CHICAGO: An explosion in genetic research is helping physicians detect and treat deadly diseases like never before, says a collection of studies. The advances could soon lead to genetic pre-screening to assess risk for a range of diseases and personalised preventative treatments.
A special issue of the Journal of the American Medical Association (JAMA) this week assessed the state of genetic-based treatments and presented a number of significant discoveries, including a genetic predisposition for developing post-traumatic stress disorder.
"The magnitude, scope, and pace of discovery in genetics and genomics research are at unprecedented levels and continue to increase exponentially," JAMA editor-in-chief Catherine DeAngelis wrote in a co-authored editorial.
Unprecedented pace of discovery
"These discoveries have important implications for understanding disease processes... for predicting disease susceptibility and progression, and for refining and individualising treatments," she said. "All of which ultimately have the potential to improve health and to increase both quality of life and longevity."
The experts noted that while fifteen years ago there were 100 genes that could be tested for clues to disease susceptibility, today there are over 1,500.
"We have about 30 to 35,000 (genes) so there's still a long way to go but things are really moving rapidly." Advanced computing technology and the completion of the Human Genome Project in 2003 and other key databases have pushed genetic research into "a rapid discovery phase," Gregory Feero of the U.S. National Human Genome Research Institute in Bethesda, Maryland, wrote in a commentary in the journal.
"In the past year, genome-wide association studies yielded highly robust information on scores of new genetic markers for common chronic disorders including diabetes, heart disease, Crohn disease, and several common cancers," he wrote.
False positives
However, the majority of genetic markers discovered in these studies have a "modest" impact on the risk of developing the disease of 10 to 40 per cent, the authors noted.
Other issues of concern surrounding genetic screening are the emotional impact on patients, the threat of discrimination and the "'blizzard of false positives' that is inevitable when hundreds of thousands of genetic markers are probed at the same time," wrote Kenneth Offit of the Memorial Sloan-Kettering Cancer Centre in New York City.
"The field is already replete with such initially promising but ultimately false-positive associations between genetic markers and schizophrenia, obesity, stroke, and Parkinson disease, for example," he said.
The research presented in the journal nonetheless presents significant advances in the genetic links to a number of common diseases, including cancer, heart disease, osteoporosis, post-traumatic stress disorder (PTSD), and blood clots.
Susceptibility to stress
Perhaps the most intriguing study was one which found that a gene related to stress response could help predict whether people who had experienced child abuse or other early trauma would later suffer from PTSD. PTSD is a common psychiatric disorder affecting at least seven per cent of the U.S. population, "with much higher rates among combat veterans and those living in high-violence areas," the authors wrote.
But people experiencing the same trauma often have different responses, and it was not clear why some developed PTSD and others did not. It appears that a gene involved in switching off the fight-or-flight response could impact whether people subjected to trauma are able to recover on their own or will end up trapped in a state of stress and anxiety.
Another large study found a gene associated with a "significant" increase of up to 20 per cent in the risk of bone fractures and lower levels of bone mineral density in the spine and hip, while a third study found a link between a protein associated with carrying cholesterol in the blood and heart disease.
