Project description:An increasing number of genes involved in chromatin structure and epigenetic regulation has been implicated in a variety of developmental disorders, often including intellectual disability. By trio exome sequencing and subsequent mutational screening we now identified two de novo frameshift mutations and one de novo missense mutation in the CTCF gene in individuals with intellectual disability, microcephaly and growth retardation. Furthermore, a patient with a larger deletion including CTCF was identified. CTCF (CCCTC-binding factor) is one of the most important chromatin organizers in vertebrates and is involved in various chromatin regulation processes such as higher order of chromatin organization, enhancer function, and maintenance of three-dimensional chromatin structure. Transcriptome analyses in all three patients with point mutations revealed deregulation of genes involved in signal transduction and emphasized the role of CTCF in enhancer-driven expression of genes. Our findings indicate that haploinsufficiency of CTCF affects genomic interaction of enhancers and their regulated gene promoters that drive developmental processes and cognition. Comparison of lymphocyte gene expression between 3 de novo CTCF mutation patients and 8 controls (4 technical replicates each, no biological replicates).
Project description:An increasing number of genes involved in chromatin structure and epigenetic regulation has been implicated in a variety of developmental disorders, often including intellectual disability. By trio exome sequencing and subsequent mutational screening we now identified two de novo frameshift mutations and one de novo missense mutation in the CTCF gene in individuals with intellectual disability, microcephaly and growth retardation. Furthermore, a patient with a larger deletion including CTCF was identified. CTCF (CCCTC-binding factor) is one of the most important chromatin organizers in vertebrates and is involved in various chromatin regulation processes such as higher order of chromatin organization, enhancer function, and maintenance of three-dimensional chromatin structure. Transcriptome analyses in all three patients with point mutations revealed deregulation of genes involved in signal transduction and emphasized the role of CTCF in enhancer-driven expression of genes. Our findings indicate that haploinsufficiency of CTCF affects genomic interaction of enhancers and their regulated gene promoters that drive developmental processes and cognition. ChIP-seq analysis of CTCF genomic binding sites in lymphocytes of a control individual (no replicates).
Project description:About 45% of congenital heart disease (CHD) is caused by rare gene mutations. Non-coding mutations that perturb cis-regulatory elements (CREs) likely contribute to CHD among the remaining cases without clear etiology. However, identifying CHD-causing non-coding variants has been problematic. We combined human induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) differentiation and a lentivirus-mediated massively parallel reporter assay (lentiMPRA) to create a high-throughput platform to measure human cardiac enhancer activity. We tested 2451 candidate human cardiac enhancers, identified 1185 with measurable activity, and functionally dissected 123 of these by systematic tiling mutagenesis. We functionally evaluated 6761 non-coding de novo variants (ncDNVs) prioritized from the whole genome sequencing (WGS) of 749 CHD trios. 397 ncDNVs significantly affected cardiac CRE activity. Remarkably, 53% of these ncDNVs increased enhancer activity, often at regions with undetectable enhancer activity in the reference sequence. We introduced 10 of these DNVs associated with CHD genes into iPSCs and found that 4 altered expression of neighboring genes. Moreover, these 4 DNVs also altered cardiomyocyte differentiation, as assessed by single nucleus RNA sequencing. Using the MPRA data, we developed a regression model to prioritize future DNVs for functional testing and demonstrate that this model finds enrichment of DNVs in a second, independent WGS cohort. Taken together, we developed a scalable system to measure the impact of non-coding DNVs on CRE activity and deployed this platform to systematically assess the contribution of non-coding DNVs to CHD.
Project description:Whole exome sequencing has proven to be a powerful tool for understanding the genetic architecture of human disease. Here we apply it to more than 2,500 simplex families, each having a child with an autistic spectrum disorder. By comparing affected to unaffected siblings, we show that 13% of de novo missense mutations and 43% of de novo likely gene-disrupting (LGD) mutations contribute to 12% and 9% of diagnoses, respectively. Including copy number variants, coding de novo mutations contribute to about 30% of all simplex and 45% of female diagnoses. Almost all LGD mutations occur opposite wild-type alleles. LGD targets in affected females significantly overlap the targets in males of lower intelligence quotient (IQ), but neither overlaps significantly with targets in males of higher IQ. We estimate that LGD mutation in about 400 genes can contribute to the joint class of affected females and males of lower IQ, with an overlapping and similar number of genes vulnerable to contributory missense mutation. LGD targets in the joint class overlap with published targets for intellectual disability and schizophrenia, and are enriched for chromatin modifiers, FMRP-associated genes and embryonically expressed genes. Most of the significance for the latter comes from affected females.
Project description:The identification of functional non-coding mutations is a key challenge in the field of genomics, where whole-genome re-sequencing can swiftly generate a set of all genomic variants in a sample, such as a tumor biopsy. The size of the human regulatory landscape places a challenge on finding recurrent cis-regulatory mutations across samples of the same cancer type. Therefore, powerful computational approaches are required to sift through the tens of thousands of non-coding variants, to identify potentially functional variants that have an impact on the gene expression profile of the sample. Here we introduce an integrative analysis pipeline, called μ-cisTarget, to filter, annotate and prioritize non-coding variants based on their putative effect on the underlying 'personal' gene regulatory network. We first validate μ-cisTarget by re-analyzing three cases of oncogenic non-coding mutations, namely the TAL1 and LMO1 enhancer mutations in T-ALL, and the TERT promoter mutation in melanoma. Next, we re-sequenced the full genome of ten cancer cell lines of six different cancer types, and used matched transcriptome data and motif discovery to infer master regulators for each sample. We identified candidate functional non-coding mutations that generate de novo binding sites for these master regulators, and that result in the up-regulation of nearby oncogenic drivers. We finally validated the predictions using tertiary data including matched epigenome data. Our approach is generally applicable to re-sequenced cancer genomes, or other genomes, when a disease- or sample-specific gene signature is available for network inference. μ-cisTarget is available from http://mucistarget.aertslab.org.
Project description:An increasing number of genes involved in chromatin structure and epigenetic regulation has been implicated in a variety of developmental disorders, often including intellectual disability. By trio exome sequencing and subsequent mutational screening we now identified two de novo frameshift mutations and one de novo missense mutation in the CTCF gene in individuals with intellectual disability, microcephaly and growth retardation. Furthermore, a patient with a larger deletion including CTCF was identified. CTCF (CCCTC-binding factor) is one of the most important chromatin organizers in vertebrates and is involved in various chromatin regulation processes such as higher order of chromatin organization, enhancer function, and maintenance of three-dimensional chromatin structure. Transcriptome analyses in all three patients with point mutations revealed deregulation of genes involved in signal transduction and emphasized the role of CTCF in enhancer-driven expression of genes. Our findings indicate that haploinsufficiency of CTCF affects genomic interaction of enhancers and their regulated gene promoters that drive developmental processes and cognition.