scholarly journals Epigenome-wide association studies: current knowledge, strategies and recommendations

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Maria Pia Campagna ◽  
Alexandre Xavier ◽  
Jeannette Lechner-Scott ◽  
Vicky Maltby ◽  
Rodney J. Scott ◽  
...  
Keyword(s):  
Complex Disease ◽  
Current Knowledge ◽  
Association Studies ◽  
Epigenetic Mechanism ◽  
Differentially Methylated Region ◽  
Blood Collection ◽  
Methylation Data ◽  
Mixed Cell ◽  
Biological Interface ◽  
Genetic And Environmental Factors

AbstractThe aetiology and pathophysiology of complex diseases are driven by the interaction between genetic and environmental factors. The variability in risk and outcomes in these diseases are incompletely explained by genetics or environmental risk factors individually. Therefore, researchers are now exploring the epigenome, a biological interface at which genetics and the environment can interact. There is a growing body of evidence supporting the role of epigenetic mechanisms in complex disease pathophysiology. Epigenome-wide association studies (EWASes) investigate the association between a phenotype and epigenetic variants, most commonly DNA methylation. The decreasing cost of measuring epigenome-wide methylation and the increasing accessibility of bioinformatic pipelines have contributed to the rise in EWASes published in recent years. Here, we review the current literature on these EWASes and provide further recommendations and strategies for successfully conducting them. We have constrained our review to studies using methylation data as this is the most studied epigenetic mechanism; microarray-based data as whole-genome bisulphite sequencing remains prohibitively expensive for most laboratories; and blood-based studies due to the non-invasiveness of peripheral blood collection and availability of archived DNA, as well as the accessibility of publicly available blood-cell-based methylation data. Further, we address multiple novel areas of EWAS analysis that have not been covered in previous reviews: (1) longitudinal study designs, (2) the chip analysis methylation pipeline (ChAMP), (3) differentially methylated region (DMR) identification paradigms, (4) methylation quantitative trait loci (methQTL) analysis, (5) methylation age analysis and (6) identifying cell-specific differential methylation from mixed cell data using statistical deconvolution.

scholarly journals Host Genetics and Gut Microbiome: Perspectives for Multiple Sclerosis

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1181
Author(s):  
Alessandro Maglione ◽  
Miriam Zuccalà ◽  
Martina Tosi ◽  
Marinella Clerico ◽  
Simona Rolla
Keyword(s):  
Multiple Sclerosis ◽  
Environmental Factors ◽  
Lupus Erythematosus ◽  
Gut Microbiome ◽  
Complex Disease ◽  
Current Knowledge ◽  
Association Studies ◽  
Future Research ◽  
Genome Wide Association Studies ◽  
Host Genetics

As a complex disease, Multiple Sclerosis (MS)’s etiology is determined by both genetic and environmental factors. In the last decade, the gut microbiome has emerged as an important environmental factor, but its interaction with host genetics is still unknown. In this review, we focus on these dual aspects of MS pathogenesis: we describe the current knowledge on genetic factors related to MS, based on genome-wide association studies, and then illustrate the interactions between the immune system, gut microbiome and central nervous system in MS, summarizing the evidence available from Experimental Autoimmune Encephalomyelitis mouse models and studies in patients. Finally, as the understanding of influence of host genetics on the gut microbiome composition in MS is in its infancy, we explore this issue based on the evidence currently available from other autoimmune diseases that share with MS the interplay of genetic with environmental factors (Inflammatory Bowel Disease, Rheumatoid Arthritis and Systemic Lupus Erythematosus), and discuss avenues for future research.

scholarly journals Current Insights in Genetics of Sarcoidosis: Functional and Clinical Impacts

2020 ◽  
Vol 9 (8) ◽  
pp. 2633 ◽  
Author(s):  
Alain Calender ◽  
Thomas Weichhart ◽  
Dominique Valeyre ◽  
Yves Pacheco
Keyword(s):  
Complex Disease ◽  
Current Knowledge ◽  
Association Studies ◽  
Genetic Research ◽  
Genome Wide Association Studies ◽  
Genome Wide ◽  
Whole Exome ◽  
Next Generation Sequencing Ngs ◽  
Generation Sequencing ◽  
Future Management

Sarcoidosis is a complex disease that belongs to the vast group of autoinflammatory disorders, but the etiological mechanisms of which are not known. At the crosstalk of environmental, infectious, and genetic factors, sarcoidosis is a multifactorial disease that requires a multidisciplinary approach for which genetic research, in particular, next generation sequencing (NGS) tools, has made it possible to identify new pathways and propose mechanistic hypotheses. Codified treatments for the disease cannot always respond to the most progressive forms and the identification of new genetic and metabolic tracks is a challenge for the future management of the most severe patients. Here, we review the current knowledge regarding the genes identified by both genome wide association studies (GWAS) and whole exome sequencing (WES), as well the connection of these pathways with the current research on sarcoidosis immune-related disorders.

