Search

It is imperative to understand the specific and shared etiologies of major depression and cardio-metabolic disease, as both traits are frequently comorbid and each represents a major burden to society. This study examined whether there is a genetic association between major depression and cardio-metabolic traits and if this association is stratified by age at onset for major depression. Polygenic risk scores analysis and linkage disequilibrium score regression was performed to examine whether differences in shared genetic etiology exist between depression case control status (N cases = 40,940, N controls = 67,532), earlier (N = 15,844), and later onset depression (N = 15,800) with body mass index, coronary artery disease, stroke, and type 2 diabetes in 11 data sets from the Psychiatric Genomics Consortium, Generation Scotland, and UK Biobank. All cardio-metabolic polygenic risk scores were associated with depression status. Significant genetic correlations were found between depression and body mass index, coronary artery disease, and type 2 diabetes. Higher polygenic risk for body mass index, coronary artery disease, and type 2 diabetes was associated with both early and later onset depression, while higher polygenic risk for stroke was associated with later onset depression only. Significant genetic correlations were found between body mass index and later onset depression, and between coronary artery disease and both early and late onset depression. The phenotypic associations between major depression and cardio-metabolic traits may partly reflect their overlapping genetic etiology irrespective of the age depression first presents., (© 2020 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics published by Wiley Periodicals LLC.)

Genetic factors appear to be highly relevant to predicting differential risk for the development of post-traumatic stress disorder (PTSD). In a discovery sample, we conducted a genome-wide association study (GWAS) for PTSD using a small military cohort (Systems Biology PTSD Biomarkers Consortium; SBPBC, N = 147) that was designed as a case-controlled sample of highly exposed, recently returning veterans with and without combat-related PTSD. A genome-wide significant single nucleotide polymorphism (SNP), rs717947, at chromosome 4p15 (N = 147, β = 31.34, P = 1.28 × 10(-8) ) was found to associate with the gold-standard diagnostic measure for PTSD (the Clinician Administered PTSD Scale). We conducted replication and follow-up studies in an external sample, a larger urban community cohort (Grady Trauma Project, GTP, N = 2006), to determine the robustness and putative functionality of this risk variant. In the GTP replication sample, SNP rs717947 associated with PTSD diagnosis in females (N = 2006, P = 0.005), but not males. SNP rs717947 was also found to be a methylation quantitative trait locus (meQTL) in the GTP replication sample (N = 157, P = 0.002). Further, the risk allele of rs717947 was associated with decreased medial and dorsolateral cortical activation to fearful faces (N = 53, P < 0.05) in the GTP replication sample. These data identify a genome-wide significant polymorphism conferring risk for PTSD, which was associated with differential epigenetic regulation and with differential cortical responses to fear in a replication sample. These results may provide new insight into understanding genetic and epigenetic regulation of PTSD and intermediate phenotypes that contribute to this disorder., (© 2015 Wiley Periodicals, Inc.)

DNA methylation has become increasingly recognized in the etiology of psychiatric disorders. Because brain tissue is not accessible in living humans, epigenetic studies are most often conducted in blood. Saliva is often collected for genotyping studies but is rarely used to examine DNA methylation because the proportion of epithelial cells and leukocytes varies extensively between individuals. The goal of this study was to evaluate whether saliva DNA is informative for studies of psychiatric disorders. DNA methylation (HumanMethylation450 BeadChip) was assessed in saliva and blood samples from 64 adult African Americans. Analyses were conducted using linear regression adjusted for appropriate covariates, including estimated cellular proportions. DNA methylation from brain tissues (cerebellum, frontal cortex, entorhinal cortex, and superior temporal gyrus) was obtained from a publically available dataset. Saliva and blood methylation was clearly distinguishable though there was positive correlation overall. There was little correlation in CpG sites within relevant candidate genes. Correlated CpG sites were more likely to occur in areas of low CpG density (i.e., CpG shores and open seas). There was more variability in CpG sites from saliva than blood, which may reflect its heterogeneity. Finally, DNA methylation in saliva appeared more similar to patterns from each of the brain regions examined overall than methylation in blood. Thus, this study provides a framework for using DNA methylation from saliva and suggests that DNA methylation of saliva may offer distinct opportunities for epidemiological and longitudinal studies of psychiatric traits., (© 2014 Wiley Periodicals, Inc.)

