Abstract MP32: Epigenome-Wide DNA Methylation Profiling in a CVD Cohort: The ARIC Study

Circulation ◽  
2013 ◽  
Vol 127 (suppl_12) ◽  
Author(s):  
James S Pankow ◽  
Ellen W Demerath ◽  
Weihua Guan ◽  
Myriam Fornage ◽  
Thomas H Mosley ◽  
...  
Keyword(s):  
Dna Methylation ◽  
X Chromosome ◽  
Methylation Level ◽  
Association Studies ◽  
Univariate Analysis ◽  
European Ancestry ◽  
Genome Wide Association Studies ◽  
Stage Of Development ◽  
Average Methylation ◽  
Aric Study

DNA methylation is mitotically heritable modification in chromatin structure that impacts transcriptional control of genes and cellular function. Recent technological advances provide opportunities to systematically interrogate variation in DNA methylation across the genome in large epidemiologic studies. However, unlike inherited changes to the genetic sequence, variation in site-specific methylation varies by tissue, stage of development, disease state, and may be affected by gender, aging and exposure to environmental factors. As a result, there is likely a greater threat of confounding in epigenome-wide methylation studies compared to genome-wide association studies of SNPs. The Illumina Infinium HumanMethylation450 BeadChip was used to measure DNA methylation in peripheral blood obtained from African American participants from the Jackson, Mississippi and Forsyth County, North Carolina field centers of the Atherosclerosis Risk in Communities (ARIC) Study, a population-based cohort of middle-aged men and women. After excluding outlier samples and CpG sites using quality control filters, we analyzed 473,687 sites in 2873 subjects who were between 47-71 years of age at the time of DNA collection. We used linear regression with robust standard errors to examine cross-sectional associations of demographic factors with the beta value, an estimate of the average methylation level at each locus, and applied a Bonferroni correction to account for multiple testing. In univariate analysis, 91% of sites on the X chromosome and 10% of sites on the autosomes exhibited statistically significant gender differences in methylation level (p<1x10-7). Average methylation was higher in women than men for most of the significant sites (63% and 89% on the X chromosome and autosomes, respectively). Percent European ancestry estimated from ancestry informative markers was significantly associated with methylation level at 4% of sites. Age was also significantly associated with methylation at 4% of sites; average methylation was lower in older subjects compared to younger subjects for the majority (58%) of these sites. As we begin to implement epigenome-wide studies of DNA methylation and CVD outcomes, these results indicate that such studies will require careful consideration of adjustment techniques to avoid confounding by gender, age, and other covariates.

scholarly journals Rare coding variants and X-linked loci associated with age at menarche

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Kathryn L. Lunetta ◽  
◽  
Felix R. Day ◽  
Patrick Sulem ◽  
Katherine S. Ruth ◽  
...  
Keyword(s):  
X Chromosome ◽  
Energy Homeostasis ◽  
Association Studies ◽  
Acid Amide ◽  
European Ancestry ◽  
Transcriptional Gene Silencing ◽  
Age At Menarche ◽  
Genome Wide Association Studies ◽  
Sources Of Variation ◽  
Coding Variants

Abstract More than 100 loci have been identified for age at menarche by genome-wide association studies; however, collectively these explain only ∼3% of the trait variance. Here we test two overlooked sources of variation in 192,974 European ancestry women: low-frequency protein-coding variants and X-chromosome variants. Five missense/nonsense variants (in ALMS1/LAMB2/TNRC6A/TACR3/PRKAG1) are associated with age at menarche (minor allele frequencies 0.08–4.6%; effect sizes 0.08–1.25 years per allele; P<5 × 10−8). In addition, we identify common X-chromosome loci at IGSF1 (rs762080, P=9.4 × 10−13) and FAAH2 (rs5914101, P=4.9 × 10−10). Highlighted genes implicate cellular energy homeostasis, post-transcriptional gene silencing and fatty-acid amide signalling. A frequently reported mutation in TACR3 for idiopathic hypogonatrophic hypogonadism (p.W275X) is associated with 1.25-year-later menarche (P=2.8 × 10−11), illustrating the utility of population studies to estimate the penetrance of reportedly pathogenic mutations. Collectively, these novel variants explain ∼0.5% variance, indicating that these overlooked sources of variation do not substantially explain the ‘missing heritability’ of this complex trait.

