42 research outputs found
Joint analysis of psychiatric disorders increases accuracy of risk prediction for schizophrenia, bipolar disorder, and major depressive disorder
No full textGenetic risk prediction has several potential applications in medical research and clinical practice and could be used, for example, to stratify a heterogeneous population of patients by their predicted genetic risk. However, for polygenic traits, such as psychiatric disorders, the accuracy of risk prediction is low. Here we use a multivariate linear mixed model and apply multi-trait genomic best linear unbiased prediction for genetic risk prediction. This method exploits correlations between disorders and simultaneously evaluates individual risk for each disorder. We show that the multivariate approach significantly increases the prediction accuracy for schizophrenia, bipolar disorder, and major depressive disorder in the discovery as well as in independent validation datasets. By grouping SNPs based on genome annotation and fitting multiple random effects, we show that the prediction accuracy could be further improved. The gain in prediction accuracy of the multivariate approach is equivalent to an increase in sample size of 34% for schizophrenia, 68% for bipolar disorder, and 76% for major depressive disorders using single trait models. Because our approach can be readily applied to any number of GWAS datasets of correlated traits, it is a flexible and powerful tool to maximize prediction accuracy. With current sample size, risk predictors are not useful in a clinical setting but already are a valuable research tool, for example in experimental designs comparing cases with high and low polygenic risk.Peer reviewe
Genomewide linkage scan of schizophrenia in a large multicenter pedigree sample using single nucleotide polymorphisms
No full textA genomewide linkage scan was carried out in eight clinical samples of informative schizophrenia families. After all quality control checks, the analysis of 707 European-ancestry families included 1615 affected and 1602 unaffected genotyped individuals, and the analysis of all 807 families included 1900 affected and 1839 unaffected individuals. Multipoint linkage analysis with correction for marker-marker linkage disequilibrium was carried out with 5861 single nucleotide polymorphisms (SNPs; Illumina version 4.0 linkage map). Suggestive evidence for linkage ( European families) was observed on chromosomes 8p21, 8q24.1, 9q34 and 12q24.1 in nonparametric and/or parametric analyses. In a logistic regression allele-sharing analysis of linkage allowing for intersite heterogeneity, genomewide significant evidence for linkage was observed on chromosome 10p12. Significant heterogeneity was also observed on chromosome 22q11.1. Evidence for linkage across family sets and analyses was most consistent on chromosome 8p21, with a one-LOD support interval that does not include the candidate gene NRG1, suggesting that one or more other susceptibility loci might exist in the region. In this era of genomewide association and deep resequencing studies, consensus linkage regions deserve continued attention, given that linkage signals can be produced by many types of genomic variation, including any combination of multiple common or rare SNPs or copy number variants in a region. Molecular Psychiatry (2009) 14, 786-795; doi:10.1038/mp.2009.11; published online 17 February 2009</p
) sequence variation in susceptibility to major depression
No full textRecent evidence suggests a potential role for the p11 gene in conferring risk to depressive disorders. p11 has been shown to influence serotonergic transmission, and its expression was found to be reduced in a mouse model of depression, as well as in post-mortem brain tissue from major depressive disorder (MDD) cases. In the present study, we tested for rare variants in p11 by resequencing promoter, exonic and flanking intronic regions in 176 MDD cases and 176 matched controls. We also assessed common variation by genotyping eight single nucleotide polymorphisms (SNPs), seven tag SNPs and one found through resequencing, in 641 cases and 650 controls. Resequencing revealed nine novel rare variants, including a missense mutation (Asp60Glu) observed in one case and one control, and four variants that occurred only in cases and not controls. The number of rare variants in cases did not exceed that expected by chance for the length of sequence analyzed, and also was not significantly greater than that observed in controls. Resequencing also identified two known SNPs, one (rs4845720) of which was significantly more frequent in cases than controls in the resequenced sample (3.1% vs. 0.9%, P = 0.03), though not in the larger sample (3% vs. 2%, P = 0.15). None of the tag SNPs showed any evidence of association. Our results do not support a major role for either common or rare p11 SNPs with MDD. Several limitations of the study are discussed
Linkage disequilibrium mapping of a chromosome 15q25-26 major depression linkage region and sequencing of NTRK3
No full textBACKGROUND:
We reported genome-wide significant linkage on chromosome 15q25.3-26.2 to recurrent early-onset major depressive disorder (MDD-RE). Here we present initial linkage-disequilibrium (LD) fine mapping of this signal and sequence analysis of NTRK3 (neurotrophic receptor kinase-3), a biologically plausible candidate gene.
METHODS:
In 300 pedigrees informative for family-based association, 1195 individuals were genotyped for 795 single nucleotide polymorphism (SNPs). We resequenced 21 exons and 7 highly conserved NTRK3 regions in 176 MDD-RE cases to test for an excess of rare functional variants and, 176 controls for case-control analysis of common variants.
