Telomere attrition

Telomere attrition is the progressive shortening of the protective TTAGGG repeat sequences at chromosome ends with each cell division, due to the end-replication problem and oxidative damage. Once telomeres reach a critical length, cells enter replicative senescence or apoptosis via a DNA-damage response. Telomerase, which can extend telomeres, is largely silenced in adult somatic cells. Accelerated attrition is associated with premature ageing syndromes, cardiovascular disease and reduced healthspan.