scholarly journals Epigenome-wide association study of seizures in childhood and adolescence

2019 ◽  
Author(s):  
Doretta Caramaschi ◽  
Charlie Hatcher ◽  
Rosa H. Mulder ◽  
Janine F. Felix ◽  
Charlotte A. M. Cecil ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Genetic Variants ◽  
Cognitive Skills ◽  
Mendelian Randomization ◽  
Independent Study ◽  
Childhood And Adolescence ◽  
Parents And Children ◽  
Genome Wide ◽  
Common Genetic Variants ◽  
The Brain

ABSTRACTThe occurrence of seizures in childhood is often associated with neurodevelopmental impairments and school underachievement. Common genetic variants associated with epilepsy have been identified and epigenetic mechanisms have also been suggested to play a role. In this study we analysed the association of genome-wide blood DNA methylation with the occurrence of seizures in ∼800 children from the Avon Longitudinal Study of Parents and Children, UK, at birth (cord blood), during childhood and adolescence (peripheral blood). We also analysed the association between the lifetime occurrence of any seizures before age 13 with blood DNA methylation levels. We sought replication of the findings in the Generation R Study and explored causality using Mendelian randomization, i.e. using genetic variants as proxies. The results showed five CpG sites which were associated cross-sectionally with seizures either in childhood or adolescence (1-5% absolute methylation difference at pFDR<0.05), although the evidence of replication in an independent study was weak. One of these sites was located in the BDNF gene, which is highly expressed in the brain, and showed high correspondence with brain methylation levels. The Mendelian randomization analyses suggested that seizures might be causal for changes in methylation rather than vice-versa. In addition, seizure-associated methylation changes could affect other outcomes such as growth, cognitive skills and educational attainment. In conclusion, we present a link between seizures and DNA methylation which suggests that DNA methylation changes might mediate some of the effects of seizures on growth and neurodevelopment.

scholarly journals Epigenome-wide association study of seizures in childhood and adolescence

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Doretta Caramaschi ◽  
Charlie Hatcher ◽  
Rosa H. Mulder ◽  
Janine F. Felix ◽  
Charlotte A. M. Cecil ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Genetic Variants ◽  
Mendelian Randomization ◽  
Independent Study ◽  
Childhood And Adolescence ◽  
Parents And Children ◽  
Genome Wide ◽  
Common Genetic Variants ◽  
The Brain ◽  
Avon Longitudinal Study

AbstractThe occurrence of seizures in childhood is often associated with neurodevelopmental impairments and school underachievement. Common genetic variants associated with epilepsy have been identified and epigenetic mechanisms have also been suggested to play a role. In this study, we analyzed the association of genome-wide blood DNA methylation with the occurrence of seizures in ~ 800 children from the Avon Longitudinal Study of Parents and Children, UK, at birth (cord blood), during childhood, and adolescence (peripheral blood). We also analyzed the association between the lifetime occurrence of any seizures before age 13 with blood DNA methylation levels. We sought replication of the findings in the Generation R Study and explored causality using Mendelian randomization, i.e., using genetic variants as proxies. The results showed five CpG sites which were associated cross-sectionally with seizures either in childhood or adolescence (1–5% absolute methylation difference at pFDR < 0.05), although the evidence of replication in an independent study was weak. One of these sites was located in the BDNF gene, which is highly expressed in the brain, and showed high correspondence with brain methylation levels. The Mendelian randomization analyses suggested that seizures might be causal for changes in methylation rather than vice-versa. In conclusion, we show a suggestive link between seizures and blood DNA methylation while at the same time exploring the limitations of conducting such study.

scholarly journals A prospective study of time-dependent exposures to childhood adversity and DNA methylation in childhood and adolescence

2021 ◽  
Author(s):  
Alexandre A Lussier ◽  
Yiwen Zhu ◽  
Brooke J Smith ◽  
Janine Cerutti ◽  
Andrew Simpkin ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Childhood Adversity ◽  
Time Dependent ◽  
Childhood And Adolescence ◽  
Parents And Children ◽  
Genome Wide ◽  
Latent Effects ◽  
Underlying Mechanisms ◽  
A Prospective Study ◽  
The Relationship

