title: The origin and significance of additional aneuploidy events in couples undergoing preimplantation genetic diagnosis for translocations by array comparative genomic hybridization.
abstract: Diagnostic application of array comparative genomic hybridization (aCGH) in preimplantation genetic diagnosis for reciprocal and Robertsonian translocations has revealed 55-65% embryos with additional aneuploidies with or without translocation-related imbalances. The occurrence of these extra abnormalities with the balanced form of the translocation reduces the number of embryos suitable for transfer. Eighty-three embryos were followed up on days 5-7 of development from 23 infertile or sub-fertile carriers for whole chromosome and segmental aneuploidies present in addition to the balanced or unbalanced translocations detected on aCGH diagnosis. Embryos were analysed by fluorescence in-situ hybridization (n = 63) and aCGH (n = 20). Meiotic aneuploidy affected 35% of embryos and 47% had mitotic events; 15% had both types. Meiotic and mitotic events were almost equal (60 versus 64), 97 affected whole chromosomes (58 meiotic, 39 mitotic) and 27 were segmental (two meiotic, 25 mitotic). In 85.5% of embryos with whole chromosome additional aneuploidies, the aneuploidy was present throughout or in more than 50% of cells. All embryos diagnosed as abnormal (translocation balanced or unbalanced) after aCGH diagnosis at cleavage stage would have remained unsuitable for transfer if tested at later stages of development. Additional aneuploidies merit full consideration when considering the choice of embryos to transfer.
authors.affiliation: Preimplantation Genetics Group, Institute for Women's Health, 86-96 Chenies Mews, University College London, London WC1E 6HX, UK. Electronic address: h.ghevaria@ucl.ac.uk.
authors.forename: Harita
authors.initials: H
authors.lastname: Ghevaria
authors.affiliation: Preimplantation Genetics Group, Institute for Women's Health, 86-96 Chenies Mews, University College London, London WC1E 6HX, UK.
authors.forename: Sioban
authors.initials: S
authors.lastname: SenGupta
authors.affiliation: Preimplantation Genetics Group, Institute for Women's Health, 86-96 Chenies Mews, University College London, London WC1E 6HX, UK.
authors.forename: Natalia
authors.initials: N
authors.lastname: Shmitova
authors.affiliation: The Centre for Reproductive and Genetic Health, 230-232 Great Portland Street, London W1W 5QS, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Serhal
authors.affiliation: Preimplantation Genetics Group, Institute for Women's Health, 86-96 Chenies Mews, University College London, London WC1E 6HX, UK.
authors.forename: Joy
authors.initials: J
authors.lastname: Delhanty
mesh_terms: D000328:Adult; D000782:Aneuploidy; D001755:Blastocyst; D002875:Chromosomes / Q000648:ultrastructure; D055028:Comparative Genomic Hybridization; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008540:Meiosis; D008938:Mitosis; D011247:Pregnancy; D019836:Preimplantation Diagnosis / Q000379:methods*; D020554:Sperm Injections, Intracytoplasmic; D014178:Translocation, Genetic; D055815:Young Adult
keywords: Aneuploidies; Meiotic; Mitotic; Reciprocal translocations; aCGH