Effect of chromosomal translocations on the development of preimplantationhuman embryos in vitro

Objective: To determine the reliability of a new technique for single human blastomere karyotyping during clinical cases for preimplantation genetic d iagnosis of translocations. Design: Controlled clinical study. Setting: Preimplantation genetic diagnosis and IVF program Patient(s): Nineteen preimplantation genetic diagnosis cases with 11 types of translocations (10 reciprocal and one Robertsonian) involving chromosome s 1, 5, 7, 8, 9, 11, 12, 13, 14, 15, 16, 18, 20, 21, and 22. Intervention(s): Blastomere biopsy followed by blastomere nucleus conversio n into metaphase chromosomes. Fluorescent in situ hybridization (whole chro mosome painting) was used fur the detection of chromosomally unbalanced pre implantation human embryos. Main Outcome Measure(s): Percentage of informative metaphase plates and eff ect of unbalanced translocations on preimplantation embryo development. Result(s): Informative metaphases were obtained for 84% of the blastomeres. Analysis of preimplantation development of the resulting embryos showed th at an unbalanced chromosomal complement does not affect embryo ability to r each the blastocyst stage in vitro. Conclusion(s): For the translocations tested, there is no evident selection against chromosomally unbalanced embryos at the preimplantation stage of e mbryo development. (Fertil Steril (R) 2000:74:672-7. (C) 2000 by American S ociety for Reproductive Medicine.).