Background: Childhood adversity influences long-term health, particularly if experienced during sensitive periods in development when physiological systems are more responsive to environmental influences. Although the underlying mechanisms remain unclear, prior studies suggest that DNA methylation (DNAm) may capture these time-dependent effects of childhood adversity. However, it remains unknown whether DNAm alterations persist into adolescence and how the timing of adversity might influence DNAm trajectories across development. Methods: We examined the relationship between time-dependent adversity and genome-wide DNAm measured at three waves from birth to adolescence using prospective data from the Avon Longitudinal Study of Parents and Children. We first assessed the relationship between the timing of exposure to seven types of adversity (measured 5-8 times between ages 0-11) and DNAm at age 15 using a structured life course modeling approach. We also characterized the persistence into adolescence of associations identified from age 7 DNAm, as well as the influence of adversity on DNAm trajectories from ages 0-15. Results: Adversity was associated with differences in age 15 DNAm at 24 loci (FDR<0.05). Most loci (19 of 24) were associated with adversity (i.e., physical/sexual abuse, one-adult households, caregiver abuse) that occurred between ages 3-5. Although no DNAm differences present at age 7 persisted into adolescence, we identified seven unique types of DNAm trajectories across development, which highlighted diverse effects of childhood adversity on DNAm. Conclusions: Our results suggest that childhood adversity, particularly between ages 3-5, can influence the trajectories of DNAm across development, exerting both immediate and latent effects on the epigenome.

scholarly journals Imprinted loci may be more widespread in humans than previously appreciated and enable limited assignment of parental allelic transmissions in unrelated individuals

2017 ◽  
Author(s):  
Gabriel Cuellar Partida ◽  
Charles Laurin ◽  
Susan M. Ring ◽  
Tom R. Gaunt ◽  
Caroline L. Relton ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Epigenetic Mechanism ◽  
Childhood And Adolescence ◽  
The Novel ◽  
Time Points ◽  
Parents And Children ◽  
Genome Wide ◽  
Parent Of Origin ◽  
Dominance Pattern ◽  
Genomic Regions

AbstractGenomic imprinting is an epigenetic mechanism leading to parent-of-origin dependent gene expression. So far, the precise number of imprinted genes in humans is uncertain. In this study, we leveraged genome-wide DNA methylation in whole blood measured longitudinally at 3 time points (birth, childhood and adolescence) and GWAS data in 740 Mother-Child duos from the Avon Longitudinal Study of Parents and Children (ALSPAC) to systematically identify imprinted loci. We reasoned that cis-meQTLs at genomic regions that were imprinted would show strong evidence of parent-of-origin associations with DNA methylation, enabling the detection of imprinted regions. Using this approach, we identified genome-wide significant cis-meQTLs that exhibited parent-of-origin effects (POEs) at 35 novel and 50 known imprinted regions (10−10< P <10−300). Among the novel loci, we observed signals near genes implicated in cardiovascular disease (PCSK9), and Alzheimer’s disease (CR1), amongst others. Most of the significant regions exhibited imprinting patterns consistent with uniparental expression, with the exception of twelve loci (including the IGF2, IGF1R, and IGF2R genes), where we observed a bipolar-dominance pattern. POEs were remarkably consistent across time points and were so strong at some loci that methylation levels enabled good discrimination of parental transmissions at these and surrounding genomic regions. The implication is that parental allelic transmissions could be modelled at many imprinted (and linked) loci and hence POEs detected in GWAS of unrelated individuals given a combination of genetic and methylation data. Our results indicate that modelling POEs on DNA methylation is effective to identify loci that may be affected by imprinting.

scholarly journals Developmental cannabidiol exposure increases anxiety and modifies genome-wide brain DNA methylation in adult female mice

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Nicole M. Wanner ◽  
Mathia Colwell ◽  
Chelsea Drown ◽  
Christopher Faulk
Keyword(s):  
Dna Methylation ◽  
Molecular Mechanisms ◽  
Coat Color ◽  
Brain Regions ◽  
Functional Enrichment ◽  
Positive Effects ◽  
Genome Wide ◽  
Nulliparous Female ◽  
The Impact ◽  
The Brain

