Interstitial deletion of chromosome 9q with coexistence of the deleted segment as a ring chromosome. A case report.

@article{Pfeiffer1991InterstitialDO,
  title={Interstitial deletion of chromosome 9q with coexistence of the deleted segment as a ring chromosome. A case report.},
  author={Rudolf Arthur Pfeiffer and Udo Trautmann and R Hirmer-Stoll},
  journal={Annales de genetique},
  year={1991},
  volume={34 3-4},
  pages={247-51}
}
In a mentally retarded female an interstitial deletion of a chromosome 9 and an additional ring chromosome was shown, which by positive hybridisation with a no 9 library was considered to be the excised segment. The functional centromere and C and DA/DAPI positive material as well on the ring chromosome are explained by a break within the centromere close to the constitutive heterochromatin and supports the hypothesis of "latent" centromere(s).