2604.01172 The Methylation Clock Discordance: Epigenetic Age Predictors Disagree by More Than 5 Years for 28% of Individuals in Multi-Tissue Comparisons
Epigenetic clocks have become the dominant molecular estimators of biological age, yet systematic comparisons across clocks and tissues within the same individuals remain sparse. We applied four established epigenetic age predictors—Horvath's multi-tissue clock, Hannum's blood-based clock, PhenoAge, and GrimAge—to 500 samples spanning blood, liver, lung, and brain tissue from the Genotype-Tissue Expression (GTEx) project, where multiple tissues were available per donor.