DNA methylation in repetitive elements and post-traumatic stress disorder: a case-control study of US military service members

Epigenomics. 2012 Feb;4(1):29-40. doi: 10.2217/epi.11.116.


Aim: We investigated serum DNA methylation patterns in genomic repetitive elements, LINE-1 and Alu, for post-traumatic stress disorder (PTSD) cases and controls who were US military service members recently deployed to Afghanistan or Iraq.

Methods: Cases (n = 75) had a postdeployment diagnosis of PTSD. Controls (n = 75) were randomly selected service members with no postdeployment PTSD diagnosis. Pre- and post-deployment sera were accessed, DNA was extracted and DNA methylation (percentage 5-methyl cytosine) was quantified via pyrosequencing. Conditional and unconditional logistic regressions were used to compare: cases post- to pre-deployment; controls post- to pre-deployment; cases to controls predeployment; cases to controls postdeployment.

Results: LINE-1 was hypermethylated in controls post- versus pre-deployment (odds ratio [OR]: 1.33; 95% CI: 1.06-1.65) and hypomethylated in cases versus controls postdeployment (OR: 0.82; 95% CI: 0.67-1.01). Alu was hypermethylated for cases versus controls predeployment (OR: 1.46; 95% CI: 1.08-1.97).

Conclusion: Patterns of hypermethylation of LINE-1 in controls postdeployment and of Alu in cases postdeployment are intriguing and may suggest resilience or vulnerability factors.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Alu Elements / genetics*
  • Case-Control Studies
  • DNA / analysis*
  • DNA / blood
  • DNA / isolation & purification
  • DNA Methylation*
  • Epigenesis, Genetic
  • Female
  • Humans
  • Logistic Models
  • Long Interspersed Nucleotide Elements / genetics*
  • Male
  • Military Personnel*
  • Odds Ratio
  • Sequence Analysis, DNA
  • Stress Disorders, Post-Traumatic / diagnosis
  • Stress Disorders, Post-Traumatic / genetics*
  • Stress Disorders, Post-Traumatic / metabolism*
  • United States
  • Young Adult


  • DNA