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1.
Nat Genet ; 51(3): 431-444, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30804558

RESUMO

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.


Assuntos
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
2.
Proc Natl Acad Sci U S A ; 116(2): 466-471, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30587579

RESUMO

Motivated by the dynamics of development, in which cells of recognizable types, or pure cell types, transition into other types over time, we propose a method of semisoft clustering that can classify both pure and intermediate cell types from data on gene expression from individual cells. Called semisoft clustering with pure cells (SOUP), this algorithm reveals the clustering structure for both pure cells and transitional cells with soft memberships. SOUP involves a two-step process: Identify the set of pure cells and then estimate a membership matrix. To find pure cells, SOUP uses the special block structure in the expression similarity matrix. Once pure cells are identified, they provide the key information from which the membership matrix can be computed. By modeling cells as a continuous mixture of K discrete types we obtain more parsimonious results than obtained with standard clustering algorithms. Moreover, using soft membership estimates of cell type cluster centers leads to better estimates of developmental trajectories. The strong performance of SOUP is documented via simulation studies, which show its robustness to violations of modeling assumptions. The advantages of SOUP are illustrated by analyses of two independent datasets of gene expression from a large number of cells from fetal brain.


Assuntos
Algoritmos , Diferenciação Celular , Proliferação de Células , Processamento Eletrônico de Dados , Modelos Biológicos , Animais , Humanos
3.
Science ; 362(6420)2018 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-30545852

RESUMO

Whole-genome sequencing (WGS) has facilitated the first genome-wide evaluations of the contribution of de novo noncoding mutations to complex disorders. Using WGS, we identified 255,106 de novo mutations among sample genomes from members of 1902 quartet families in which one child, but not a sibling or their parents, was affected by autism spectrum disorder (ASD). In contrast to coding mutations, no noncoding functional annotation category, analyzed in isolation, was significantly associated with ASD. Casting noncoding variation in the context of a de novo risk score across multiple annotation categories, however, did demonstrate association with mutations localized to promoter regions. We found that the strongest driver of this promoter signal emanates from evolutionarily conserved transcription factor binding sites distal to the transcription start site. These data suggest that de novo mutations in promoter regions, characterized by evolutionary and functional signatures, contribute to ASD.


Assuntos
Transtorno do Espectro Autista/genética , Mutação , Regiões Promotoras Genéticas/genética , Sítios de Ligação/genética , Sequência Conservada , Análise Mutacional de DNA , Loci Gênicos , Variação Genética , Humanos , Linhagem , Risco , Fatores de Transcrição/metabolismo
4.
Nat Genet ; 50(7): 1032-1040, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29892012

RESUMO

Identifying disease-associated missense mutations remains a challenge, especially in large-scale sequencing studies. Here we establish an experimentally and computationally integrated approach to investigate the functional impact of missense mutations in the context of the human interactome network and test our approach by analyzing ~2,000 de novo missense mutations found in autism subjects and their unaffected siblings. Interaction-disrupting de novo missense mutations are more common in autism probands, principally affect hub proteins, and disrupt a significantly higher fraction of hub interactions than in unaffected siblings. Moreover, they tend to disrupt interactions involving genes previously implicated in autism, providing complementary evidence that strengthens previously identified associations and enhances the discovery of new ones. Importantly, by analyzing de novo missense mutation data from six disorders, we demonstrate that our interactome perturbation approach offers a generalizable framework for identifying and prioritizing missense mutations that contribute to the risk of human disease.

5.
Nat Genet ; 50(5): 727-736, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29700473

RESUMO

Genomic association studies of common or rare protein-coding variation have established robust statistical approaches to account for multiple testing. Here we present a comparable framework to evaluate rare and de novo noncoding single-nucleotide variants, insertion/deletions, and all classes of structural variation from whole-genome sequencing (WGS). Integrating genomic annotations at the level of nucleotides, genes, and regulatory regions, we define 51,801 annotation categories. Analyses of 519 autism spectrum disorder families did not identify association with any categories after correction for 4,123 effective tests. Without appropriate correction, biologically plausible associations are observed in both cases and controls. Despite excluding previously identified gene-disrupting mutations, coding regions still exhibited the strongest associations. Thus, in autism, the contribution of de novo noncoding variation is probably modest in comparison to that of de novo coding variants. Robust results from future WGS studies will require large cohorts and comprehensive analytical strategies that consider the substantial multiple-testing burden.

