ABSTRACT
Our understanding of epigenetic phenomena has progressed essentially in parallel with the application of assisted reproductive technology (ART) over the past three decades. It could be argued that had the current knowledge base concerning mammalian imprinting and epigenetics been known in advance of the application of ART in humans, the latter might have been viewed as at best questionable, and at worst, dangerous: some authors now suggest that this is in fact the case. However, it is difficult to reconcile the birth of millions of healthy human babies after ART with the presence of widespread or serious problems related to epigenetic phenomena. Nevertheless, proper epigenetic processing is a critical component of mammalian development. Much of this processing occurs during stages that concern ART, during the development of the gametes and early embryos, and epigenetic processing has an undisputed association with aberrant development and serious disease states in the human, including late onset diseases such as cancer.1 Furthermore, our understanding of epigenetic phenomena is far from complete, particularly as it relates to our understanding of the regulation of epigenetic phenomena, natural variation among individuals, developmental stages of similar age, and environmental triggers. This chapter reviews current information about epigenetic phenomena as it relates to human assisted reproduction. In the final analysis, it must be accepted that the jury is still out on this matter. While there is certainly some cause for concern, a balanced analysis of the data suggests that a clear connection between human ART techniques and epigenetic-related problems remains to be demonstrated. However, due to the potentially
serious nature of this issue, elucidating the true nature and source of potential epigenetic disturbance in ART should be an important research goal. We begin with a general description of basic epigenetic concepts. This is followed by a description of experimental and clinical evidence of a relationship between ART techniques and epigenetic perturbations. The review concludes with a discussion of the potential consequences of such perturbations in the application of ART.
