scholarly journals Robust Association Tests for the Replication of Genome-Wide Association Studies

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Jungnam Joo ◽  
Ju-Hyun Park ◽  
Bora Lee ◽  
Boram Park ◽  
Sohee Kim ◽  
...  

In genome-wide association study (GWAS), robust genetic association tests such as maximum of three CATTs (MAX3), each corresponding to recessive, additive, and dominant genetic models, the minimumpvalue of Pearson’s Chi-square test with 2 degrees of freedom, and CATT based on additive genetic model (MIN2), genetic model selection (GMS), and genetic model exclusion (GME) methods have been shown to provide better power performance under wide range of underlying genetic models. In this paper, we demonstrate how these robust tests can be applied to the replication study of GWAS and how the overall statistical significance can be evaluated using the combined test formed bypvalues of the discovery and replication studies.

2021 ◽  
Vol 89 (6) ◽  
Author(s):  
Dylan Duchen ◽  
Rashidul Haque ◽  
Laura Chen ◽  
Genevieve Wojcik ◽  
Poonum Korpe ◽  
...  

ABSTRACT Shigella is a leading cause of moderate-to-severe diarrhea globally and the causative agent of shigellosis and bacillary dysentery. Associated with 80 to 165 million cases of diarrhea and >13% of diarrheal deaths, in many regions, Shigella exposure is ubiquitous while infection is heterogenous. To characterize host-genetic susceptibility to Shigella-associated diarrhea, we performed two independent genome-wide association studies (GWAS) including Bangladeshi infants from the PROVIDE and CBC birth cohorts in Dhaka, Bangladesh. Cases were infants with Shigella-associated diarrhea (n = 143) and controls were infants with no Shigella-associated diarrhea in the first 13 months of life (n = 446). Shigella-associated diarrhea was identified via quantitative PCR (qPCR) threshold cycle (CT) distributions for the ipaH gene, carried by all four Shigella species and enteroinvasive Escherichia coli. Host GWAS were performed under an additive genetic model. A joint analysis identified protective loci on chromosomes 11 (rs582240, within the KRT18P59 pseudogene; P = 6.40 × 10−8; odds ratio [OR], 0.43) and 8 (rs12550437, within the lincRNA RP11-115J16.1; P = 1.49 × 10−7; OR, 0.48). Conditional analyses identified two previously suggestive loci, a protective locus on chromosome 7 (rs10266841, within the 3′ untranslated region [UTR] of CYTH3; Pconditional = 1.48 × 10−7; OR, 0.44) and a risk-associated locus on chromosome 10 (rs2801847, an intronic variant within MPP7; Pconditional = 8.37 × 10−8; OR, 5.51). These loci have all been indirectly linked to bacterial type 3 secretion system (T3SS) activity, its components, and bacterial effectors delivered into host cells. Host genetic factors that may affect bacterial T3SS activity and are associated with the host response to Shigella-associated diarrhea may provide insight into vaccine and drug development efforts for Shigella-associated diarrheal disease.


2020 ◽  
Author(s):  
AUGUSTO Rojas-Martinez ◽  
Valentina Colistro ◽  
Raquel Cruz ◽  
Clara Ruiz ◽  
Inés Quintela ◽  
...  

Abstract Background: Genome-wide association studies (GWAS) for colorectal cancer (CRC) have detected high-risk genetic variants associated with CRC in several ethnic groups, but Latin American communities are still underrepresented. The aim was to identify variants related to CRC in an admixed Latin American population. Methods: The study was performed in 831 cases and 881 controls from Mexico, who were genotyped for 1,006,703 autosomal SNPs. Logistic regression was carried out including covariants, such as sex, age and genetic ancestry. Lastly, we performed a sequence-kernel association test (SKAT) to consider the joint effect of several SNPs lying in genes.Results: Eight chromosomal regions reached genome-wide significance level ( p < 5×10 -8 ): 1p36.22, 1p31.1, 1q42.13, 6p22, 7p14.1, 12q24.32, 16q12.2 and 21q22.2 and 63 variants reached borderline statistical significance ( p < 1×10 − 6 ). SKAT analysis detected 13 loci associated with CRC, none of them previously associated with CRC. Conclusions: We found 8 SNPs and 13 loci associated with CRC. These signals may contribute to enrich the panoply of genes involved with CRC. Further analyses remain to be done to validate the associations in other Latin American populations. This study highlights the importance of conducting GWAS in poorly explored admixed populations.


