title: Chromosomal cryptic insertion of the terminal region and its formative mechanism determined by fluorescence in situ hybridization.
abstract: OBJECTIVE
  To determine the karyotype of a cryptic structural abnormality and explore the mechanism of apparent chromosomal terminal deletion.
  
  
  METHODS
  Fluorescence in situ hybridization(FISH) with a whole chromosome 7 painting probe and a 7q subterminal probe (7q36-->qter), prepared by chromosome microdissection technique, was used to analyze a case with a history of spontaneous abortion and 7q terminal deletion detected by conventional G-banding technique.
  
  
  RESULTS
  The case was a maternal cryptic insertional translocation between chromosome region 1p32 and 7q32-->q35. The region of chromosome 7q36-->qter was not inserted in to chromosome 1, and the abnormal chromosome 7 was not a terminal deletion but an interstitial deletion.
  
  
  CONCLUSIONS
  Chromosome insertion of the terminal region retains its telomere, which is consistent with the concept of a three-break rearrangement. Interstitial deletion may be regarded as another mechanism for terminal deletion in the chromosome banding level. Combined with chromosome microdissection, FISH technique could be a powerful diagnostic tool for detecting chromosome structural abnormalities.
authors.affiliation: Human Reproductive Engineering Laboratory, Xiangya School of Medicine, Central South University, Changsha 410078, China.
authors.forename: Yueqiu
authors.initials: Y
authors.lastname: Tan
authors.forename: Guangxiu
authors.initials: G
authors.lastname: Lu
mesh_terms: D000328:Adult; D002869:Chromosome Aberrations; D002878:Chromosomes, Human, Pair 1; D002897:Chromosomes, Human, Pair 7; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*