Abstract
Losing one’s only child is a major traumatic life event that may lead to posttraumatic stress disorder (PTSD); however, not all parents who experience this trauma develop PTSD. Genetic variants are associated with the risk of developing PTSD. Catechol-O-methyltransferase (COMT) rs4680 and brain-derived neurotrophic factor (BDNF) rs6265 are two most well-described single-nucleotide polymorphisms that relate to stress response; however, the neural mechanism underlying their effects on adults who lost an only child remains poorly understood. Two hundred and ten Han Chinese adults who had lost their only child (55 with PTSD and 155 without PTSD) were included in this imaging genetics study. Participants were divided into subgroups according to their COMT rs4680 and BDNF rs6265 genotypes. Degree Centrality (DC)—a resting-state fMRI index reflecting the brain network communication—was compared with a three-way (PTSD diagnosis, COMT, and BDNF polymorphisms) analysis of covariance. Diagnosis state had a significant effect on DC in bilateral inferior parietal lobules and right middle frontal gyrus (MFG), where PTSD adults showed weaker DC. BDNF × diagnosis interaction effect was found in the right MFG and hippocampus, and these two regions were reversely modulated. Also, there was a significant COMT × BDNF interaction effect in left cuneus, middle temporal gyrus, right inferior occipital gyrus, and bilateral putamen, independent of PTSD diagnosis. These findings suggest that the modulatory effect of BDNF polymorphism on the MFG and hippocampus may contribute to PTSD development in bereaved adults. Interactions of COMT × BDNF polymorphisms modulate some cortices and basal ganglia, irrespective of PTSD development.
Highlights
The “One-Child Policy”—which permits each family to have only one child—was implemented in mainland China for more than 30 years[1,2]
The failure to replicate these results could possibly be due to the wide variations in the types of trauma, the severity of posttraumatic stress disorder (PTSD) symptoms, and race/ethnicity populations involved in these genetic studies of PTSD25
We aimed to examine the main effects of COMT rs4680, brain-derived neurotrophic factor (BDNF) rs6265, and their interaction effect on brain function as seen using resting-state functional magnetic resonance imaging in Chinese adults who had lost their only child
Summary
The “One-Child Policy”—which permits each family to have only one child—was implemented in mainland China for more than 30 years[1,2] This policy succeeded in slowing the rapid population growth rate in China, its associated problems are becoming. Several unbiased genome-wide association studies (GWAS) based on the clinical diagnosis of PTSD have been performed[21,22,23,24]. These studies have helped us to understand the genetic basis of PTSD development and its genetic overlap with other mental disorders such as schizophrenia[24]. The failure to replicate these results could possibly be due to the wide variations in the types of trauma, the severity of PTSD symptoms, and race/ethnicity populations involved in these genetic studies of PTSD25
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