Epigenetic Clocks: DNA Methylation Marks as Accurate Predictors of Biological Age
research · Horvath S. DNA methylation age of human tissues and cell types. Genome Biol. 2013 (2013)
Epigenetic clocks are algorithms that estimate biological age from DNA methylation patterns at specific CpG sites. These clocks, such as Horvath's multi-tissue clock and the PhenoAge clock, correlate with chronological age and predict mortality and disease risk more accurately than chronological age alone. They are widely used to evaluate anti-aging interventions by measuring changes in biological age over time.
Core Concepts
The Problem
Chronological age is a poor predictor of individual health and aging rate; a biomarker that captures functional aging is needed.
The Claim
DNA methylation-based clocks provide a robust, reproducible measure of biological age that can be used to test longevity interventions.
Key Evidence
- •Horvath's 2013 clock accurately predicted chronological age across dozens of tissues.
- •Subsequent clocks (PhenoAge, GrimAge) outperform chronological age in predicting mortality.
- •Studying interventions like diet, exercise, and drugs against these clocks has become standard in geroscience.
Practical Implication
Epigenetic clocks enable rapid screening of anti-aging strategies and personalized health monitoring.
Nuance & Limits
Clocks may not capture all aspects of aging; improvements in methylation age do not always translate to functional rejuvenation.
Source Material
Citation Density
high
Gaps
- ⚠ Need for clocks that reflect organ-specific aging
- ⚠ Validation against hard clinical endpoints like frailty
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