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  • 1
    In: Genome Medicine, Springer Science and Business Media LLC, Vol. 12, No. 1 ( 2020-12)
    Abstract: Autism spectrum disorder (ASD) is a neurodevelopmental disorder with complex heritability and higher prevalence in males. The neonatal epigenome has the potential to reflect past interactions between genetic and environmental factors during early development and influence future health outcomes. Methods We performed whole-genome bisulfite sequencing of 152 umbilical cord blood samples from the MARBLES and EARLI high-familial risk prospective cohorts to identify an epigenomic signature of ASD at birth. Samples were split into discovery and replication sets and stratified by sex, and their DNA methylation profiles were tested for differentially methylated regions (DMRs) between ASD and typically developing control cord blood samples. DMRs were mapped to genes and assessed for enrichment in gene function, tissue expression, chromosome location, and overlap with prior ASD studies. DMR coordinates were tested for enrichment in chromatin states and transcription factor binding motifs. Results were compared between discovery and replication sets and between males and females. Results We identified DMRs stratified by sex that discriminated ASD from control cord blood samples in discovery and replication sets. At a region level, 7 DMRs in males and 31 DMRs in females replicated across two independent groups of subjects, while 537 DMR genes in males and 1762 DMR genes in females replicated by gene association. These DMR genes were significantly enriched for brain and embryonic expression, X chromosome location, and identification in prior epigenetic studies of ASD in post-mortem brain. In males and females, autosomal ASD DMRs were significantly enriched for promoter and bivalent chromatin states across most cell types, while sex differences were observed for X-linked ASD DMRs. Lastly, these DMRs identified in cord blood were significantly enriched for binding sites of methyl-sensitive transcription factors relevant to fetal brain development. Conclusions At birth, prior to the diagnosis of ASD, a distinct DNA methylation signature was detected in cord blood over regulatory regions and genes relevant to early fetal neurodevelopment. Differential cord methylation in ASD supports the developmental and sex-biased etiology of ASD and provides novel insights for early diagnosis and therapy.
    Type of Medium: Online Resource
    ISSN: 1756-994X
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2020
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  • 2
    In: Genome Biology, Springer Science and Business Media LLC, Vol. 23, No. 1 ( 2022-02-16)
    Abstract: Autism spectrum disorder (ASD) involves complex genetics interacting with the perinatal environment, complicating the discovery of common genetic risk. The epigenetic layer of DNA methylation shows dynamic developmental changes and molecular memory of in utero experiences, particularly in placenta, a fetal tissue discarded at birth. However, current array-based methods to identify novel ASD risk genes lack coverage of the most structurally and epigenetically variable regions of the human genome. Results We use whole genome bisulfite sequencing in placenta samples from prospective ASD studies to discover a previously uncharacterized ASD risk gene, LOC105373085 , renamed NHIP . Out of 134 differentially methylated regions associated with ASD in placental samples, a cluster at 22q13.33 corresponds to a 118-kb hypomethylated block that replicates in two additional cohorts. Within this locus, NHIP is functionally characterized as a nuclear peptide-encoding transcript with high expression in brain, and increased expression following neuronal differentiation or hypoxia, but decreased expression in ASD placenta and brain. NHIP overexpression increases cellular proliferation and alters expression of genes regulating synapses and neurogenesis, overlapping significantly with known ASD risk genes and NHIP -associated genes in ASD brain. A common structural variant disrupting the proximity of NHIP to a fetal brain enhancer is associated with NHIP expression and methylation levels and ASD risk, demonstrating a common genetic influence. Conclusions Together, these results identify and initially characterize a novel environmentally responsive ASD risk gene relevant to brain development in a hitherto under-characterized region of the human genome.
