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1.
Artigo em Inglês | MEDLINE | ID: mdl-34780848

RESUMO

BACKGROUND: Integration of metabolomics with genetics may advance understanding of disease pathogenesis but has been underutilized in asthma genetic studies. OBJECTIVE: We aimed to discover new genetic effects in asthma and to characterize the molecular consequences of asthma genetic risk through integration with the metabolome in a homogenous population. METHODS: From fasting serum samples collected on 348 Tangier Island residents, we quantified 2,612 compounds using untargeted metabolomics. Genotyping was performed using Illumina's MEGA array imputed to the TOPMed reference panel. To prioritize metabolites for genome-wide association analysis (GWAS), we performed a metabolome-wide association study with asthma, selecting asthma-associated metabolites with heritability q-value<0.01 for GWAS. We also tested the association between all metabolites and 8,451 candidate asthma SNPs previously associated with asthma in the UK Biobank. We followed up significant associations by characterizing shared genetic signal for metabolites and asthma using colocalization analysis. For detailed Methods, please see this article's Online Repository at www.jacionline.org RESULTS: 60 metabolites were associated with asthma (p<0.01), including 40 heritable metabolites tested in GWAS. We observed a strong association peak for the endocannabinoid linoleoyl ethanolamide on chromosome 6 in VNN1 (p<2.7E-9). We found strong evidence (co-localization posterior probability >75%) for a shared causal variant between three metabolites and asthma, including the polyamine acisoga and variants in LPP, and derivative leukotriene B4 and intergenic variants in chr10p14. CONCLUSION: We identified novel metabolite quantitative trait loci with asthma associations. Identification and characterization of these genetically-driven metabolites may provide insight into the functional consequences of genetic risk factors for asthma.

2.
Lancet Child Adolesc Health ; 5(12): 862-872, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34762840

RESUMO

BACKGROUND: Pharmacogenetic studies in asthma cohorts, primarily made up of White people of European descent, have identified loci associated with response to inhaled beta agonists and corticosteroids (ICSs). Differences exist in how individuals from different ancestral backgrounds respond to long-acting beta agonist (LABA) and ICSs. Therefore, we sought to understand the pharmacogenetic mechanisms regulating therapeutic responsiveness in individuals of African descent. METHODS: We did ancestry-based pharmacogenetic studies of children (aged 5-11 years) and adolescents and adults (aged 12-69 years) from the Best African Response to Drug (BARD) trials, in which participants with asthma uncontrolled with low-dose ICS (fluticasone propionate 50 µg in children, 100 µg in adolescents and adults) received different step-up combination therapies. The hierarchal composite outcome of pairwise superior responsiveness in BARD was based on asthma exacerbations, a 31-day difference in annualised asthma-control days, or a 5% difference in percentage predicted FEV1. We did whole-genome admixture mapping of 15 159 ancestral segments within 312 independent regions, stratified by the two age groups. The two co-primary outcome comparisons were the step up from low-dose ICS to the quintuple dose of ICS (5 × ICS: 250 µg twice daily in children and 500 µg twice daily in adolescents and adults) versus double dose (2-2·5 × ICS: 100 µg twice daily in children, 250 µg twice daily in adolescents and adults), and 5 × ICS versus 100 µg fluticasone plus a LABA (salmeterol 50 µg twice daily). We used a genome-wide significance threshold of p<1·6 × 10-4, and tested for replication using independent cohorts of individuals of African descent with asthma. FINDINGS: We included 249 unrelated children and 267 unrelated adolescents and adults in the BARD pharmacogenetic analysis. In children, we identified a significant admixture mapping peak for superior responsiveness to 5 × ICS versus 100 µg fluticasone plus salmeterol on chromosome 12 (odds ratio [ORlocal African] 3·95, 95% CI 2·02-7·72, p=6·1 × 10-5) fine mapped to a locus adjacent to RNFT2 and NOS1 (rs73399224, ORallele dose 0·17, 95% CI 0·07-0·42, p=8·4 × 10-5). In adolescents and adults, we identified a peak for superior responsiveness to 5 × ICS versus 2·5 × ICS on chromosome 22 (ORlocal African 3·35, 1·98-5·67, p=6·8 × 10-6) containing a locus adjacent to TPST2 (rs5752429, ORallele dose 0·21, 0·09-0·52, p=5·7 × 10-4). We replicated rs5752429 and nominally replicated rs73399224 in independent African American cohorts. INTERPRETATION: BARD is the first genome-wide pharmacogenetic study of LABA and ICS response in clinical trials of individuals of African descent to detect and replicate genome-wide significant loci. Admixture mapping of the composite BARD trial outcome enabled the identification of novel pharmacogenetic variation accounting for differential therapeutic responses in people of African descent with asthma. FUNDING: National Institutes of Health, National Heart, Lung, and Blood Institute.