6.
Psychiatry Res ; 261: 148-153, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29306175

RESUMO

Several studies have indicated infectious and immune-related abnormalities in schizophrenia (Scz), including elevated serum C-reactive protein (CRP) - a well-known proxy for infections/immune abnormalities. A portion of the genetic risk for Scz can be estimated using the polygenic risk score (PGRS). It is not known whether there is an interaction in the risks traceable to CRP and PGRS. Patients with Scz and individuals without psychosis were evaluated systematically using DSM IV criteria (N=794, N=446, respectively). To estimate risk for Scz attributable to CRP and PGRS, serum from these participants was assayed for CRP levels using enzyme linked immunosorbent assays. PGRS was estimated from common DNA polymorphisms associated with Scz from genome wide association studies. CRP level and PGRS were not significantly correlated. Using a generalized linear logistic model, case/control status was evaluated in relation to the following predictors: CRP, PGRS, and demographic variables. CRP and PGRS were individually associated with case status; CRP: odds ratio (OR) 1.27, 95% confidence intervals (95% CI) 1.12, 1.43; p = 0.0001; PGRS: OR 1.66, 95% CI 1.47, 1.89; p = 1.28 ×10-15. There were no significant interactions between PGRS and CRP for predicting Scz versus control status.


Assuntos
Proteína C-Reativa/genética , Proteína C-Reativa/metabolismo , Predisposição Genética para Doença/genética , Herança Multifatorial/genética , Esquizofrenia/sangue , Esquizofrenia/genética , Adulto , Estudos de Casos e Controles , Feminino , Estudo de Associação Genômica Ampla , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos Psicóticos/sangue , Transtornos Psicóticos/diagnóstico , Transtornos Psicóticos/genética , Fatores de Risco , Esquizofrenia/diagnóstico
7.
Biol Psychiatry ; 83(7): 589-597, 2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29100626

RESUMO

BACKGROUND: Autism spectrum disorder (ASD) has both genetic and environmental origins, including potentially maternal effects. Maternal effects describe the association of one or more maternal phenotypes with liability to ASD in progeny that are independent of maternally transmitted risk alleles. While maternal effects could play an important role, consistent with association to maternal traits such as immune status, no study has estimated maternal, additive genetic, and environmental effects in ASD. METHODS: Using a population-based sample consisting of all children born in Sweden from 1998 to 2007 and their relatives, we fitted statistical models to family data to estimate the variance in ASD liability originating from maternal, additive genetic, and shared environmental effects. We calculated sibling and cousin family recurrence risk ratio as a direct measure of familial, genetic, and environmental risk factors and repeated the calculations on diagnostic subgroups, specifically autistic disorder (AD) and spectrum disorder (SD), which included Asperger's syndrome and/or pervasive developmental disorder not otherwise specified. RESULTS: The sample consisted of 776,212 children of whom 11,231 had a diagnosis of ASD: 4554 with AD, 6677 with SD. We found support for large additive genetic contribution to liability; heritability (95% confidence interval [CI]) was estimated to 84.8% (95% CI: 73.1-87.3) for ASD, 79.6% (95% CI: 61.2-85.1) for AD, and 76.4% (95% CI: 63.0-82.5) for SD. CONCLUSIONS: There was modest, if any, contribution of maternal effects to liability for ASD, including subtypes AD and SD, and there was no support for shared environmental effects. These results show liability to ASD arises largely from additive genetic variation.

