Assessment of functional tag single nucleotide polymorphisms within the DRD2 gene as risk factors for post-traumatic stress disorder in the Han Chinese population

Proposing a two-stage screening approach to distinguish between transient and enduring postnatal depressive symptoms: A prospective cohort study

Background

Screening for perinatal depression using the Edinburgh Postnatal Depression Scale (EPDS) improves detection and increases health service utilization. However, previous studies with antenatal samples indicate that positive screenings might reflect transient distress that resolves without intervention, raising concerns about over-pathologizing typical postnatal responses and inefficiencies in referral practices. Therefore, distinguishing between transient and enduring depressive symptoms for appropriate referrals to secondary services is crucial, highlighting the need for a refined screening practice.

Objectives

We aimed to assess the prevalence of transient distress among postnatal women who initially screened positive on the EPDS and evaluate the effectiveness of a refined two-stage screening approach. Three research questions were addressed: Can the "transient phenomenon" be replicated in a postnatal sample? Can initial screening data predict transient status? What are the implications of adopting a two-stage screening approach?

Methods

In a prospective cohort study, 427 postnatal women in Copenhagen who scored above the cut-off on their initial EPDS screening (EPDS-1) underwent a second screening (EPDS-2) 1-4 weeks later, without intervention in between. We analyzed the predictive power for transient versus enduring distress using EPDS-1 total scores, responses to item 10 ("self-harm item"), parity, maternal age, and a history of depression. Three screening scenarios were compared for their clinical and ethical implications: (i) a traditional single screening approach where all individuals screening positive at EPDS-1 are directly referred to secondary services, (ii) a simple two-stage approach where all positive screenings at EPDS-1 undergo a second screening before referral, and (iii) a refined two-stage screening approach where selected criteria determine immediate referral or further screening.

Results

Among women who screened positive, 29.3 % displayed transient distress with a clinically meaningful decrease in EPDS scores. An EPDS-1 score of 15 or more was the most robust predictor of enduring symptoms (OR = 6.28, 95 % CI 3.5-11.8; Absolute Risk = 90.4 %) and was used along with a positive score on item 10 as indicators of immediate referral in scenario-iii. The refined two-stage approach reduced unnecessary referrals by 24 %, directly referred 60 % of women with enduring symptoms, and effectively managed suicidal risk.

Conclusions

A substantial proportion of postnatal women experience transient symptoms that are distinguishable from enduring symptoms through a refined two-stage screening strategy. This approach significantly improves referral efficiency and minimizes over-pathologization, enhancing clinical practice in perinatal mental health.

Association between DRD2/ANKK1 rs1800497 C > T polymorphism and post-traumatic stress disorder susceptibility: a multivariate meta-analysis

Background

Previous studies have suggested that the DRD2/ANKK1 rs1800497 C > T polymorphism plays a critical role in the risk of post-traumatic stress disorder (PTSD). However, published data are inconsistent or even contradictory. Therefore, we conducted a meta-analysis to explore the underlying correlation between the rs1800497 C > T polymorphism and PTSD risk.

Materials and methods

A total of five online databases were searched, and all related studies were reviewed up to 1 October 2022. Critical information was extracted, and quality assessment was conducted for all included studies. Multivariate meta-analyses were performed for the genetic model choice, and the odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated to examine the statistical power of the genetic models. In addition, heterogeneity, sensitivity, cumulative analysis, and publication bias were analyzed to guarantee statistical power.

Result

Overall, 12 observational studies involving 5,515 subjects were included and analyzed in this meta-analysis. Multivariate analysis indicated that a co-dominant genetic model was most likely the best choice. Pooled results revealed an elevated PTSD risk in mutated homozygote TT carriers in the general population (TT vs. CC: OR = 1.73, 95% CI = 1.14-2.62, P = 0.01, I2 = 58.9%) and other specific subgroups. Moreover, similar results were observed in other genetic models using univariate analysis.

Conclusion

Current evidence suggests that the DRD2/ANKK1 rs1800497 C > T polymorphism may contribute to PTSD susceptibility.

Assessment of genetic variants in D2 dopamine receptor (DRD2) gene as risk factors for post-traumatic stress disorder (PTSD) and major depressive disorder (MDD): A systematic review and meta-analysis

BACKGROUND

Many studies have performed assessments of genetic variants in the D2 dopamine receptor (DRD2) gene as risk factors for post-traumatic stress disorder (PTSD) and major depressive disorder (MDD). However, the results are inconsistent. This meta-analysis aimed to systematically summarize published data to evaluate the reliable association between the DRD2 genetic variants and the risk of PTSD and MDD.

METHODS

A systematic literature search was conducted using the Web of Science, PubMed, Google Scholar, Excerpta Medica Database (EMBASE), Springer, ScienceDirect, Wiley Online Library, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database (CBM), WANFANG Data, CQVIP, and Chinese National Knowledge Infrastructure (CNKI) databases before January 1st, 2022.

