It is plausible that decreased Fkbp5 may represent an adaptive mechanism, since decreased Fkbp5 expression has been observed in resilient mice in a model of PTSD [67], Fkbp5-knockout mice display behavioural stress resilience [68] and distinct FKBP5 methylation patterns have been associated with post-traumatic growth in humans [69]. The gene discussed is FKBP5; the disease is post-traumatic stress disorder.