Two genes linked to predisposition for PTSD

Chuck Bednar for redOrbit.com Your Universe Online

While severe trauma can cause post-traumatic stress disorder, not everyone who experiences such events develop PTSD, and now UCLA scientists believe they know why.

Dr. Armen Goenjian, a researcher at the Semel Institute for Neuroscience and Human Behavior at UCLA, and his colleagues report in the February edition of the Journal of Affective Disorders that they have linked to gene variants to the trauma-related anxiety disorder.

The findings, they explained, could provide a biological basis for diagnosing and treating PTSD more effectively in the future. It could also lead to faster diagnoses for patients, they added.

Many people suffer with post-traumatic stress disorder after surviving a life-threatening ordeal like war, rape or a natural disaster, Dr. Goenjian explained. But not everyone who experiences trauma suffers from PTSD. We investigated whether PTSD has genetic underpinnings that make some people more vulnerable to the syndrome than others.

Dr. Goenjian, an Armenian American, travelled to that country after a 6.8 magnitude earthquake leveled towns and cities and killed over 25,000 people in 1988. He and his colleagues, with the assistance of the Armenian Relief Society, established a pair of psychiatric clinics that provided treatment to survivors of the earthquake for more than two decades.

Twelve multigenerational families in northern Armenia gave permission to have their blood samples sent to UCLA, where Dr. Goenjian and his colleagues analyzed the DNA of 200 men and women in search of genetic clues to psychiatric vulnerability.

In April 2012, research by his team revealed that that PTSD was more common in survivors who carried two gene variants associated with depression. Now, along with UCLA Fielding School of Public Health adjunct assistant professor of epidemiology Julia Bailey, Dr. Goenjian focused on two genes (COMT and TPH-2) known to play key roles in the function of the brain.

COMT, the researchers explain, is an enzyme that degrades the neurotransmitter dopamine, which controls the reward and pleasure center of the brain and helps regulate mood. Too much or too little dopamine can influence various neurological and psychological disorders, they said.

TPH-2, on the other hand, controls the production of the brain hormone serotonin, which regulates mood, sleep and alertness. All three are affected by PTSD, and a type of antidepressant known as selective serotonin re-uptake inhibitors (SSRIs) target the hormone to treat depression. An increasing number of doctors are prescribing them to treat PTSD, the study authors noted.

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Two genes linked to predisposition for PTSD