RORA and posttraumatic stress trajectories: main effects and interactions with childhood physical abuse history
Sarah R. Lowe3 
Jacquelyn L. Meyers3 
Sandro Galea5 
Allison E. Aiello1 
Monica Uddin4 
Derek E. Wildman2 
[1] Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina;Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, Illinois;Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York;Department of Psychology, University of Illinois Urbana-Champaign, Champaign, Illinois;Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts
Longitudinal studies of posttraumatic stress (PTS) have documented environmental factors as predictors of trajectories of higher, versus lower, symptoms, among them experiences of childhood physical abuse. Although it is now well-accepted that genes and environments jointly shape the risk of PTS, no published studies have investigated genes, or gene-by-environment interactions (GxEs), as predictors of PTS trajectories. The purpose of this study was to fill this gap.
Methods and Materials
We examined associations between variants of the retinoid-related orphan receptor alpha (RORA) gene and trajectory membership among a sample of predominantly non-Hispanic Black urban adults (N =473). The RORA gene was selected based on its association with posttraumatic stress disorder (PTSD) in the first PTSD genome wide association study. Additionally, we explored GxEs between RORA variants and childhood physical abuse history.
Results
We found that the minor allele of the RORA SNP rs893290 was a significant predictor of membership in a trajectory of consistently high PTS, relatively to a trajectory of consistently low PTS. Additionally, the GxE of rs893290 with childhood physical abuse was significant. Decomposition of the interaction showed that minor allele frequency was more strongly associated with membership in consistently high or decreasing PTS trajectories, relative to a consistently low PTS trajectory, among participants with higher levels of childhood physical abuse.
Conclusion
The results of the study provide preliminary evidence that variation in the RORA gene is associated with membership in trajectories of higher PTS and that these associations are stronger among persons exposed to childhood physical abuse. Replication and analysis of functional data are needed to further our understanding of how RORA relates to PTS trajectories.