title: Analysis using fish of sperm and embryos from two carriers of rare rob(13;21) and rob(15;22) robertsonian translocation undergoing PGD.
abstract: The majority of fluorescence in situ hybridization (FISH) studies on the meiotic segregation of Robertsonian translocations focus on the most common types, rob(13; 14) and rob(14; 21). Here we report the first study for carriers of rare Robertsonian translocations rob(13; 21) and rob(15; 22) combining analysis of meiotic segregation in sperm and blastomeres following pre-implantation genetic diagnosis (PGD). Dual-colour FISH was applied to nuclei from spermatozoa and blastomeres from PGD embryos using two subterminal contig probes for each translocation, and a second round with probes for chromosomes 16 and 18. Patient 1 had a rob(13; 21) and patient 2 had a rob(15; 22), and 86.3% and 87.5% of gametes respectively were consistent with meiotic segregation resulting in a normal or balanced chromosome complement. Analysis of embryos showed that for patient 1 and 2 respectively, 25% and 46% were balanced, and of the unbalanced embryos, 50% and 31% were mosaic or chaotic. Our patients with a rob(13; 21) and rob(15; 22) were found to have a similar meiotic segregation pattern to that for male carriers of the common Robertsonian translocations. The observed rate in unbalanced embryos being mosaic or chaotic may result in an increased risk of chromosomal abnormalities. Our results may help to improve the genetic counseling for carriers of rare Robertsonian translocations.
authors.affiliation: Unité de Cytogénétique DPI, Département de Biologie de la Reproduction, CHU Montpellier, Hôpital Arnaud de Villeneuve, 34295 Montpellier, France.
authors.forename: Izabel
authors.initials: I
authors.lastname: Bernicot
authors.forename: Anouck
authors.initials: A
authors.lastname: Schneider
authors.forename: Alexandra
authors.initials: A
authors.lastname: Mace
authors.forename: Samir
authors.initials: S
authors.lastname: Hamamah
authors.forename: Bernard
authors.initials: B
authors.lastname: Hedon
authors.forename: Franck
authors.initials: F
authors.lastname: Pellestor
authors.forename: Tal
authors.initials: T
authors.lastname: Anahory
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000378:metabolism* / Q000473:pathology; D001757:Blastomeres / Q000378:metabolism* / Q000473:pathology; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics; D005817:Genetic Counseling; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007248:Infertility, Male / Q000235:genetics*; D008297:Male; D008540:Meiosis / Q000235:genetics; D013094:Spermatozoa / Q000378:metabolism* / Q000473:pathology; D014178:Translocation, Genetic