Epigenetics in Child Psychiatry

Child psychiatric disorders do not follow a simple linear gene–phenotype, rendering the quest for gene discovery challenging. The rapidly expanding field of epigenetics, which focuses on the regulation of gene activity and expression, may provide the missing components that may explain some of the complexity. Numerous environmental factors such as maternal stress, hypoxia, and nutritional deficiencies, among others, are being consistently associated with increased risk for several of the major child psychiatric disorders, and some with small effect have been shown to have a significant effect within the context of a positive family history. The mechanisms by which epigenetic factors silence or enhance gene expression in child psychiatric disorders remains to be discovered. Recent advances in the role of microRNAs and epigenetic reconfiguration in normal brains, where over 50% of methylation was discovered to occur in non-CpG nucleotides, will undoubtedly accelerate discoveries.