A wide-ranging study published Wednesday identifies possible genetic links to an increased risk of post-traumatic stress disorder.
Scientists from UC San Diego School of Medicine, the Veterans Affairs San Diego Healthcare System and other institutions analyzed DNA samples from more than 13,000 U.S. soldiers and discovered two statistically significant genetic variants that might be associated with PTSD.
The study, published online in JAMA Psychiatry, used data from a pair of Army tests in which the genomes of soldiers were scanned.
One test was performed on 3,167 soldiers with diagnosed PTSD and 4,607 trauma-exposed control subjects, and the other on 947 diagnosed cases and 4,969 trauma-exposed controls.
Dr. Murray B. Stein, a professor of psychiatry, family medicine and public health at UCSD, said two notable genetic variants were discovered.
"The first, in samples from African-American soldiers with PTSD, was in a gene — ANKRD55 — on chromosome 5," Stein said.
"In prior research, this gene has been found to be associated with various autoimmune and inflammatory disorders, including multiple sclerosis, type II diabetes, celiac disease, and rheumatoid arthritis," he said. "The other variant was found on chromosome 19 in European-American samples."
The research also found links to rheumatoid arthritis, and to a lesser extent, psoriasis.
According to UCSD Health, the U.S. Department of Veterans Affairs estimates 11 to 20 percent of veterans from the Afghanistan and Iraq conflicts have or will develop PTSD. The percentage is even higher among Vietnam War veterans.
Prevalence of PTSD in the general U.S. population is 7 to 8 percent, the scientists said.
Researchers with the Uniformed Services University of Bethesda, Maryland, Massachusetts General Hospital, the Harvard Medical School, Yale University, the Broad Institute of the Massachusetts Institute of Technology, University of Michigan and National Institutes of Health also participated in the study.
The research was funded by the Army, the U.S. Department of Health and Human Services, the National Institutes of Health, the National Institute for Mental Health and the National Institute of Drug Abuse.