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Research Article

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

    ,
    Ligong Chen

    Department of Preventive Medicine, Uniformed Services University, Bethesda, MD, USA

    ,
    Vasantha Srikantan

    Department of Preventive Medicine, Uniformed Services University, Bethesda, MD, USA

    ,
    Lei Zhang

    Center for the Study of Traumatic Stress, Department of Psychiatry, Uniformed Services University, Bethesda, MD, USA

    ,
    Liying Yan

    EpigenDx Inc., Worcester, MA, USA

    , &
    Andrea Baccarelli

    Exposure, Epidemiology & Risk Program, Harvard School of Public Health, Harvard University, Boston, MA, USA

    Published Online:https://doi.org/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.

    Papers of special note have been highlighted as: ▪ of interest ▪▪ of considerable interest

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