Epidemiological studies have recognized a genetic diathesis for suicidal behavior, which is independent of other psychiatric disorders. Genome-wide association studies (GWAS) on suicide attempt (SA) and ideation have failed to identify specific genetic variants. Here, we conduct further GWAS and for the first time, use polygenic score analysis in cohorts of patients with mood disorders, to test for common genetic variants for mood disorders and suicide phenotypes. Genome-wide studies for SA were conducted in the RADIANT and GSK-Munich recurrent depression samples and London Bipolar Affective Disorder Case-Control Study (BACCs) then meta-analysis was performed. A GWAS on suicidal ideation during antidepressant treatment had previously been conducted in the Genome Based Therapeutic Drugs for Depression (GENDEP) study. We derived polygenic scores from each sample and tested their ability to predict SA in the mood disorder cohorts or ideation status in the GENDEP study. Polygenic scores for major depressive disorder, bipolar disorder and schizophrenia from the Psychiatric Genomics Consortium were used to investigate pleiotropy between psychiatric disorders and suicide phenotypes. No significant evidence for association was detected at any SNP in GWAS or meta-analysis. Polygenic scores for major depressive disorder significantly predicted suicidal ideation in the GENDEP pharmacogenetics study and also predicted SA in a combined validation dataset. Polygenic scores for SA showed no predictive ability for suicidal ideation. Polygenic score analysis suggests pleiotropy between psychiatric disorders and suicidal ideation whereas the tendency to act on such thoughts may have a partially independent genetic diathesis., (© 2014 Wiley Periodicals, Inc.)

A non-synonymous, single nucleotide polymorphism (SNP) in the gene coding for steroid 5-α-reductase type 2 (SRD5A2) is associated with reduced conversion of testosterone to dihydrotestosterone (DHT). Because SRD5A2 participates in the regulation of testosterone and cortisol metabolism, hormones shown to be dysregulated in patients with PTSD, we examined whether the V89L variant (rs523349) influences risk for post-traumatic stress disorder (PTSD). Study participants (N = 1,443) were traumatized African-American patients of low socioeconomic status with high rates of lifetime trauma exposure recruited from the primary care clinics of a large, urban hospital. PTSD symptoms were measured with the post-traumatic stress symptom scale (PSS). Subjects were genotyped for the V89L variant (rs523349) of SRD5A2. We initially found a significant sex-dependent effect of genotype in male but not female subjects on symptoms. Associations with PTSD symptoms were confirmed using a separate internal replication sample with identical methods of data analysis, followed by pooled analysis of the combined samples (N = 1,443, sex × genotype interaction P < 0.002; males: n = 536, P < 0.001). These data support the hypothesis that functional variation within SRD5A2 influences, in a sex-specific way, the severity of post-traumatic stress symptoms and risk for diagnosis of PTSD., (Copyright © 2013 Wiley Periodicals, Inc.)

Genome-wide association studies have identified common variants associated with common diseases. Most variants, however, explain only a small proportion of the estimated heritability, suggesting that rare variants might contribute to a larger extent to common diseases than assumed to date. Here, we use next-generation sequencing to test whether such variants contribute to the risk for anxiety disorders by re-sequencing 40 kb including all exons of the TMEM132D locus which we have previously shown to be associated with panic disorder and anxiety severity measures. DNA from 300 patients suffering from anxiety disorders, mostly panic disorder (84.7%), and 300 healthy controls was screened for the presence of genetic variants using next-generation re-sequencing in a pooled approach. Results were verified by individual re-genotyping. We identified 371 variants of which 247 had not been reported before, including 15 novel non-synonymous variants. The majority, 76% of these variants had a minor allele frequency less than 5%. While we did not identify additional common variants in TMEM132D associated with panic disorders, we observed an overrepresentation of presumably functional coding variants in healthy controls as compared to cases as well as a higher rate of private coding variants in cases, with one non-synonymous coding variant present in four patients but not in any of the matched controls nor in over 5,500 individuals of different ethnic origins from publicly available re-sequencing datasets. Our data suggest that not only common but also putatively functional and/or rare variants within TMEM132D might contribute to the risk to develop anxiety disorders., (Copyright © 2012 Wiley Periodicals, Inc.)

