Variations in a gene involved in response to stress appear to be predictive of increased risk for post-traumatic stress disorder symptoms in adults who were abused as children, according to an article in the March 19 issue of the Journal of the American Medical Association.

Rebekah G. Bradley, PhD, of the Emory University School of Medicine, Atlanta, and colleagues wrote "Posttraumatic stress disorder (PTSD) is a debilitating stress-related psychiatric disorder, with prevalence rates of at least 7 percent to 8 percent in the U.S. population, and with much higher rates among combat veterans and those living in high-violence areas. Initially viewed as a potentially normative response to traumatic exposure, it became clear that not everyone experiencing trauma develops PTSD. Thus, a central question in research on PTSD is why some individuals are more likely than others to develop the disorder in the face of similar levels of trauma exposure."

Researchers conducted a study to determine the role of variations (polymorphisms) in one of the genes related to stress response, FKBP5, in predicting disorder symptoms in a sample of highly traumatized, low-income men and women living in an urban area, and whether these genetic variations interact with increasing levels of both child abuse and other types of trauma exposure to be a predictor of PTSD symptoms during adulthood.

The study consisted of an examination of genetic and psychological risk factors in 900 general medical clinic patients with significant levels of childhood abuse as well as other types of trauma, using a survey combined with genetic testing (single-nucleotide polymorphism [SNP] genotyping). Participants were primarily urban, low-income, black men and women seeking care in the general medical care and obstetrics-gynecology clinics of an urban public hospital between 2005 and 2007.

The researchers found that both level of child abuse and level of other types of trauma each separately predicted level of adult PTSD symptomatology. Although genetic variations (FKBP5 SNPs) did not directly predict PTSD symptom outcome or interact with level of non?child abuse trauma to predict PTSD symptom severity, four variations (SNPs) in the FKBP5 locus significantly interacted with the severity of child abuse to predict level of adult PTSD symptoms. This gene?environment interaction remained significant when controlling for depression severity scores, age, sex, levels of trauma exposure other than child abuse and genetic ancestry.

"The most novel and important finding of our study was the interaction between FKBP5 polymorphisms and child abuse history to predict the levels of adult PTSD symptoms," the authors wrote. "These genotypes potentially serve as predictors of both risk and resilience for adult PTSD among survivors of child physical and sexual abuse."