Antonio Capalbo1,2, Eva R Hoffmann3, Danilo Cimadomo1,4, Filippo Maria Ubaldi1,2, Laura Rienzi1,2. 1. Clinica Valle Giulia, G.EN.E.R.A. Center for Reproductive Medicine, via G. De Notaris 2b, 00197 Rome, Italy. 2. GENETYX, molecular biology laboratory, via Fermi 1, 36063 Marostica (VI), Italy. 3. Center for Chromosome Stability, Institute of Molecular and Cellular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, Copenhagen, Denmark. 4. Dipartimento di Scienze Anatomiche, Istologiche, Medico Legali e dell'Apparato Locomotore, Sezione Istologia ed Embriologia Medica, University of Rome 'Sapienza', Via Antonio Scarpa 16, Rome, Italy.
Abstract
BACKGROUND: The unbalanced transmission of chromosomes in human gametes and early preimplantation embryos causes aneuploidy, which is a major cause of infertility and pregnancy failure. A baseline of 20% of human oocytes are estimated to be aneuploid and this increases exponentially from 30 to 35 years, reaching on average 80% by 42 years. As a result, reproductive senescence in human females is predominantly determined by the accelerated decline in genetic quality of oocytes from 30 years of age. OBJECTIVE AND RATIONALE: Understanding mechanisms of chromosome segregation and aneuploidies in the female germline is a crucial step towards the development of new diagnostic approaches and, possibly, for the development of therapeutic targets and molecules. Here, we have reviewed emerging mechanisms that may drive human aneuploidy, in particular the maternal age effect. SEARCH METHODS: We conducted a systematic search in PubMed Central of the primary literature from 1990 through 2016 following the PRISMA guidelines, using MeSH terms related to human aneuploidy. For model organism research, we conducted a literature review based on references in human oocytes manuscripts and general reviews related to chromosome segregation in meiosis and mitosis. OUTCOMES: Advances in genomic and imaging technologies are allowing unprecedented insight into chromosome segregation in human oocytes. This includes the identification of a novel chromosome segregation error, termed reverse segregation, as well as sister kinetochore configurations that were not predicted based on murine models. WIDER IMPLICATIONS: Elucidation of mechanisms that result in errors in chromosome segregation in meiosis may lead to therapeutic developments that could improve reproductive outcomes by reducing aneuploidy.
BACKGROUND: The unbalanced transmission of chromosomes in human gametes and early preimplantation embryos causes aneuploidy, which is a major cause of infertility and pregnancy failure. A baseline of 20% of human oocytes are estimated to be aneuploid and this increases exponentially from 30 to 35 years, reaching on average 80% by 42 years. As a result, reproductive senescence in human females is predominantly determined by the accelerated decline in genetic quality of oocytes from 30 years of age. OBJECTIVE AND RATIONALE: Understanding mechanisms of chromosome segregation and aneuploidies in the female germline is a crucial step towards the development of new diagnostic approaches and, possibly, for the development of therapeutic targets and molecules. Here, we have reviewed emerging mechanisms that may drive humananeuploidy, in particular the maternal age effect. SEARCH METHODS: We conducted a systematic search in PubMed Central of the primary literature from 1990 through 2016 following the PRISMA guidelines, using MeSH terms related to humananeuploidy. For model organism research, we conducted a literature review based on references in human oocytes manuscripts and general reviews related to chromosome segregation in meiosis and mitosis. OUTCOMES: Advances in genomic and imaging technologies are allowing unprecedented insight into chromosome segregation in human oocytes. This includes the identification of a novel chromosome segregation error, termed reverse segregation, as well as sister kinetochore configurations that were not predicted based on murine models. WIDER IMPLICATIONS: Elucidation of mechanisms that result in errors in chromosome segregation in meiosis may lead to therapeutic developments that could improve reproductive outcomes by reducing aneuploidy.
Authors: C Scarica; D Cimadomo; L Dovere; A Giancani; M Stoppa; A Capalbo; F M Ubaldi; L Rienzi; R Canipari Journal: J Assist Reprod Genet Date: 2019-02-01 Impact factor: 3.412