Panic disorder (PD) is a common mental disorder, ranking highest among the anxiety disorders in terms of disease burden. The pathogenesis of PD is multifactorial with significant heritability, however only a few convincing risk genes have been reported thus far. One of the most promising candidates is the gene encoding monoamine oxidase A (MAOA), due to its key role in monoaminergic neurotransmission, established validity of animal models, and the efficacy of MAO inhibitors in the treatment of PD. A promoter repeat polymorphism in MAOA (MAOA-uVNTR) impacts on gene expression; high-expression alleles have been reported to increase the risk for PD. To further scrutinize the role of this polymorphism, we performed a formal meta-analysis on MAOA-uVNTR and PD using original data from four published European (Estonian, German, Italian, and Polish) samples and genotypes from three hitherto unpublished German PD samples, resulting in the largest (n = 1,115 patients and n = 1,260 controls) genetic study on PD reported to date. In the unpublished samples, evidence for association of MAOA-uVNTR with PD was obtained in one of the three samples. Results of the meta-analysis revealed a significant and female-specific association when calculating an allelic model (OR = 1.23, P = 0.006). This sex-specific effect might be explained by a gene-dose effect causing higher MAOA expression in females. Taken together, our meta-analysis therefore argues that high-expression MAOA-uVNTR alleles significantly increase the risk towards PD in women. However, epigenetic mechanisms might obfuscate the genetic association, calling for ascertainment in larger samples as well as assessment of the MAOA promoter methylation status therein., (2012 Wiley Periodicals, Inc)

The monoamine neurotransmitter, serotonin, critically regulates the function of the cerebral cortex and is involved in psychiatric disorders. Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the synthesis of serotonin with the neuron-specific TPH2 isoform present exclusively in the brain and encoded by the TPH2 gene on chromosome 12q21. The haplotype structure of TPH2 was defined for 16 single-nucleotide polymorphisms (SNPs) in a healthy subject population and a haplotype block analysis confirmed the presence of a six SNP haplotype in a yin configuration that has previously been associated with risk for suicidality, depression, and anxiety disorders. Functional magnetic resonance imaging (fMRI) was used to assess the influence of TPH2 variation on brain function related to cognitive control using the Multi-Source Interference Task (MSIT). The MSIT-related blood oxygen level-dependent (BOLD) response was increased with increasing copies of the TPH2 yin haplotype for the dorsal anterior cingulate cortex (dACC), right inferior frontal cortex (IFC), and anterior striatum. A functional connectivity analysis further revealed that increasing numbers of the TPH2 yin haplotype was associated with diminished functional coupling between the dACC and the right IFC, precentral gyrus, parietal cortex and dlPFC. A moderation analysis indicated that the relationship between neural processing networks and cognitive control was significantly modulated by allelic variation for the TPH2 yin haplotype. These findings suggest that the association of risk for psychiatric disorders with a common TPH2 yin haplotype is related to the inefficient functional engagement of cortical areas involved in cognitive control and alterations in the mode of functional connectivity of dACC pathways., (2012 Wiley Periodicals, Inc)

