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1.
Am J Hum Genet ; 105(4): 773-787, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31564431

RESUMO

Genome-wide association studies (GWASs) have identified thousands of genetic loci associated with cardiometabolic traits including type 2 diabetes (T2D), lipid levels, body fat distribution, and adiposity, although most causal genes remain unknown. We used subcutaneous adipose tissue RNA-seq data from 434 Finnish men from the METSIM study to identify 9,687 primary and 2,785 secondary cis-expression quantitative trait loci (eQTL; <1 Mb from TSS, FDR < 1%). Compared to primary eQTL signals, secondary eQTL signals were located further from transcription start sites, had smaller effect sizes, and were less enriched in adipose tissue regulatory elements compared to primary signals. Among 2,843 cardiometabolic GWAS signals, 262 colocalized by LD and conditional analysis with 318 transcripts as primary and conditionally distinct secondary cis-eQTLs, including some across ancestries. Of cardiometabolic traits examined for adipose tissue eQTL colocalizations, waist-hip ratio (WHR) and circulating lipid traits had the highest percentage of colocalized eQTLs (15% and 14%, respectively). Among alleles associated with increased cardiometabolic GWAS risk, approximately half (53%) were associated with decreased gene expression level. Mediation analyses of colocalized genes and cardiometabolic traits within the 434 individuals provided further evidence that gene expression influences variant-trait associations. These results identify hundreds of candidate genes that may act in adipose tissue to influence cardiometabolic traits.

2.
Nature ; 572(7769): 323-328, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31367044

RESUMO

Exome-sequencing studies have generally been underpowered to identify deleterious alleles with a large effect on complex traits as such alleles are mostly rare. Because the population of northern and eastern Finland has expanded considerably and in isolation following a series of bottlenecks, individuals of these populations have numerous deleterious alleles at a relatively high frequency. Here, using exome sequencing of nearly 20,000 individuals from these regions, we investigate the role of rare coding variants in clinically relevant quantitative cardiometabolic traits. Exome-wide association studies for 64 quantitative traits identified 26 newly associated deleterious alleles. Of these 26 alleles, 19 are either unique to or more than 20 times more frequent in Finnish individuals than in other Europeans and show geographical clustering comparable to Mendelian disease mutations that are characteristic of the Finnish population. We estimate that sequencing studies of populations without this unique history would require hundreds of thousands to millions of participants to achieve comparable association power.

3.
Proc Natl Acad Sci U S A ; 116(22): 10883-10888, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31076557

RESUMO

We integrate comeasured gene expression and DNA methylation (DNAme) in 265 human skeletal muscle biopsies from the FUSION study with >7 million genetic variants and eight physiological traits: height, waist, weight, waist-hip ratio, body mass index, fasting serum insulin, fasting plasma glucose, and type 2 diabetes. We find hundreds of genes and DNAme sites associated with fasting insulin, waist, and body mass index, as well as thousands of DNAme sites associated with gene expression (eQTM). We find that controlling for heterogeneity in tissue/muscle fiber type reduces the number of physiological trait associations, and that long-range eQTMs (>1 Mb) are reduced when controlling for tissue/muscle fiber type or latent factors. We map genetic regulators (quantitative trait loci; QTLs) of expression (eQTLs) and DNAme (mQTLs). Using Mendelian randomization (MR) and mediation techniques, we leverage these genetic maps to predict 213 causal relationships between expression and DNAme, approximately two-thirds of which predict methylation to causally influence expression. We use MR to integrate FUSION mQTLs, FUSION eQTLs, and GTEx eQTLs for 48 tissues with genetic associations for 534 diseases and quantitative traits. We identify hundreds of genes and thousands of DNAme sites that may drive the reported disease/quantitative trait genetic associations. We identify 300 gene expression MR associations that are present in both FUSION and GTEx skeletal muscle and that show stronger evidence of MR association in skeletal muscle than other tissues, which may partially reflect differences in power across tissues. As one example, we find that increased RXRA muscle expression may decrease lean tissue mass.

