Genetic variant linked to biological ageing

Scientists from King's and the University of Leicester have for the first time identified definitive variants associated with biological ageing in humans. The discovery has important implications for the understanding of cancer and age associated diseases.

The team analysed more than 500,000 genetic variations across the entire human genome to identify the variants, which are located near a gene called TERC. The study was conducted in collaboration with the University of Groningen in the Netherlands and has been published in Nature Genetics today.

The researchers explained that there are two forms of ageing – chronological ageing i.e. how old someone is in years, and biological ageing whereby the cells of some individuals are older (or younger) than suggested by their actual age.

Professor Tim Spector at King's, Director of the TwinsUK cohort, who co-led this project, added, "The variants identified lie near a gene called TERC which is already known to play an important role in maintaining telomere length. 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 three to four years of biological ageing 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."

Professor Nilesh Samani from the Department of Cardiovascular Sciences at the University of Leicester said, "There is accumulating evidence that the risk of age-associated diseases including heart disease and some types of cancers are more closely related to biological rather than chronological age. What we studied are structures called telomeres which are parts of one's chromosomes. Individuals are born with telomeres of certain length and in many cells telomeres shorten as the cells divide and age. Telomere length is therefore considered a marker of biological ageing.

"In this study 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.'

(The paper was published online in Nature Genetics on 07 February 2010 and can be viewed at http://www.nature.com/naturegenetics. The study was funded by The Wellcome Trust and the British Heart Foundation.)