials: YQ
authors.lastname: Xu
authors.forename: Jin-ying
authors.initials: JY
authors.lastname: Li
mesh_terms: D002871:Chromosome Banding; D002890:Chromosomes, Human, Pair 20 / Q000235:genetics*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D018404:Isochromosomes; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000235:genetics*