Authors:
Armen K. Goenjian, Ernest P. Noble, Alan M. Steinberg, David P. Walling, Sofia T. Stepanyan, Sugandha Dandekar, & Julia N. Bailey
Summary:
Background - Dopaminergic and serotonergic systems have been implicated in PTSD. The present study evaluated the association of four catechol-O-methyltransferase (COMT) gene loci, and the joint effect of COMT and tryptophan hydroxylase 2 (TPH2) genes on PTSD symptoms.
Methods - Subjects included 200 Caucasian Armenian adults exposed to the 1988 Spitak earthquake from 12 multigenerational (3–5 generations) families. Instruments used included the UCLA PTSD Reaction Index based on DSM-5 criteria, and the Beck Depression Inventory.
Results - The adjusted heritabilitiy of vulnerability to DSM-5 based PTSD symptoms was 0.60 (p<10−4). There was a significant association of the COMT allele rs4633C with total PTSD (p<0.03), and D category (p<0.04) (negative alterations in cognitions and mood) severity scores, but not with C category (avoidance) scores. There was no genetic correlation between C and D category severity scores. COMT allele rs4633C and the TPH-2 allele rs11178997T together accounted for 7% of the variance in PTSD severity scores (p<0.001). None of the COMT alleles were associated with depression.
Limitations - The ratings of earthquake exposure and prior trauma may have been subject to recall bias. The findings may not be generalizable to other ethnic/racial populations.
Conclusion - COMT allele rs4633C may be causally related and/or is in linkage disequilibrium with gene(s) that are causally related to PTSD symptoms. Carriers of these COMT and the TPH-2 alleles may be at increased risk for PTSD. The findings provide biological support for dividing DSM-IV category C symptoms into DSM-5 categories C and D.
Source:
Journal of Affective Disorders; Vol. 172, 472-478 (02/01/15)