An explosion in genetic research is helping physicians detect and treat deadly diseases and could soon lead to genetic prescreening to assess risk and design personalized preventative treatments, researchers said Tuesday.
A special issue of the Journal of the American Medical Association 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.
"These discoveries have important implications for understanding disease processes ... for predicting disease susceptibility and progression, and for refining and individualizing treatments - all of which ultimately have the potential to improve health and to increase both quality of life and longevity."
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," lead author Gregory Feero of the National Human Genome Research Institute wrote in a commentary.
"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.
But the majority of genetic markers discovered in these studies have a "modest" impact on the risk of developing the disease of 10 to 40 percent, he wrote.
And clinical applications for preventative treatment is currently limited by a "lack of information on how the prevalence and risk contribution of these markers vary across population groups" and "fragmentary information on how most genetic risk factors interact with environmental factors."
Other issues of concern surrounding genetic screening is 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 Center.
"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 wrote.
The research presented in the journal nonetheless present significant advances in the genetic links to a number of common diseases, including cancer, heart disease, osteoporosis, post traumatic stress disorder, and blood clots.
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 post traumatic stress disorder (PTSD.)
PTSD is a common psychiatric disorder affecting at least seven percent of the US 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.
"The most novel and important finding of our study was the interaction between (the genotype) FKBP5 polymorphisms and child abuse history to predict the levels of adult PTSD symptoms," wrote lead author Rebekah Bradley of the Emory University School of Medicine.
"These genotypes potentially serve as predictors of both risk and resilience for adult PTSD among survivors of child physical and sexual abuse."
Another large study found a gene associated with a "significant" increase of up to 20 percent 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.