178 research outputs found

    16p11.2 600 kb Duplications confer risk for typical and atypical Rolandic epilepsy

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    Rolandic epilepsy (RE) is the most common idiopathic focal childhood epilepsy. Its molecular basis is largely unknown and a complex genetic etiology is assumed in the majority of affected individuals. The present study tested whether six large recurrent copy number variants at 1q21, 15q11.2, 15q13.3, 16p11.2, 16p13.11 and 22q11.2 previously associated with neurodevelopmental disorders also increase risk of RE. Our association analyses revealed a significant excess of the 600 kb genomic duplication at the 16p11.2 locus (chr16: 29.5-30.1 Mb) in 393 unrelated patients with typical (n = 339) and atypical (ARE; n = 54) RE compared with the prevalence in 65 046 European population controls (5/393 cases versus 32/65 046 controls; Fisher's exact test P = 2.83 × 10−6, odds ratio = 26.2, 95% confidence interval: 7.9-68.2). In contrast, the 16p11.2 duplication was not detected in 1738 European epilepsy patients with either temporal lobe epilepsy (n = 330) and genetic generalized epilepsies (n = 1408), suggesting a selective enrichment of the 16p11.2 duplication in idiopathic focal childhood epilepsies (Fisher's exact test P = 2.1 × 10−4). In a subsequent screen among children carrying the 16p11.2 600 kb rearrangement we identified three patients with RE-spectrum epilepsies in 117 duplication carriers (2.6%) but none in 202 carriers of the reciprocal deletion. Our results suggest that the 16p11.2 duplication represents a significant genetic risk factor for typical and atypical R

    Disentangling determinants of egg size in the Geometridae (Lepidoptera) using an advanced phylogenetic comparative method

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    We present a phylogenetic comparative study assessing the evolutionary determinants of egg size in the moth family Geometridae. These moths were found to show a strong negative allometric relationship between egg size and maternal body size. Using recently developed comparative methods based on an Ornstein-Uhlenbeck process, we show that maternal body size explains over half the variation in egg size. However, other determinants are less clear: ecological factors, previously hypothesized to affect egg size, were not found to have a considerable influence in the Geometridae. The limited role of such third factors suggests a direct causal link between egg size and body size rather than an indirect correlation mediated by some ecological factors. Notably, no large geometrid species lay small eggs. This pattern suggests that maternal body size poses a physical constraint on egg size, but within these limits, there appears to be a rather invariable selection for larger eggs.Estonian Science Foundation Grant 7699, targeted financing project SF0180122s08 and by the European Union through the European Regional Development Fund (Center of Excellence FIBIR).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1420-9101nf201

    Recurrent deletions and duplications of chromosome 2q11.2 and 2q13 are associated with variable outcomes

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/115980/1/ajmga37269_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/115980/2/ajmga37269.pd

    Expanding the Genetic and Phenotypic Spectrum of <em>POLRMT</em>-Related Mitochondrial Disease

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    \ua9 2025 The Author(s). Clinical Genetics published by John Wiley &amp; Sons Ltd.Mitochondrial diseases are a complex group of conditions exhibiting significant phenotypic and genetic heterogeneity. Genomic testing is increasingly used as the first step in the diagnostic pathway for mitochondrial diseases. We used next-generation sequencing followed by bioinformatic data analysis to identify potentially damaging variants in the POLRMT gene (NM_005035.4) in six new affected individuals. Structural protein analysis predicted the detrimental impact of variants on POLRMT protein structure. Patients show extended phenotypic abnormalities often presenting early in life with features including global developmental delay, cognitive impairment, short stature and muscular hypotonia. This study expands the genetic and phenotypic landscape of mitochondrial disease associated with POLRMT variants

    Frameshift mutations at the C-terminus of HIST1H1E result in a specific DNA hypomethylation signature

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    BACKGROUND: We previously associated HIST1H1E mutations causing Rahman syndrome with a specific genome-wide methylation pattern. RESULTS: Methylome analysis from peripheral blood samples of six affected subjects led us to identify a specific hypomethylated profile. This "episignature" was enriched for genes involved in neuronal system development and function. A computational classifier yielded full sensitivity and specificity in detecting subjects with Rahman syndrome. Applying this model to a cohort of undiagnosed probands allowed us to reach diagnosis in one subject. CONCLUSIONS: We demonstrate an epigenetic signature in subjects with Rahman syndrome that can be used to reach molecular diagnosis

    Refining the 9q34.3 microduplication syndrome reveals mild neurodevelopmental features associated with a distinct global DNA methylation profile

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    Precise regulation of gene expression is important for correct neurodevelopment. 9q34.3 deletions affecting the EHMT1 gene result in a syndromic neurodevelopmental disorder named Kleefstra syndrome. In contrast, duplications of the 9q34.3 locus encompassing EHMT1 have been suggested to cause developmental disorders, but only limited information has been available. We have identified 15 individuals from 10 unrelated families, with 9q34.3 duplications &lt;1.5 Mb in size, encompassing EHMT1 entirely. Clinical features included mild developmental delay, mild intellectual disability or learning problems, autism spectrum disorder, and behavior problems. The individuals did not consistently display dysmorphic features, congenital anomalies, or growth abnormalities. DNA methylation analysis revealed a weak DNAm profile for the cases with 9q34.3 duplication encompassing EHMT1, which could segregate the majority of the affected cases from controls. This study shows that individuals with 9q34.3 duplications including EHMT1 gene present with mild non-syndromic neurodevelopmental disorders and DNA methylation changes different from Kleefstra syndrome.</p

