16 June 2008
ByAppeared in BioNews 462
Italian researchers, based at the University of Calabri, have found that a gene variant previously linked to high Intelligence Quotient (IQ) also increases the likelihood of carriers surviving to an old age. The findings, published in New Scientist magazine, suggest that carriers of the SSADH (succinic semialdehyde dehydrogenase) gene variant may live up to 100 years.
The SSADH gene triggers a molecular detox in the brain that breaks down excess acid removing free radicals that dampen brain activity, cause drowsiness and accelerate the aging process. The gene occurs in two forms: the 'good' C form and the 'bad' T form - with T being 20 per cent less efficient.
Whilst looking at a sample of 500 Italians, researchers noticed that those carrying the T form were unlikely to live beyond 85 years whilst those carrying the C form had a chance of celebrating their centennial. From the original sample group, the 115 volunteers who fell between 65 and 85 performed a series of cognitive tests, normally used to identify Alzheimer's disease, and those carrying the T variant performed significantly less well - confirming previous findings.
Group leader Professor Giuseppe Passarino tempered worries that the 'bad' version of the gene immediately conferred a low IQ and a shortened lifespan. 'There's no doubt that lifestyle, such as reading, having challenging work and enriching your cultural life, is far more important than having the bad variant', he said.
Despite acknowledging the significance of the result, Professor Robert Plomin, of the Institute of Psychiatry in London, who first identified the link between SSADH and intelligence, criticised the size of the study, saying that 'the sample size is small, with only 115 taking the test compared with the thousands expected in today's studies'.