Abstract Background Use of cannabidiol (CBD), the primary non-psychoactive compound found in cannabis, has recently risen dramatically, while relatively little is known about the underlying molecular mechanisms of its effects. Previous work indicates that direct CBD exposure strongly impacts the brain, with anxiolytic, antidepressant, antipsychotic, and other effects being observed in animal and human studies. The epigenome, particularly DNA methylation, is responsive to environmental input and can direct persistent patterns of gene regulation impacting phenotype. Epigenetic perturbation is particularly impactful during embryogenesis, when exogenous exposures can disrupt critical resetting of epigenetic marks and impart phenotypic effects lasting into adulthood. The impact of prenatal CBD exposure has not been evaluated; however, studies using the psychomimetic cannabinoid Δ9-tetrahydrocannabinol (THC) have identified detrimental effects on psychological outcomes in developmentally exposed adult offspring. We hypothesized that developmental CBD exposure would have similar negative effects on behavior mediated in part by the epigenome. Nulliparous female wild-type Agouti viable yellow (Avy) mice were exposed to 20 mg/kg CBD or vehicle daily from two weeks prior to mating through gestation and lactation. Coat color shifts, a readout of DNA methylation at the Agouti locus in this strain, were measured in F1 Avy/a offspring. Young adult F1 a/a offspring were then subjected to tests of working spatial memory and anxiety/compulsive behavior. Reduced-representation bisulfite sequencing was performed on both F0 and F1 cerebral cortex and F1 hippocampus to identify genome-wide changes in DNA methylation for direct and developmental exposure, respectively. Results F1 offspring exposed to CBD during development exhibited increased anxiety and improved memory behavior in a sex-specific manner. Further, while no significant coat color shift was observed in Avy/a offspring, thousands of differentially methylated loci (DMLs) were identified in both brain regions with functional enrichment for neurogenesis, substance use phenotypes, and other psychologically relevant terms. Conclusions These findings demonstrate for the first time that despite positive effects of direct exposure, developmental CBD is associated with mixed behavioral outcomes and perturbation of the brain epigenome.

scholarly journals Genome-wide association study identifies 48 common genetic variants associated with handedness

2019 ◽  
Author(s):  
Gabriel Cuellar Partida ◽  
Joyce Y Tung ◽  
Nicholas Eriksson ◽  
Eva Albrecht ◽  
Fazil Aliev ◽  
...  
Keyword(s):  
Association Study ◽  
Genetic Variants ◽  
Complex Traits ◽  
Genome Wide Association Study ◽  
Genetic Correlations ◽  
Genome Wide Association ◽  
Left Handedness ◽  
Left Handed ◽  
Genome Wide ◽  
Common Genetic Variants

AbstractHandedness, a consistent asymmetry in skill or use of the hands, has been studied extensively because of its relationship with language and the over-representation of left-handers in some neurodevelopmental disorders. Using data from the UK Biobank, 23andMe and 32 studies from the International Handedness Consortium, we conducted the world’s largest genome-wide association study of handedness (1,534,836 right-handed, 194,198 (11.0%) left-handed and 37,637 (2.1%) ambidextrous individuals). We found 41 genetic loci associated with left-handedness and seven associated with ambidexterity at genome-wide levels of significance (P < 5×10−8). Tissue enrichment analysis implicated the central nervous system and brain tissues including the hippocampus and cerebrum in the etiology of left-handedness. Pathways including regulation of microtubules, neurogenesis, axonogenesis and hippocampus morphology were also highlighted. We found suggestive positive genetic correlations between being left-handed and some neuropsychiatric traits including schizophrenia and bipolar disorder. SNP heritability analyses indicated that additive genetic effects of genotyped variants explained 5.9% (95% CI = 5.8% – 6.0%) of the underlying liability of being left-handed, while the narrow sense heritability was estimated at 12% (95% CI = 7.2% – 17.7%). Further, we show that genetic correlation between left-handedness and ambidexterity is low (rg = 0.26; 95% CI = 0.08 – 0.43) implying that these traits are largely influenced by different genetic mechanisms. In conclusion, our findings suggest that handedness, like many other complex traits is highly polygenic, and that the genetic variants that predispose to left-handedness may underlie part of the association with some psychiatric disorders that has been observed in multiple observational studies.

scholarly journals Smoking, DNA methylation and lung function: a Mendelian randomization analysis to investigate causal relationships

2019 ◽  
Author(s):  
Emily Jamieson ◽  
Roxanna Korologou-Linden ◽  
Robyn E. Wootton ◽  
Anna L. Guyatt ◽  
Thomas Battram ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Lung Function ◽  
Mendelian Randomization ◽  
Causal Effect ◽  
Forced Expiratory Volume ◽  
Multiple Trait ◽  
Genome Wide ◽  
Causal Variants ◽  
Association Data ◽  
Randomization Analysis

AbstractWhether smoking-associated DNA methylation has a causal effect on lung function has not been thoroughly evaluated. We investigated the causal effects of 474 smoking-associated CpGs on forced expiratory volume in one second (FEV1) in two-sample Mendelian randomization (MR) using methylation quantitative trait loci and genome-wide association data for FEV1. We found evidence of a possible causal effect for DNA methylation on FEV1 at 18 CpGs (p<1.2×10−4). Replication analysis supported a causal effect at three CpGs (cg21201401 (ZGPAT), cg19758448 (PGAP3) and cg12616487 (AHNAK) (p<0.0028). DNA methylation did not clearly mediate the effect of smoking on FEV1, although DNA methylation at some sites may influence lung function via effects on smoking. Using multiple-trait colocalization, we found evidence of shared causal variants between lung function, gene expression and DNA methylation. Findings highlight potential therapeutic targets for improving lung function and possibly smoking cessation, although large, tissue-specific datasets are required to confirm these results.