4.
Nat Genet ; 51(1): 51-62, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30578418

RESUMO

In this trans-ethnic multi-omic study, we reinterpret the genetic architecture of blood pressure to identify genes, tissues, phenomes and medication contexts of blood pressure homeostasis. We discovered 208 novel common blood pressure SNPs and 53 rare variants in genome-wide association studies of systolic, diastolic and pulse pressure in up to 776,078 participants from the Million Veteran Program (MVP) and collaborating studies, with analysis of the blood pressure clinical phenome in MVP. Our transcriptome-wide association study detected 4,043 blood pressure associations with genetically predicted gene expression of 840 genes in 45 tissues, and mouse renal single-cell RNA sequencing identified upregulated blood pressure genes in kidney tubule cells.


Assuntos
Pressão Sanguínea/genética , Grupos Étnicos/genética , Adolescente , Animais , Feminino , Expressão Gênica/genética , Estudo de Associação Genômica Ampla/métodos , Humanos , Túbulos Renais/fisiologia , Masculino , Camundongos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Transcriptoma/genética , Regulação para Cima/genética
5.
Nat Commun ; 9(1): 3753, 2018 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-30218074

RESUMO

A detailed understanding of the genome-wide variability of single-nucleotide germline mutation rates is essential to studying human genome evolution. Here, we use ~36 million singleton variants from 3560 whole-genome sequences to infer fine-scale patterns of mutation rate heterogeneity. Mutability is jointly affected by adjacent nucleotide context and diverse genomic features of the surrounding region, including histone modifications, replication timing, and recombination rate, sometimes suggesting specific mutagenic mechanisms. Remarkably, GC content, DNase hypersensitivity, CpG islands, and H3K36 trimethylation are associated with both increased and decreased mutation rates depending on nucleotide context. We validate these estimated effects in an independent dataset of ~46,000 de novo mutations, and confirm our estimates are more accurate than previously published results based on ancestrally older variants without considering genomic features. Our results thus provide the most refined portrait to date of the factors contributing to genome-wide variability of the human germline mutation rate.

6.
PLoS One ; 13(4): e0195788, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29659628

RESUMO

From whole organisms to individual cells, responses to environmental conditions are influenced by genetic makeup, where the effect of genetic variation on a trait depends on the environmental context. RNA-sequencing quantifies gene expression as a molecular trait, and is capable of capturing both genetic and environmental effects. In this study, we explore opportunities of using allele-specific expression (ASE) to discover cis-acting genotype-environment interactions (GxE)-genetic effects on gene expression that depend on an environmental condition. Treating 17 common, clinical traits as approximations of the cellular environment of 267 skeletal muscle biopsies, we identify 10 candidate environmental response expression quantitative trait loci (reQTLs) across 6 traits (12 unique gene-environment trait pairs; 10% FDR per trait) including sex, systolic blood pressure, and low-density lipoprotein cholesterol. Although using ASE is in principle a promising approach to detect GxE effects, replication of such signals can be challenging as validation requires harmonization of environmental traits across cohorts and a sufficient sampling of heterozygotes for a transcribed SNP. Comprehensive discovery and replication will require large human transcriptome datasets, or the integration of multiple transcribed SNPs, coupled with standardized clinical phenotyping.


Assuntos
Microambiente Celular , Regulação da Expressão Gênica , Interação Gene-Ambiente , Variação Genética , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Metabolismo Energético , Estudos de Associação Genética , Genótipo , Humanos , Músculo Esquelético/citologia , Fenótipo , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas
8.
Proc Natl Acad Sci U S A ; 115(2): 379-384, 2018 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-29279374

RESUMO

A major challenge in evaluating the contribution of rare variants to complex disease is identifying enough copies of the rare alleles to permit informative statistical analysis. To investigate the contribution of rare variants to the risk of type 2 diabetes (T2D) and related traits, we performed deep whole-genome analysis of 1,034 members of 20 large Mexican-American families with high prevalence of T2D. If rare variants of large effect accounted for much of the diabetes risk in these families, our experiment was powered to detect association. Using gene expression data on 21,677 transcripts for 643 pedigree members, we identified evidence for large-effect rare-variant cis-expression quantitative trait loci that could not be detected in population studies, validating our approach. However, we did not identify any rare variants of large effect associated with T2D, or the related traits of fasting glucose and insulin, suggesting that large-effect rare variants account for only a modest fraction of the genetic risk of these traits in this sample of families. Reliable identification of large-effect rare variants will require larger samples of extended pedigrees or different study designs that further enrich for such variants.


