from Section 5 - Pathology
Published online by Cambridge University Press: 05 October 2013
Introduction
As a treatment for female infertility, assisted reproductive technology (ART) commonly uses a number of treatments and manipulations, including hormonal stimulation of follicular development and ovulation, cryopreservation, in vitro maturation (IVM), in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) and embryo culture, all of which could adversely affect oocyte development or function during early embryogenesis. Over the last decade, concern has been raised about possible increases in the occurrence of rare genomic imprinting disorders, in particular Beckwith–Wiedemann syndrome (BWS) and Angelman syndrome (AS), in ART-conceived children. The genomic imprinting disorders seen in children conceived using ART were accompanied in many cases by a loss of maternal DNA methylation at imprinted loci. Genomic imprinting refers to the acquisition of a unique epigenetic profile in a small subset of genes during gametogenesis. This differential epigenetic mark in the gametes results in a parent-of-origin-specific expression of these imprinted genes in the offspring. Most imprinted genes exist in clusters in the genome and their allele-specific expression is regulated by sequence elements called imprinting control regions (ICRs). Genomic imprinting is under the control of epigenetic mechanisms including DNA methylation at ICRs, also known as differentially methylated domains or regions (DMDs, DMRs). One of the best studied epigenetic mechanisms, DNA methylation, is heritable and reversible and susceptible to being perturbed during development. At most ICRs, DNA methylation occurs in the female germ line and is inherited from the mother. Following fertilization, male and female gametic imprints must be maintained through preimplantation development and into adulthood. Thus any factor that affects the ability of oocytes to acquire imprints or normal epigenetic patterns during oogenesis or maintain these patterns after fertilization could potentially predispose to imprinting disorders in the offspring. This chapter reviews current data on the effects of ART on genomic imprinting in humans, along with the human and animal research that is beginning to help explain how perturbations in oocyte biology may be linked to the etiology of ART-associated epigenetic dysregulation and abnormalities in genomic imprinting.
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.