The risk of posttraumatic stress disorder (PTSD) following trauma is heritable, but robustcommon variants have yet to be identified. In a multi-ethnic cohort including over 30,000PTSD cases and 170,000 controls we conduct a genome-wide association study of PTSD. Wedemonstrate SNP-based heritability estimates of 5–20%, varying by sex. Three genome-widesignificant loci are identified, 2 in European and 1 in African-ancestry analyses. Analysesstratified by sex implicate 3 additional loci in men. Along with other novel genes andnon-coding RNAs, a Parkinson’s disease gene involved in dopamine regulation,PARK2,isassociated with PTSD. Finally, we demonstrate that polygenic risk for PTSD is significantlypredictive of re-experiencing symptoms in the Million Veteran Program dataset, althoughspecific loci did not replicate. These results demonstrate the role of genetic variation in thebiology of risk for PTSD and highlight the necessity of conducting sex-stratified analyses andexpanding GWAS beyond European ancestry populations.
