Gene glitches may hold secret of a long life

• Ian Sample, science correspondent

This article appeared in the Guardian on Tuesday March 04 2008 on p7 of the UK news section. It was last updated at 00:04 on March 04 2008.

A series of rare genetic mutations that boost human lifespan have been discovered by a team of scientists studying centenarians and their elderly children.

The genetic glitches are thought to interfere with the normal growth of cells, halting the ageing process.

The discovery mirrors similar findings from studies on animals, which have shown that certain variations of genes linked to an insulin-like growth hormone can extend animals' lives dramatically.

Dr Nir Barzilai, director of the Institute for Ageing Research at Albert Einstein College of Medicine in New York, found a series of mutations exclusively among centenarians which affect sensitivity to "insulin growth factor 1", or IGF-1. This hormone influences the development of almost every cell in the body. It is crucial for children's growth and continues contributing to tissue generation throughout adulthood.

Barzilai's team discovered the genetic markers after scanning the genetic codes of 384 participants whose ages ranged from 95 to 110, with an average age of 100. They were compared with 312 controls, who came from families with a typical life span, none of whom had lived to 95.

Tests on cells taken from the elderly volunteers showed they were less sensitive to IGF-1, suggesting that the mutated genes were disrupting the body's ability to grow normally.

The study is published in the Proceedings of the National Academy of Sciences.