Human Genetics

, Volume 99, Issue 6, pp 755–760

Multicolour FISH detects frequent chromosomal mosaicism and chaotic division in normal preimplantation embryos from fertile patients

  • J. D. A. Delhanty
  • Joyce C. Harper
  • Asangla Ao
  • Alan H. Handyside
  • Robert M. L. Winston
Original investigation

DOI: 10.1007/s004390050443

Cite this article as:
Delhanty, J., Harper, J., Ao, A. et al. Hum Genet (1997) 99: 755. doi:10.1007/s004390050443

Abstract

We have used multicolour fluorescent in situ hybridisation (FISH) with DNA probes for chromosomes X, Y and 1 to analyse spare untransferred cleavage-stage embryos after preimplantation diagnosis to avoid X-linked disease. In total, 93 morphologically normal embryos were available from seven patients (six of proven fertility) who had undergone fourteen in vitro fertilisation (IVF) cycles. The chromosome patterns observed were classified into four groups; normal, abnormal (non-mosaic), mosaic and chaotic (uncontrolled division). Approximately half of the embryos were normal for the chromosomes tested. Two embryos only were aneuploid (non-mosaic) throughout but, after excluding those showing chaotic division, 30% were considered to be chromosomal mosaics. Of these, a minority had arisen because of mitotic non-disjunction or chromosome loss or gain, whereas the majority were ploidy mosaics, with haploidy being the most common. The occurrence of chaotically dividing embryos was strongly patient-related, i.e. some patients had ‘chaotic’ embryos in repeated cycles, whereas other patients were completely free of this type of anomaly. ‘Chaotic’ embryos are unlikely to progress beyond implantation. These findings have important implications both for routine IVF and preimplantation genetic diagnosis.

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • J. D. A. Delhanty
    • 1
  • Joyce C. Harper
    • 1
  • Asangla Ao
    • 2
  • Alan H. Handyside
    • 2
  • Robert M. L. Winston
    • 2
  1. 1.Human Genetics Group, Galton Laboratory, Wolfson House, University College London, 4 Stephenson Way, London, NW1 2HE, UK Tel.: +44-171-380-7409; Fax: +44-171-380-7429GB
  2. 2.Institute of Obstetrics & Gynaecology, Royal Postgraduate Medical School, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UKGB