3.
Artigo em Inglês | MEDLINE | ID: mdl-34536413

RESUMO

BACKGROUND: Total serum IgE (tIgE) is an important intermediate phenotype of allergic disease. Whole genome genetic association studies across ancestries may identify important determinants of IgE. OBJECTIVE: We aimed to increase understanding of genetic variants affecting tIgE production across the ancestry and allergic disease spectrum by leveraging data from the National Heart, Lung and Blood Institute Trans-Omics for Precision Medicine program; the Consortium on Asthma among African-ancestry Populations in the Americas (CAAPA); and the Atopic Dermatitis Research Network (N = 21,901). METHODS: We performed genome-wide association within strata of study, disease, and ancestry groups, and we combined results via a meta-regression approach that models heterogeneity attributable to ancestry. We also tested for association between HLA alleles called from whole genome sequence data and tIgE, assessing replication of associations in HLA alleles called from genotype array data. RESULTS: We identified 6 loci at genome-wide significance (P < 5 × 10-9), including 4 loci previously reported as genome-wide significant for tIgE, as well as new regions in chr11q13.5 and chr15q22.2, which were also identified in prior genome-wide association studies of atopic dermatitis and asthma. In the HLA allele association study, HLA-A∗02:01 was associated with decreased tIgE level (Pdiscovery = 2 × 10-4; Preplication = 5 × 10-4; Pdiscovery+replication = 4 × 10-7), and HLA-DQB1∗03:02 was strongly associated with decreased tIgE level in Hispanic/Latino ancestry populations (PHispanic/Latino discovery+replication = 8 × 10-8). CONCLUSION: We performed the largest genome-wide association study and HLA association study of tIgE focused on ancestrally diverse populations and found several known tIgE and allergic disease loci that are relevant in non-European ancestry populations.

4.
Am J Hum Genet ; 108(10): 1836-1851, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34582791

RESUMO

Many common and rare variants associated with hematologic traits have been discovered through imputation on large-scale reference panels. However, the majority of genome-wide association studies (GWASs) have been conducted in Europeans, and determining causal variants has proved challenging. We performed a GWAS of total leukocyte, neutrophil, lymphocyte, monocyte, eosinophil, and basophil counts generated from 109,563,748 variants in the autosomes and the X chromosome in the Trans-Omics for Precision Medicine (TOPMed) program, which included data from 61,802 individuals of diverse ancestry. We discovered and replicated 7 leukocyte trait associations, including (1) the association between a chromosome X, pseudo-autosomal region (PAR), noncoding variant located between cytokine receptor genes (CSF2RA and CLRF2) and lower eosinophil count; and (2) associations between single variants found predominantly among African Americans at the S1PR3 (9q22.1) and HBB (11p15.4) loci and monocyte and lymphocyte counts, respectively. We further provide evidence indicating that the newly discovered eosinophil-lowering chromosome X PAR variant might be associated with reduced susceptibility to common allergic diseases such as atopic dermatitis and asthma. Additionally, we found a burden of very rare FLT3 (13q12.2) variants associated with monocyte counts. Together, these results emphasize the utility of whole-genome sequencing in diverse samples in identifying associations missed by European-ancestry-driven GWASs.


Assuntos
Asma/epidemiologia , Biomarcadores/metabolismo , Dermatite Atópica/epidemiologia , Leucócitos/patologia , Polimorfismo de Nucleotídeo Único , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Locos de Características Quantitativas , Asma/genética , Asma/metabolismo , Asma/patologia , Dermatite Atópica/genética , Dermatite Atópica/metabolismo , Dermatite Atópica/patologia , Predisposição Genética para Doença , Genoma Humano , Estudo de Associação Genômica Ampla , Humanos , National Heart, Lung, and Blood Institute (U.S.) , Fenótipo , Prognóstico , Proteoma/análise , Proteoma/metabolismo , Doença Pulmonar Obstrutiva Crônica/genética , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/patologia , Reino Unido/epidemiologia , Estados Unidos/epidemiologia , Sequenciamento Completo do Genoma
5.
Artigo em Inglês | MEDLINE | ID: mdl-34111454

