Incidental identification of balanced translocation carrier patients through comprehensive chromosome screening of IVF-derived blastocysts

PURPOSE: To demonstrate that translocation carrier patients can be identified by analysis of chromosomes in preimplantation human embryos. METHODS: A report of 3 cases in which multiple embryos were found to possess consistent segmental imbalances by CCS. The parents then had a conventional karyotype performed. RESULTS: In each case, parental karyotyping revealed the presence of an otherwise unknown balanced translocation. Original blastocyst CCS results were then reinterpreted to consider the presence of unbalanced derivative chromosomes and to modify the diagnosis of embryos eligible for transfer. CONCLUSIONS: It is possible to identify patients that are carriers of balanced translocations through the analysis of chromosomes in their IVF-derived embryos. Given that translocation carrier screening is not routinely performed, the growing use of CCS may facilitate discovery and provide both an etiology of reproductive failure and an improved more focused treatment strategy going forward. Future work will involve a large retrospective study to define the sensitivity and frequency of detection using this methodology.