RESULTS

A total of 27 genetic variants in the DRD2 gene were retrieved, and 7 of them met the inclusion criteria for meta-analysis. Our meta-analysis results indicated that the rs1800497 (TaqIA) polymorphism was significantly associated with the increased risk of PTSD (Dominant model (A1A1 + A1A2 vs. A2A2): OR = 1.49, 95 % CI, 1.08-2.04 Z = 2.46, P = 0.014). Subgroup analysis for ethnicity suggested that a significantly increased risk of PTSD was observed in Asians (Dominant model (A1A1 + A1A2 vs. A2A2): OR = 1.39, 95 % CI, 1.08-1.79, Z = 2.60, P = 0.009) and Caucasians (Dominant model (A1A1 + A1A2 vs. A2A2): OR = 1.87, 95 % CI 1.02-3.41, Z = 2.04, P = 0.042). Meanwhile, we detected significant association strengths between the rs1799978 and rs2075652 polymorphisms in the DRD2 gene and MDD (for rs1799978, Homozygote comparison (GG vs. AA): OR = 0.60, 95 % CI = 0.37-0.97, Z = 2.08, P = 0.038; for rs2075652, Homozygote comparison (AA vs. GG): OR = 1.82, 95 % CI = 1.32-2.50, Z = 3.67, P < 0.001). Our cumulative meta-analyses indicated a continuous trend toward association strength with PTSD and MDD.

CONCLUSIONS

This meta-analysis indicated that genetic variants in the DRD2 gene might potentially contribute to genetic susceptibility for PTSD and MDD. The utilization of DRD2 genetic variants as risk factors for PTSD and MDD requires further validation by large well-designed case-control studies.

Throwing open the doors of perception: The role of dopamine in visual processing

Animals form associations between visual cues and behaviours. Although dopamine is known to be critical in many areas of the brain to bind sensory information with appropriate responses, dopamine's role in the visual system is less well understood. Visual signals, which indicate the likely occurrence of a rewarding or aversive stimulus or indicate the context within which such stimuli may arrive, modulate activity in the superior colliculus and alter behaviour. However, such signals primarily originate in cortical and basal ganglia circuits, and evidence of direct signalling from midbrain dopamine neurons to superior colliculus is lacking. Instead, hypothalamic A13 dopamine neurons innervate the superior colliculus, and dopamine receptors are differentially expressed in the superior colliculus, with D1 receptors in superficial layers and D2 receptors in deep layers. However, it remains unknown if A13 dopamine neurons control behaviours through their effect on afferents within the superior colliculus. We propose that A13 dopamine neurons may play a critical role in processing information in the superior colliculus, modifying behavioural responses to visual cues, and propose some testable hypotheses regarding dopamine's effect on visual perception.

Computational analysis of deleterious single nucleotide polymorphisms in catechol O-Methyltransferase conferring risk to post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is one of the prevalent neurological disorder which is drawing increased attention over the past few decades. Major risk factors for PTSD can be categorized into environmental and genetic factors. Among the genetic risk factors, polymorphisms in the catechol-O-methyltransferase (COMT) gene is known to be associated with the risk for PTSD. In the present study, we analysed the impact of deleterious single nucleotide polymorphisms (SNPs) in the COMT gene conferring risk to PTSD using computational based approaches followed by molecular dynamic simulations. The data on COMT gene associated with PTSD were collected from several databases including Online Mendelian Inheritance in Man (OMIM) search. Datasets related to SNP were downloaded from the dbSNP database. To study the structural and dynamic effects of COMT wild type and mutant forms, we performed molecular dynamics simulations (MD simulations) at a time scale of 300 ns. Results from screening the SNPs using the computational tools SIFT and Polyphen-2 demonstrated that the SNP rs4680 (V158M) in COMT has a deleterious effect with phenotype in PTSD. Results from the MD simulations showed that there is some major fluctuations in the structural features including root mean square deviation (RMSD), radius of gyration (Rg), root mean square fluctuation (RMSF) and secondary structural elements including α-helices, sheets and turns between wild-type (WT) and mutant forms of COMT protein. In conclusion, our study provides novel insights into the deleterious effects and impact of V158M mutation on COMT protein structure which plays a key role in PTSD.