RESUMO

BACKGROUND: While numerous genetic loci associated with atopic dermatitis (AD) have been discovered, to date, work leveraging the combined burden of AD risk variants across the genome to predict disease risk has been limited. OBJECTIVES: This study aims to determine whether polygenic risk scores (PRSs) relying on genetic determinants for AD provide useful predictions for disease occurrence and severity. It also explicitly tests the value of including genome-wide association studies of related allergic phenotypes and known FLG loss-of-function (LOF) variants. METHODS: AD PRSs were constructed for 1619 European American individuals from the Atopic Dermatitis Research Network using an AD training dataset and an atopic training dataset including AD, childhood onset asthma, and general allergy. Additionally, whole genome sequencing data were used to explore genetic scoring specific to FLG LOF mutations. RESULTS: Genetic scores derived from the AD-only genome-wide association studies were predictive of AD cases (PRSAD: odds ratio [OR], 1.70; 95% CI, 1.49-1.93). Accuracy was first improved when PRSs were built off the larger atopy genome-wide association studies (PRSAD+: OR, 2.16; 95% CI, 1.89-2.47) and further improved when including FLG LOF mutations (PRSAD++: OR, 3.23; 95% CI, 2.57-4.07). Importantly, while all 3 PRSs correlated with AD severity, the best prediction was from PRSAD++, which distinguished individuals with severe AD from control subjects with OR of 3.86 (95% CI, 2.77-5.36). CONCLUSIONS: This study demonstrates how PRSs for AD that include genetic determinants across atopic phenotypes and FLG LOF variants may be a promising tool for identifying individuals at high risk for developing disease and specifically severe disease.

6.
Heliyon ; 7(4): e06878, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33997407

RESUMO

Congenital Zika virus syndrome (CZS) is associated with damage to neural progenitor cells by ZIKA virus infection. There are no accurate statistics on the percentage of pregnant mothers who have had babies affected by the syndrome. Few cases of discordant twins have been described in the literature and, therefore, we hypothesize that the genetic background of the progeny and/or mother may play a role in the fate of the syndrome. We performed a complete exome sequencing in a set of dizygotic individuals and their parents. After that, we selected discordant variants on the MTOR gene between the affected and unaffected twin and we observed a mutation (rs2295079), placed in a region restricted to proximal 5'-UTR, as a strong possible causal variant. In addition, in most brain tissues (including fetal brain) evaluated for expression quantitative trait loci (eQTL), this locus is strongly correlated with post-translational modifications of histones (promoter and enhancer marks) and hypersensitivity to DNAse I (open chromatin mark). Taken together, our data suggest that changes in the MTOR gene may be related to CZS. Additional functional studies should be carried out to prove how and why a MTOR mutation can predispose the fetus to the syndrome.

7.
Artigo em Inglês | MEDLINE | ID: mdl-33713768

RESUMO

BACKGROUND: Genetic ancestry plays a role in asthma health disparities. OBJECTIVE: Our aim was to evaluate the impact of ancestry on and identify genetic variants associated with asthma, total serum IgE level, and lung function. METHODS: A total of 436 Peruvian children (aged 9-19 years) with asthma and 291 without asthma were genotyped by using the Illumina Multi-Ethnic Global Array. Genome-wide proportions of indigenous ancestry populations from continental America (NAT) and European ancestry from the Iberian populations in Spain (IBS) were estimated by using ADMIXTURE. We assessed the relationship between ancestry and the phenotypes and performed a genome-wide association study. RESULTS: The mean ancestry proportions were 84.7% NAT (case patients, 84.2%; controls, 85.4%) and 15.3% IBS (15.8%; 14.6%). With adjustment for asthma, NAT was associated with higher total serum IgE levels (P < .001) and IBS was associated with lower total serum IgE levels (P < .001). NAT was associated with higher FEV1 percent predicted values (P < .001), whereas IBS was associated with lower FEV1 values in the controls but not in the case patients. The HLA-DR/DQ region on chromosome 6 (Chr6) was strongly associated with total serum IgE (rs3135348; P = 3.438 × 10-10) and was independent of an association with the haplotype HLA-DQA1∼HLA-DQB1:04.01∼04.02 (P = 1.55 × 10-05). For lung function, we identified a locus (rs4410198; P = 5.536 × 10-11) mapping to Chr19, near a cluster of zinc finger interacting genes that colocalizes to the long noncoding RNA CTD-2537I9.5. This novel locus was replicated in an independent sample of pediatric case patients with asthma with similar admixture from Brazil (P = .005). CONCLUSION: This study confirms the role of HLA in atopy, and identifies a novel locus mapping to a long noncoding RNA for lung function that may be specific to children with NAT.