Circulation ◽  
2017 ◽  
Vol 135 (suppl_1) ◽  
Author(s):  
Changwei Li ◽  
Shengxu Li ◽  
James E Hixon

Background: Genome-wide association studies (GWASs) have identified multiple genomic loci associated with atherosclerotic diseases. However, specific genes underlying the observed associations are largely unknown. Objectives: We aimed to examine the associations between genes that harbor variants in high LD with index variants in GWAS-identified loci and pathologically determined atherosclerosis in major arteries from the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study. Methods and Results: Data for 1,938 single nucleotide polymorphisms (SNPs) from 28 genes were retrieved from whole exome sequence data. Atherosclerosis was confirmed by postmortem examination of major arteries from 1,005 young persons (aged 15-34 years) who died from non-cardiovascular causes. Logistic regression was used to evaluate associations between common SNPs and atherosclerosis controlling for age and sex. Gene-based analysis was conducted using Sequence Kernel Association Test (SKAT) method to test the combined effect of rare and common variants on atherosclerosis controlling for age and gender. All analyses were performed separately in blacks and whites. Statistical significance was determined by false positive discovery rate (FDR) method. In gene-based analyses, BUD13 ( P =1.11х10 -2 ) and COL4A1 ( P =3.58х10 -2 ) were associated with atherosclerosis among young blacks; none of the 28 genes was associated with atherosclerosis in whites. In single marker analysis of common SNPs, LRP1 missense variant rs7397167 ( P =8.50х10 -3 ), COL4A1 variant rs16975492 ( P =4.60х10 -3 ), STK32B variant rs168985 ( P =4.00х10 -3 ), and SMARCA4 variant rs8104480 ( P =1.20х10 -3 ) were associated with atherosclerosis in blacks; MIA3 variant rs17465637 ( P =8.00х10 -3 ), DUS4L missense variant rs6957510 ( P =6.4х10 -3 ), BOLL variant rs771018 ( P =6.2х10 -3 ), BUD3 missense variant rs11820589 ( P =2.1х10 -3 ), and COL4A1 variant rs1133219 ( P =1.8х10 -3 ) were associated with atherosclerosis in whites. Conclusion: Genes in GWAS-identified loci may play a role in the development of atherosclerosis at a young age.


2021 ◽  
Author(s):  
Yann C. Klimentidis ◽  
Michelle Newell ◽  
Matthijs D. van der Zee ◽  
Victoria L. Bland ◽  
Sebastian May-Wilson ◽  
...  

A lack of physical activity (PA) is one of the most pressing health issues facing society today. Our individual propensity for PA is partly influenced by genetic factors. Stated liking of various PA behaviors may capture additional dimensions of PA behavior that are not captured by other measures, and contribute to our understanding of the genetics of PA behavior. Here, in over 157,000 individuals from the UK Biobank, we sought to complement and extend previous findings on the genetics of PA behavior by performing genome-wide association studies of self-reported liking of several PA-related behaviors plus an additional derived trait of overall PA-liking. We identified a total of 19 unique genome-wide significant loci across all traits, only four of which overlap with loci previously identified for PA behavior. The PA-liking traits were genetically correlated with self-reported (rg: 0.38 to 0.80) and accelerometry-derived (rg: 0.26 to 0.49) PA measures, and with a wide range of health-related traits and dietary behaviors. Replication in the Netherlands Twin Register (NTR; n>7,300) and the TwinsUK (n>1,300) study revealed directionally consistent associations. Polygenic risk scores (PRS) were then trained in UKB for each PA-liking trait and for self-reported PA behavior. The PA-liking PRS significantly predicted the same liking trait in NTR. The PRS for liking of going to the gym predicted PA behavior in NTR (r2 = 0.40%) nearly as well as the one constructed based on self-reported PA behavior (r2 = 0.42%). Combining the two PRS into a single model increased the r2 to 0.59%, suggesting that although these PRS correlate with each other, they are also capturing distinct dimensions of PA behavior. In conclusion, we have identified the first loci associated with PA-liking, and extended and refined our understanding of the genetic basis of PA behavior.