8.
Psychiatr Genet ; 27(5): 169-177, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28570395

RESUMO

OBJECTIVES: Inbreeding increases the probability of homozygosity of deleterious alleles. Inbreeding and runs of homozygosity (ROH) are associated with an increased risk for disease phenotypes, including schizophrenia and other psychiatric disorders. The effects of inbreeding, ROH, homozygous deletions, and other copy number variations (CNVs) on risk for depression and suicide attempt (SA) were quantified in an Arab Bedouin Kindred. METHODS: We carried out genetic analyses of 439 individuals from an Arab kindred with high rates of depression and suicidal behavior. We obtained complete ascertainment of SAs and first-degree relatives of individuals who have attempted or died by suicide. RESULTS: We found extensive regions of ROH. On average, 5% of the genome is covered by ROH for these individuals, two-fold higher than ROH rates for individuals from populations of European ancestry. Inbreeding and total length of ROH were not associated with risk for depression or attempt. For CNVs, an increased number of duplications more than 500 kb was associated with an increased risk for attempt (odds ratio: 2.9; P=0.01; 95% confidence interval: 1.3-6.6). Although not significant after correction for multiple testing, the risk for SA appears to increase with copy number for a CNV on chromosome 9p24.1. This possibility is intriguing because the CNV covers GLDC, which encodes glycine dehydrogenase that binds to glycine, a co-agonist at N-methyl-D-aspartate glutamate receptors, and is involved in glutamatergic neurotransmission. CONCLUSION: Our findings add to the growing evidence of genetic risk factors that act pleiotropically to increase the risk for several neuropsychiatric disorders, including depression and SA, irrespective of ancestry.


Assuntos
Árabes/genética , Variações do Número de Cópias de DNA/genética , Depressão/genética , Grupos Étnicos/genética , Predisposição Genética para Doença , Ideação Suicida , Adolescente , Adulto , Consanguinidade , Feminino , Homozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Reprodutibilidade dos Testes , Fatores de Risco , Adulto Jovem
9.
Mol Neuropsychiatry ; 2(4): 173-184, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28277564

RESUMO

To localize genetic variation affecting risk for psychotic disorders in the population of Palau, we genotyped DNA samples from 203 Palauan individuals diagnosed with psychotic disorders, broadly defined, and 125 control subjects using a genome-wide single nucleotide polymorphism array. Palau has unique features advantageous for this study: due to its population history, Palauans are substantially interrelated; affected individuals often, but not always, cluster in families; and we have essentially complete ascertainment of affected individuals. To localize risk variants to genomic regions, we evaluated long-shared haplotypes, ≥10 Mb, identifying clusters of affected individuals who share such haplotypes. This extensive sharing, typically identical by descent, was significantly greater in cases than population controls, even after controlling for relatedness. Several regions of the genome exhibited substantial excess of shared haplotypes for affected individuals, including 3p21, 3p12, 4q28, and 5q23-q31. Two of these regions, 4q28 and 5q23-q31, showed significant linkage by traditional LOD score analysis and could harbor variants of more sizeable risk for psychosis or a multiplicity of risk variants. The pattern of haplotype sharing in 4q28 highlights PCDH10, encoding a cadherin-related neuronal receptor, as possibly involved in risk.

10.
Nat Neurosci ; 19(11): 1442-1453, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27668389

RESUMO

Over 100 genetic loci harbor schizophrenia-associated variants, yet how these variants confer liability is uncertain. The CommonMind Consortium sequenced RNA from dorsolateral prefrontal cortex of people with schizophrenia (N = 258) and control subjects (N = 279), creating a resource of gene expression and its genetic regulation. Using this resource, ∼20% of schizophrenia loci have variants that could contribute to altered gene expression and liability. In five loci, only a single gene was involved: FURIN, TSNARE1, CNTN4, CLCN3 or SNAP91. Altering expression of FURIN, TSNARE1 or CNTN4 changed neurodevelopment in zebrafish; knockdown of FURIN in human neural progenitor cells yielded abnormal migration. Of 693 genes showing significant case-versus-control differential expression, their fold changes were ≤ 1.33, and an independent cohort yielded similar results. Gene co-expression implicates a network relevant for schizophrenia. Our findings show that schizophrenia is polygenic and highlight the utility of this resource for mechanistic interpretations of genetic liability for brain diseases.


