Genes tend to become deregulated with age in that genes that are switched off become active in the wrong cells and at the wrong times. Gene deregulation deviates from the chronological epigenetic process which can be triggered by various environmental factors. Genes that are supposed to active become switched off while genes that supposed to be inactive become turned on. This could contribute to many detrimental characteristics seen in aged cells such as abnormal size and shape, accumulation of molecular and cellular damage and degrading vesicles such as lysosomes, overproduction of unnecessary and tissue-inappropriate proteins, and so forth.

Two DNA modification mechanisms are involved in gene deregulation. One is histone deacetylation/acetylation, a process where histones (a protein involved in DNA packaging) are chemically modified (deacetylation) will inactivate a gene it attached to while histone-acetylation (the reverse process) activate genes. The other mechanism is called DNA methylation. When DNA is methylated (methyl groups are attached to DNA), the gene becomes inactive. Conversely, the removal of methyl groups (demethylation) increases activity of genes.

Generally, histone deacetylation/acetylation is a more dynamic and more easily disrupted mechanism of gene regulation (as compared to methylation/demethylation). This may be one reason why it appears to play an particularly important role in the aging process.The enzymes responsible for histone deacetylation and thus for gene silencing have been known for some time the most important of which is sirtuins. Sirtuins are known to play a role in the aging process and life extension.