    Type of Medium: Online Resource
    ISSN: 1474-760X
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2040529-7
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  • 3
    In: Molecular Autism, Springer Science and Business Media LLC, Vol. 10, No. 1 ( 2019-12)
    Abstract: Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects more than 1% of children in the USA. ASD risk is thought to arise from both genetic and environmental factors, with the perinatal period as a critical window. Understanding early transcriptional changes in ASD would assist in clarifying disease pathogenesis and identifying biomarkers. However, little is known about umbilical cord blood gene expression profiles in babies later diagnosed with ASD compared to non-typically developing and non-ASD (Non-TD) or typically developing (TD) children. Methods Genome-wide transcript levels were measured by Affymetrix Human Gene 2.0 array in RNA from cord blood samples from both the Markers of Autism Risk in Babies-Learning Early Signs (MARBLES) and the Early Autism Risk Longitudinal Investigation (EARLI) high-risk pregnancy cohorts that enroll younger siblings of a child previously diagnosed with ASD. Younger siblings were diagnosed based on assessments at 36 months, and 59 ASD, 92 Non-TD, and 120 TD subjects were included. Using both differential expression analysis and weighted gene correlation network analysis, gene expression between ASD and TD, and between Non-TD and TD, was compared within each study and via meta-analysis. Results While cord blood gene expression differences comparing either ASD or Non-TD to TD did not reach genome-wide significance, 172 genes were nominally differentially expressed between ASD and TD cord blood (log 2 (fold change)  〉  0.1, p   〈  0.01). These genes were significantly enriched for functions in xenobiotic metabolism, chromatin regulation, and systemic lupus erythematosus (FDR q   〈  0.05). In contrast, 66 genes were nominally differentially expressed between Non-TD and TD, including 8 genes that were also differentially expressed in ASD. Gene coexpression modules were significantly correlated with demographic factors and cell type proportions. Limitations ASD-associated gene expression differences identified in this study are subtle, as cord blood is not the main affected tissue, it is composed of many cell types, and ASD is a heterogeneous disorder. Conclusions This is the first study to identify gene expression differences in cord blood specific to ASD through a meta-analysis across two prospective pregnancy cohorts. The enriched gene pathways support involvement of environmental, immune, and epigenetic mechanisms in ASD etiology.
    Type of Medium: Online Resource
    ISSN: 2040-2392
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2019
    detail.hit.zdb_id: 2540930-X
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  • 4
    In: Environmental Research, Elsevier BV, Vol. 220 ( 2023-03), p. 115227-
    Type of Medium: Online Resource
    ISSN: 0013-9351
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2023
    detail.hit.zdb_id: 205699-9
    detail.hit.zdb_id: 1467489-0
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  • 5
    In: Liver International, Wiley, Vol. 40, No. 11 ( 2020-11), p. 2776-2787
    Abstract: Wilson disease (WD) is caused by mutations in the copper transporter ATP7B , with its main pathology attributed to copper‐mediated oxidative damage. The limited therapeutic effect of copper chelators and the early occurrence of mitochondrial deficits, however, undermine the prevalence of this mechanism. Methods We characterized mitochondrial DNA copy number and mutations as well as bioenergetic deficits in blood from patients with WD and in livers of tx‐j mice, a mouse model of hepatic copper accumulation. In vitro experiments with hepatocytes treated with CuSO 4 were conducted to validate in vivo studies. Results Here, for the first time, we characterized the bioenergetic deficits in WD as consistent with a mitochondrial DNA depletion‐like syndrome. This is evidenced by enriched DNA synthesis/replication pathways in serum metabolomics and decreased mitochondrial DNA copy number in blood of WD patients as well as decreased mitochondrial DNA copy number, increased citrate synthase activity, and selective Complex IV deficit in livers of the tx‐j mouse model of WD. Tx‐j mice treated with the copper chelator penicillamine, methyl donor choline or both ameliorated mitochondrial DNA damage but further decreased mitochondrial DNA copy number. Experiments with copper‐loaded HepG2 cells validated the concept of a direct copper‐mitochondrial DNA interaction. Conclusions This study underlines the relevance of targeting the copper‐mitochondrial DNA pool in the treatment of WD separate from the established copper‐induced oxidative stress‐mediated damage.
