US scientists studying the genes of a large group of centenarians found 150 unique DNA sequences predicted exceptional longevity with 77 per cent accuracy, and showed that 19 clusters of the sequences or "genetic signatures" had strong links with different age-related diseases: but perhaps most remarkably they found that these genetic signatures predicted longevity more strongly than the absence of disease-related variants. They hope their findings will be useful for developing better prevention and screening tools and personalized medicine.
The researchers also cautioned that the discovery that genes play such a strong part in exceptional longevity does not mean lifestyle factors such as following a healthy diet and exercising are ineffective; they still play an important role in helping humans live to a healthy old age, they stressed.
Drs Paola Sebastiani, a professor of biostatistics at the Boston University (BU) School of Public Health and Thomas Perls, associate professor of medicine at the BU School of Medicine and a geriatrician at Boston Medical Center, led the study, which is published in the 1 July online issue of Science.
While healthy aging appears to be influenced by environment and family history, it would appear from this study that genetic variants have a strong and complex influence on exceptional longevity.
As a first step, the researchers conducted a genome-wide association study in 1,055 centenarians and 1,267 controls. Centenarians are considered a model of healthy aging because they tend not to get many of the diseases of aging until they are well into the mid 90s.
From the genome data the researchers built a model based on 150 single-nucleotide polymorphisms (SNPs: unique sequences of DNA from inside or between genes).
Using the 150 SNP model the team found they could predict exceptional longevity (living to late 90s or more) with 77 per cent accuracy in a separate, independent group of centenarians and controls.
They also noted that 45 per cent of the oldest centenarians (110 years old or more), had the highest proportion of longevity- linked SNPs.
In a second analysis the researchers showed there were strong links between 19 clusters of SNPs, which they termed "genetic signatures", and the prevalence and onset of age-related diseases like dementia, high blood pressure and cardiovascular disease, in 90 per cent of the centenarians.
Although these genetic signatures had varying predictive value the team said they may help identify key subgroups of healthy aging.
Perls, who is founder and director of the New England Centenarian Study, told the press that the discovery of these genetic signatures is an important step towards the development of personalized and predictive medicine that takes into account the genetic make up of the patient.
Article Date: 02 Jul 2010
http://www.medicalnewstoday.com/articles/193644.php