Assuntos
Diabetes Mellitus Tipo 2/genética , Predisposição Genética para Doença/genética , Variação Genética , Americanos Mexicanos/genética , Diabetes Mellitus Tipo 2/etnologia , Diabetes Mellitus Tipo 2/patologia , Saúde da Família , Feminino , Frequência do Gene , Predisposição Genética para Doença/etnologia , Estudo de Associação Genômica Ampla/métodos , Genótipo , Humanos , Masculino , Linhagem , Fenótipo , Locos de Características Quantitativas/genética , Sequenciamento Completo do Genoma/métodos
9.
Diabetes ; 67(2): 334-342, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29141982

RESUMO

Rare fully penetrant mutations in AKT2 are an established cause of monogenic disorders of glucose metabolism. Recently, a novel partial loss-of-function AKT2 coding variant (p.Pro50Thr) was identified that is nearly specific to Finns (frequency 1.1%), with the low-frequency allele associated with an increase in fasting plasma insulin level and risk of type 2 diabetes. The effects of the p.Pro50Thr AKT2 variant (p.P50T/AKT2) on insulin-stimulated glucose uptake (GU) in the whole body and in different tissues have not previously been investigated. We identified carriers (N = 20) and matched noncarriers (N = 25) for this allele in the population-based Metabolic Syndrome in Men (METSIM)study and invited these individuals back for positron emission tomography study with [18F]-fluorodeoxyglucose during euglycemic hyperinsulinemia. When we compared p.P50T/AKT2 carriers to noncarriers, we found a 39.4% reduction in whole-body GU (P = 0.006) and a 55.6% increase in the rate of endogenous glucose production (P = 0.038). We found significant reductions in GU in multiple tissues-skeletal muscle (36.4%), liver (16.1%), brown adipose (29.7%), and bone marrow (32.9%)-and increases of 16.8-19.1% in seven tested brain regions. These data demonstrate that the p.P50T substitution of AKT2 influences insulin-mediated GU in multiple insulin-sensitive tissues and may explain, at least in part, the increased risk of type 2 diabetes in p.P50T/AKT2 carriers.


Assuntos
Diabetes Mellitus Tipo 2/genética , Predisposição Genética para Doença , Resistência à Insulina , Mutação com Perda de Função , Proteínas Proto-Oncogênicas c-akt/genética , Absorção Fisiológica/efeitos dos fármacos , Idoso , Alelos , Substituição de Aminoácidos , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/diagnóstico por imagem , Diabetes Mellitus Tipo 2/metabolismo , Diagnóstico Precoce , Finlândia , Fluordesoxiglucose F18/metabolismo , Seguimentos , Estudos de Associação Genética , Variação Genética , Heterozigoto , Humanos , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Proteínas Proto-Oncogênicas c-akt/metabolismo
10.
Diabetes ; 66(9): 2521-2530, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28684635

RESUMO

Molecular mechanisms remain unknown for most type 2 diabetes genome-wide association study identified loci. Variants associated with type 2 diabetes and fasting glucose levels reside in introns of ADCY5, a gene that encodes adenylate cyclase 5. Adenylate cyclase 5 catalyzes the production of cyclic AMP, which is a second messenger molecule involved in cell signaling and pancreatic ß-cell insulin secretion. We demonstrated that type 2 diabetes risk alleles are associated with decreased ADCY5 expression in human islets and examined candidate variants for regulatory function. rs11708067 overlaps a predicted enhancer region in pancreatic islets. The type 2 diabetes risk rs11708067-A allele showed fewer H3K27ac ChIP-seq reads in human islets, lower transcriptional activity in reporter assays in rodent ß-cells (rat 832/13 and mouse MIN6), and increased nuclear protein binding compared with the rs11708067-G allele. Homozygous deletion of the orthologous enhancer region in 832/13 cells resulted in a 64% reduction in expression level of Adcy5, but not adjacent gene Sec22a, and a 39% reduction in insulin secretion. Together, these data suggest that rs11708067-A risk allele contributes to type 2 diabetes by disrupting an islet enhancer, which results in reduced ADCY5 expression and impaired insulin secretion.


