A Candidate Gene Association Study of FKBP5 and CRHR1 Polymorphisms in Relation to War-Related Posttraumatic Stress Disorder.
BACKGROUND Posttraumatic stress disorder (PTSD) is a highly frequent and disabling psychiatric condition among war-affected populations. The FK506-binding protein 5 (FKBP5) gene and the corticotropin-releasing hormone receptor 1 (CRHR1) gene have previously been implicated in an elevated risk of peritraumatic dissociation and PTSD development. Our aim was to investigate the association between FKBP5 and CRHR1 genotypes and PTSD diagnosis and severity among individuals who were affected by the Balkan wars during the 1990s. SUBJECTS AND METHODS This study included participants with current PTSD, remitted PTSD and healthy volunteers (N=719, 487 males), who were recruited between 2013 and 2015 within the framework of the South Eastern Europe (SEE) - PTSD Study. Psychometric methods comprised the Mini International Neuropsychiatric Interview (M.I.N.I.), the Clinician Administrated PTSD Scale (CAPS), and the Brief Symptom Inventory (BSI). FKBP5 rs1360780 and CRHR1 rs17689918 genotypes were determined using a KASP genotyping assay. RESULTS Tests for deviation from Hardy Weinberg equilibrium showed no significant results. Logistic and linear regression was used to examine the associations between the FKBP5 SNP rs1360780 and the CRHR1 SNP rs17689918 with PTSD diagnosis and severity, as well as general psychiatric symptom severity, separately for current and remitted PTSD patients. There were nominally significant associations under a dominant model between the rs1360780 C allele and PTSD diagnosis as well as symptom severity, which however, were not significant anymore after Bonferroni adjustment (α=0.002). For CRHR1 rs17689918 no significant associations were detected. CONCLUSION We found nominally, but not Bonferroni corrected significant associations between the FKBP5 polymorphism rs1360780 and PTSD susceptibility among individuals affected by the Balkan wars. For elucidating this gene's real resilience/vulnerability potential, environmental influences should be taken into account.