Assuntos
Regulação da Expressão Gênica/genética , Predisposição Genética para Doença , Herança Multifatorial/genética , Esquizofrenia/genética , Encéfalo/metabolismo , Feminino , Estudo de Associação Genômica Ampla , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , Risco
11.
Gastroenterology ; 151(4): 724-32, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27492617

RESUMO

BACKGROUND & AIMS: Genome-wide association studies have identified 200 inflammatory bowel disease (IBD) loci, but the genetic architecture of Crohn's disease (CD) and ulcerative colitis remain incompletely defined. Here, we aimed to identify novel associations between IBD and functional genetic variants using the Illumina ExomeChip (San Diego, CA). METHODS: Genotyping was performed in 10,523 IBD cases and 5726 non-IBD controls. There were 91,713 functional single-nucleotide polymorphism loci in coding regions analyzed. A novel identified association was replicated further in 2 independent cohorts. We further examined the association of the identified single-nucleotide polymorphism with microbiota from 338 mucosal lavage samples in the Mucosal Luminal Interface cohort measured using 16S sequencing. RESULTS: We identified an association between CD and a missense variant encoding alanine or threonine at position 391 in the zinc transporter solute carrier family 39, member 8 protein (SLC39A8 alanine 391 threonine, rs13107325) and replicated the association with CD in 2 replication cohorts (combined meta-analysis P = 5.55 × 10(-13)). This variant has been associated previously with distinct phenotypes including obesity, lipid levels, blood pressure, and schizophrenia. We subsequently determined that the CD risk allele was associated with altered colonic mucosal microbiome composition in both healthy controls (P = .009) and CD cases (P = .0009). Moreover, microbes depleted in healthy carriers strongly overlap with those reduced in CD patients (P = 9.24 × 10(-16)) and overweight individuals (P = 6.73 × 10(-16)). CONCLUSIONS: Our results suggest that an SLC39A8-dependent shift in the gut microbiome could explain its pleiotropic effects on multiple complex diseases including CD.


Assuntos
Proteínas de Transporte de Cátions/genética , Colite Ulcerativa/genética , Doença de Crohn/genética , Microbioma Gastrointestinal/genética , Mutação de Sentido Incorreto , Alelos , Estudos de Casos e Controles , Colite Ulcerativa/microbiologia , Doença de Crohn/microbiologia , Feminino , Pleiotropia Genética , Genótipo , Humanos , Masculino , Fatores de Risco
12.
Neuron ; 87(6): 1215-1233, 2015 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-26402605

RESUMO

Analysis of de novo CNVs (dnCNVs) from the full Simons Simplex Collection (SSC) (N = 2,591 families) replicates prior findings of strong association with autism spectrum disorders (ASDs) and confirms six risk loci (1q21.1, 3q29, 7q11.23, 16p11.2, 15q11.2-13, and 22q11.2). The addition of published CNV data from the Autism Genome Project (AGP) and exome sequencing data from the SSC and the Autism Sequencing Consortium (ASC) shows that genes within small de novo deletions, but not within large dnCNVs, significantly overlap the high-effect risk genes identified by sequencing. Alternatively, large dnCNVs are found likely to contain multiple modest-effect risk genes. Overall, we find strong evidence that de novo mutations are associated with ASD apart from the risk for intellectual disability. Extending the transmission and de novo association test (TADA) to include small de novo deletions reveals 71 ASD risk loci, including 6 CNV regions (noted above) and 65 risk genes (FDR ≤ 0.1).


Assuntos
Transtorno do Espectro Autista/diagnóstico , Transtorno do Espectro Autista/genética , Loci Gênicos/genética , Variação Genética/genética , Mapas de Interação de Proteínas/genética , Feminino , Humanos , Masculino
13.
Nat Commun ; 6: 6404, 2015 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-25752243

RESUMO

Recent studies implicate chromatin modifiers in autism spectrum disorder (ASD) through the identification of recurrent de novo loss of function mutations in affected individuals. ASD risk genes are co-expressed in human midfetal cortex, suggesting that ASD risk genes converge in specific regulatory networks during neurodevelopment. To elucidate such networks, we identify genes targeted by CHD8, a chromodomain helicase strongly associated with ASD, in human midfetal brain, human neural stem cells (hNSCs) and embryonic mouse cortex. CHD8 targets are strongly enriched for other ASD risk genes in both human and mouse neurodevelopment, and converge in ASD-associated co-expression networks in human midfetal cortex. CHD8 knockdown in hNSCs results in dysregulation of ASD risk genes directly targeted by CHD8. Integration of CHD8-binding data into ASD risk models improves detection of risk genes. These results suggest loss of CHD8 contributes to ASD by perturbing an ancient gene regulatory network during human brain development.


