A new study makes the link between a gene and human lifespan for the first time. In this week’s Nature Genetics, a team of mostly UK researchers report on a particular genetic variation in people who are biologically years older than the age printed on their drivers’ licenses.
“What our study suggests is that some people are genetically programmed to age at a faster rate,” says co-author Tim Spector (AFP). “The effect was quite considerable in those with the variant, equivalent to between three-to-four years of ‘biological ageing’.”
Chronological age is measured in years, but the pace of biological ageing varies. This age has a lot to do with smoking, unhealthy diets, and the length of your telomeres—the little caps at the end of chromosomes that shorten every time cells copy themselves. Shorter telomeres means biologically older. When telomere length reaches a critical value, the result is cell death.
“I see patients in their 80s with high blood pressure who have healthy coronary arteries and I see people in their 40s who don’t seem to have any risk factors yet have advanced heart disease,” says co-author Nilesh Samani (Guardian).
After studying 500,000 genetic variations, the researchers find that a variant near the gene TERC determines how long telomeres are and how quickly they shorten. This variant may make people more vulnerable to many age-related maladies, including some types of cancer.
“It is the first step to understanding why people age,” Samani says (Telegraph). “Once we have a full understanding we should be able to manipulate it in a manner to influence how someone ages.”
People carrying this genetic sequence probably make less telomerase, an enzyme that repair telomeres, when they are growing in the womb. However, simply “introducing telomerase might protect you from heart disease, but if you turn it on willy nilly you could cause cancer instead,” Samani warns (Guardian).
Still, the discovery paves the way for screening programmes and raises the best hope yet for drugs that prevent the biological wear and tear behind common age-related conditions (Guardian).