Biomarkers of Childhood Trauma
Description
DNA sequencing has proven itself both reliable and valid in determining whether a person was involved in a crime or not and Mehta and colleagues (2013) have begun to extend a similar forensic approach into the area of childhood trauma. Genes are encoded in DNA, but the DNA molecule is wrapped in a complex assembly of proteins and RNA molecules called chromatin, which in turn determines whether a gene is expressed and at what level (epigenetics). To assess whether such an approach can discriminate between trauma victims with or without a history of child abuse, the gene expression profiles and the epigenetic state of differentially-expressed genes were examined in the relevant adult demographics.
Validity and Reliability of Epigenetic Biomarkers for Child-Abuse History
The sample size was 396 adults, of which 169 had experienced trauma with or without childhood abuse (Mehta et al., 2013). All were scored using the reliable and valid PTSD Symptomatic Scale (PSS), with scores above 20 judged to be clinically significant. The BDI was used to measure current depression. Both the PSS and BDI were able to significantly discriminate between trauma and non-trauma subjects (p < 8.47x10-18), as was the gene expression profiles (p < .05); however, the PSS, but not BDI, could discriminate between trauma victims with or without a history...
Surprisingly, the gene expression profile was almost completely distinct between the two trauma groups with only 14 out of 244 genes overlapping. There was also a 12-fold difference in the levels of epigenetic changes at selected genes between trauma victims with or without a history of child abuse. These findings suggest that gene expression profiling and epigenetic analysis is at least as sensitive as the PSS in discriminating between controls and trauma victims and between trauma victims with or without a history of child abuse. Based on these comparisons, these biomarkers are valid for discriminating between controls and the two different trauma groups. In terms of reliability, the experimental approach screened against genes and epigenetic markers producing unacceptably high variance (SD > 5-10%) between subjects and therefore established reliability experimentally. This work suggests that trauma at least, produces an epigenetic 'fingerprint' that can be easily measured using blood samples.
References
Gillihan, Seth J., Aderka, Idan M., Conklin, Phoebe H., Capaldi, Sandra, and Foa, Edna B. (2012). The Child PTSD Symptom Scale: Psychometric properties in female adolescent sexual assault survivors. Psychological Assessment, 25(1), 23-31.
Mehta, Divya, Klengel, Torsten, Conneely, Karen N., Smith, Alicia K., Altmann, Andre, Pace, Thaddeus…
