Epigenetic alterations

Epigenetic alterations are age-related changes in DNA methylation patterns, histone modifications, chromatin architecture and non-coding RNA expression that occur without changes to the underlying DNA sequence. With age, the epigenome typically shows global hypomethylation alongside focal hypermethylation, loss of heterochromatin and altered transcription. These shifts underpin epigenetic clocks such as the Horvath and GrimAge clocks, which estimate biological age and predict mortality more accurately than chronological age.