Epigenetics in childhood health and disease

Abstract

The part that epigenetic modifications play in the development of childhood health and disease is being established by ongoing research and discoveries in this field. Right after the establishment of the genetic blueprint at the time of fertilization and zygote formation, the human organism is subject to complex and necessary series of epigenetic modifications of this genetic code to bring about differentiation and development. There are well-recognized stages during this process where the epigenetic changes have the most lasting and profound effects and these are considered critical periods of vulnerability. Depending on the timing of insult within the critical time periods in the human life cycle where epigenetic modifications occur, the effect on health and disease could be transient or may persist across many generations. In this chapter classification of human conditions based on the timing and etiology of epigenetic change has been attempted. Beginning with the time of fertilization of the egg with the sperm and subsequent fetal development and continuing from birth to the attainment of puberty, adulthood, and the generation of gametes for the next generation, the list of conditions where epigenetics has been found to play a key role have been listed and described. The role of epigenetics in certain special circumstances such as assisted reproductive technologies, developmental origins of adult disease, and in the brain and behavioral disorders are also discussed. Understanding the critical period of causation of epigenetic effects may yield important clues in prognostication and in designing therapeutic approaches for these conditions.