Genetic control elicited by factors other than modification of the genetic code found in the sequence of DNA. Epigenetic changes determine which genes are being expressed, which in turn may influence disease risk. Some epigenetic changes are heritable.

An extremely rare genetic disorder in which symptoms resembling aspects of aging are manifested at a very early age. People born with progeria typically live to their mid teens to early twenties. Although the term progeria applies strictly speaking to all diseases characterized by premature aging symptoms, it is often applied specifically in reference to Hutchinson–Gilford progeria syndrome (HGPS).

An enzyme that extends the telomeres of chromosomes. Telomerase adds specific nucleotide sequences to the ends of existing chromosomes. Telomerase activity is highly regulated during development, and its activity is at an almost undetectable level of activity in fully developed cells. This lack of activity causes the cell to age. If telomerase is activated in a cell, the cell will continue to grow and divide, or become "immortal," which is important to both aging and cancer. Telomerase enzyme activity has been detected in more than 90 percent of human cancers.

Distinctive structures comprised of short, repetitive sequences of DNA located on the ends of chromosomes. Telomeres form a protective “cap” – a sort of disposable buffer that gradually shortens with age – that prevents chromosomes from losing genes or sticking to other chromosomes during cell division. When the telomeres on a cell’s chromosomes get too short, the chromosome reaches a “critical length,” and the cell stops dividing (senescence) or dies (apoptosis). Telomeres are replenished by the enzyme telomerase, a reverse transcriptase.