8.
Allergy ; 76(8): 2510-2523, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33548076

RESUMO

BACKGROUND: Eczema herpeticum (EH) is a rare complication of atopic dermatitis (AD) caused by disseminated herpes simplex virus (HSV) infection. The role of rare and/or deleterious genetic variants in disease etiology is largely unknown. This study aimed to identify genes that harbor damaging genetic variants associated with HSV infection in AD with a history of recurrent eczema herpeticum (ADEH+). METHODS: Whole genome sequencing (WGS) was performed on 49 recurrent ADEH+ (≥3 EH episodes), 491 AD without a history of eczema herpeticum (ADEH-) and 237 non-atopic control (NA) subjects. Variants were annotated, and a gene-based approach (SKAT-O) was used to identify genes harboring damaging genetic variants associated with ADEH+. Genes identified through WGS were studied for effects on HSV responses and keratinocyte differentiation. RESULTS: Eight genes were identified in the comparison of recurrent ADEH+to ADEH-and NA subjects: SIDT2, CLEC7A, GSTZ1, TPSG1, SP110, RBBP8NL, TRIM15, and FRMD3. Silencing SIDT2 and RBBP8NL in normal human primary keratinocytes (NHPKs) led to significantly increased HSV-1 replication. SIDT2-silenced NHPKs had decreased gene expression of IFNk and IL1b in response to HSV-1 infection. RBBP8NL-silenced NHPKs had decreased gene expression of IFNk, but increased IL1b. Additionally, silencing SIDT2 and RBBP8NL also inhibited gene expression of keratinocyte differentiation markers keratin 10 (KRT10) and loricrin (LOR). CONCLUSION: SIDT2 and RBBP8NL participate in keratinocyte's response to HSV-1 infection. SIDT2 and RBBP8NL also regulate expression of keratinocyte differentiation genes of KRT10 and LOR.


Assuntos
Dermatite Atópica , Herpesvirus Humano 1 , Erupção Variceliforme de Kaposi , Proteínas de Transporte de Nucleotídeos , Dermatite Atópica/genética , Glutationa Transferase , Herpesvirus Humano 1/genética , Humanos , Erupção Variceliforme de Kaposi/genética , Mutação , Sequenciamento Completo do Genoma
9.
Nat Commun ; 11(1): 6417, 2020 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-33339817

RESUMO

Pharmaceutical drugs targeting dyslipidemia and cardiovascular disease (CVD) may increase the risk of fatty liver disease and other metabolic disorders. To identify potential novel CVD drug targets without these adverse effects, we perform genome-wide analyses of participants in the HUNT Study in Norway (n = 69,479) to search for protein-altering variants with beneficial impact on quantitative blood traits related to cardiovascular disease, but without detrimental impact on liver function. We identify 76 (11 previously unreported) presumed causal protein-altering variants associated with one or more CVD- or liver-related blood traits. Nine of the variants are predicted to result in loss-of-function of the protein. This includes ZNF529:p.K405X, which is associated with decreased low-density-lipoprotein (LDL) cholesterol (P = 1.3 × 10-8) without being associated with liver enzymes or non-fasting blood glucose. Silencing of ZNF529 in human hepatoma cells results in upregulation of LDL receptor and increased LDL uptake in the cells. This suggests that inhibition of ZNF529 or its gene product should be prioritized as a novel candidate drug target for treating dyslipidemia and associated CVD.