scholarly journals Joint Influence of SNPs and DNA Methylation on Lipids in African Americans From Hypertensive Sibships

2018 ◽  
Vol 20 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Michelle L. Wright ◽  
Erin B. Ware ◽  
Jennifer A. Smith ◽  
Sharon L. R. Kardia ◽  
Jacquelyn Y. Taylor
Keyword(s):  
Dna Methylation ◽  
African Americans ◽  
Serum Lipid ◽  
Large Scale ◽  
Association Studies ◽  
Plasma Concentrations ◽  
European Ancestry ◽  
Genome Wide Association Studies ◽  
Lipid Levels ◽  
Serum Lipid Levels

Introduction: Plasma concentrations of lipids (i.e., total cholesterol, high-density cholesterol, low-density cholesterol, and triglycerides) are amenable to therapeutic intervention and remain important factors for assessing risk of cardiovascular diseases. Some of the observed variability in serum lipid concentrations has been associated with genetic and epigenetic variants among cohorts with European ancestry (EA). Serum lipid levels have also been associated with genetic variants in multiethnic populations. Methods: The purpose of this study was to determine whether single-nucleotide polymorphisms (SNPs) and DNA methylation (DNAm) differences contribute to lipid variation among African Americans ([AAs], N = 739) in the Genetic Epidemiology Network of Arteriopathy (GENOA) study. Results: Previous meta-analyses identified 161 SNPs that are associated with lipid traits in populations of EA. We evaluated these SNPs and 66 DNAm sites within the genes containing the SNPs in the GENOA cohort using linear mixed-effects modeling. We did not identify any significant associations of SNPs or DNAm with serum lipid levels. These results suggest that the SNPs identified as being significant for lipid levels through the EA genome-wide association studies may not be significant across AA populations. Conclusions: Reductions in morbidity and mortality due to variation in lipids among AAs may be achieved through a better understanding of the genetic and epigenetic factors associated with serum lipid levels for early and appropriate screening. Further large-scale studies specifically within AA and other non-EA populations are warranted.

scholarly journals Gene-methylation interactions: Discovering region-wise DNA methylation levels that modify SNP-associated disease risk

2019 ◽  
Author(s):  
Julia Romanowska ◽  
Øystein A. Haaland ◽  
Astanand Jugessur ◽  
Miriam Gjerdevik ◽  
Zongli Xu ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Methylation Level ◽  
Disease Risk ◽  
Association Studies ◽  
R Package ◽  
Epigenetic Mark ◽  
Genome Wide Association Studies ◽  
Association Analyses ◽  
Cpg Dinucleotides ◽  
New Methods

AbstractThe genetic code is tightly linked to epigenetic instructions as to what genes to express, and when and where to express them. The most studied epigenetic mark is DNA methylation at CpG dinucleotides. Today’s technology enables a rapid assessment of DNA sequence and methylation levels at a single-site resolution for hundreds of thousands of sites in the human genome, in thousands of individuals at a time. Recent years have seen a rapid increase in epigenome-wide association studies (EWAS) searching for the causes of risk for genetic diseases that previous genome-wide association studies (GWAS) could not pinpoint. However, those single-omics data analyses led to even more questions and it has become clear that only by integrating data one can get closer to answers. Here, we propose two new methods within genetic association analyses that treat the level of DNA methylation at a given CpG site as environmental exposure. Our analyses search for statistical interactions between a given allele and DNA methylation (G×Me), and between a parent-of-origin effect and DNA methylation (PoO× Me). The new methods were implemented in the R package Haplin and were tested on a dataset comprising genotype data from mother-father-child triadsm with DNA methylation data from the children only. The phenotype here was orofacial clefts (OFC), a relatively common birth defect in humans, which is known to have a genetic origin and an environmental component possibly mediated by DNA methylation. We found no significant PoO×Me interactions and a few significant G×Me interactions. Our results show that the significance of these interaction effects depends on the genomic region in which the CpGs reside and on the number of strata of methylation level. We demonstrate that, by including the methylation level around the SNP in the analyses, the estimated relative risk of OFC can change significantly. We also discuss the importance of including control data in such analyses. The new methods will be of value for all the researchers who want to explore genome- and epigenome-wide datasets in an integrative manner. Moreover, thanks to the implementation in a popular R package, the methods are easily accessible and enable fast scans of the genome- and epigenome-wide datasets.