RESULTS:
LD mapping showed nominally significant association in NTRK3, FLJ12484, RHCG, DKFZp547K1113, VPS33B, SV2B, SLCO3A1, RGMA, and MCTP2 with MDD-RE. In NTRK3, five SNPs had nominally significant p values (.035-.001). Sequence analysis revealed 35 variants (24 novel, including 9 rare exonic); the number of rare variants did not exceed chance expectation. Case-control analysis of 13 common variants showed modest nominal association of MDD-RE with rs4887379, rs6496463, and rs3825882 (p = .008, .048, and .034), which were in partial LD with four of five associated SNPs from the family-based experiment.
CONCLUSIONS:
Common variants in NTRK3 or other genes identified might play a role in MDD-RE. However, much larger studies are required for full evaluation of this region
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A Comparison Of The Familiality Of Chronic Depression In Recurrent Early-onset Depression Pedigrees Using Different Definitions Of Chronicity
No full textBackground: The study of chronicity in the course of major depression has been complicated by varying definitions of this illness feature. Because familial clustering is one component of diagnostic validity we compared family clustering of chronicity as defined in the DSM-IV to that of chronicity determined by an assessment of lifetime course of depressive illness
Needles and the damage done: reasons for admission and financial costs associated with injecting drug use in a Central London Teaching Hospital.
No full textOBJECTIVES: To establish the clinical reasons for inpatient admissions among injecting drug users. To determine the frequency of behavioural issues during their care and to estimate the financial implications of injecting drug use to the health service. METHODS: Retrospective cohort study at University College London Hospital. Clinical, laboratory and financial data were extracted from case notes and electronic records. The cost of each admission was compared to the income received for the period of care. RESULTS: 124 injecting drug users required 191 admissions between 2005 and 2009. Skin and soft tissue infections (58%) and pneumonia (18%) were the commonest reasons for admission. Bacteraemia at admission was often not accompanied by an inflammatory response. Exposure to HIV (4%), hepatitis B (49%) and C (84%) was common. Drug misuse (16%) during admission was frequent. The cost to the NHS of treating soft tissue infections in drug users was approximately £77 million per annum. After a median follow-up of 40 months, 10 patients (8%) had died. All deaths were attributable to drug use. CONCLUSIONS: Bacterial and viral infections are largely responsible for the significant mortality and morbidity of injecting drug users presenting to secondary care. The financial burden to the NHS is substantial
Genetics of recurrent early‐onset depression (GenRED): Design and preliminary clinical characteristics of a repository sample for genetic linkage studies
No full textThis is an initial report on a six-site collaborative project, Genetics of Recurrent Early-Onset Depression (GenRED). This is a study of a large sample of families with recurrent major depressive disorder (DSM-IV) beginning by the age 30 in probands or 40 in relatives. Evidence suggests that early onset and recurrence of depressive episodes predict substantially increased risk of depression in first-degree relatives compared with the general population, suggesting that susceptibility genes might be mapped with this phenotype. The projected sample of 800-1,000 affected sibling pairs (ASPs) and other relatives will be studied using genome scan methods. Biological materials and blinded clinical data will be made available through the NIMH cell repository program. The sample should have good-to-excellent power to detect a locus associated with a 24% or greater population-wide increase in risk to siblings. We describe 838 affected individuals from the first 305 families containing 434 independent ASPs, or 613 ASPs counting all possible pairs. The mean age at the onset was 18.5 years, with a mean of 7.3 episodes and longest episode of 655 days. Almost all subjects had experienced at least 4 weeks of depression with five or more additional symptom criteria. Frequencies of symptoms and psychiatric and medical comorbid are provided. Substance use was more common in males, and panic disorder in females. Within pairs of affected siblings, correlations were significant for age at onset, substance abuse/dependence, panic disorder, obsessive-compulsive disorder and nicotine initiation and persistence. We replicated previously reported associations among comorbid panic disorder and social phobia, chronicity of depression and suicidal behavior. This suggests comparability of our cases to those in earlier large family studies. This dataset should prove useful for genetic studies of a highly familial form of major depressive disorder
Stratified medicine for mental disorders
