title: Tetraploidy and partial endoreduplication in a tripronuclear zygote obtained after intracytoplasmic sperm injection.
abstract: OBJECTIVE
  To describe a peculiar combination of cytogenetic abnormalities in a tripronuclear zygote obtained after intracytoplasmic sperm injection (ICSI).
  
  
  METHODS
  Case report.
  
  
  METHODS
  A university hospital.
  
  
  METHODS
  A couple with a 4-year history of primary infertility. Intracytoplasmic sperm injection was performed because of male factor infertility (oligoteratozoospermia).
  
  
  METHODS
  Ultrasound-guided transvaginal follicular aspiration.
  
  
  METHODS
  Chromosomal karyotype of a tripronuclear one-cell zygote.
  
  
  RESULTS
  Unexpectedly, a tetraploid [92,XXYY, end3, -18, end18] chromosome complement was found, indicating injection of a diploid spermatozoon carrying two Y chromosomes. The parental origin of the other abnormalities could not be determined. The missing chromosomes may be attributed either to a hypodiploid [44,YY,-18,-18] sperm cell or to a hypohaploid [22,X,-18] oocyte. The exact tetraploid count was restored by endoreduplication of two chromosomes. This event could have occurred in one and the same or in two different pronuclei.
  
  
  CONCLUSIONS
  Cytogenetic analysis of multipronuclear zygotes appears useful for assessing the incidence of chromosomal abnormalities at the earliest stage of conception. In addition to other methods, it also may contribute to evaluation of the transmission of aberrations by spermatozoa from infertile men.
authors.affiliation: Department of Gynecology and Obstetrics, University of Ulm, Germany.
authors.forename: B E
authors.initials: BE
authors.lastname: Rosenbusch
authors.forename: M
authors.initials: M
authors.lastname: Schneider
authors.forename: V
authors.initials: V
authors.lastname: Hanf
mesh_terms: D000328:Adult; D002869:Chromosome Aberrations / Q000235:genetics*; D025063:Chromosome Disorders; D002887:Chromosomes, Human, Pair 18; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects* / Q000379:methods; D006801:Humans; D007248:Infertility, Male / Q000235:genetics / Q000628:therapy*; D007621:Karyotyping; D008297:Male; D008845:Microinjections; D011123:Polyploidy; D013094:Spermatozoa / Q000166:cytology*; D015053:Zygote / Q000648:ultrastructure