    Type of Medium: Online Resource
    ISSN: 1478-3223 , 1478-3231
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2124684-1
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  • 6
    In: Human Molecular Genetics, Oxford University Press (OUP), Vol. 29, No. 21 ( 2021-01-06), p. 3465-3476
    Abstract: Neonatal dried blood spots (NDBS) are a widely banked sample source that enables retrospective investigation into early life molecular events. Here, we performed low-pass whole genome bisulfite sequencing (WGBS) of 86 NDBS DNA to examine early life Down syndrome (DS) DNA methylation profiles. DS represents an example of genetics shaping epigenetics, as multiple array-based studies have demonstrated that trisomy 21 is characterized by genome-wide alterations to DNA methylation. By assaying over 24 million CpG sites, thousands of genome-wide significant (q  & lt; 0.05) differentially methylated regions (DMRs) that distinguished DS from typical development and idiopathic developmental delay were identified. Machine learning feature selection refined these DMRs to 22 loci. The DS DMRs mapped to genes involved in neurodevelopment, metabolism, and transcriptional regulation. Based on comparisons with previous DS methylation studies and reference epigenomes, the hypermethylated DS DMRs were significantly (q  & lt; 0.05) enriched across tissues while the hypomethylated DS DMRs were significantly (q  & lt; 0.05) enriched for blood-specific chromatin states. A ~28 kb block of hypermethylation was observed on chromosome 21 in the RUNX1 locus, which encodes a hematopoietic transcription factor whose binding motif was the most significantly enriched (q  & lt; 0.05) overall and specifically within the hypomethylated DMRs. Finally, we also identified DMRs that distinguished DS NDBS based on the presence or absence of congenital heart disease (CHD). Together, these results not only demonstrate the utility of low-pass WGBS on NDBS samples for epigenome-wide association studies, but also provide new insights into the early life mechanisms of epigenomic dysregulation resulting from trisomy 21.
    Type of Medium: Online Resource
    ISSN: 0964-6906 , 1460-2083
    RVK:
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 1474816-2
    SSG: 12
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  • 7
    In: Autism Research, Wiley, Vol. 14, No. 1 ( 2021-01), p. 11-28
    Abstract: The prenatal period is a critical window for the development of autism spectrum disorder (ASD). The relationship between prenatal nutrients and gestational gene expression in mothers of children later diagnosed with ASD or non‐typical development (Non‐TD) is poorly understood. Maternal blood collected prospectively during pregnancy provides insights into the effects of nutrition, particularly one‐carbon metabolites, on gene pathways and neurodevelopment. Genome‐wide transcriptomes were measured with microarrays in 300 maternal blood samples in Markers of Autism Risk in Babies‐Learning Early Signs. Sixteen different one‐carbon metabolites, including folic acid, betaine, 5′‐methyltretrahydrofolate (5‐MeTHF), and dimethylglycine (DMG) were measured. Differential expression analysis and weighted gene correlation network analysis (WGCNA) were used to compare gene expression between children later diagnosed as typical development (TD), Non‐TD and ASD, and to one‐carbon metabolites. Using differential gene expression analysis, six transcripts ( TGR‐AS1 , SQSTM1 , HLA‐C , and RFESD ) were associated with child outcomes (ASD, Non‐TD, and TD) with genome‐wide significance. Genes nominally differentially expressed between ASD and TD significantly overlapped with seven high confidence ASD genes. WGCNA identified co‐expressed gene modules significantly correlated with 5‐MeTHF, folic acid, DMG, and betaine. A module enriched in DNA methylation functions showed a suggestive protective association with folic acid/5‐MeTHF concentrations and ASD risk. Maternal plasma betaine and DMG concentrations were associated with a block of co‐expressed genes enriched for adaptive immune, histone modification, and RNA processing functions. These results suggest that the prenatal maternal blood transcriptome is a sensitive indicator of gestational one‐carbon metabolite status and changes relevant to children's later neurodevelopmental outcomes. Lay Summary Pregnancy is a time when maternal nutrition could interact with genetic risk for autism spectrum disorder. Blood samples collected during pregnancy from mothers who had a prior child with autism were examined for gene expression and nutrient metabolites, then compared to the diagnosis of the child at age three. Expression differences in gene pathways related to the immune system and gene regulation were observed for pregnancies of children with autism and non‐typical neurodevelopment and were associated with maternal nutrients.
