Although the heritability of PTSD is estimated to be in the range of 30% to 40% by twin studies (7,8), no genetic variants have been conclusively identified to contribute to PTSD risk by candidate gene association studies (15). A study showed that an SNP in gene ADCYAP1R1 was associated with PTSD in women (39). However, it was not replicated in two independent samples (40). Recently, Logue et al. (41) performed a PTSD GWAS study and observed that the RORA gene was a significant risk locus for PTSD. However, our study failed to replicate the results (Table S3 in Supplement 1). In the current GWAS, only one genomic region (TLL1) was successfully replicated and reached genome-wide significance. It is important to ascertain whether this region can be replicated in other independent samples. Due to the relatively small sample size, we likely missed true risk variants. It is also possible that common variants do not make a large contribution to the risk of PTSD.
