A study performed at Columbia University's Mailman School of Public Health may be a new model of the effect of post-traumatic stress disorder (PTSD) and how genes may be altered by the stress response.
"The new study is the first large scale investigation to search for trauma-induced changes in the genes of people with PTSD. DNA samples were obtained from participants in the Detroit Neighborhood Health Study (DNHS), a longitudinal epidemiologic study investigating PTSD and other mental disorders in the city of Detroit. The researchers analyzed the methylation patterns of over 14,000 genes from blood samples taken from 100 Detroit residents, 23 of whom suffer from PTSD."
Antibodies to the herpes virus were at high levels in those with post-traumatic stress disorder which indicated that their immune systems were compromised. The stress response was deregulated and overactive which caused dysfunction in the immune system. Further research may provide valuable information as to how trauma can affect genetic activity.
http://www.sciencedaily.com/releases/2010/05/100504102124.htm