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First Genetic Variants Associated with Biological Aging in Humans

Scientists announced that they have identified, for the first time, definitive genetic variants associated with biological aging, as indicated by mean telomere length, in humans. An international team, led by researchers at the University of Leicester and King’s College London, analyzed more than 500,000 genetic variations across the entire human genome to identify the aging-related variants which are located near a gene called TERC, a gene that is known to play a role in telomere length. Telomeres are capping-like structures located at the tips of chromosomes. “Individuals are born with telomeres of certain length and in many cells telomeres shorten as the cells divide and age,” said Dr. Nilesh Samani, a co-leader of the project. “Telomere length is therefore considered a marker of biological aging." Dr. Samani explained that there are two forms of aging--chronological aging, i.e., how old you are in years, and biological aging whereby the cells of some individuals are older (or younger) than suggested by their chronological age. “In this study,” Dr. Samani said, “what we found was that those individuals carrying a particular genetic variant had shorter telomeres, i.e., looked biologically older. Given the association of shorter telomeres with age-associated diseases, the finding raises the question whether individuals carrying the variant are at greater risk of developing such diseases." Dr. Tim Spector, also a co-leader of the project, noted, “What our study suggests is that some people are genetically programmed to age at a faster rate. The effect was quite considerable in those with the variant, equivalent to between 3-4 years of 'biological aging’ as measured by telomere length loss. Alternatively, genetically susceptible people may age even faster when exposed to proven 'bad' environments for telomeres, like smoking, obesity, or lack of exercise--and end up several years biologically older or succumbing to more age-related diseases." The discovery of the genetic variant associated with shorter telomere length was reported online on February 7 in Nature Genetics. The original body of seminal work describing the nature of telomeres was recognized by the awarding of the 2009 Nobel Prize in Physiology or Medicine to Dr. Elizabeth Blackburn, Dr. Carol Greider, and Dr. Jack Szostak. [Press release] [Nature Genetics abstract] [Nobel Prize press release]