Identification of Antineoplastic Targets with Systems Approaches, Using Resveratrol as an In-Depth Case Study

2017 ◽  
Vol 23 (32) ◽  
pp. 4773-4793 ◽  
Author(s):  
Nivedita Singh ◽  
Sherry Freiesleben ◽  
Olaf Wolkenhauer ◽  
Yogeshwer Shukla ◽  
Shailendra K. Gupta
Keyword(s):  
Drug Target ◽  
Complex Disease ◽  
Biological Targets ◽  
Systems Approaches ◽  
Anticancer Mechanism ◽  
Genetic And Environmental Factors ◽  
Key Steps ◽  
Network Approaches ◽  
Novel Drug

The identification and validation of novel drug–target combinations are key steps in the drug discovery processes. Cancer is a complex disease that involves several genetic and environmental factors. High-throughput omics technologies are now widely available, however the integration of multi-omics data to identify viable anticancer drug-target combinations, that allow for a better clinical outcome when considering the efficacy-toxicity spectrum, is challenging. This review article provides an overview of systems approaches which help to integrate a broad spectrum of technologies and data. We focus on network approaches and investigate anticancer mechanism and biological targets of resveratrol using reverse pharmacophore mapping as an in-depth case study. The results of this case study demonstrate the use of systems approaches for a better understanding of the behavior of small molecule inhibitors in receptor binding sites. The presented network analysis approach helps in formulating hypotheses and provides mechanistic insights of resveratrol in neoplastic transformations.

scholarly journals Twelve years of GWAS discoveries for osteoporosis and related traits: advances, challenges and applications

Bone Research ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaowei Zhu ◽  
Weiyang Bai ◽  
Houfeng Zheng
Keyword(s):  
Drug Targets ◽  
Complex Disease ◽  
Association Studies ◽  
Osteoporotic Fractures ◽  
Disease Prediction ◽  
Genome Wide Association Studies ◽  
Mineral Density ◽  
Small Effect Size ◽  
Endocrine Status ◽  
Meta Analyses

AbstractOsteoporosis is a common skeletal disease, affecting ~200 million people around the world. As a complex disease, osteoporosis is influenced by many factors, including diet (e.g. calcium and protein intake), physical activity, endocrine status, coexisting diseases and genetic factors. In this review, we first summarize the discovery from genome-wide association studies (GWASs) in the bone field in the last 12 years. To date, GWASs and meta-analyses have discovered hundreds of loci that are associated with bone mineral density (BMD), osteoporosis, and osteoporotic fractures. However, the GWAS approach has sometimes been criticized because of the small effect size of the discovered variants and the mystery of missing heritability, these two questions could be partially explained by the newly raised conceptual models, such as omnigenic model and natural selection. Finally, we introduce the clinical use of GWAS findings in the bone field, such as the identification of causal clinical risk factors, the development of drug targets and disease prediction. Despite the fruitful GWAS discoveries in the bone field, most of these GWAS participants were of European descent, and more genetic studies should be carried out in other ethnic populations to benefit disease prediction in the corresponding population.

scholarly journals Epigenome-wide associations between observed maternal sensitivity and offspring DNA methylation: a population-based prospective study in children

2020 ◽  
pp. 1-11
Author(s):  
Lorenza Dall’ Aglio ◽  
Jolien Rijlaarsdam ◽  
Rosa H. Mulder ◽  
Alexander Neumann ◽  
Janine F. Felix ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Stress Responses ◽  
Association Studies ◽  
Maternal Sensitivity ◽  
Population Based ◽  
Epigenetic Mechanism ◽  
Developmental Problems ◽  
Maternal Caregiving ◽  
Typical Variation