Assuntos
Transtorno do Espectro Autista/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Redes Reguladoras de Genes/genética , Modelos Neurológicos , Sistema Nervoso/embriologia , Fatores de Transcrição/metabolismo , Animais , Montagem e Desmontagem da Cromatina/genética , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Sistema Nervoso/metabolismo , Células-Tronco Neurais/metabolismo , Fatores de Transcrição/genética
14.
Biol Psychiatry ; 77(9): 775-84, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25534755

RESUMO

BACKGROUND: Phenotypic heterogeneity in autism has long been conjectured to be a major hindrance to the discovery of genetic risk factors, leading to numerous attempts to stratify children based on phenotype to increase power of discovery studies. This approach, however, is based on the hypothesis that phenotypic heterogeneity closely maps to genetic variation, which has not been tested. Our study examines the impact of subphenotyping of a well-characterized autism spectrum disorder (ASD) sample on genetic homogeneity and the ability to discover common genetic variants conferring liability to ASD. METHODS: Genome-wide genotypic data of 2576 families from the Simons Simplex Collection were analyzed in the overall sample and phenotypic subgroups defined on the basis of diagnosis, IQ, and symptom profiles. We conducted a family-based association study, as well as estimating heritability and evaluating allele scores for each phenotypic subgroup. RESULTS: Association analyses revealed no genome-wide significant association signal. Subphenotyping did not increase power substantially. Moreover, allele scores built from the most associated single nucleotide polymorphisms, based on the odds ratio in the full sample, predicted case status in subsets of the sample equally well and heritability estimates were very similar for all subgroups. CONCLUSIONS: In genome-wide association analysis of the Simons Simplex Collection sample, reducing phenotypic heterogeneity had at most a modest impact on genetic homogeneity. Our results are based on a relatively small sample, one with greater homogeneity than the entire population; if they apply more broadly, they imply that analysis of subphenotypes is not a productive path forward for discovering genetic risk variants in ASD.


Assuntos
Transtorno do Espectro Autista/genética , Transtorno Autístico/genética , Fenótipo , Transtorno do Espectro Autista/fisiopatologia , Transtorno do Espectro Autista/psicologia , Transtorno Autístico/fisiopatologia , Transtorno Autístico/psicologia , Família , Feminino , Predisposição Genética para Doença , Variação Genética , Estudo de Associação Genômica Ampla/métodos , Humanos , Masculino , Polimorfismo de Nucleotídeo Único
15.
Nature ; 515(7526): 209-15, 2014 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-25363760

RESUMO

The genetic architecture of autism spectrum disorder involves the interplay of common and rare variants and their impact on hundreds of genes. Using exome sequencing, here we show that analysis of rare coding variation in 3,871 autism cases and 9,937 ancestry-matched or parental controls implicates 22 autosomal genes at a false discovery rate (FDR) < 0.05, plus a set of 107 autosomal genes strongly enriched for those likely to affect risk (FDR < 0.30). These 107 genes, which show unusual evolutionary constraint against mutations, incur de novo loss-of-function mutations in over 5% of autistic subjects. Many of the genes implicated encode proteins for synaptic formation, transcriptional regulation and chromatin-remodelling pathways. These include voltage-gated ion channels regulating the propagation of action potentials, pacemaking and excitability-transcription coupling, as well as histone-modifying enzymes and chromatin remodellers-most prominently those that mediate post-translational lysine methylation/demethylation modifications of histones.