Assuntos
Doenças Cardiovasculares/genética , Genoma Humano , Mutação com Perda de Função/genética , Terapia de Alvo Molecular , Bancos de Espécimes Biológicos , Doenças Cardiovasculares/sangue , Inativação Gênica , Marcação de Genes , Estudo de Associação Genômica Ampla , Humanos , Lipídeos/sangue , Fígado/metabolismo , Fenômica , Receptores de LDL/genética , Reino Unido
10.
Curr Opin Immunol ; 66: 136-142, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33171417

RESUMO

In this review, we summarize recent published work interrogating the relationship between genetic variation or gene expression regulation across the genome and asthma or asthma treatment outcomes. This includes 11 genome-wide association studies of asthma phenotypes that collectively identified 64 novel loci; transcriptome-wide asthma association studies which identified genes involved in virus recognition, bacterial infection, lung tissue remodeling, eosinophilic and neutrophilic inflammation and genes in the chromosome 17q12 asthma susceptibility locus; and three epigenome-wide studies of asthma that had robust sample sizes and replicated findings. We also highlight pharmacogenomic studies of corticosteroids, bronchodilator response to albuterol and zileuton, although finding from these studies may still be preliminary due to their relatively small sample sizes and limited availability of replication cohorts.


Assuntos
Asma/genética , Farmacogenética , Variação Genética/genética , Humanos
11.
Nat Commun ; 11(1): 5182, 2020 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-33057025

RESUMO

Chronic obstructive pulmonary disease (COPD), diagnosed by reduced lung function, is a leading cause of morbidity and mortality. We performed whole genome sequence (WGS) analysis of lung function and COPD in a multi-ethnic sample of 11,497 participants from population- and family-based studies, and 8499 individuals from COPD-enriched studies in the NHLBI Trans-Omics for Precision Medicine (TOPMed) Program. We identify at genome-wide significance 10 known GWAS loci and 22 distinct, previously unreported loci, including two common variant signals from stratified analysis of African Americans. Four novel common variants within the regions of PIAS1, RGN (two variants) and FTO show evidence of replication in the UK Biobank (European ancestry n ~ 320,000), while colocalization analyses leveraging multi-omic data from GTEx and TOPMed identify potential molecular mechanisms underlying four of the 22 novel loci. Our study demonstrates the value of performing WGS analyses and multi-omic follow-up in cohorts of diverse ancestry.


Assuntos
Afro-Americanos/genética , Loci Gênicos , Doença Pulmonar Obstrutiva Crônica/genética , Fenômenos Fisiológicos Respiratórios/genética , Sequenciamento Completo do Genoma , Adulto , Idoso , Idoso de 80 Anos ou mais , Dioxigenase FTO Dependente de alfa-Cetoglutarato/genética , Proteínas de Ligação ao Cálcio/genética , Estudos de Viabilidade , Feminino , Seguimentos , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Pulmão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Proteínas Inibidoras de STAT Ativados/genética , Doença Pulmonar Obstrutiva Crônica/etnologia , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética
12.
F1000Res ; 9: 223, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32765839

RESUMO

Assignment of cell types from single-cell RNA sequencing (scRNA-seq) data remains a time-consuming and error-prone process. Current packages for identity assignment use limited types of reference data and often have rigid data structure requirements. We developed the clustifyr R package to leverage several external data types, including gene expression profiles to assign likely cell types using data from scRNA-seq, bulk RNA-seq, microarray expression data, or signature gene lists. We benchmark various parameters of a correlation-based approach and implement gene list enrichment methods. clustifyr is a lightweight and effective cell-type assignment tool developed for compatibility with various scRNA-seq analysis workflows. clustifyr is publicly available at https://github.com/rnabioco/clustifyr.


Assuntos
RNA Citoplasmático Pequeno , Análise de Sequência de RNA/métodos , Análise de Célula Única , Software , Perfilação da Expressão Gênica , Humanos
13.
Immunogenetics ; 72(5): 305-314, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32556499

RESUMO

Several genetic studies have implicated genes that encode for components of the innate immune response in tuberculosis (TB) susceptibility. The complement system is an early player in the innate immune response and provides the host with initial protection by promoting phagocytosis of apoptotic or necrotic cells. The C1q molecule is the first component of the classical pathway that leads to the activation of complement by binding to immune complexes and is encoded by the C1Q gene cluster. We investigated variants in this region to determine its association with TB susceptibility. Five single nucleotide polymorphisms (SNPs) (rs12033074, rs631090, rs172378, rs587585, and rs665691) were genotyped using TaqMan® SNP assays in 456 TB cases and 448 healthy controls and analysed by logistic regression models. The rs587585 variant showed a significant additive allelic association where the minor G allele was found more frequently in TB cases than in controls in both the discovery (p = 0.023; OR = 1.30; 95% CI, 1.04-1.64) and validation cohort (p = 0.038; OR = 1.31; 95% CI, 1.22-1.40). In addition, we detected increased C1qA expression when comparing cases and controls (p = 0.037) and linked this to a dosage effect of the G allele, which increased C1qA expression in TB cases. This is the first study to report the association of C1Q gene polymorphisms with progression to tuberculosis.


