A dicentric recombinant 9 derived from a paracentric inversion: phenotype, cytogenetics, and molecular analysis of centromeres

Am J Hum Genet. 1989 Jan;44(1):115-23.


A 4-year-old girl with multiple malformations and severe developmental delay has been shown to have a karyotype of 46,XX-9,+rec(9),dup p,inv(9) (q22.1q34.3)mat, with duplication 9pter-q22.1 and deficiency 9q34.3-qter. This case confirms that a stable recombinant chromosome can result from a paracentric inversion. The recombinant was derived by two crossovers, one within the inversion loop and a second outside the inversion loop, between 9q21 and the beginning of the meiotic inversion at 9q22.1. In 87 cells the rec(9) had one Cd-positive primary constriction. In 13 cells the rec(9) had two primary constrictions; in 12 of these cells there was one Cd-positive centromere, and in one of these cells both primary constrictions were Cd-positive. Nuclear projections were observed in 10% of fibroblast interphase cells harvested in situ, suggesting that there was some spindle-fiber activity of the "latent" centromere. In situ hybridization with a centromere-specific probe (p82H) and a satellite III probe (L6) revealed no differences between the two C-band regions of the rec(9) and the normal 9 or inverted 9 chromosomes.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Centromere*
  • Child, Preschool
  • Chromosome Banding
  • Chromosome Inversion*
  • Chromosomes*
  • Chromosomes, Human, Pair 9*
  • DNA Probes
  • Female
  • Humans
  • Karyotyping
  • Male
  • Nucleic Acid Hybridization
  • Pedigree
  • Phenotype
  • Trisomy


  • DNA Probes