title: Evaluation of cytogenetic analysis for clinical preimplantation diagnosis.
abstract: OBJECTIVE
  To evaluate the feasibility of using cytogenetic analysis in preimplantation diagnosis.
  
  
  METHODS
  Two different biopsy protocols (chemical drilling and zona cutting) and two fixation methods were tested in a mouse model. Afterwards, the efficiency of obtaining chromosome preparations from untransferable human embryos depending on the method used to obtain the blastomeres (embryos biopsy or removal of the zona pellucida and blastomere disaggregation) was determined. The chances of obtaining chromosome preparations depending on the type of embryo (haploid, diploid, triploid, and apparently unfertilized) were also evaluated.
  
  
  RESULTS
  Results from the mouse model showed that chemical drilling yields better results than cutting in terms of metaphases per biopsied embryo and surviving rate after biopsy. In human embryos, biopsy of diploid embryos produced 46.6% chromosome preparations, while 29% were obtained after blastomere disaggregation and 20.4% when biopsying triploid embryos.
  
  
  CONCLUSIONS
  These results suggest that the disaggregating procedure and triploid embryos cannot be considered as good models to assess the feasibility of cytogenetic analysis in preimplantation diagnosis. Poor chromosome quality and loss during fixation are the main problems to use cytogenetics in preimplantation diagnosis; a combination of cytogenetics and other techniques is suggested in cases of balanced translocations.
authors.affiliation: Departament de Biologia Cellular i Fisiologia, Facultat de Ciències, Universitat Autònoma de Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Santaló
authors.forename: A
authors.initials: A
authors.lastname: Veiga
authors.forename: J M
authors.initials: JM
authors.lastname: Calafell
authors.forename: G
authors.initials: G
authors.lastname: Calderón
authors.forename: F
authors.initials: F
authors.lastname: Vidal
authors.forename: P N
authors.initials: PN
authors.lastname: Barri
authors.forename: C
authors.initials: C
authors.lastname: Giménes
authors.forename: J
authors.initials: J
authors.lastname: Egozcue
mesh_terms: D000818:Animals; D001706:Biopsy / Q000379:methods; D001755:Blastocyst; D002875:Chromosomes; D003582:Cytogenetics / Q000379:methods*; D005240:Feasibility Studies; D006801:Humans; D051379:Mice / Q000196:embryology; D008815:Mice, Inbred Strains; D011003:Ploidies; D013048:Specimen Handling / Q000379:methods; D016707:Tissue Fixation / Q000379:methods