Posttraumatic stress disorder (PTSD) is a serious public health concern. Genome-wide association study (GWAS) of PTSD can provide insight into its etiology. Several GWAS on PTSD diagnosis have been published, including our GWAS on PTSD in the Army Study of Risk and Resilience in Servicemembers (Army STARRS). PTSD is a complex syndrome comprising several symptom domains. To better understand the etiology of PTSD, we performed genome-wide analysis for PTSD symptom domains in Army STARRS.
We performed genome-wide analysis in 8,920 European American, 1,932 African American, and 2,622 Latino American samples with traumatic experiences. The lifetime severity of three PTSD symptom domains (re-experiencing, avoidance, and hyperarousal) were collected using the PTSD Checklist (abbreviated version). The association analyses were performed using linear regression adjusted for 10 principal components of ancestry, age, and gender. SNP-based heritability and genetic correlation among domains was estimated in the European American subsample.
None of the genome-wide analyses showed evidence of confounding by ancestry (lambda_GC from 0.99 to 1.02). We identified 1 locus for re-experiencing severity in the European American sample (chr. 18, rs2311207, Beta=0.2260, P=2.5×10-8). SNP-based heritability were 0.060 for re-experiencing (P=0.070), 0.043 for avoidance (P=0.138) and 0.085 for hyperarousal (P=0.019) symptoms. We observed strong genetic correlations between the three PTSD symptom domains (0.80 to 1.00).
We identified 1 locus for PTSD re-experiencing severity in European American. Our analyses suggest modest SNP-based heritability but strong genetic correlations among PTSD symptom domains, suggesting predominantly shared contributions of common variation. Replications of these results in independent samples are warranted.