Allele-specific DNA methylation level of FKBP5 is associated with post-traumatic stress disorder.

•FKBP5 is involved in human stress responses and regulation of HPA axis.•An interaction effect of FKBP5 genotype and PTSD status on FKBP5 methylation level.•The risk allele of rs1360780 was associated with lower FKBP5 methylation levels.•Genetic and epigenetic modulation of FKBP5 may play a role in PTSD pathophysiology.