Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors

Background Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. Methods We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors. Results Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged. Conclusions Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.Peer reviewe

Genomic investigations of unexplained acute hepatitis in children

Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children

Psychometric qualities of the Dutch version of the Pediatric Inventory for Parents (PIP): a multi-center study

Objectives: Diagnosis and treatment of childhood cancer are continuous stressors in the lives of the entire family involved. Disease-related tools for the assessment of parental stress and adaptation are scarce. For that reason, the Pediatric Inventory for Parents (PIP), a disease-related measure, was translated into Dutch and its psychometric qualities were determined to prove its value. Methods: The PIP and three other measures (State-Trait Anxiety Inventory, General Health Questionnaire and Parenting Stress Index, Short Form) were administered to 174 parents of 107 children diagnosed with cancer in three university medical centers in the Netherlands. Results: Internal consistency (Crohnbach's alpha = 0.94 and 0.95) and test-retest reliability (Pearson's r between 0.67 and 0.87) of the Dutch PIP total scales are satisfactory. Validity was illustrated by a high correlation between PIP-scores and anxiety and general stress. Confirmatory factor analysis showed acceptable fit to the data for the original four-factor and the one-factor models; the four-factor model showed slightly better fit. Conclusion: The PIP can be used in clinical practice to assess disease-related parental stress. Further psychometric testing is highly recommended. Copyright (C) 2009 John Wiley & Sons, Ltd

Multilaboratory Comparison of Streptococcus pneumoniae Opsonophagocytic Killing Assays and Their Level of Agreement for the Determination of Functional Antibody Activity in Human Reference Sera ▿ †

Antibody-mediated killing of Streptococcus pneumoniae (pneumococcus) by phagocytes is an important mechanism of protection of the human host against pneumococcal infections. Measurement of opsonophagocytic antibodies by use of a standardized opsonophagocytic assay (OPA) is important for the evaluation of candidate vaccines and required for the licensure of new pneumococcal conjugate vaccine formulations. We assessed agreement among six laboratories that used their own optimized OPAs on a panel of 16 human reference sera for 13 pneumococcal serotypes. Consensus titers, estimated using an analysis-of-variance (ANOVA) mixed-effects model, provided a common reference for assessing agreement among these laboratories. Agreement was evaluated in terms of assay accuracy, reproducibility, repeatability, precision, and bias. We also reviewed four acceptance criterion intervals for assessing the comparability of protocols when assaying the same reference sera. The precision, accuracy, and concordance results among laboratories and the consensus titers revealed acceptable agreement. The results of this study indicate that the bioassays evaluated in this study are robust, and the resultant OPA values are reproducible for the determination of functional antibody titers specific to 13 pneumococcal serotypes when performed by laboratories using highly standardized but not identical assays. The statistical methodologies employed in this study may serve as a template for evaluating future multilaboratory studies