Epigenetics and neonatology: the birth of a new era

Although an individual's cells all have the same DNA, each cell type has a different pattern of active (expressed) and inactive genes. Such patterns are established or programmed during development by epigenetic modifications involving small molecules that covalently bind to specific sites in DNA or DNA-packaging proteins. The modifications regulate gene activity without changing the DNA sequence. Diet, lifestyle factors, and exposure to toxins or other adverse factors as well as random epigenetic mutations can result in de novo epigenetic modifications that may influence the course of development. The perinatal period is a time of rapid physiologic change during which some epigenetic reprogramming is likely to occur. Further, adverse events at this time may lead to epigenetic changes that have implications for future health and well-being. Evidence suggests that epigenetics plays a part in mediating effects of the perinatal environment and that such epigenetic changes may be reversed later in life. This has major implications for understanding of the cause of preterm birth as well as the consequences of prematurity.