U-type exchange in a paracentric inversion as a possible mechanism of origin of an inverted tandem duplication of chromosome 8

Am J Med Genet. 1994 Feb 15;49(4):384-7. doi: 10.1002/ajmg.1320490406.


A mentally retarded male with dysmorphic features was found to have a de novo 46,XY,inv dup(8) (p.23.1-->12). Confirmation of the segments duplicated in the rearrangement was achieved by biochemical analysis of glutathione reductase, which maps to 8p21.1, and DNA studies using the chromosome specific probe y-19-1D (D85131), which maps to 8p21. Assay of cathepsin B, which has been localised to 8p22, did not differ from controls with normal chromosomal constitution. DNA studies using the Defensin 1 gene probe, which maps to 8p23, showed a previously undetected deletion of that segment. We propose that the inverted tandem duplication/deletion arose as a single U-type exchange within an inversion loop.

Publication types

  • Case Reports

MeSH terms

  • Abnormalities, Multiple / genetics
  • Child, Preschool
  • Chromosome Inversion*
  • Chromosomes, Human, Pair 8*
  • Face / abnormalities
  • Humans
  • Intellectual Disability / genetics*
  • Karyotyping
  • Male
  • Multigene Family*