No full textThere is recognition that biomedical research into the causes of mental disorders and their treatment needs to adopt new approaches to research. Novel biomedical techniques have advanced our understanding of how the brain develops and is shaped by behaviour and environment. This has led to the advent of stratified medicine, which translates advances in basic research by targeting aetiological mechanisms underlying mental disorder. The resulting increase in diagnostic precision and targeted treatments may provide a window of opportunity to address the large public health burden, and individual suffering associated with mental disorders. While mental health and mental disorders have significant representation in the "health, demographic change and wellbeing" challenge identified in Horizon 2020, the framework programme for research and innovation of the European Commission (2014-2020), and in national funding agencies, clear advice on a potential strategy for mental health research investment is needed. The development of such a strategy is supported by the EC-funded "Roadmap for Mental Health Research" (ROAMER) which will provide recommendations for a European mental health research strategy integrating the areas of biomedicine, psychology, public health well being, research integration and structuring, and stakeholder participation. Leading experts on biomedical research on mental disorders have provided an assessment of the state of the art in core psychopathological domains, including arousal and stress regulation, affect, cognition social processes, comorbidity and pharmacotherapy. They have identified major advances and promising methods and pointed out gaps to be addressed in order to achieve the promise of a stratified medicine for mental disorders
Mood Disorder Susceptibility Gene CACNA1C Modifies Mood-Related Behaviors in Mice and Interacts with Sex to Influence Behavior in Mice and Diagnosis in Humans
No full textBackground: Recent genome-wide association studies have associated polymorphisms in the gene CACNA1C, which codes for Cav1.2, with a bipolar disorder and depression diagnosis. Methods: The behaviors of wild-type and Cacna1c heterozygous mice of both sexes were evaluated in a number of tests. Based upon sex differences in our mouse data, we assessed a gene ϫ sex interaction for diagnosis of mood disorders in human subjects. Data from the National Institute of Mental Health Genetics Initiative Bipolar Disorder Consortium and the Genetics of Recurrent Early-Onset Major Depression Consortium were examined using a combined dataset that included 2021 mood disorder cases (1223 female cases) and 1840 control subjects (837 female subjects). Results: In both male and female mice, Cacna1c haploinsufficiency was associated with lower exploratory behavior, decreased response to amphetamine, and antidepressant-like behavior in the forced swim and tail suspension tests. Female, but not male, heterozygous mice displayed decreased risk-taking behavior or increased anxiety in multiple tests, greater attenuation of amphetamine-induced hyperlocomotion, decreased development of learned helplessness, and a decreased acoustic startle response, indicating a sex-specific role of Cacna1c. In humans, sex-specific genetic association was seen for two intronic single nucleotide polymorphisms, rs2370419 and rs2470411, in CACNA1C, with effects in female subjects (odds ratio ϭ 1.64, 1.32) but not in male subjects (odds ratio ϭ .82, .86). The interactions by sex were significant after correction for testing 190 single nucleotide polymorphisms (p ϭ 1.4 ϫ 10Ϫ4, 2.1 ϫ 10Ϫ4; pcorrected ϭ .03, .04) and were consistent across two large datasets. Conclusions: Our preclinical results support a role for CACNA1C in mood disorder pathophysiology, and the combination of human genetic and preclinical data support an interaction between sex and genotype
A mega-analysis of genome-wide association studies for major depressive disorder
No full textPrior genome-wide association studies (GWAS) of major depressive disorder (MDD) have met with limited success. We sought to increase statistical power to detect disease loci by conducting a GWAS mega-analysis for MDD. In the MDD discovery phase, we analyzed more than 1.2 million autosomal and X chromosome single-nucleotide polymorphisms (SNPs) in 18 759 independent and unrelated subjects of recent European ancestry (9240 MDD cases and 9519 controls). In the MDD replication phase, we evaluated 554 SNPs in independent samples (6783 MDD cases and 50 695 controls). We also conducted a cross-disorder meta-analysis using 819 autosomal SNPs with P<0.0001 for either MDD or the Psychiatric GWAS Consortium bipolar disorder (BIP) mega-analysis (9238 MDD cases/8039 controls and 6998 BIP cases/7775 controls). No SNPs achieved genome-wide significance in the MDD discovery phase, the MDD replication phase or in pre-planned secondary analyses (by sex, recurrent MDD, recurrent early-onset MDD, age of onset, pre-pubertal onset MDD or typical-like MDD from a latent class analyses of the MDD criteria). In the MDD-bipolar cross-disorder analysis, 15 SNPs exceeded genome-wide significance (P<5x10(-8)), and all were in a 248 kb interval of high LD on 3p21.1 (chr3:52 425 083-53 822 102, minimum P=5.9x10(-9) at rs2535629). Although this is the largest genome-wide analysis of MDD yet conducted, its high prevalence means that the sample is still underpowered to detect genetic effects typical for complex traits. Therefore, we were unable to identify robust and replicable findings. We discuss what this means for genetic research for MDD. The 3p21.1 MDD-BIP finding should be interpreted with caution as the most significant SNP did not replicate in MDD samples, and genotyping in independent samples will be needed to resolve its status. Molecular Psychiatry (2013) 18, 497-511; doi:10.1038/mp.2012.21; published online 3 April 2012