2013 ◽  
Vol 2013 ◽  
pp. 1-12
Author(s):  
Dong-Dong Pan ◽  
Wen-Jun Xiong ◽  
Ji-Yuan Zhou ◽  
Ying Pan ◽  
Guo-Li Zhou ◽  
...  

Genome-wide association studies (GWASs) in identifying the disease-associated genetic variants have been proved to be a great pioneering work. Two-stage design and analysis are often adopted in GWASs. Considering the genetic model uncertainty, many robust procedures have been proposed and applied in GWASs. However, the existing approaches mostly focused on binary traits, and few work has been done on continuous (quantitative) traits, since the statistical significance of these robust tests is difficult to calculate. In this paper, we develop a powerfulF-statistic-based robust joint analysis method for quantitative traits using the combined raw data from both stages in the framework of two-staged GWASs. Explicit expressions are obtained to calculate the statistical significance and power. We show using simulations that the proposed method is substantially more robust than theF-test based on the additive model when the underlying genetic model is unknown. An example for rheumatic arthritis (RA) is used for illustration.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Daniel L. McCartney ◽  
Josine L. Min ◽  
Rebecca C. Richmond ◽  
Ake T. Lu ◽  
Maria K. Sobczyk ◽  
...  

Abstract Background Biological aging estimators derived from DNA methylation data are heritable and correlate with morbidity and mortality. Consequently, identification of genetic and environmental contributors to the variation in these measures in populations has become a major goal in the field. Results Leveraging DNA methylation and SNP data from more than 40,000 individuals, we identify 137 genome-wide significant loci, of which 113 are novel, from genome-wide association study (GWAS) meta-analyses of four epigenetic clocks and epigenetic surrogate markers for granulocyte proportions and plasminogen activator inhibitor 1 levels, respectively. We find evidence for shared genetic loci associated with the Horvath clock and expression of transcripts encoding genes linked to lipid metabolism and immune function. Notably, these loci are independent of those reported to regulate DNA methylation levels at constituent clock CpGs. A polygenic score for GrimAge acceleration showed strong associations with adiposity-related traits, educational attainment, parental longevity, and C-reactive protein levels. Conclusion This study illuminates the genetic architecture underlying epigenetic aging and its shared genetic contributions with lifestyle factors and longevity.


2018 ◽  
Author(s):  
Natalie Terzikhan ◽  
Fangui Sun ◽  
Fien M. Verhamme ◽  
Hieab H.H. Adams ◽  
Daan Loth ◽  
...  

AbstractBackgroundAlthough several genome wide association studies (GWAS) have investigated the genetics of pulmonary ventilatory function, little is known about the genetic factors that influence gas exchange.AimTo investigate the heritability of, and genetic variants associated with the diffusing capacity of the lung.MethodsGWAS was performed on diffusing capacity, measured by carbon monoxide uptake (DLCO) and per alveolar volume (DLCO/VA) using the single-breath technique, in 8,372 individuals from two population-based cohort studies, the Rotterdam Study and the Framingham Heart Study. Heritability was estimated in related (n=6,246) and unrelated (n=3,286) individuals.ResultsHeritability of DLCO and DLCO/VA ranged between 23% and 28% in unrelated individuals and between 45% and 49% in related individuals. Meta-analysis identified a genetic variant in GPR126 that is significantly associated with DLCO/VA. Gene expression analysis of GPR126 in human lung tissue revealed a decreased expression in patients with COPD and subjects with decreased DLCO/VA.ConclusionDLCO and DLCO/VA are heritable traits, with a considerable proportion of variance explained by genetics. A functional variant in GPR126 gene region was significantly associated with DLCO/VA. Pulmonary GPR126 expression was decreased in patients with COPD.


Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2386
Author(s):  
Pierre-Olivier Hébert ◽  
Martin Laforest ◽  
Dong Xu ◽  
Marie Ciotola ◽  
Mélanie Cadieux ◽  
...  

Bacterial leaf spot of lettuce, caused by Xanthomonas hortorum pv. vitians, is an economically important disease worldwide. For instance, it caused around 4 million CAD in losses in only a few months during the winter of 1992 in Florida. Because only one pesticide is registered to control this disease in Canada, the development of lettuce cultivars tolerant to bacterial leaf spot remains the most promising approach to reduce the incidence and severity of the disease in lettuce fields. The lack of information about the genetic diversity of the pathogen, however, impairs breeding programs, especially when disease resistance is tested on newly developed lettuce germplasm lines. To evaluate the diversity of X. hortorum pv. vitians, a multilocus sequence analysis was performed on 694 isolates collected in Eastern Canada through the summers of 2014 to 2017 and two isolates in 1996 and 2007. All isolates tested were clustered into five phylogroups. Six pathotypes were identified following pathogenicity tests conducted in greenhouses, but when phylogroups were compared with pathotypes, no correlation could be drawn. However, in vitro production of xanthan and xanthomonadins was investigated, and isolates with higher production of xanthomonadins were generally causing less severe symptoms on the tolerant cultivar Little Gem. Whole-genome sequencing was undertaken for 95 isolates belonging to the pathotypes identified, and de novo assembly made with reads unmapped to the reference strain’s genome sequence resulted in 694 contigs ranging from 128 to 120,795 bp. Variant calling was performed prior to genome-wide association studies computed with single-nucleotide polymorphisms (SNPs), copy-number variants and gaps. Polymorphisms with significant p-values were only found on the cultivar Little Gem. Our results allowed molecular identification of isolates likely to cause bacterial leaf spot of lettuce, using two SNPs identified through genome-wide association study.


2019 ◽  
Vol 22 (8) ◽  
pp. 1063-1069 ◽  
Author(s):  
N. S. Yudin ◽  
N. L. Podkolodnyy ◽  
T. A. Agarkova ◽  
E. V. Ignatieva

Selection by means of genetic markers is a promising approach to the eradication of infectious diseases in farm animals, especially in the absence of effective methods of treatment and prevention. Bovine leukemia virus (BLV) is spread throughout the world and represents one of the biggest problems for the livestock production and food security in Russia. However, recent genome-wide association studies have shown that sensitivity/resistance to BLV is polygenic. The aim of this study was to create a catalog of cattle genes and genes of other mammalian species involved in the pathogenesis of BLV-induced infection and to perform gene prioritization using bioinformatics methods. Based on manually collected information from a range of open sources, a total of 446 genes were included in the catalog of cattle genes and genes of other mammals involved in the pathogenesis of BLV-induced infection. The following criteria were used to prioritize 446 genes from the catalog: (1) the gene is associated with leukemia according to a genome-wide association study; (2) the gene is associated with leukemia according to a case-control study; (3) the role of the gene in leukemia development has been studied using knockout mice; (4) protein-protein interactions exist between the gene-encoded protein and either viral particles or individual viral proteins; (5) the gene is annotated with Gene Ontology terms that are overrepresented for a given list of genes; (6) the gene participates in biological pathways from the KEGG or REACTOME databases, which are over-represented for a given list of genes; (7) the protein encoded by the gene has a high number of protein-protein interactions with proteins encoded by other genes from the catalog. Based on each criterion, a rank was assigned to each gene. Then the ranks were summarized and an overall rank was determined. Prioritization of 446 candidate genes allowed us to identify 5 genes of interest (TNF,LTB,BOLA-DQA1,BOLA-DRB3,ATF2), which can affect the sensitivity/resistance of cattle to leukemia.


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