Genome-wide studies in major depression have identified few replicated associations, potentially due to heterogeneity within the disorder. Several studies have suggested that age at onset (AAO) can distinguish sub-types of depression with specific heritable components. This paper investigates the role of AAO in the genetic susceptibility for depression using genome-wide association data on 2,746 cases and 1,594 screened controls from the RADIANT studies, with replication performed in 1,471 cases and 1,403 controls from two Munich studies. Three methods were used to analyze AAO: First a time-to-event analysis with controls censored, secondly comparing controls to case-subsets defined using AAO cut-offs, and lastly analyzing AAO as a quantitative trait. In the time-to-event analysis three SNPs reached suggestive significance (P < 5E-06), overlapping with the original case-control analysis of this study. In a case-control analysis using AAO thresholds, SNPs in 10 genomic regions showed suggestive association though again none reached genome-wide significance. Lastly, case-only analysis of AAO as a quantitative trait resulted in 5 SNPs reaching suggestive significance. Sex specific analysis was performed as a secondary analysis, yielding one SNP reaching genome-wide significance in early-onset males. No SNPs achieved significance in the replication study after correction for multiple testing. Analysis of AAO as a quantitative trait did suggest that, across all SNPs, common genetic variants explained a large proportion of the variance (51%, P = 0.04). This study provides the first focussed analysis of the genetic contribution to AAO in depression, and establishes a statistical framework that can be applied to a quantitative trait underlying any disorder., (2012 Wiley Periodicals, Inc)

The High-Throughput Disease-specific target Identification Program (HiTDIP) aimed to study case-control association samples for 18 common diseases. Here we present the results of a follow-up case-control association study of HiTDIP in major depressive disorder (MDD). The HiTDIP in MDD was conducted in a sample of 974 cases of recurrent MDD of white German origin collected at the Max-Planck Institute (MP-GSK) and 968 ethnically matched controls screened for lifetime absence of depression. Six genes were identified as of interest for a follow-up, based on the strength of the association and based on the interest as potential candidate target for developing new treatment for depression: Solute Carrier Family 4 Member 10 (SLC4A10), Dipeptidyl Peptidase IV (DPP4), Dopamine Receptor D3 (DRD3), Zinc Finger Protein 80 (ZNF80), Nitric Oxide Synthase 2A (NOS2A) and Peroxisome Proliferator-Activated Receptor-Gamma, Coactivator 1, Alpha (PPARGC1A). Within the current study, we attempted to follow-up these findings in a sample from the UK, the Depression Case Control (DeCC) sample consisting of 1,196 cases and 842 screened controls, phenotyped using exactly the same methods as the MP-GSK sample. Performing Cochran-Mantel-Haenzel statistics to test for genotypic and/or allelic differences between the DeCC and MP-GSK samples, we found no significant differences, thus being able to combine the two samples for association testing. In the combined sample of 2,170 MDD cases and 1,810 controls, there were positive findings in the Nitric Oxide Synthase 2A (NOS2A) gene both using single SNP analysis and haplotype analysis., (Copyright © 2011 Wiley-Liss, Inc.)

Gene x environment (G x E) interactions mediating depressive symptoms have been separately identified in the stress-sensitive serotonergic (5-HTTLPR) and corticotropin-releasing hormone (CRHR1) systems. Our objective was to examine whether the effects of child abuse are moderated by gene x gene (G x G) interactions between CRHR1 and 5-HTTLPR polymorphisms. We used an association study examining G x G x E interactions of CRHR1 and 5-HTTLPR polymorphisms and measures of child abuse on adult depressive symptomatology. The participant population (N = 1,392) was African-American, of low socioeconomic status (60% with <$1,000/month family income), and with high rates of childhood and lifetime trauma. Depressive symptoms were measured with Beck Depression Inventory (BDI) and history of Major Depression by Structure Clinical Interview based on DSM-IV (SCID). We first replicated an interaction of child abuse and 5-HTTLPR on lifetime SCID diagnosis of major depression in a subsample (N = 236) of the study population-the largest African-American 5-HTTLPR cohort reported to date. We then extended our previously reported interaction with both a CRHR1 SNP (rs110402) and TCA haplotype interacting with child abuse to predict current symptoms (N = 1,059; P = 0.0089). We found that the 5-HTTLPR S allele interacted with CRHR1 haplotypes and child abuse to predict current depressive symptoms (N = 856, P = 0.016). These data suggest that G x E interactions predictive of depressive symptoms may be differentially sensitive to levels of childhood trauma, and the effects of child abuse are moderated by genetic variation at both the CRHR1 and 5-HTTLPR loci and by their G x G interaction.