Assuntos
Adenilil Ciclases/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Regulação da Expressão Gênica/fisiologia , Variação Genética , Estudo de Associação Genômica Ampla , Ilhotas Pancreáticas/metabolismo , Adenilil Ciclases/genética , Diabetes Mellitus Tipo 2/genética , Humanos , Insulina/metabolismo
11.
Diabetes ; 66(11): 2888-2902, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28566273

RESUMO

To characterize type 2 diabetes (T2D)-associated variation across the allele frequency spectrum, we conducted a meta-analysis of genome-wide association data from 26,676 T2D case and 132,532 control subjects of European ancestry after imputation using the 1000 Genomes multiethnic reference panel. Promising association signals were followed up in additional data sets (of 14,545 or 7,397 T2D case and 38,994 or 71,604 control subjects). We identified 13 novel T2D-associated loci (P < 5 × 10-8), including variants near the GLP2R, GIP, and HLA-DQA1 genes. Our analysis brought the total number of independent T2D associations to 128 distinct signals at 113 loci. Despite substantially increased sample size and more complete coverage of low-frequency variation, all novel associations were driven by common single nucleotide variants. Credible sets of potentially causal variants were generally larger than those based on imputation with earlier reference panels, consistent with resolution of causal signals to common risk haplotypes. Stratification of T2D-associated loci based on T2D-related quantitative trait associations revealed tissue-specific enrichment of regulatory annotations in pancreatic islet enhancers for loci influencing insulin secretion and in adipocytes, monocytes, and hepatocytes for insulin action-associated loci. These findings highlight the predominant role played by common variants of modest effect and the diversity of biological mechanisms influencing T2D pathophysiology.


Assuntos
Diabetes Mellitus Tipo 2/genética , Grupo com Ancestrais do Continente Europeu , Regulação da Expressão Gênica/fisiologia , Estudo de Associação Genômica Ampla , Variação Genética , Humanos
12.
Am J Hum Genet ; 100(3): 428-443, 2017 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-28257690

RESUMO

Subcutaneous adipose tissue stores excess lipids and maintains energy balance. We performed expression quantitative trait locus (eQTL) analyses by using abdominal subcutaneous adipose tissue of 770 extensively phenotyped participants of the METSIM study. We identified cis-eQTLs for 12,400 genes at a 1% false-discovery rate. Among an approximately 680 known genome-wide association study (GWAS) loci for cardio-metabolic traits, we identified 140 coincident cis-eQTLs at 109 GWAS loci, including 93 eQTLs not previously described. At 49 of these 140 eQTLs, gene expression was nominally associated (p < 0.05) with levels of the GWAS trait. The size of our dataset enabled identification of five loci associated (p < 5 × 10-8) with at least five genes located >5 Mb away. These trans-eQTL signals confirmed and extended the previously reported KLF14-mediated network to 55 target genes, validated the CIITA regulation of class II MHC genes, and identified ZNF800 as a candidate master regulator. Finally, we observed similar expression-clinical trait correlations of genes associated with GWAS loci in both humans and a panel of genetically diverse mice. These results provide candidate genes for further investigation of their potential roles in adipose biology and in regulating cardio-metabolic traits.


Assuntos
Doenças Cardiovasculares/genética , Regulação da Expressão Gênica , Síndrome Metabólica/genética , Locos de Características Quantitativas , Gordura Subcutânea/metabolismo , Idoso , Animais , Bases de Dados Genéticas , Perfilação da Expressão Gênica , Estudo de Associação Genômica Ampla , Técnicas de Genotipagem , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fenótipo , Reprodutibilidade dos Testes , Transativadores/genética , Transativadores/metabolismo
13.
Diabetes ; 66(7): 2019-2032, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28341696