scholarly journals Genome-wide association studies identify 137 genetic loci for DNA methylation biomarkers of aging

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Daniel L. McCartney ◽  
Josine L. Min ◽  
Rebecca C. Richmond ◽  
Ake T. Lu ◽  
Maria K. Sobczyk ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Genome Wide Association Study ◽  
Association Studies ◽  
Genome Wide Association ◽  
Biological Aging ◽  
Genome Wide Association Studies ◽  
Genetic Loci ◽  
Biomarkers Of Aging ◽  
Genome Wide ◽  
Shared Genetic

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.

scholarly journals Causal Association between Periodontitis and Parkinson’s Disease: A Bidirectional Mendelian Randomization Study

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 772
Author(s):  
João Botelho ◽  
Vanessa Machado ◽  
José João Mendes ◽  
Paulo Mascarenhas
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Instrumental Variables ◽  
Mendelian Randomization ◽  
Association Studies ◽  
European Ancestry ◽  
Genome Wide Association Studies ◽  
Nucleotide Polymorphisms ◽  
Genetic Liability ◽  
Bidirectional Association

The latest evidence revealed a possible association between periodontitis and Parkinson’s disease (PD). We explored the causal relationship of this bidirectional association through two-sample Mendelian randomization (MR) in European ancestry populations. To this end, we used openly accessible data of genome-wide association studies (GWAS) on periodontitis and PD. As instrumental variables for periodontitis, seventeen single-nucleotide polymorphisms (SNPs) from a GWAS of periodontitis (1817 periodontitis cases vs. 2215 controls) and eight non-overlapping SNPs of periodontitis from an additional GWAS for validation purposes. Instrumental variables to explore for the reverse causation included forty-five SNPs from a GWAS of PD (20,184 cases and 397,324 controls). Multiple approaches of MR were carried-out. There was no evidence of genetic liability of periodontitis being associated with a higher risk of PD (B = −0.0003, Standard Error [SE] 0.0003, p = 0.26). The eight independent SNPs (B = −0.0000, SE 0.0001, p = 0.99) validated this outcome. We also found no association of genetically primed PD towards periodontitis (B = −0.0001, SE 0.0001, p = 0.19). These MR study findings do not support a bidirectional causal genetic liability between periodontitis and PD. Further GWAS studies are needed to confirm the consistency of these results.

scholarly journals Genetics and Epigenetics in Asthma

2021 ◽  
Vol 22 (5) ◽  
pp. 2412
Author(s):  
Polyxeni Ntontsi ◽  
Andreas Photiades ◽  
Eleftherios Zervas ◽  
Georgina Xanthou ◽  
Konstantinos Samitas
Keyword(s):  
Dna Methylation ◽  
Association Studies ◽  
Airway Remodeling ◽  
Methylation Pattern ◽  
Atopic Asthma ◽  
Genome Wide Association Studies ◽  
Childhood Onset ◽  
Gene Markers ◽  
Asthmatic Patients ◽  
Asthma Susceptibility