Assuntos
Complemento C1q/genética , Complemento C1q/metabolismo , Predisposição Genética para Doença/genética , Tuberculose/genética , Adulto , Grupo com Ancestrais do Continente Africano/genética , Alelos , Estudos de Casos e Controles , Feminino , Estudos de Associação Genética , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Família Multigênica , Polimorfismo de Nucleotídeo Único , Tuberculose/imunologia , Adulto Jovem
14.
Proc Natl Acad Sci U S A ; 117(5): 2560-2569, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31964835

RESUMO

De novo mutations (DNMs), or mutations that appear in an individual despite not being seen in their parents, are an important source of genetic variation whose impact is relevant to studies of human evolution, genetics, and disease. Utilizing high-coverage whole-genome sequencing data as part of the Trans-Omics for Precision Medicine (TOPMed) Program, we called 93,325 single-nucleotide DNMs across 1,465 trios from an array of diverse human populations, and used them to directly estimate and analyze DNM counts, rates, and spectra. We find a significant positive correlation between local recombination rate and local DNM rate, and that DNM rate explains a substantial portion (8.98 to 34.92%, depending on the model) of the genome-wide variation in population-level genetic variation from 41K unrelated TOPMed samples. Genome-wide heterozygosity does correlate with DNM rate, but only explains <1% of variation. While we are underpowered to see small differences, we do not find significant differences in DNM rate between individuals of European, African, and Latino ancestry, nor across ancestrally distinct segments within admixed individuals. However, we did find significantly fewer DNMs in Amish individuals, even when compared with other Europeans, and even after accounting for parental age and sequencing center. Specifically, we found significant reductions in the number of C→A and T→C mutations in the Amish, which seem to underpin their overall reduction in DNMs. Finally, we calculated near-zero estimates of narrow sense heritability (h 2), which suggest that variation in DNM rate is significantly shaped by nonadditive genetic effects and the environment.


Assuntos
Amish/genética , Genoma Humano , Adulto , Estudos de Coortes , Análise Mutacional de DNA , Feminino , Genética Populacional , Heterozigoto , Humanos , Masculino , Mutação , Linhagem , Sequenciamento Completo do Genoma , Adulto Jovem
15.
J Allergy Clin Immunol ; 146(1): 147-155, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31981624

RESUMO

BACKGROUND: Asthma is a complex chronic inflammatory disease of the airways. Association studies between HLA and asthma were first reported in the 1970s, and yet, the precise role of HLA alleles in asthma is not fully understood. Numerous genome-wide association studies were recently conducted on asthma, but were always limited to simple genetic markers (single nucleotide polymorphisms) and not complex HLA gene polymorphisms (alleles/haplotypes), therefore not capturing the biological relevance of this complex locus for asthma pathogenesis. OBJECTIVE: To run the first HLA-centric association study with asthma and specific asthma-related phenotypes in a large cohort of African-ancestry individuals. METHODS: We collected high-density genomics data for the Consortium on Asthma among African-ancestry Populations in the Americas (N = 4993) participants. Using computer-intensive machine-learning attribute bagging methods to infer HLA alleles, and Easy-HLA to infer HLA 5-gene haplotypes, we conducted a high-throughput HLA-centric association study of asthma susceptibility and total serum IgE (tIgE) levels in subjects with and without asthma. RESULTS: Among the 1607 individuals with asthma, 972 had available tIgE levels, with a mean tIgE level of 198.7 IU/mL. We could not identify any association with asthma susceptibility. However, we showed that HLA-DRB1∗09:01 was associated with increased tIgE levels (P = 8.5 × 10-4; weighted effect size, 0.51 [0.15-0.87]). CONCLUSIONS: We identified for the first time an HLA allele associated with tIgE levels in African-ancestry individuals with asthma. Our report emphasizes that by leveraging powerful computational machine-learning methods, specific/extreme phenotypes, and population diversity, we can explore HLA gene polymorphisms in depth and reveal the full extent of complex disease associations.


