LOS ANGELES, June 20 (UPI) -- Although genetic risk factors for post traumatic stress disorder have been identified before, researchers in a recent study in Los Angeles went looking for genetic factors that affect the manifestation of symptoms in the disorder, finding a potential target for new treatment.
Researchers at Children's Hospital Los Angeles found blocking a gene associated with fear learning prevented mice from learning fear, or even expressing it after learning fear, suggesting new ways to treat the effects of PTSD.
Biomarkers have previously been identified thought to help predict risk for PTSD, though researchers in the new study were specifically looking for genes that may indicate risk for "high" or "low" expression of symptoms, they say.
"We're suggesting that instead of focusing only on the genes that are thought to cause a disorder -- for example, PTSD or anxiety disorder -- it is important to discover those genes that can have a profound effect on how severely an individual is impacted by their disorder," Dr. Pat Levitt, a professor of pediatrics, neuroscience, psyciatry and pharmacy at the University of Southern California, said in a press release.
For the study, published in The Journal of Neuroscience, researchers tested mice with a wide range of high and low anxiety to see how well they learned to detect threats -- normal fear learning. When fear learning is exaggerated, symptoms of anxiety and PTSD can develop.
Researchers mapped the genomes of 65 mouse strains, finding genes related to fear acquisition and fear expression, finding one, the Hcn1 gene, is necessary for both.
Researchers found blocking expression of the Hcn1 gene prevented the mice from displaying fears they had already acquired, and by blocking the gene before entering a situation where they may learn fear, the mice did not acquire the instinct.
"By understanding the biological origins of individual behavioral differences -- in this case a measure of anxiety -- we can move beyond a single disorder diagnosis and treat the dimensions that produce a behavior spanning a multitude of diagnoses," said Dr. Allison Knoll, a post-doctoral researcher at Children's Hospital Los Angeles.
