All eukaryotic chromosomes are capped by telomeres, structures composed of DNA and associated proteins comprising the ends of each linear chromosome.
Telomere binding proteins include:
Genetic aberrations that increase rates of telomere erosion and inhibit normal DNA repair from occurring at the telomere synergize to cause premature aging, a phenomenon seen in several disorders that feature predisposition to neoplasias.
Atlas of Genetics and Cytogenetics in Oncology and Haematology 2004-04-01
Online version: http://atlasgeneticsoncology.org/teaching/30060/telomeres