Chromosomal mosaicism in cleavage-stage human embryos and the accuracy of single-cell genetic analysis

J Assist Reprod Genet. 1998 May;15(5):276-80. doi: 10.1023/a:1022588326219.


Purpose: Our purpose was to assess the effect of chromosomal mosaicism in cleavage-stage human embryos on the accuracy of single-cell analysis for preimplantation genetic diagnosis.

Methods: Multicolor fluorescence in situ hybridization with X, Y, and 7 or X, Y, 7, and 18 chromosome-specific probes was used to detect aneuploidy in cleavage-stage human embryos.

Results: Most nuclei were diploid for the chromosomes tested but there was extensive mosaicism including monosomic, double-monosomic, nullisomic, chaotic, and haploid nuclei.

Conclusions: Identification of sex by analysis of a single cleavage-stage nucleus is accurate but 7% of females are not identified. One or both parental chromosomes 7 were absent in at least 6.5% of the nuclei. With autosomal recessive conditions such as cystic fibrosis, carriers would be misdiagnosed as normal or affected. With autosomal dominant conditions, failure to analyze the affected parents allele (1.6-2.5%) would cause a serious misdiagnosis and analysis of at least two nuclei is necessary to reduce errors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromosome Aberrations / diagnosis
  • Chromosome Aberrations / genetics
  • Chromosome Disorders
  • Chromosomes, Human, Pair 18 / genetics
  • Chromosomes, Human, Pair 7 / genetics
  • Cleavage Stage, Ovum / cytology*
  • Cystic Fibrosis / diagnosis
  • Cystic Fibrosis / genetics
  • Female
  • Humans
  • In Situ Hybridization, Fluorescence
  • Lymphocytes / cytology
  • Male
  • Mosaicism / diagnosis*
  • Mosaicism / genetics*
  • Pregnancy
  • Preimplantation Diagnosis
  • X Chromosome / genetics
  • Y Chromosome / genetics