Asthma is one of the most common respiratory disease that affects both children and adults worldwide, with diverse phenotypes and underlying pathogenetic mechanisms poorly understood. As technology in genome sequencing progressed, scientific efforts were made to explain and predict asthma’s complexity and heterogeneity, and genome-wide association studies (GWAS) quickly became the preferred study method. Several gene markers and loci associated with asthma susceptibility, atopic and childhood-onset asthma were identified during the last few decades. Markers near the ORMDL3/GSDMB genes were associated with childhood-onset asthma, interleukin (IL)33 and IL1RL1 SNPs were associated with atopic asthma, and the Thymic Stromal Lymphopoietin (TSLP) gene was identified as protective against the risk to TH2-asthma. The latest efforts and advances in identifying and decoding asthma susceptibility are focused on epigenetics, heritable characteristics that affect gene expression without altering DNA sequence, with DNA methylation being the most described mechanism. Other less studied epigenetic mechanisms include histone modifications and alterations of miR expression. Recent findings suggest that the DNA methylation pattern is tissue and cell-specific. Several studies attempt to describe DNA methylation of different types of cells and tissues of asthmatic patients that regulate airway remodeling, phagocytosis, and other lung functions in asthma. In this review, we attempt to briefly present the latest advancements in the field of genetics and mainly epigenetics concerning asthma susceptibility.

scholarly journals Children’s Greenness Exposure and IQ-Associated DNA Methylation: A Prospective Cohort Study

2021 ◽  
Vol 18 (14) ◽  
pp. 7429
Author(s):  
Kyung-Shin Lee ◽  
Yoon-Jung Choi ◽  
Jin-Woo Cho ◽  
Sung-Ji Moon ◽  
Youn-Hee Lim ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cohort Study ◽  
Literature Review ◽  
Cognitive Ability ◽  
Prospective Cohort Study ◽  
Prospective Cohort ◽  
Association Studies ◽  
The Body ◽  
Genome Wide Association Studies ◽  
Regulatory Pathways

Epigenetics is known to be involved in regulatory pathways through which greenness exposure influences child development and health. We aimed to investigate the associations between residential surrounding greenness and DNA methylation changes in children, and further assessed the association between DNA methylation and children’s intelligence quotient (IQ) in a prospective cohort study. We identified cytosine-guanine dinucleotide sites (CpGs) associated with cognitive abilities from epigenome- and genome-wide association studies through a systematic literature review for candidate gene analysis. We estimated the residential surrounding greenness at age 2 using a geographic information system. DNA methylation was analyzed from whole blood using the HumanMethylationEPIC array in 59 children at age 2. We analyzed the association between greenness exposure and DNA methylation at age 2 at the selected CpGs using multivariable linear regression. We further investigated the relationship between DNA methylation and children’s IQ. We identified 8743 CpGs associated with cognitive ability based on the literature review. Among these CpGs, we found that 25 CpGs were significantly associated with greenness exposure at age 2, including cg26269038 (Bonferroni-corrected p ≤ 0.05) located in the body of SLC6A3, which encodes a dopamine transporter. DNA methylation at cg26269038 at age 2 was significantly associated with children’s performance IQ at age 6. Exposure to surrounding greenness was associated with cognitive ability-related DNA methylation changes, which was also associated with children’s IQ. Further studies are warranted to clarify the epigenetic pathways linking greenness exposure and neurocognitive function.

Trans-Ethnic Meta-Analysis of Interactions Between Genetics and Early-Life Socioeconomic Context on Memory Performance and Decline in Older Americans

2021 ◽  
Author(s):  
Jessica D Faul ◽  
Minjung Kho ◽  
Wei Zhao ◽  
Kalee E Rumfelt ◽  
Miao Yu ◽  
...  
Keyword(s):  
Parental Education ◽  
Association Studies ◽  
Memory Performance ◽  
Meta Analysis ◽  
African Ancestry ◽  
Later Life ◽  
European Ancestry ◽  
Genome Wide Association Studies ◽  
Multiple Testing Correction ◽  
Socioeconomic Context