RESUMO

To identify novel coding association signals and facilitate characterization of mechanisms influencing glycemic traits and type 2 diabetes risk, we analyzed 109,215 variants derived from exome array genotyping together with an additional 390,225 variants from exome sequence in up to 39,339 normoglycemic individuals from five ancestry groups. We identified a novel association between the coding variant (p.Pro50Thr) in AKT2 and fasting plasma insulin (FI), a gene in which rare fully penetrant mutations are causal for monogenic glycemic disorders. The low-frequency allele is associated with a 12% increase in FI levels. This variant is present at 1.1% frequency in Finns but virtually absent in individuals from other ancestries. Carriers of the FI-increasing allele had increased 2-h insulin values, decreased insulin sensitivity, and increased risk of type 2 diabetes (odds ratio 1.05). In cellular studies, the AKT2-Thr50 protein exhibited a partial loss of function. We extend the allelic spectrum for coding variants in AKT2 associated with disorders of glucose homeostasis and demonstrate bidirectional effects of variants within the pleckstrin homology domain of AKT2.


Assuntos
Diabetes Mellitus Tipo 2/genética , Grupo com Ancestrais do Continente Europeu/genética , Jejum/metabolismo , Resistência à Insulina/genética , Insulina/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Afro-Americanos/genética , Alelos , Grupo com Ancestrais do Continente Asiático/genética , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2/metabolismo , Finlândia , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Hispano-Americanos/genética , Humanos , Razão de Chances
14.
Proc Natl Acad Sci U S A ; 114(9): 2301-2306, 2017 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-28193859

RESUMO

Genome-wide association studies (GWAS) have identified >100 independent SNPs that modulate the risk of type 2 diabetes (T2D) and related traits. However, the pathogenic mechanisms of most of these SNPs remain elusive. Here, we examined genomic, epigenomic, and transcriptomic profiles in human pancreatic islets to understand the links between genetic variation, chromatin landscape, and gene expression in the context of T2D. We first integrated genome and transcriptome variation across 112 islet samples to produce dense cis-expression quantitative trait loci (cis-eQTL) maps. Additional integration with chromatin-state maps for islets and other diverse tissue types revealed that cis-eQTLs for islet-specific genes are specifically and significantly enriched in islet stretch enhancers. High-resolution chromatin accessibility profiling using assay for transposase-accessible chromatin sequencing (ATAC-seq) in two islet samples enabled us to identify specific transcription factor (TF) footprints embedded in active regulatory elements, which are highly enriched for islet cis-eQTL. Aggregate allelic bias signatures in TF footprints enabled us de novo to reconstruct TF binding affinities genetically, which support the high-quality nature of the TF footprint predictions. Interestingly, we found that T2D GWAS loci were strikingly and specifically enriched in islet Regulatory Factor X (RFX) footprints. Remarkably, within and across independent loci, T2D risk alleles that overlap with RFX footprints uniformly disrupt the RFX motifs at high-information content positions. Together, these results suggest that common regulatory variations have shaped islet TF footprints and the transcriptome and that a confluent RFX regulatory grammar plays a significant role in the genetic component of T2D predisposition.


Assuntos
Diabetes Mellitus Tipo 2/genética , Predisposição Genética para Doença , Genoma Humano , Ilhotas Pancreáticas/metabolismo , Locos de Características Quantitativas , Transcriptoma , Alelos , Sequência de Bases , Sítios de Ligação , Cromatina/química , Cromatina/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Epigênese Genética , Perfilação da Expressão Gênica , Variação Genética , Estudo de Associação Genômica Ampla , Impressão Genômica , Humanos , Ilhotas Pancreáticas/patologia , Polimorfismo de Nucleotídeo Único , Ligação Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Fatores de Transcrição de Fator Regulador X/genética , Fatores de Transcrição de Fator Regulador X/metabolismo
15.
Nat Genet ; 48(10): 1279-83, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27548312

RESUMO

We describe a reference panel of 64,976 human haplotypes at 39,235,157 SNPs constructed using whole-genome sequence data from 20 studies of predominantly European ancestry. Using this resource leads to accurate genotype imputation at minor allele frequencies as low as 0.1% and a large increase in the number of SNPs tested in association studies, and it can help to discover and refine causal loci. We describe remote server resources that allow researchers to carry out imputation and phasing consistently and efficiently.