The Pan social brain: An evolutionary history of neurochemical receptor genes and their potential impact on sociocognitive differences

Humans have unique cognitive capacities that, compared with apes, are not only simply expressed as a higher level of general intelligence, but also as a quantitative difference in sociocognitive skills. Humans' closest living relatives, bonobos (Pan paniscus), and chimpanzees (Pan troglodytes), show key between-species differences in social cognition despite their close phylogenetic relatedness, with bonobos arguably showing greater similarities to humans. To better understand the evolution of these traits, we investigate the neurochemical mechanisms underlying sociocognitive skills by focusing on variation in genes encoding proteins with well-documented roles in mammalian social cognition: the receptors for vasopressin (AVPR1A), oxytocin (OXTR), serotonin (HTR1A), and dopamine (DRD2). Although these genes have been well studied in humans, little is known about variation in these genes that may underlie differences in social behavior and cognition in apes. We comparatively analyzed sequence data for 33 bonobos and 57 chimpanzees, together with orthologous sequence data for other apes. In all four genes, we describe genetic variants that alter the amino acid sequence of the respective receptors, raising the possibility that ligand binding or signal transduction may be impacted. Overall, bonobos show 57% more fixed substitutions than chimpanzees compared with the ancestral Pan lineage. Chimpanzees, show 31% more polymorphic coding variation, in line with their larger historical effective population size estimates and current wider distribution. An extensive literature review comparing allelic changes in Pan with known human behavioral variants revealed evidence of homologous evolution in bonobos and humans (OXTR rs4686301(T) and rs237897(A)), while humans and chimpanzees shared OXTR rs2228485(A), DRD2 rs6277(A), and DRD2 rs11214613(A) to the exclusion of bonobos. Our results offer the first in-depth comparison of neurochemical receptor gene variation in Pan and put forward new variants for future behavior-genotype association studies in apes, which can increase our understanding of the evolution of social cognition in modern humans.

Ventral Tegmental Area Dysfunction and Disruption of Dopaminergic Homeostasis: Implications for Post-traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric condition characterized by intrusive recollections of the traumatic event, avoidance behaviors, hyper-arousal to event-related cues, cognitive disruption, and mood dysregulation. Accumulating preclinical and clinical evidence implicates dysfunction of the ventral tegmental area (VTA) dopaminergic system in PTSD pathogenesis. This article reviews recent advances in our knowledge of the relationship between dopaminergic dyshomeostasis and PTSD, including the contributions of specific dopaminergic gene variants to disease susceptibility, alterations in VTA dopamine neuron activity, dysregulation of dopaminergic transmission, and potential pharmacological and psychological interventions for PTSD targeting the dopaminergic system. An in-depth understanding of PTSD etiology is crucial for the development of innovative risk assessment, diagnostic, and treatment strategies following traumatic events.

Association of DRD2 gene polymorphisms with schizophrenia in the young Bangladeshi population: A pilot study

Purpose

DRD2 gene is considered one of the most important candidate genes for the schizophrenia (SCZ) development due to its role in dopamine signaling and no genetic association study has been conducted yet on the Bangladeshi SCZ patients. The objective of the present study was to investigate the association of DRD2 genetic polymorphisms (rs4648317, rs4936270, and rs7131056) with SCZ in the Bangladeshi population.

Patients and methods

This case-control study consisted of 101 SCZ patients and 101 controls. Genotyping was performed by the polymerase chain reaction and restriction fragment length polymorphism (PCR–RFLP) method.

Results

The average ages were 22.15 and 22.09 years in patients and controls, respectively (p > 0.05). CT genotype of rs4936270 showed a significantly higher risk for the development of SCZ compared to CC genotype (OR = 2.0, p = 0.023), whereas no association was found for TT genotype. For the dominant model and T allele, rs4936270 showed a higher risk for the development of SCZ (OR = 2.01, p = 0.020; OR = 1.76, p = 0.021, respectively), while the recessive model had no association with SCZ. A statistically significant (OR = 2.70, p = 0.036) higher risk was found for the AA genotype, but no association was found for GA genotype of rs4648317 SNP compared to GG genotype. In case of dominant and recessive models, rs4648317 showed no association with SCZ. ‘A’ allele of rs4648317 SNP was found to be significantly associated with the elevated risk of SCZ (OR = 1.50, p = 0.044). No association with SCZ of rs7131056 SNP was found for AC, CC genotypes, dominant, recessive, and allele models. Furthermore, from the haplotyping analysis, we found that CAA and TAA haplotypes of rs4936270, rs7131056 and rs4648317 SNPs are associated with SCZ (χ2 = 8.26, p = 0.004; χ2 = 5.31, p = 0.021, respectively). After Bonferroni correction, the association of SCZ did not withstand with any genotype, allele and haplotype (p < 0.017) except CAA haplotype.

Conclusion

Our results suggest that DRD2 gene polymorphisms may be associated with the susceptibility of SCZ in the young Bangladeshi population.

Effects of COMT rs4680 and BDNF rs6265 polymorphisms on brain degree centrality in Han Chinese adults who lost their only child

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.

