By Jonathan Leake
http://www.timesonline.co.uk/tol/news/science/biology_evolution/article7127753.ece

SCIENTISTS have discovered the “Methuselah” genes whose lucky carriers have a much improved chance of living to 100 even if they indulge in an unhealthy lifestyle.

The genes appear to protect people against the effects of smoking and bad diet and can also delay the onset of age-related illnesses such as cancer and heart disease by up to three decades.

No single gene is a guaranteed fountain of youth. Instead, the secret of longevity probably lies in having the right “suite” of genes, according to new studies of centenarians and their families. Such combinations are extremely rare — only one person in 10,000 reaches the age of 100.

The genes found so far each appear to give a little extra protection against the diseases of old age. Centenarians appear to have a high chance of having several such genes embedded in their DNA.

“Long-lived people do not have fewer disease genes or ageing genes,” said Eline Slagboom of Leiden University, who is leading a study into 3,500 Dutch nonagenarians. “Instead they have other genes that stop those disease genes from being switched on. Longevity is strongly genetic and inherited.”

Slagboom and her colleagues recently published studies showing how the physiology of people in long-lived families differs from normal people. Other studies, showing the genetic causes of those differences, are due for publication soon.

“People who live to a great age metabolise fats and glucose differently, their skin ages more slowly and they have lower prevalence of heart disease, diabetes and hypertension,” she said.

“These factors are all under strong genetic control, so we see the same features in the children of very old people.”

The so-called Methuselah genes — named after the biblical patriarch who lived to 969 — are thought to include ADIPOQ, which is found in about 10% of young people but in nearly 30% of people living past 100. The CETP gene and the ApoC3 gene are found in 10% of young people, but in about 20% of centenarians.

Some of those genes were discovered by a research group at Albert Einstein College of Medicine in New York, led by Prof Nir Barzilai, following an analysis of the genes of over 500 centenarians and their offspring.

The studies show that tiny mutations in the make-up of particular genes can sharply increase a person’s lifespan. Nonetheless, environmental factors such as the decline in infectious diseases are an important factor in the steady rise in the number of centenarians. The human genome contains about 28,000 genes, but they are controlled by a tiny number of so-called regulator genes.

Dr Barzilai told a Royal Society conference that the discovery of such genes gave scientists clear targets for developing drugs that could prevent or delay the onset of age-related diseases, potentially lengthening people's lives and keeping them healthier for longer.

Dr David Gems, a longevity researcher at University College London, believes that treatments to slow ageing will become widespread.

“If we know which genes control longevity then we can find out what proteins they make and then target them with drugs. That makes it possible to slow down ageing. We need to reclassify it as a disease rather than as a benign, natural process,” he said.

“Much of the pain and suffering in the world are caused by ageing. If we can find a way to reduce that, then we are morally obliged to take it.”

An anti-ageing drug which might be taken by millions of people, perhaps from middle age onwards, could be the ultimate blockbuster for the pharmaceutical industry.

Michelle Mitchell of Age UK said: “Ageing is a natural part of life. The key is to ensure that we do not simply extend life but extend the years of healthy life so that people can enjoy, not endure, their later years.”