Assuntos
Genótipo , Haplótipos , Polimorfismo de Nucleotídeo Único , Alelos , Técnicas Genéticas , Estudo de Associação Genômica Ampla , Humanos , Internet , Valores de Referência
16.
Nat Genet ; 48(10): 1284-1287, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27571263

RESUMO

Genotype imputation is a key component of genetic association studies, where it increases power, facilitates meta-analysis, and aids interpretation of signals. Genotype imputation is computationally demanding and, with current tools, typically requires access to a high-performance computing cluster and to a reference panel of sequenced genomes. Here we describe improvements to imputation machinery that reduce computational requirements by more than an order of magnitude with no loss of accuracy in comparison to standard imputation tools. We also describe a new web-based service for imputation that facilitates access to new reference panels and greatly improves user experience and productivity.


Assuntos
Algoritmos , Genótipo , Simulação por Computador , Estudo de Associação Genômica Ampla , Haplótipos , Humanos , Internet
17.
Nat Commun ; 7: 11764, 2016 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-27353450

RESUMO

Type 2 diabetes (T2D) results from the combined effects of genetic and environmental factors on multiple tissues over time. Of the >100 variants associated with T2D and related traits in genome-wide association studies (GWAS), >90% occur in non-coding regions, suggesting a strong regulatory component to T2D risk. Here to understand how T2D status, metabolic traits and genetic variation influence gene expression, we analyse skeletal muscle biopsies from 271 well-phenotyped Finnish participants with glucose tolerance ranging from normal to newly diagnosed T2D. We perform high-depth strand-specific mRNA-sequencing and dense genotyping. Computational integration of these data with epigenome data, including ATAC-seq on skeletal muscle, and transcriptome data across diverse tissues reveals that the tissue-specific genetic regulatory architecture of skeletal muscle is highly enriched in muscle stretch/super enhancers, including some that overlap T2D GWAS variants. In one such example, T2D risk alleles residing in a muscle stretch/super enhancer are linked to increased expression and alternative splicing of muscle-specific isoforms of ANK1.


Assuntos
Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Estudo de Associação Genômica Ampla , Músculo Esquelético/metabolismo , Alelos , Epigenômica , Feminino , Regulação da Expressão Gênica , Predisposição Genética para Doença , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , RNA Mensageiro , Análise de Sequência de RNA
18.
JAMA Psychiatry ; 73(6): 590-7, 2016 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-27120077

RESUMO

IMPORTANCE: Complex disorders, such as bipolar disorder (BD), likely result from the influence of both common and rare susceptibility alleles. While common variation has been widely studied, rare variant discovery has only recently become feasible with next-generation sequencing. OBJECTIVE: To utilize a combined family-based and case-control approach to exome sequencing in BD using multiplex families as an initial discovery strategy, followed by association testing in a large case-control meta-analysis. DESIGN, SETTING, AND PARTICIPANTS: We performed exome sequencing of 36 affected members with BD from 8 multiplex families and tested rare, segregating variants in 3 independent case-control samples consisting of 3541 BD cases and 4774 controls. MAIN OUTCOMES AND MEASURES: We used penalized logistic regression and 1-sided gene-burden analyses to test for association of rare, segregating damaging variants with BD. Permutation-based analyses were performed to test for overall enrichment with previously identified gene sets. RESULTS: We found 84 rare (frequency <1%), segregating variants that were bioinformatically predicted to be damaging. These variants were found in 82 genes that were enriched for gene sets previously identified in de novo studies of autism (19 observed vs. 10.9 expected, P = .0066) and schizophrenia (11 observed vs. 5.1 expected, P = .0062) and for targets of the fragile X mental retardation protein (FMRP) pathway (10 observed vs. 4.4 expected, P = .0076). The case-control meta-analyses yielded 19 genes that were nominally associated with BD based either on individual variants or a gene-burden approach. Although no gene was individually significant after correction for multiple testing, this group of genes continued to show evidence for significant enrichment of de novo autism genes (6 observed vs 2.6 expected, P = .028). CONCLUSIONS AND RELEVANCE: Our results are consistent with the presence of prominent locus and allelic heterogeneity in BD and suggest that very large samples will be required to definitively identify individual rare variants or genes conferring risk for this disorder. However, we also identify significant associations with gene sets composed of previously discovered de novo variants in autism and schizophrenia, as well as targets of the FRMP pathway, providing preliminary support for the overlap of potential autism and schizophrenia risk genes with rare, segregating variants in families with BD.