Assuntos
Afro-Americanos/genética , Alelos , Cadeias HLA-DRB1/genética , Imunoglobulina E/imunologia , Polimorfismo de Nucleotídeo Único , Asma , Feminino , Cadeias HLA-DRB1/imunologia , Humanos , Masculino
16.
Bioinformatics ; 36(7): 2157-2164, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-31750874

RESUMO

MOTIVATION: The HLA system plays a pivotal role in both clinical applications and immunology research. Typing HLA genes in patient and donor is indeed required in hematopoietic stem cell and solid-organ transplantation, and the histocompatibility complex region exhibits countless genetic associations with immune-related pathologies. Since the discovery of HLA antigens, the HLA system nomenclature and typing methods have constantly evolved, which leads to difficulties in using data generated with older methodologies. RESULTS: Here, we present Easy-HLA, a web-based software suite designed to facilitate analysis and gain knowledge from HLA typing, regardless of nomenclature or typing method. Easy-HLA implements a computational and statistical method of HLA haplotypes inference based on published reference populations containing over 600 000 haplotypes to upgrade missing or partial HLA information: 'HLA-Upgrade' tool infers high-resolution HLA typing and 'HLA-2-Haplo' imputes haplotype pairs and provides additional functional annotations (e.g. amino acids and KIR ligands). We validated both tools using two independent cohorts (total n = 2500). For HLA-Upgrade, we reached a prediction accuracy of 92% from low- to high-resolution of European genotypes. We observed a 96% call rate and 76% accuracy with HLA-2-Haplo European haplotype pairs prediction. In conclusion, Easy-HLA tools facilitate large-scale immunogenetic analysis and promotes the multi-faceted HLA expertise beyond allelic associations by providing new functional immunogenomics parameters. AVAILABILITY AND IMPLEMENTATION: Easy-HLA is a web application freely available (free account) at: https://hla.univ-nantes.fr. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Antígenos HLA , Alelos , Genótipo , Haplótipos , Teste de Histocompatibilidade , Humanos
17.
PLoS Genet ; 15(12): e1008500, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31869403

RESUMO

Most genome-wide association and fine-mapping studies to date have been conducted in individuals of European descent, and genetic studies of populations of Hispanic/Latino and African ancestry are limited. In addition, these populations have more complex linkage disequilibrium structure. In order to better define the genetic architecture of these understudied populations, we leveraged >100,000 phased sequences available from deep-coverage whole genome sequencing through the multi-ethnic NHLBI Trans-Omics for Precision Medicine (TOPMed) program to impute genotypes into admixed African and Hispanic/Latino samples with genome-wide genotyping array data. We demonstrated that using TOPMed sequencing data as the imputation reference panel improves genotype imputation quality in these populations, which subsequently enhanced gene-mapping power for complex traits. For rare variants with minor allele frequency (MAF) < 0.5%, we observed a 2.3- to 6.1-fold increase in the number of well-imputed variants, with 11-34% improvement in average imputation quality, compared to the state-of-the-art 1000 Genomes Project Phase 3 and Haplotype Reference Consortium reference panels. Impressively, even for extremely rare variants with minor allele count <10 (including singletons) in the imputation target samples, average information content rescued was >86%. Subsequent association analyses of TOPMed reference panel-imputed genotype data with hematological traits (hemoglobin (HGB), hematocrit (HCT), and white blood cell count (WBC)) in ~21,600 African-ancestry and ~21,700 Hispanic/Latino individuals identified associations with two rare variants in the HBB gene (rs33930165 with higher WBC [p = 8.8x10-15] in African populations, rs11549407 with lower HGB [p = 1.5x10-12] and HCT [p = 8.8x10-10] in Hispanics/Latinos). By comparison, neither variant would have been genome-wide significant if either 1000 Genomes Project Phase 3 or Haplotype Reference Consortium reference panels had been used for imputation. Our findings highlight the utility of the TOPMed imputation reference panel for identification of novel rare variant associations not previously detected in similarly sized genome-wide studies of under-represented African and Hispanic/Latino populations.