Assuntos
Transtornos Globais do Desenvolvimento Infantil/genética , Cromatina/genética , Predisposição Genética para Doença/genética , Mutação/genética , Sinapses/metabolismo , Transcrição Genética/genética , Sequência de Aminoácidos , Transtornos Globais do Desenvolvimento Infantil/patologia , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina , Exoma/genética , Feminino , Mutação em Linhagem Germinativa/genética , Humanos , Masculino , Dados de Sequência Molecular , Mutação de Sentido Incorreto/genética , Rede Nervosa/metabolismo , Razão de Chances
16.
Nat Genet ; 46(8): 881-5, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25038753

RESUMO

A key component of genetic architecture is the allelic spectrum influencing trait variability. For autism spectrum disorder (herein termed autism), the nature of the allelic spectrum is uncertain. Individual risk-associated genes have been identified from rare variation, especially de novo mutations. From this evidence, one might conclude that rare variation dominates the allelic spectrum in autism, yet recent studies show that common variation, individually of small effect, has substantial impact en masse. At issue is how much of an impact relative to rare variation this common variation has. Using a unique epidemiological sample from Sweden, new methods that distinguish total narrow-sense heritability from that due to common variation and synthesis of results from other studies, we reach several conclusions about autism's genetic architecture: its narrow-sense heritability is ∼52.4%, with most due to common variation, and rare de novo mutations contribute substantially to individual liability, yet their contribution to variance in liability, 2.6%, is modest compared to that for heritable variation.


Assuntos
Transtorno Autístico/genética , Mutação , Adolescente , Adulto , Idoso , Alelos , Criança , Predisposição Genética para Doença , Humanos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Suécia , Adulto Jovem
17.
Am J Med Genet B Neuropsychiatr Genet ; 165B(6): 521-30, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24980794

RESUMO

An increased abundance of runs of homozygosity (ROH) has been associated with risk for various diseases, including schizophrenia. Here we investigate the characteristics of ROH in Palau, an Oceanic population, evaluating whether these characteristics are related to risk for psychotic disorders and the nature of this association. To accomplish these aims we evaluate a sample of 203 cases with schizophrenia and related psychotic disorders-representing almost complete ascertainment of affected individuals in the population-and contrast their ROH to that of 125 subjects chosen to function as controls. While Palauan diagnosed with psychotic disorders tend to have slightly more ROH regions than controls, the distinguishing features are that they have longer ROH regions, greater total length of ROH, and their ROH tends to co-occur more often at the same locus. The nature of the sample allows us to investigate whether rare, highly penetrant recessive variants generate such case-control differences in ROH. Neither rare, highly penetrant recessive variants nor individual common variants of large effect account for a substantial proportion of risk for psychosis in Palau. These results suggest a more nuanced model for risk is required to explain patterns of ROH for this population.


Assuntos
Predisposição Genética para Doença , Transtornos Psicóticos/genética , Alelos , Estudos de Casos e Controles , Genoma Humano/genética , Haplótipos/genética , Homozigoto , Humanos , Palau , Polimorfismo de Nucleotídeo Único/genética , Fatores de Risco
18.
Am J Hum Genet ; 94(6): 870-83, 2014 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-24906019

RESUMO

Reciprocal copy-number variation (CNV) of a 593 kb region of 16p11.2 is a common genetic cause of autism spectrum disorder (ASD), yet it is not completely penetrant and can manifest in a wide array of phenotypes. To explore its molecular consequences, we performed RNA sequencing of cerebral cortex from mouse models with CNV of the syntenic 7qF3 region and lymphoblast lines from 34 members of 7 multiplex ASD-affected families harboring the 16p11.2 CNV. Expression of all genes in the CNV region correlated well with their DNA copy number, with no evidence of dosage compensation. We observed effects on gene expression outside the CNV region, including apparent positional effects in cis and in trans at genomic segments with evidence of physical interaction in Hi-C chromosome conformation data. One of the most significant positional effects was telomeric to the 16p11.2 CNV and includes the previously described "distal" 16p11.2 microdeletion. Overall, 16p11.2 CNV was associated with altered expression of genes and networks that converge on multiple hypotheses of ASD pathogenesis, including synaptic function (e.g., NRXN1, NRXN3), chromatin modification (e.g., CHD8, EHMT1, MECP2), transcriptional regulation (e.g., TCF4, SATB2), and intellectual disability (e.g., FMR1, CEP290). However, there were differences between tissues and species, with the strongest effects being consistently within the CNV region itself. Our analyses suggest that through a combination of indirect regulatory effects and direct effects on nuclear architecture, alteration of 16p11.2 genes disrupts expression networks that involve other genes and pathways known to contribute to ASD, suggesting an overlap in mechanisms of pathogenesis.