Glutamate decarboxylase (GAD) is the rate limiting enzyme for conversion of glutamic acid to gamma-aminobutyric acid (GABA). The GAD 65 kDa isoform is encoded by the gene GAD2 and is mainly expressed in synaptic terminals. It serves as an apoenzyme, which shows enhanced availability in situations of stress, responding to short-term demands for GABA. We analyzed 18 single nucleotide polymorphisms (SNPs) in the GAD2-gene region for associations with psychiatric diagnosis and behavioral inhibition (BI) derived from the personality traits neuroticism and extraversion as defined by the Eysenck Personality Questionaire (EPQ). A total of 268 patients with anxiety disorder (AD), 541 with unipolar depression (MD), and 541 healthy controls were included. We observe associations for five tag-SNPs with BI in the AD- and control samples as well as two additional case-control associations in the MD-sample. The associated SNPs lie within a 16KB linkage disequilibrium-block, including putative 5' GAD2-promoter-elements as well as the 3' end of the gene MYO3A. Using open access mRNA-expression data, we could show that BI-associated SNPs appear to be associated with differences in MYO3A- but not GAD2 lymphoblastoid-mRNA expression levels. These results support earlier studies that suggest associations of polymorphisms within the GAD2 locus with anxiety and affective disorders. However, data from expression studies imply that these polymorphisms could tag functional effects on the neighboring gene MYO3A, which is also expressed in the brain, including the cingulate cortex and the amygdala., (2009 Wiley-Liss, Inc.)

Accumulating evidence from animal studies suggests that the corticotropin releasing hormone (CRH) and arginine vasopressin (AVP) neuropeptide systems, contribute to anxiety behavior. To investigate whether polymorphisms in the genes regulating these two systems may alter susceptibility to anxiety disorders in humans, we genotyped 71 single nucleotide polymorphisms (SNPs) in CRH, CRHR1, CRHR2, AVP, AVPR1A, AVPR1B in a German sample from Munich with patients suffering from panic disorder and matched healthy controls (n = 186/n = 299). Significant associations were then replicated in a second German sample with 173 patients with panic disorder and 495 controls. In both samples separately and the combined sample, SNPs within CHRH1 and AVPR1B were nominally associated with panic disorder. We then tested two locus multiplicative and interaction effects of polymorphisms of these two genes on panic disorder. Fifteen SNP pairs showed significant multiplicative effects in both samples. The SNP pair with the most significant association in the combined sample (P = 0.00057), which withstood correction for multiple testing, was rs878886 in CRHR1 and rs28632197 in AVPR1B. Both SNPs are of potential functional relevance as rs878886 is located in the 3' untranslated region of the CRHR1 and rs28632197 leads to an arginine to histidine amino acid exchange at position 364 of AVPR1B which is located in the intracellular C-terminal domain of the receptor. These data suggest that polymorphisms in the AVPR1B and the CRHR1 genes alter the susceptibility to panic disorder.

Anxiety disorders and specifically panic disorder (PD) are caused by complex interactions of environmental and genetic factors. The latter comprise many different genes, from which those involved in serotonergic neurotransmission have received particular attention. Here we report the results from an association candidate-gene approach, where we analyzed 15 single nucleotide polymorphisms (SNPs) within the gene coding for the serotonin-receptor 2A (HTR2A) in patients suffering from PD and a control sample. We found that the SNP rs2296972 shows an association between the number of T-alleles and severity of symptoms in PD. By performing tests according to the Fisher product method (FPM), an association between HTR2A and the personality trait reward dependence could be shown. Most pronounced effects were observable for the SNPs rs2770304, rs6313, and rs6311. Furthermore, the polymorphisms rs3742278, rs2296972, and rs2770292 form a haplotype, which may be associated with higher susceptibility for PD. These results further underline a possible important role of genetic variations within the system controlling serotonergic neurotransmission for the development and course of disease in PD., ((c) 2007 Wiley-Liss, Inc.)