Abstract Background Later-life cognitive function is influenced by genetics as well as early- and later-life socioeconomic context. However, few studies have examined the interaction between genetics and early childhood factors. Methods Using gene-based tests (interaction sequence kernel association test [iSKAT]/iSKAT optimal unified test), we examined whether common and/or rare exonic variants in 39 gene regions previously associated with cognitive performance, dementia, and related traits had an interaction with childhood socioeconomic context (parental education and financial strain) on memory performance or decline in European ancestry (EA, N = 10 468) and African ancestry (AA, N = 2 252) participants from the Health and Retirement Study. Results Of the 39 genes, 22 in EA and 19 in AA had nominally significant interactions with at least one childhood socioeconomic measure on memory performance and/or decline; however, all but one (father’s education by solute carrier family 24 member 4 [SLC24A4] in AA) were not significant after multiple testing correction (false discovery rate [FDR] &lt; .05). In trans-ethnic meta-analysis, 2 genes interacted with childhood socioeconomic context (FDR &lt; .05): mother’s education by membrane-spanning 4-domains A4A (MS4A4A) on memory performance, and father’s education by SLC24A4 on memory decline. Both interactions remained significant (p &lt; .05) after adjusting for respondent’s own educational attainment, apolipoprotein-ε4 allele (APOE ε4) status, lifestyle factors, body mass index, and comorbidities. For both interactions in EA and AA, the genetic effect was stronger in participants with low parental education. Conclusions Examination of common and rare variants in genes discovered through genome-wide association studies shows that childhood context may interact with key gene regions to jointly impact later-life memory function and decline. Genetic effects may be more salient for those with lower childhood socioeconomic status.

scholarly journals Genome-Wide Meta-Analysis Validates a Role for S1PR1 in Microtubule Targeting Agent-Induced Sensory Peripheral Neuropathy

2020 ◽  
Author(s):  
Katherina C. Chua ◽  
Chenling Xiong ◽  
Carol Ho ◽  
Taisei Mushiroda ◽  
Chen Jiang ◽  
...  
Keyword(s):  
Peripheral Neuropathy ◽  
Association Studies ◽  
Meta Analysis ◽  
Regulatory Elements ◽  
Hazard Ratio ◽  
European Ancestry ◽  
Genome Wide Association Studies ◽  
Sensory Peripheral Neuropathy ◽  
Genome Wide ◽  
Microtubule Targeting Agents

AbstractMicrotubule targeting agents (MTAs) are anticancer therapies commonly prescribed for breast cancer and other solid tumors. Sensory peripheral neuropathy (PN) is the major dose-limiting toxicity for MTAs and can limit clinical efficacy. The current pharmacogenomic study aimed to identify genetic variations that explain patient susceptibility and drive mechanisms underlying development of MTA-induced PN. A meta-analysis of genome-wide association studies (GWAS) from two clinical cohorts treated with MTAs (CALGB 40502 and CALGB 40101) was conducted using a Cox regression model with cumulative dose to first instance of grade 2 or higher PN. Summary statistics from a GWAS of European subjects (n = 469) in CALGB 40502 that estimated cause-specific risk of PN were meta-analyzed with those from a previously published GWAS of European ancestry (n = 855) from CALGB 40101 that estimated the risk of PN. Novel single nucleotide polymorphisms in an enhancer region downstream of sphingosine-1-phosphate receptor 1 (S1PR1 encoding S1PR1; e.g., rs74497159, βCALGB40101 per allele log hazard ratio (95% CI) = 0.591 (0.254 - 0.928), βCALGB40502 per allele log hazard ratio (95% CI) = 0.693 (0.334 - 1.053); PMETA = 3.62×10−7) were the most highly ranked associations based on P-values with risk of developing grade 2 and higher PN. In silico functional analysis identified multiple regulatory elements and potential enhancer activity for S1PR1 within this genomic region. Inhibition of S1PR1 function in iPSC-derived human sensory neurons shows partial protection against paclitaxel-induced neurite damage. These pharmacogenetic findings further support ongoing clinical evaluations to target S1PR1 as a therapeutic strategy for prevention and/or treatment of MTA-induced neuropathy.

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