Sunday, April 13, 2008

Longevity Genes: Long Life Just a Mutation Away

As time goes on, we grow old. While many of us would like to deny it, our bodies are aging from day one, and inevitably our cells maintenance and repair mechanisms begin to deteriorate. But what if there was a way to postpone our fate, not with anti-ageing creams but with our genes? Unlocking the secrets to longevity may now well rest on the understanding of our bodies on a cellular level.

While it has been observed before many times in worms and mice, a mutation in a certain set of genes has now been found in humans. A study conducted on the Ashkenazi Jews has led to an intriguing discovery in some of its most long-lived individuals. Those who have lived past the age of 95 have been discovered to be much more likely to carry one of two mutations in the gene for insulinlike growth factor 1 receptor (IGF1R).

This mutation appears to make cells less responsive to the insulinlike growth factor 1 (IGF1) which is a key growth hormone secreted by the liver, and it is these mutations that may well be linked to longevity. Previous studies have shown that IGF1 disruption in mice led to a life up to 40% longer, while delaying the onset of age related diseases.

A group of 348 Ashkenazi Jewish seniors with a history of longevity (aged 95 – 105) were asked to participate in a study along with a control group of 312 living and dead individuals. The groups could not be compared directly as the control group died nearly 30 years ago, but the solution was to examine both groups’ offspring, searching for clues in their genetic makeup.

It was found that the female offspring of the centenarians were on average up to 2.5 centimetres shorter than their control counterparts (a sign that the IGF1R may be less responsive), and upon examination of their genes 2 IGF1R mutations were found in 9 of the centenarians, but only one of the controls. The centenarians also possessed up to 35% more IGF1 in their blood, a possible reaction to the less responsive IGF1 receptors. Males however, could be unaffected by the mutation as they have many other hormones that make them sensitive to IGF1.

This leaves us with a tantalising insight into the correlation between certain genes and long life, but it is likely it requires more than one lucky gene. Until we discover the perfect gene cocktail for longevity, we may have to wait before we can enjoy a shorter, yet longer life.

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