Abstract Background Experimental work in animals has shown that DNA methylation (DNAm), an epigenetic mechanism regulating gene expression, is influenced by typical variation in maternal care. While emerging research in humans supports a similar association, studies to date have been limited to candidate gene and cross-sectional approaches, with a focus on extreme deviations in the caregiving environment. Methods Here, we explored the prospective association between typical variation in maternal sensitivity and offspring epigenome-wide DNAm, in a population-based cohort of children (N = 235). Maternal sensitivity was observed when children were 3- and 4-years-old. DNAm, quantified with the Infinium 450 K array, was extracted at age 6 (whole blood). The influence of methylation quantitative trait loci (mQTLs), DNAm at birth (cord blood), and confounders (socioeconomic status, maternal psychopathology) was considered in follow-up analyses. Results Genome-wide significant associations between maternal sensitivity and offspring DNAm were observed at 13 regions (p < 1.06 × 10−07), but not at single sites. Follow-up analyses indicated that associations at these regions were in part related to genetic factors, confounders, and baseline DNAm levels at birth, as evidenced by the presence of mQTLs at five regions and estimate attenuations. Robust associations with maternal sensitivity were found at four regions, annotated to ZBTB22, TAPBP, ZBTB12, and DOCK4. Conclusions These findings provide novel leads into the relationship between typical variation in maternal caregiving and offspring DNAm in humans, highlighting robust regions of associations, previously implicated in psychological and developmental problems, immune functioning, and stress responses.

scholarly journals New Horizons in the Genetic Etiology of Systemic Lupus Erythematosus and Lupus-Like Disease: Monogenic Lupus and Beyond

2020 ◽  
Vol 9 (3) ◽  
pp. 712 ◽  
Author(s):  
Erkan Demirkaya ◽  
Sezgin Sahin ◽  
Micol Romano ◽  
Qing Zhou ◽  
Ivona Aksentijevich
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Current Knowledge ◽  
Association Studies ◽  
Severe Disease ◽  
Genetic Diagnosis ◽  
Genome Wide Association Studies ◽  
Systemic Lupus ◽  
Degree Relative ◽  
Adult Age

Systemic lupus erythematosus (SLE) is a clinically and genetically heterogeneous autoimmune disease. The etiology of lupus and the contribution of genetic, environmental, infectious and hormonal factors to this phenotype have yet to be elucidated. The most straightforward approach to unravel the molecular pathogenesis of lupus may rely on studies of patients who present with early-onset severe phenotypes. Typically, they have at least one of the following clinical features: childhood onset of severe disease (<5 years), parental consanguinity, and presence of family history for autoimmune diseases in a first-degree relative. These patients account for a small proportion of patients with lupus but they inform considerable knowledge about cellular pathways contributing to this inflammatory phenotype. In recent years with the aid of new sequencing technologies, novel or rare pathogenic variants have been reported in over 30 genes predisposing to SLE and SLE-like diseases. Future studies will likely discover many more genes with private variants associated to lupus-like phenotypes. In addition, genome-wide association studies (GWAS) have identified a number of common alleles (SNPs), which increase the risk of developing lupus in adult age. Discovery of a possible shared immune pathway in SLE patients, either with rare or common variants, can provide important clues to better understand this complex disorder, it’s prognosis and can help guide new therapeutic approaches. The aim of this review is to summarize the current knowledge of the clinical presentation, genetic diagnosis and mechanisms of disease in patents with lupus and lupus-related phenotypes.

scholarly journals Association of angiotensin II type 1-receptor gene polymorphisms with the risk of developing hypertension in Mexican individuals

2011 ◽  
Vol 13 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Nancy Martínez-Rodríguez ◽  
Carlos Posadas-Romero ◽  
Guillermo Cardoso ◽  
José Manuel Pérez-Rodríguez ◽  
Nonanzit Pérez-Hernández ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Gene Polymorphisms ◽  
Complex Disease ◽  
Receptor Gene ◽  
Renin Angiotensin System ◽  
Similar Distribution ◽  
Increased Risk ◽  
Receptor Gene Polymorphisms ◽  
Genetic And Environmental Factors