Assuntos
Transtorno Bipolar/genética , Exoma/genética , Análise de Sequência de DNA , Alelos , Transtorno Autístico/genética , Transtorno Autístico/psicologia , Transtorno Bipolar/diagnóstico , Transtorno Bipolar/psicologia , Estudos de Casos e Controles , Proteína do X Frágil de Retardo Mental/genética , Heterogeneidade Genética , Predisposição Genética para Doença/genética , Variação Genética/genética , Estudo de Associação Genômica Ampla , Humanos , Esquizofrenia/genética , Psicologia do Esquizofrênico
19.
Nat Genet ; 47(12): 1415-25, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26551672

RESUMO

We performed fine mapping of 39 established type 2 diabetes (T2D) loci in 27,206 cases and 57,574 controls of European ancestry. We identified 49 distinct association signals at these loci, including five mapping in or near KCNQ1. 'Credible sets' of the variants most likely to drive each distinct signal mapped predominantly to noncoding sequence, implying that association with T2D is mediated through gene regulation. Credible set variants were enriched for overlap with FOXA2 chromatin immunoprecipitation binding sites in human islet and liver cells, including at MTNR1B, where fine mapping implicated rs10830963 as driving T2D association. We confirmed that the T2D risk allele for this SNP increases FOXA2-bound enhancer activity in islet- and liver-derived cells. We observed allele-specific differences in NEUROD1 binding in islet-derived cells, consistent with evidence that the T2D risk allele increases islet MTNR1B expression. Our study demonstrates how integration of genetic and genomic information can define molecular mechanisms through which variants underlying association signals exert their effects on disease.


Assuntos
Mapeamento Cromossômico , Diabetes Mellitus Tipo 2/genética , Loci Gênicos , Predisposição Genética para Doença , Fator 3-beta Nuclear de Hepatócito/genética , Polimorfismo de Nucleotídeo Único/genética , Receptor MT2 de Melatonina/genética , Sítios de Ligação , Estudos de Casos e Controles , Imunoprecipitação da Cromatina , Regulação da Expressão Gênica , Estudo de Associação Genômica Ampla , Genômica , Fator 3-beta Nuclear de Hepatócito/metabolismo , Humanos , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Fígado/metabolismo , Fígado/patologia , Anotação de Sequência Molecular , Receptor MT2 de Melatonina/metabolismo
20.
Bioinformatics ; 30(17): i393-400, 2014 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-25161225

RESUMO

MOTIVATION: Functional enrichment testing facilitates the interpretation of Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) data in terms of pathways and other biological contexts. Previous methods developed and used to test for key gene sets affected in ChIP-seq experiments treat peaks as points, and are based on the number of peaks associated with a gene or a binary score for each gene. These approaches work well for transcription factors, but histone modifications often occur over broad domains, and across multiple genes. RESULTS: To incorporate the unique properties of broad domains into functional enrichment testing, we developed Broad-Enrich, a method that uses the proportion of each gene's locus covered by a peak. We show that our method has a well-calibrated false-positive rate, performing well with ChIP-seq data having broad domains compared with alternative approaches. We illustrate Broad-Enrich with 55 ENCODE ChIP-seq datasets using different methods to define gene loci. Broad-Enrich can also be applied to other datasets consisting of broad genomic domains such as copy number variations. AVAILABILITY AND IMPLEMENTATION: http://broad-enrich.med.umich.edu for Web version and R package. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Imunoprecipitação da Cromatina/métodos , Genômica/métodos , Histonas/metabolismo , Linhagem Celular , Loci Gênicos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Modelos Logísticos , Análise de Sequência de DNA , Fatores de Transcrição/metabolismo
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