scholarly journals Maternal and fetal genetic contribution to gestational weight gain

2017 ◽  
Author(s):  
Nicole M Warrington ◽  
Rebecca Richmond ◽  
Bjarke Fenstra ◽  
Ronny Myhre ◽  
Romy Gaillard ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Weight Gain ◽  
Gestational Weight Gain ◽  
Genetic Variants ◽  
Genetic Contribution ◽  
Gestational Weight ◽  
Genome Wide ◽  
Common Genetic Variants ◽  
Maternal Bmi

AbstractBackgroundClinical recommendations to limit gestational weight gain (GWG) imply high GWG is causally related to adverse outcomes in mother or offspring, but GWG is the sum of several inter-related complex phenotypes (maternal fat deposition and vascular expansion, placenta, amniotic fluid and fetal growth). Understanding the genetic contribution to GWG could help clarify the potential effect of its different components on maternal and offspring health. Here we explore the genetic contribution to total, early and late GWG.Participants and MethodsA genome-wide association study was used to identify maternal and fetal variants contributing to GWG in up to 10,543 mothers and up to 16,317 offspring of European origin, with replication in 10,660 mothers and 7,561 offspring. Additional analyses determined the proportion of variability in GWG from maternal and fetal common genetic variants and the overlap of established genome-wide significant variants for phenotypes relevant to GWG (e.g. maternal BMI and glucose, birthweight).ResultsWe found that approximately 20% of the variability in GWG was tagged by common maternal genetic variants, and that the fetal genome made a surprisingly minor contribution to explaining variation in GWG. We were unable to identify any genetic variants that reached genome-wide levels of significance (P<5×10−8) and replicated. Some established maternal variants associated with increased BMI, fasting glucose and type 2 diabetes were associated with lower early, and higher later GWG. Maternal variants related to higher systolic blood pressure were related to lower late GWG. Established maternal and fetal birthweight variants were largely unrelated to GWG.ConclusionWe found a modest contribution of maternal common variants to GWG and some overlap of maternal BMI, glucose and type 2 diabetes variants with GWG. These findings suggest that associations between GWG and later offspring/maternal outcomes may be due to the relationship of maternal BMI and diabetes with GWG.

scholarly journals A transcriptome-wide Mendelian randomization study to uncover tissue-dependent regulatory mechanisms across the human phenome

2019 ◽  
Author(s):  
Tom G Richardson ◽  
Gibran Hemani ◽  
Tom R Gaunt ◽  
Caroline L Relton ◽  
George Davey Smith
Keyword(s):  
Gene Expression ◽  
Genetic Variants ◽  
Complex Traits ◽  
Mendelian Randomization ◽  
Drug Repositioning ◽  
Association Studies ◽  
Thyroid Tissue ◽  
Genome Wide Association Studies ◽  
Tissue Specific ◽  
Genome Wide

AbstractBackgroundDeveloping insight into tissue-specific transcriptional mechanisms can help improve our understanding of how genetic variants exert their effects on complex traits and disease. By applying the principles of Mendelian randomization, we have undertaken a systematic analysis to evaluate transcriptome-wide associations between gene expression across 48 different tissue types and 395 complex traits.ResultsOverall, we identified 100,025 gene-trait associations based on conventional genome-wide corrections (P < 5 × 10−08) that also provided evidence of genetic colocalization. These results indicated that genetic variants which influence gene expression levels in multiple tissues are more likely to influence multiple complex traits. We identified many examples of tissue-specific effects, such as genetically-predicted TPO, NR3C2 and SPATA13 expression only associating with thyroid disease in thyroid tissue. Additionally, FBN2 expression was associated with both cardiovascular and lung function traits, but only when analysed in heart and lung tissue respectively.We also demonstrate that conducting phenome-wide evaluations of our results can help flag adverse on-target side effects for therapeutic intervention, as well as propose drug repositioning opportunities. Moreover, we find that exploring the tissue-dependency of associations identified by genome-wide association studies (GWAS) can help elucidate the causal genes and tissues responsible for effects, as well as uncover putative novel associations.ConclusionsThe atlas of tissue-dependent associations we have constructed should prove extremely valuable to future studies investigating the genetic determinants of complex disease. The follow-up analyses we have performed in this study are merely a guide for future research. Conducting similar evaluations can be undertaken systematically at http://mrcieu.mrsoftware.org/Tissue_MR_atlas/.

Sign in / Sign up

Export Citation Format

Share Document