Assuntos
Afro-Americanos/genética , Hispano-Americanos/genética , Medicina de Precisão/métodos , Sequenciamento Completo do Genoma/métodos , Globinas beta/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Biologia Computacional/métodos , Bases de Dados Genéticas , Feminino , Frequência do Gene , Predisposição Genética para Doença , Genética Populacional , Estudo de Associação Genômica Ampla , Técnicas de Genotipagem , Humanos , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-Idade , Estados Unidos
19.
Chest ; 156(6): 1068-1079, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31557467

RESUMO

BACKGROUND: Asthma is a common respiratory disorder with a highly heterogeneous nature that remains poorly understood. The objective was to use whole genome sequencing (WGS) data to identify regions of common genetic variation contributing to lung function in individuals with a diagnosis of asthma. METHODS: WGS data were generated for 1,053 individuals from trios and extended pedigrees participating in the family-based Genetic Epidemiology of Asthma in Costa Rica study. Asthma affection status was defined through a physician's diagnosis of asthma, and most participants with asthma also had airway hyperresponsiveness (AHR) to methacholine. Family-based association tests for single variants were performed to assess the associations with lung function phenotypes. RESULTS: A genome-wide significant association was identified between baseline FEV1/FVC ratio and a single-nucleotide polymorphism in the top hit cysteine-rich secretory protein LCCL domain-containing 2 (CRISPLD2) (rs12051168; P = 3.6 × 10-8 in the unadjusted model) that retained suggestive significance in the covariate-adjusted model (P = 5.6 × 10-6). Rs12051168 was also nominally associated with other related phenotypes: baseline FEV1 (P = 3.3 × 10-3), postbronchodilator (PB) FEV1 (7.3 × 10-3), and PB FEV1/FVC ratio (P = 2.7 × 10-3). The identified baseline FEV1/FVC ratio and rs12051168 association was meta-analyzed and replicated in three independent cohorts in which most participants with asthma also had confirmed AHR (combined weighted z-score P = .015) but not in cohorts without information about AHR. CONCLUSIONS: These findings suggest that using specific asthma characteristics, such as AHR, can help identify more genetically homogeneous asthma subgroups with genotype-phenotype associations that may not be observed in all children with asthma. CRISPLD2 also may be important for baseline lung function in individuals with asthma who also may have AHR.


Assuntos
Asma/genética , Asma/fisiopatologia , Moléculas de Adesão Celular/genética , Volume Expiratório Forçado/genética , Fatores Reguladores de Interferon/genética , Capacidade Vital/genética , Sequenciamento Completo do Genoma , Adolescente , Adulto , Criança , Pré-Escolar , Costa Rica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fenômenos Fisiológicos Respiratórios/genética , Adulto Jovem
20.
Clin Epigenetics ; 11(1): 122, 2019 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-31443688

RESUMO

BACKGROUND: Although epigenetic mechanisms are important risk factors for allergic disease, few studies have evaluated DNA methylation differences associated with atopic dermatitis (AD), and none has focused on AD with eczema herpeticum (ADEH+). We will determine how methylation varies in AD individuals with/without EH and associated traits. We modeled differences in genome-wide DNA methylation in whole blood cells from 90 ADEH+, 83 ADEH-, and 84 non-atopic, healthy control subjects, replicating in 36 ADEH+, 53 ADEH-, and 55 non-atopic healthy control subjects. We adjusted for cell-type composition in our models and used genome-wide and candidate-gene approaches. RESULTS: We replicated one CpG which was significantly differentially methylated by severity, with suggestive replication at four others showing differential methylation by phenotype or severity. Not adjusting for eosinophil content, we identified 490 significantly differentially methylated CpGs (ADEH+ vs healthy controls, genome-wide). Many of these associated with severity measures, especially eosinophil count (431/490 sites). CONCLUSIONS: We identified a CpG in IL4 associated with serum tIgE levels, supporting a role for Th2 immune mediating mechanisms in AD. Changes in eosinophil level, a measure of disease severity, are associated with methylation changes, providing a potential mechanism for phenotypic changes in immune response-related traits.


Assuntos
Metilação de DNA , Dermatite Atópica/genética , Interleucina-4/genética , Erupção Variceliforme de Kaposi/genética , Estudos de Casos e Controles , Ilhas de CpG , Dermatite Atópica/imunologia , Eosinófilos/imunologia , Epigênese Genética , Feminino , Estudo de Associação Genômica Ampla , Humanos , Imunoglobulina E/metabolismo , Erupção Variceliforme de Kaposi/imunologia , Masculino , Índice de Gravidade de Doença , Células Th2/imunologia
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