    Type of Medium: Online Resource
    ISSN: 1939-3792 , 1939-3806
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2418112-2
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  • 8
    In: Epigenetics, Informa UK Limited, Vol. 13, No. 3 ( 2018-03-04), p. 318-330
    Type of Medium: Online Resource
    ISSN: 1559-2294 , 1559-2308
    Language: English
    Publisher: Informa UK Limited
    Publication Date: 2018
    detail.hit.zdb_id: 2248598-3
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  • 9
    In: Human Molecular Genetics, Oxford University Press (OUP), Vol. 28, No. 16 ( 2019-08-15), p. 2659-2674
    Abstract: DNA methylation acts at the interface of genetic and environmental factors relevant for autism spectrum disorder (ASD). Placenta, normally discarded at birth, is a potentially rich source of DNA methylation patterns predictive of ASD in the child. Here, we performed whole methylome analyses of placentas from a prospective study MARBLES (Markers of Autism Risk in Babies—Learning Early Signs) of high-risk pregnancies. A total of 400 differentially methylated regions (DMRs) discriminated placentas stored from children later diagnosed with ASD compared to typically developing controls. These ASD DMRs were significantly enriched at promoters, mapped to 596 genes functionally enriched in neuronal development, and overlapped genetic ASD risk. ASD DMRs at CYP2E1 and IRS2 reached genome-wide significance, replicated by pyrosequencing and correlated with expression differences in brain. Methylation at CYP2E1 associated with both ASD diagnosis and genotype within the DMR. In contrast, methylation at IRS2 was unaffected by within DMR genotype but modified by preconceptional maternal prenatal vitamin use. This study therefore identified two potentially useful early epigenetic markers for ASD in placenta.
    Type of Medium: Online Resource
    ISSN: 0964-6906 , 1460-2083
    RVK:
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2019
    detail.hit.zdb_id: 1474816-2
    SSG: 12
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  • 10
    Online Resource
    Online Resource
    Oxford University Press (OUP) ; 2022
    In:  Briefings in Bioinformatics Vol. 23, No. 2 ( 2022-03-10)
    In: Briefings in Bioinformatics, Oxford University Press (OUP), Vol. 23, No. 2 ( 2022-03-10)
    Abstract: Health outcomes are frequently shaped by difficult to dissect inter-relationships between biological, behavioral, social and environmental factors. DNA methylation patterns reflect such multivariate intersections, providing a rich source of novel biomarkers and insight into disease etiologies. Recent advances in whole-genome bisulfite sequencing enable investigation of DNA methylation over all genomic CpGs, but existing bioinformatic approaches lack accessible system-level tools. Here, we develop the R package Comethyl, for weighted gene correlation network analysis of user-defined genomic regions that generates modules of comethylated regions, which are then tested for correlations with multivariate sample traits. First, regions are defined by CpG genomic location or regulatory annotation and filtered based on CpG count, sequencing depth and variability. Next, correlation networks are used to find modules of interconnected nodes using methylation values within the selected regions. Each module containing multiple comethylated regions is reduced in complexity to a single eigennode value, which is then tested for correlations with experimental metadata. Comethyl has the ability to cover the noncoding regulatory regions of the genome with high relevance to interpretation of genome-wide association studies and integration with other types of epigenomic data. We demonstrate the utility of Comethyl on a dataset of male cord blood samples from newborns later diagnosed with autism spectrum disorder (ASD) versus typical development. Comethyl successfully identified an ASD-associated module containing regions mapped to genes enriched for brain glial functions. Comethyl is expected to be useful in uncovering the multivariate nature of health disparities for a variety of common disorders. Comethyl is available at github.com/cemordaunt/comethyl with complete documentation and example analyses.
    Type of Medium: Online Resource
    ISSN: 1467-5463 , 1477-4054
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
    detail.hit.zdb_id: 2036055-1
    SSG: 12
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