Epigenetics: Influence on Behavioral Disorders


Epigenetic modifications of the genome are critically important for normal functioning of a cell. In addition to DNA sequence variation, which has been the primary research target in human morbid biology, epigenetic dysregulation of genes may represent a fundamental mechanism of human diseases.

Keywords: epigenetics; neuropsychiatric disorders; Prader–Willi and Angelman syndromes; fragile X mental retardation; Rett syndrome; complex non‐Mendelian diseases; schizophrenia; DNA methylation; histone acetylation

Figure 1.

Unmethylated (left) and methylated (right) cytosines.

Figure 2.

Partial stability, or metastability, of epigenetic signals in cells during mitotic divisions. Methyl groups (squares) may be lost (top scenario) or de novo methylation may occur (bottom scenario), which results in different epigenotypes in cells with identical genotype, and which may lead to differential expression (wiggly lines represent mRNA molecules) of a homologous gene across the cells.

Figure 3.

DNA methylation and histone acetylation act in concert in epigenetic regulation of gene expression. (a) Histone acylation and low density of metC in the regulatory region of a gene correlate with high transcriptional activity of a gene. (b) Histone deacylation and high density of metC result in compact chromatin structure, which inhibits transcription (according to Robertson KD and Wolffe AP (2000) Nature Reviews Genetics1: 11–19.)

Figure 4.

Epigenetic mechanism of discordance of monozygotic twins. Despite their identity in DNA sequences, monozygotic co‐twins exhibit epigenetic differences that result in differential expression of genes and differential susceptibility to a disease in genetically identical twins.



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Further Reading

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Petronis, Arturas(Jul 2006) Epigenetics: Influence on Behavioral Disorders. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0005234]