Genetics of Energy Expenditure in Humans
Claude Bouchard in The Genetics of Obesity, 2020
Two kinds of genetic effects will be considered in this chapter. The first one is the additive genetic effect, or the so-called heritability, and the second one is the genotype-environment interaction effect. The heritability of a given phenotype is the fraction of the phenotypic variance attributable to genetic factors. It is most often assessed from twin or family data obtained on various kinds of relatives by descent or adoption. The genotype-environment interaction effect results from the differential response of genotypes to changes in the environment. For energy expenditure phenotypes, this effect can be estimated using an experimental approach1 in which the within and between monozygotic (MZ) twin pair responses to standardized positive or negative energy balance conditions are compared.
Genetics
Cathy Laver-Bradbury, Margaret J.J. Thompson, Christopher Gale, Christine M. Hooper in Child and Adolescent Mental Health, 2021
The environment in which children grow and develop can have a profound influence on their mental health. These influences are not distinct from genetic liability. Accumulating evidence suggests that genetic risks influence environmental factors and environmental exposures can impact on gene expression. Gene–environment correlation occurs when exposure to environmental conditions depends on an individual’s genotype or that of their parents, i.e. environmental risks are shaped by genetically influenced behaviours. Gene–environment interaction, on the other hand, occurs when the effect of a genetic risk factor is altered by the presence of environmental factors. Both gene–environment correlation and gene–environment interaction are likely to be important in contributing to psychiatric risk. To date, there is strong evidence that many environmental exposures, e.g. nicotine exposure in utero, life events and parent–child hostility, are correlated with genetic liability for different psychiatric disorders (Thapar and Rutter, 2019).
Analysis of Gene-Environment Interactions
Ørnulf Borgan, Norman E. Breslow, Nilanjan Chatterjee, Mitchell H. Gail, Alastair Scott, Christopher J. Wild in Handbook of Statistical Methods for Case-Control Studies, 2018
While a gene-environment interaction has various meanings in epidemiology, it can be generally defined as a joint effect of genetic and environmental risk factors that cannot be explained by their separate marginal effects (Thomas, 2010). A common statistical definition of interaction depends on the concept of a disease risk model that describes the relationship between a response disease outcome and genetic and environmental factors, which will be further described in Section 1.2. Statistically, an interaction can be measured as a departure from the underlying disease risk model, which can be tested by examining whether the cross product term based on genetic and environmental effects is zero or not.
Cigarette smoking and the pathogenesis of systemic lupus erythematosus
Published in Expert Review of Clinical Immunology, 2018
Cameron B. Speyer, Karen H. Costenbader
Interactions between genetic and environmental factors are critical in disease etiology, but have yet to be well examined in SLE. Genetic and environmental risk factors must be studied simultaneously to uncover the pathogenic mechanisms involved in SLE risk. In statistical terms, a gene-environment interaction is present when the effect of genotype on disease risk depends on the level of exposure to an environmental factor, or vice versa [36,37]. The multiple gene-environment interactions that could occur may explain why no single gene or single environmental factor has been found to be associated with SLE in most individuals. Some genes, such as PTPN22 and certain HLA types, have been associated with increased risk of several autoimmune diseases and may be general ‘autoimmune susceptibility genes,’ responsible for common steps in the break of immune tolerance. Similarly, some environmental exposures may act to trigger several autoimmune diseases, acting non-specifically to cause systemic inflammation, oxidative stress and the up-regulation of many genetic pathways via epigenetic mechanisms. Other exposures may be related to risks of specific autoimmune diseases and subtypes, given their biologic effects and the underlying genetic susceptibility of the individual. Analyses of gene-environment interactions and their relationships to immune phenomena have been very informative in RA [38–42], are an essential next step in the study of SLE etiology, and may lead to new strategies for identification of those at highest risk and for prevention of this severe autoimmune disease.
Gene-environment Interaction in Spherical Equivalent and Myopia: An Evidence-based Review
Published in Ophthalmic Epidemiology, 2022
Xiyan Zhang, Qiao Fan, Fengyun Zhang, Gang Liang, Chen-Wei Pan
Gene-environment effects, which might play an essential role in the increasing trend of myopia, should be considered.23–26 Moreover, it could offer an attractive explanation for how environmental exposures and genetic factors can contribute to the change of myopia prevalence. Gene-environment interaction on myopia can be defined as “a different effect of an environmental exposure (near work/ outdoor activities) on myopia with different candidate genetic factors,” or equivalently “a different effect of a candidate gene on myopia with different environmental exposures”.27 Why should the interaction effect be studied? Traditional studies cannot explain the relationship between statistical interactions at the population level and biological interactions at the individual level. Potentially gene-environment interactions allow us better to understand the underlying genetic architecture of a particular trait, and as such we can begin to fill in the missing heritability for a particular phenotype.28 However, data on the relationship between gene-environment interaction and myopia in previous studies is limited. We conducted a systematic review to give a more comprehensive display of the current research on this issue.
Genetic and stress influences on the prevalence of hypertension among hispanics/latinos in the hispanic community health study/study of latinos (HCHS/SOL)
Published in Blood Pressure, 2022
Liana K. Preudhomme, Marc D. Gellman, Nora Franceschini, Krista M. Perreira, Lindsay E. Fernández-Rhodes, Linda C. Gallo, Carmen R. Isasi, Sylvia Smoller, Sheila F. Castañeda, Martha Daviglus, Christina Hutten, Richard S. Cooper, Jianwen Cai, Neil Schneiderman, Maria M. Llabre
There are also several points to consider when interpreting the findings from the present study. An unweighted genetic risk score was calculated from a limited number of single nucleotide polymorphisms and used in the current analyses. The relative effect size (beta coefficient), used to calculate a weighted genetic risk score, was unavailable because the present study drew from two separate GWAS [5,6]. Additionally, only single nucleotide polymorphisms generalisable to Hispanics/Latinos were used, and the relatively small number of single nucleotide polymorphisms (10 single nucleotide polymorphisms) may not have the predictive power to detect a gene × environment interaction. It remains possible that there are other major population-variants that were excluded from the current analyses based on our definition of single nucleotide polymorphisms.
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