Association of DRD2, 5-HTTLPR, and 5-HTTVNTR Gene Polymorphisms With Posttraumatic Stress Disorder in Tibetan Adolescents: A Case-Control Study

BACKGROUND

Earthquake exposure is a source of stress, yet only a minority of survivors experience clinically meaningful disturbance in psychological function. Genetic epidemiological research has found that posttraumatic stress disorder (PTSD) symptoms are associated with genetic factors. Further research to reveal which genetic loci relate to the development of PTSD is warranted.

METHOD

We investigated the relationships between PTSD and the dopamine D2 receptor ( DRD2) gene Taq I polymorphism and the serotonin transporter gene ( SCL6A4) polymorphisms 5-hydroxytryptamine transporter gene-linked polymorphic region (5-HTTLPR) and 5-HTTVNTR in 565 adolescent earthquake survivors. PTSD-positive adolescents were identified using the PTSD Checklist-Civilian Version and the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders 4. Genotypes were analyzed using the polymerase chain reaction-restriction fragment length polymorphism analysis. The Pearson χ² test was used to investigate the differences in genotype and allele frequencies between case and control groups. Binary logistic regression analysis was performed to identify possible influencing factors for PTSD.

RESULTS

The DRD2 Taq I and 5-HTTVNTR polymorphisms had statistically significant effects on PTSD, while 5-HTTLPR did not. Specifically, the DRD2 Taq I A1 allele was highly positively correlated with PTSD, whereas the 10 allele of 5-HTTVNTR was negatively correlated.

CONCLUSIONS

These data suggest that the DRD2 Taq I and 5-HTTVNTR genotypes moderate sensitivity to stress and the expression of emotional disturbance involving PTSD symptoms. These findings have important implications for PTSD etiology as well as for both primary prevention and treatment strategies.

Identification of Key Genes and Pathways in Post-traumatic Stress Disorder Using Microarray Analysis

Introduction: Post-traumatic stress disorder (PTSD) is characterized by impaired fear extinction, excessive anxiety, and depression. However, the potential pathogenesis and cause of PTSD are not fully understood. Hence, the purpose of this study was to identify key genes and pathway involved in PTSD and reveal underlying molecular mechanisms by using bioinformatics analysis. Methods: The mRNA microarray expression profile dataset was retrieved and downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) were screened using GEO2R. Gene ontology (GO) was used for gene function annotations and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway was performed for enrichment analysis. Subsequently, protein-protein interaction (PPI) network and module analysis by the plugin MCODE were mapped by Cytoscape software. Finally, these key genes were verified in stress-exposed models by Real-Time quantitative (qRT-PCR). In addition, we performed text mining among the key genes and pathway with PTSD by using COREMINE. Results: A total of 1004 DEGs were identified. Gene functional annotations and enrichment analysis indicated that the most associated pathway was closely related to the Wnt signaling pathway. Using PPI network and module analysis, we identified a group of "seed" genes. These genes were further verified by qRT-PCR. In addition, text mining indicated that the altered CYP1A2, SYT1, and NLGN1 affecting PTSD might work via the Wnt signaling pathway. Conclusion: By using bioinformatics analysis, we identified a number of genes and relevant pathway which may represent key mechanisms associated with PTSD. However, these findings require verification in future experimental studies.

Association between genetic variation in the dopamine system and motor recovery after stroke

BACKGROUND

The dopamine system plays a key role in motor learning and neuroplasticity. Several studies have studied the efficacy of dopaminergic drugs in enhancing motor recovery after stroke, but the effects are controversial. Although genetic variations in plasticity-related genes influence each individual's capacity for recovery after stroke, limited studies have investigated the effects of polymorphism of dopamine-related genes.

OBJECTIVE

We aimed to investigate the association between motor recovery in stroke patients and polymorphisms in the dopamine-related genes catechol-O-methyltransferase (COMT), dopamine receptor D1 (DRD1), DRD2, and DRD3.

METHODS

We enrolled 74 patients with first-ever stroke (42 males, 32 females, mean age: 61.4±14.1 y). During admission, blood samples were collected, and the genotypes of COMT, DRD1, DRD2, and DRD3 were analyzed. The primary outcome was assessed with Fugl-Meyer Assessment (FMA) at 1 week, 3 months, and 6 months after stroke; secondary outcomes were assessed with Functional Independence Measure (FIM) and mini-mental state examination at 3 and 6 months after stroke. The association between polymorphisms and functional outcome was analyzed.

RESULTS

There were no significant associations between COMT polymorphisms and FMA or FIM scores at 1 week after stroke or between DRD1, DRD2, or DRD3 genotypes and FMA or FIM scores at any point. COMT genotypes were significantly associated with FMA and FIM at 3 months (p < 0.01 and p < 0.05, respectively) and at 6 months (p < 0.01 and p < 0.05, respectively).

CONCLUSION

These data suggest that genetic variation of dopamine-related genes may affect motor recovery after stroke and that COMT polymorphism could be useful for predicting motor recovery.