Assuntos
Transtorno Autístico/genética , Deleção Cromossômica , Duplicação Cromossômica , Cromossomos Humanos Par 16/genética , Animais , Córtex Cerebral/patologia , Criança , Variações do Número de Cópias de DNA , Feminino , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Deficiência Intelectual/genética , Masculino , Camundongos , Linhagem , Fenótipo , Análise de Sequência de RNA , Transcrição Genética
19.
Mol Autism ; 5: 31, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24860643

RESUMO

BACKGROUND: Whole-exome sequencing studies in autism spectrum disorder (ASD) have identified de novo mutations in novel candidate genes, including the synaptic gene Eighty-five Requiring 3A (EFR3A). EFR3A is a critical component of a protein complex required for the synthesis of the phosphoinositide PtdIns4P, which has a variety of functions at the neural synapse. We hypothesized that deleterious mutations in EFR3A would be significantly associated with ASD. METHODS: We conducted a large case/control association study by deep resequencing and analysis of whole-exome data for coding and splice site variants in EFR3A. We determined the potential impact of these variants on protein structure and function by a variety of conservation measures and analysis of the Saccharomyces cerevisiae Efr3 crystal structure. We also analyzed the expression pattern of EFR3A in human brain tissue. RESULTS: Rare nonsynonymous mutations in EFR3A were more common among cases (16 / 2,196 = 0.73%) than matched controls (12 / 3,389 = 0.35%) and were statistically more common at conserved nucleotides based on an experiment-wide significance threshold (P = 0.0077, permutation test). Crystal structure analysis revealed that mutations likely to be deleterious were also statistically more common in cases than controls (P = 0.017, Fisher exact test). Furthermore, EFR3A is expressed in cortical neurons, including pyramidal neurons, during human fetal brain development in a pattern consistent with ASD-related genes, and it is strongly co-expressed (P < 2.2 × 10(-16), Wilcoxon test) with a module of genes significantly associated with ASD. CONCLUSIONS: Rare deleterious mutations in EFR3A were found to be associated with ASD using an experiment-wide significance threshold. Synaptic phosphoinositide metabolism has been strongly implicated in syndromic forms of ASD. These data for EFR3A strengthen the evidence for the involvement of this pathway in idiopathic autism.

20.
Autism Res ; 7(3): 355-62, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24821083

RESUMO

The proximal region of chromosome 15 is one of the genomic hotspots for copy number variants (CNVs). Among the rearrangements observed in this region, CNVs from the interval between the common breakpoints 1 and 2 (BP1 and BP2) have been reported cosegregating with autism spectrum disorder (ASD). Although evidence supporting an association between BP1-BP2 CNVs and autism accumulates, the magnitude of the effect of BP1-BP2 CNVs remains elusive, posing a great challenge to recurrence-risk counseling. To gain further insight into their pathogenicity for ASD, we estimated the penetrance of the BP1-BP2 CNVs for ASD as well as their effects on ASD-related phenotypes in a well-characterized ASD sample (n = 2525 families). Transmission disequilibrium test revealed significant preferential transmission only for the duplicated chromosome in probands (20T:9NT). The penetrance of the BP1-BP2 CNVs for ASD was low, conferring additional risks of 0.3% (deletion) and 0.8% (duplication). Stepwise regression analyses suggest a greater effect of the CNVs on ASD-related phenotype in males and when maternally inherited. Taken together, the results are consistent with BP1-BP2 CNVs as risk factors for autism. However, their effect is modest, more akin to that seen for common variants. To be consistent with the current American College of Medical Genetics guidelines for interpretation of postnatal CNV, the BP1-BP2 deletion and duplication CNVs would probably best be classified as variants of uncertain significance (VOUS): they appear to have an impact on risk, but one so modest that these CNVs do not merit pathogenic status.


Assuntos
Transtornos Globais do Desenvolvimento Infantil/genética , Deleção Cromossômica , Cromossomos Humanos Par 15/genética , Variações do Número de Cópias de DNA/genética , Predisposição Genética para Doença/genética , Adulto , Criança , Feminino , Humanos , Masculino
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