    Distinct effects on mRNA export factor GANP underlie neurological disease phenotypes and alter gene expression depending on intron content

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    Defects in the mRNA export scaffold protein GANP, encoded by the MCM3AP gene, cause autosomal recessive early-onset peripheral neuropathy with or without intellectual disability. We extend here the phenotypic range associated with MCM3AP variants, by describing a severely hypotonic child and a sibling pair with a progressive encephalopathic syndrome. In addition, our analysis of skin fibroblasts from affected individuals from seven unrelated families indicates that disease variants result in depletion of GANP except when they alter critical residues in the Sac3 mRNA binding domain. GANP depletion was associated with more severe phenotypes compared with the Sac3 variants. Patient fibroblasts showed transcriptome alterations that suggested intron content-dependent regulation of gene expression. For example, all differentially expressed intronless genes were downregulated, including ATXN7L3B, which couples mRNA export to transcription activation by association with the TREX-2 and SAGA complexes. Our results provide insight into the molecular basis behind genotype-phenotype correlations in MCM3AP-associated disease and suggest mechanisms by which GANP defects might alter RNA metabolism.Peer reviewe

    Single-Cell Epigenomics and Functional Fine-Mapping of Atherosclerosis GWAS Loci

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    Rationale: Genome-wide association studies have identified hundreds of loci associated with coronary artery disease (CAD). Many of these loci are enriched in cisregulatory elements but not linked to cardiometabolic risk factors nor to candidate causal genes, complicating their functional interpretation. Objective: Single-nucleus chromatin accessibility profiling of the human atherosclerotic lesions was used to investigate cell type-specific patterns of cisregulatory elements, to understand transcription factors establishing cell identity, and to interpret CAD-relevant, noncoding genetic variation. Methods and Results: We used single-nucleus ATAC-seq (assay for transposase-accessible chromatin with sequencing) to generate DNA accessibility maps in >7000 cells derived from human atherosclerotic lesions. We identified 5 major lesional cell types including endothelial cells, smooth muscle cells, monocyte/macrophages, natural killer/T cells, and B cells and further investigated subtype characteristics of macrophages and smooth muscle cells transitioning into fibromyocytes. We demonstrated that CAD-associated genetic variants are particularly enriched in endothelial and smooth muscle cell-specific open chromatin. Using single-cell coaccessibility and cis-expression quantitative trait loci information, we prioritized putative target genes and candidate regulatory elements for approximate to 30% of all known CAD loci. Finally, we performed genome-wide experimental fine-mapping of the CAD variants identified in genome-wide association studies using epigenetic quantitative trait loci analysis in primary human aortic endothelial cells and self-transcribing active regulatory region sequencing (STARR-Seq) massively parallel reporter assay in smooth muscle cells. This analysis identified potential causal single-nucleotide polymorphisms (SNPs) and the associated target gene for over 30 CAD loci. We present several examples where the chromatin accessibility and gene expression could be assigned to one cell type predicting the cell type of action for CAD loci. Conclusions: These findings highlight the potential of applying single-nucleus ATAC-seq to human tissues in revealing relative contributions of distinct cell types to diseases and in identifying genes likely to be influenced by noncoding genome-wide association study variants.</p

    Loss-of-function and missense variants in NSD2 cause decreased methylation activity and are associated with a distinct developmental phenotype

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    PURPOSE: Despite a few recent reports of patients harboring truncating variants in NSD2, a gene considered critical for the Wolf–Hirschhorn syndrome (WHS) phenotype, the clinical spectrum associated with NSD2 pathogenic variants remains poorly understood. METHODS: We collected a comprehensive series of 18 unpublished patients carrying heterozygous missense, elongating, or truncating NSD2 variants; compared their clinical data to the typical WHS phenotype after pooling them with ten previously described patients; and assessed the underlying molecular mechanism by structural modeling and measuring methylation activity in vitro. RESULTS: The core NSD2-associated phenotype includes mostly mild developmental delay, prenatal-onset growth retardation, low body mass index, and characteristic facial features distinct from WHS. Patients carrying missense variants were significantly taller and had more frequent behavioral/psychological issues compared with those harboring truncating variants. Structural in silico modeling suggested interference with NSD2’s folding and function for all missense variants in known structures. In vitro testing showed reduced methylation activity and failure to reconstitute H3K36me2 in NSD2 knockout cells for most missense variants. CONCLUSION: NSD2 loss-of-function variants lead to a distinct, rather mild phenotype partially overlapping with WHS. To avoid confusion for patients, NSD2 deficiency may be named Rauch–Steindl syndrome after the delineators of this phenotype
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