The Role of Epigenetics in Pediatric Developmental Delay

‘’Epigenetic landscape’’ is a medical term first described by an embryologist about 60 yr ago. There are additional nuclear-encoded genetic instructions and less importantly environmental factors that influence the genes products in different human tissues despite similar genetic material in these diverse tissues. The role of environmental factors on modifications of human genome presentation has been increased during these years. The most known patterns of epigenetic process are DNA methylation by acovalent reaction at 5’ position of cytosine nucleotide, post-transcriptional modification and nucleosomes density or chromatin structure modifiers. Environmental factors have been more taken into account in recent years in epigenetic landscape. Nutritional factors and diet such as folate and methionine deficiency or famine, cigarette exposure, and post-traumatic stress could influence epigenetic factors followed by significant changes in human genes products in recent studies. Epigenetic factors have been studied extensively in human cancers and the mechanism of tumor development in various tissues may more similar than it is believed. In the same manner resistance to a standard protocol of treatment in tumors or presence or absence of metastasis may be related to heterogeneity in epigenetic modifiers. Increase our knowledge about epigenetic factors and how their relationship with environmental agents could be helpful to develop new adjuvant therapies or disease risk assessment based on epigeneticmodifier changes especially in cancers, autoimmune diseases, autism, and diabetes mellitus type 2. Epigenetic studies on CHARGE syndrome as a common potential cause ofintellectual disability in association with multiple birth anomalies caused by a mutation in CHD7 gene has shown that results in remodeling of chromatin structure. Therefore, there are some epigenetic developmental disorders that could be focused on for adjuvant treatment in the field of pediatric developmental disorders. Another example is Rubinstein-Taybi Syndrome that is associated with variable degree of intellectual disability and caused by mutation in CBP gene or less commonly in EP300 gene. CPB product has a role in acetyltransfereation of histones and initiation of transcription process.