Editing Down syndrome (section)

===Epigenetics===
Down syndrome is associated with an increased risk of some chronic diseases that are typically associated with older age such as Alzheimer's disease. It is believed that accelerated aging occurs and increases the biological age of tissues, but molecular evidence for this hypothesis is sparse. According to a biomarker of tissue age known as [[epigenetic clock]], it is hypothesized that trisomy 21 increases the age of blood and brain tissue (on average by 6.6 years).<ref name="Horvath2015DownSyndrome">{{cite journal | vauthors = Horvath S, Garagnani P, Bacalini MG, Pirazzini C, Salvioli S, Gentilini D, Di Blasio AM, Giuliani C, Tung S, Vinters HV, Franceschi C | display-authors = 6 | title = Accelerated epigenetic aging in Down syndrome | journal = Aging Cell | volume = 14 | issue = 3 | pages = 491–495 | date = June 2015 | pmid = 25678027 | pmc = 4406678 | doi = 10.1111/acel.12325 }}</ref>