Introduction: Hypertension is a complex disease in which a significant interaction between genetic and environmental factors takes place. The renin–angiotensin system plays an important role regulating blood pressure to maintain homeostasis and vascular tone. In the present work, the role of angiotensin II type 1-receptor (AGTR1) gene polymorphisms as susceptibility markers for hypertension was evaluated. Materials and methods: Five polymorphisms in the AGTR1 gene were genotyped by 5′ exonuclease TaqMan genotyping assays in 239 hypertensive and 371 non-hypertensive individuals. Results: A similar distribution of rs275651, rs275652, rs275653, and rs5183 polymorphisms was observed in both studied groups. Different distribution of rs5182 genotypes was observed between the studied groups ( p = 0.016). According to the co-dominant model, individuals with rs5182 CC genotype have a 1.83-fold increased risk of developing hypertension ( p = 0.009). Polymorphisms were distributed in two blocks: block 1 included the rs275651, rs275652, and rs275653 polymorphisms, whereas block 2 included the rs5183 and rs5182 polymorphisms. Individuals with hypertension showed increased frequency of ‘ CA’ haplotype of block 2 when compared to non-hypertensive individuals ( p = 0.015, odds ratio = 1.33). Conclusion: The results suggest that the rs5182 gene polymorphism could be involved in the risk of developing hypertension in Mexican individuals.

scholarly journals Genetic Vectors as a Tool in Association Studies: Definitions and Application for Study of Rheumatoid Arthritis

2015 ◽  
Vol 2015 ◽  
pp. 1-13
Author(s):  
Igor Sandalov ◽  
Leonid Padyukov
Keyword(s):  
Rheumatoid Arthritis ◽  
Complex Disease ◽  
Association Studies ◽  
Healthy Population ◽  
Common Complex Disease ◽  
New Approach ◽  
Functional Studies ◽  
Biological Interpretation ◽  
Genetic Vectors ◽  
Efficient Selection

To identify putative relations between different genetic factors in the human genome in the development of common complex disease, we mapped the genetic data to an ensemble of spin chains and analysed the data as a quantum system. Each SNP is considered as a spin with three states corresponding to possible genotypes. The combined genotype represents a multispin state, described by the product of individual-spin states. Each person is characterized by a single genetic vector (GV) and individuals with identical GVs comprise the GV group. This consolidation of genotypes into GVs provides integration of multiple genetic variants for a single statistical test and excludes ambiguity of biological interpretation known for allele and haplotype associations. We analyzed two independent cohorts, with 2633 rheumatoid arthritis cases and 2108 healthy controls, and data for 6 SNPs from the HTR2A locus plus shared epitope allele. We found that GVs based on selected markers are highly informative and overlap for 98.3% of the healthy population between two cohorts. Interestingly, some of the GV groups contain either only controls or only cases, thus demonstrating extreme susceptibility or protection features. By using this new approach we confirmed previously detected univariate associations and demonstrated the most efficient selection of SNPs for combined analyses for functional studies.

scholarly journals Genetic and Epigenetic Modifiers of Alcoholic Liver Disease

2018 ◽  
Vol 19 (12) ◽  
pp. 3857 ◽  
Author(s):  
Marica Meroni ◽  
Miriam Longo ◽  
Raffaela Rametta ◽  
Paola Dongiovanni
Keyword(s):  
Liver Disease ◽  
Alcohol Consumption ◽  
Alcoholic Liver Disease ◽  
Complex Disease ◽  
Wide Spectrum ◽  
Association Studies ◽  
Phenotypic Variability ◽  
Genome Wide Association Studies ◽  
Epigenetic Factors ◽  
Excessive Alcohol Consumption

Alcoholic liver disease (ALD), a disorder caused by excessive alcohol consumption is a global health issue. More than two billion people consume alcohol in the world and about 75 million are classified as having alcohol disorders. ALD embraces a wide spectrum of hepatic lesions including steatosis, alcoholic steatohepatitis (ASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). ALD is a complex disease where environmental, genetic, and epigenetic factors contribute to its pathogenesis and progression. The severity of alcohol-induced liver disease depends on the amount, method of usage and duration of alcohol consumption as well as on age, gender, presence of obesity, and genetic susceptibility. Genome-wide association studies and candidate gene studies have identified genetic modifiers of ALD that can be exploited as non-invasive biomarkers, but which do not completely explain the phenotypic variability. Indeed, ALD development and progression is also modulated by epigenetic factors. The premise of this review is to discuss the role of genetic variants and epigenetic modifications, with particular attention being paid to microRNAs, as pathogenic markers, risk predictors, and therapeutic targets in ALD.

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