Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Mais filtros

Base de dados
Intervalo de ano de publicação
Mol Psychiatry ; 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31591465


Schizophrenia is a common, chronic and debilitating neuropsychiatric syndrome affecting tens of millions of individuals worldwide. While rare genetic variants play a role in the etiology of schizophrenia, most of the currently explained liability is within common variation, suggesting that variation predating the human diaspora out of Africa harbors a large fraction of the common variant attributable heritability. However, common variant association studies in schizophrenia have concentrated mainly on cohorts of European descent. We describe genome-wide association studies of 6152 cases and 3918 controls of admixed African ancestry, and of 1234 cases and 3090 controls of Latino ancestry, representing the largest such study in these populations to date. Combining results from the samples with African ancestry with summary statistics from the Psychiatric Genomics Consortium (PGC) study of schizophrenia yielded seven newly genome-wide significant loci, and we identified an additional eight loci by incorporating the results from samples with Latino ancestry. Leveraging population differences in patterns of linkage disequilibrium, we achieve improved fine-mapping resolution at 22 previously reported and 4 newly significant loci. Polygenic risk score profiling revealed improved prediction based on trans-ancestry meta-analysis results for admixed African (Nagelkerke's R2 = 0.032; liability R2 = 0.017; P < 10-52), Latino (Nagelkerke's R2 = 0.089; liability R2 = 0.021; P < 10-58), and European individuals (Nagelkerke's R2 = 0.089; liability R2 = 0.037; P < 10-113), further highlighting the advantages of incorporating data from diverse human populations.

Nat Genet ; 51(3): 431-444, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30804558


Autism spectrum disorder (ASD) is a highly heritable and heterogeneous group of neurodevelopmental phenotypes diagnosed in more than 1% of children. Common genetic variants contribute substantially to ASD susceptibility, but to date no individual variants have been robustly associated with ASD. With a marked sample-size increase from a unique Danish population resource, we report a genome-wide association meta-analysis of 18,381 individuals with ASD and 27,969 controls that identified five genome-wide-significant loci. Leveraging GWAS results from three phenotypes with significantly overlapping genetic architectures (schizophrenia, major depression, and educational attainment), we identified seven additional loci shared with other traits at equally strict significance levels. Dissecting the polygenic architecture, we found both quantitative and qualitative polygenic heterogeneity across ASD subtypes. These results highlight biological insights, particularly relating to neuronal function and corticogenesis, and establish that GWAS performed at scale will be much more productive in the near term in ASD.

Transtorno do Espectro Autista/genética , Predisposição Genética para Doença/genética , Polimorfismo de Nucleotídeo Único/genética , Adolescente , Estudos de Casos e Controles , Criança , Pré-Escolar , Dinamarca , Feminino , Estudo de Associação Genômica Ampla/métodos , Humanos , Masculino , Herança Multifatorial/genética , Fenótipo , Fatores de Risco
Infect Immun ; 82(3): 1234-42, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24379282


Despite the importance of Staphylococcus aureus as a common invasive bacterial pathogen, the humoral response to infection remains inadequately defined, particularly in children. The purpose of this study was to assess the humoral response to extracellular staphylococcal virulence factors, including the bicomponent leukotoxins, which are critical for the cytotoxicity of S. aureus toward human neutrophils. Children with culture-proven S. aureus infection were prospectively enrolled and stratified by disease type. Fifty-three children were enrolled in the study, of which 90% had invasive disease. Serum samples were obtained during the acute (within 48 h) and convalescent (4 to 6 weeks postinfection) phases, at which point both IgG titers against S. aureus exotoxins were determined, and the functionality of the generated antibodies was evaluated. Molecular characterization of clinical isolates was also performed. We observed a marked rise in antibody titer from acute-phase to convalescent-phase sera for LukAB, the most recently described S. aureus bicomponent leukotoxin. LukAB production by the isolates was strongly correlated with cytotoxicity in vitro, and sera containing anti-LukAB antibodies potently neutralized cytotoxicity. Antibodies to S. aureus antigens were detectable in healthy pediatric controls but at much lower titers than in sera from infected subjects. The discovery of a high-titer, neutralizing antibody response to LukAB during invasive infections suggests that this toxin is produced in vivo and that it elicits a functional humoral response.

Anticorpos Neutralizantes/imunologia , Proteínas de Bactérias/imunologia , Citotoxinas/imunologia , Leucocidinas/imunologia , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/imunologia , Criança , Feminino , Humanos , Masculino , Fatores de Virulência/imunologia
Mol Microbiol ; 79(3): 814-25, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21255120


Staphylococcus aureus is an important pathogen that continues to be a significant global health threat because of the prevalence of methicillin-resistant S. aureus strains (MRSA). The pathogenesis of this organism is partly attributed to the production of a large repertoire of cytotoxins that target and kill innate immune cells, which provide the first line of defence against S. aureus infection. Here we demonstrate that leukocidin A/B (LukAB) is required and sufficient for the ability of S. aureus, including MRSA, to kill human neutrophils, macrophages and dendritic cells. LukAB targets the plasma membrane of host cells resulting in cellular swelling and subsequent cell death. We found that S. aureus lacking lukAB are severely impaired in their ability to kill phagocytes during bacteria-phagocyte interaction, which in turn renders the lukAB-negative staphylococci more susceptible to killing by neutrophils. Notably, we show that lukAB is expressed in vivo within abscesses in a murine infection model and that it contributes significantly to pathogenesis of MRSA in an animal host. Collectively, these results extend our understanding of how S. aureus avoids phagocyte-mediated clearance, and underscore LukAB as an important factor that contributes to staphylococcal pathogenesis.

Citotoxinas/metabolismo , Staphylococcus aureus/patogenicidade , Morte Celular , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Citoproteção , Células HL-60 , Humanos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Fagócitos/citologia , Fagócitos/metabolismo , Fagócitos/ultraestrutura