Human Genetics

, Volume 97, Issue 6, pp 705–709 | Cite as

Interstitial deletion of chromosome 6q: Precise definition of the breakpoints by microdissection, DNA amplification, and reverse painting

  • N. Rubtsov
  • G. Senger
  • A. Neumann
  • C. Kelbova
  • K. Junker
  • V. Beensen
  • U. Claussen
  • N. Rubtsov
  • H. Kuzcera
Original Investigation

Abstract

Routine chromosomal analysis using GTG-banding alone showed a mosaic terminal deletion of 6q in a 14-week-old boy with developmental retardation, facial anomalies, agenesis of corpus callosum, cleft palate, hypotonia, short neck and pterygium colli, and minor anomalies of hands and feet. Discrepancies between the clinical findings on our patient and those described in the literature on patients having terminal deletions led to a more precise analysis of the karyotype. Reverse painting was performed on normal G-banded metaphases for exact determination of the breakpoints and on metaphases of the patient for evaluation of mosaicism. A DNA library that was obtained by microdissection of three deleted chromosomes 6 was used as a painting probe. Subsequent DNA amplification was performed with the help of topoisomerase-pretreated degenerate oligonucleotide primers. Unexpectedly, the hybridization pattern on normal metaphase chromosomes revealed an interstitial deletion with breakpoints at 6825.1 and 6827 instead of a terminal deletion. Hybridization on metaphases of the patient showed one deleted chromosome 6 in all metaphases analyzed at a higher resolution rather than mosaicism as previously assumed karyotype, 46,XYdel(6)(g25.1→g27)]. We assume that in the single cases of 6q described in the literature the deletions are misclassified. This might be due to difficulties in distinguishing between interstitial and terminal deletions at 6q and in precisely defining chromosomal breakpoints after GTG-banding alone.

Keywords

Metaphase Chromosome Cleft Palate Pterygium Delete Chromosome Short Neck 

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Copyright information

© Springer-Verlag 1996

Authors and Affiliations

  • N. Rubtsov
    • 1
  • G. Senger
    • 1
  • A. Neumann
    • 1
  • C. Kelbova
    • 1
  • K. Junker
    • 1
  • V. Beensen
    • 1
  • U. Claussen
    • 1
  • N. Rubtsov
    • 2
  • H. Kuzcera
    • 3
  1. 1.Institute of Human Genetics and AnthropologyUniversity JenaJenaGermany
  2. 2.Institute of Cytology and GeneticsNovosibirskRussia
  3. 3.Südharz-Hospital NordhausenNordhausenGermany

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