Project description:We identified a missense variant in PSMD12 gene, recently associated to an emerging syndromic form of NDD, in a patient with intellectual disability/speech delay, congenital anomalies and facial dysmorphisms. The variant described herein is useful to expand the molecular spectrum of heterozygous PSMD12 mutations and to provide insight into the molecular pathogenesis of this new condition since it is, to the best of our knowledge, the first missense substitution to date reported in medical literature. Finally, our patient is the one with the most detailed dysmorphic characterization and for this reason useful to start defining a typical facial gestalt that addresses the diagnosis.
Project description:Nuclear deubiquitinase BAP1 (BRCA1-Associated Protein 1) is a core component of multiprotein complexes that promote transcription by reversing the ubiquitination of histone 2A (H2A). BAP1 is a tumor suppressor gene whose germline loss-of-function variants predispose to cancer. To our knowledge, there are very rare examples of different germline variants in the same gene causing either a NDD or a tumor predisposition syndrome. Here, we report a series of 11 de novo germline heterozygous missense BAP1 variants associated with a rare syndromic neurodevelopmental disorder (NDD). Functional analysis showed that most of the variants cannot rescue the consequences of BAP1 inactivation, suggesting a loss-of-function mechanism. In T cells isolated from two affected children, H2A deubiquitination was impaired in matching peripheral blood mononuclear cells, histone H3 K27 acetylation ChIP-seq indicated that these BAP1 variants induced genome-wide chromatin state alterations, with enrichment for regulatory regions surrounding genes of the ubiquitin-proteasome system (UPS). Altogether, these results define a clinical syndrome caused by rare germline missense BAP1 variants that alter chromatin remodeling through abnormal histone ubiquitination and lead to transcriptional dysregulation of developmental genes.
Project description:Genome wide DNA methylation profiling of control and neurodevelopmental disorder lymphoblastoid cell lines (LCL). The Illumina Infinium 27k Human DNA methylation Beadchip v1.2 was used to obtain DNA methylation profiles across approximately 27,000 CpGs in LCLs. Samples included 19 control, 18 Rett syndrome, 17 autism and 6 generalized epilepsy LCL samples. Six technical replicates were also included in the analysis. Bisulphite converted DNA from the 60 samples and 5 technical replicates were hybridised to the Illumina Infinium 27k Human Methylation Beadchip v1.2
Project description:Rare germline heterozygous missense variants of the BRCA1-Associated Protein 1 gene, BAP1, heterozygous missense variants cause a syndromic neurodevelopmental disorder
Project description:Genome wide DNA methylation profiling of control and neurodevelopmental disorder lymphoblastoid cell lines (LCL). The Illumina Infinium 27k Human DNA methylation Beadchip v1.2 was used to obtain DNA methylation profiles across approximately 27,000 CpGs in LCLs. Samples included 19 control, 18 Rett syndrome, 17 autism and 6 generalized epilepsy LCL samples. Six technical replicates were also included in the analysis.
Project description:We report a new immunodeficiency disorder in mice caused by a viable hypomorphic mutation of Snrnp40, an essential gene encoding a subunit of the U5 small nuclear ribonucleoprotein (snRNP) complex of the spliceosome. Snrnp40 is ubiquitous but strongly expressed in lymphoid tissue. Homozygous mutant mice showed hypersusceptibility to infection by murine cytomegalovirus and multiple defects of lymphoid development, stability and function. Cell-intrinsic defects of hematopoietic stem cell differentiation also affected homozygous mutants. SNRNP40 deficiency in primary hematopoietic stem cells or T cells or the EL4 cell line increased the frequency of splicing errors, mostly intron retention, in several hundred messenger RNAs. Altered expression of proteins associated with immune cell function was also observed in Snrnp40-mutant cells. The immunological consequences of SNRNP40 deficiency presumably result from cumulative, moderate effects on processing of many different mRNA molecules and secondary reductions in the expression of critical immune proteins, yielding a syndromic immune disorder.
Project description:De novo mutations cause a variety of neurodevelopmental disorders including autism. Recent whole genome sequencing has identified hundreds of mutations in untranslated regions (UTRs) of genes from individuals with autism, but it is impossible to predict from sequence alone which are functional, and thus might be causal. Therefore, we developed a high throughput assay to screen the consequence over 1,000 variants from 5'UTRs mutations on transcript abundance and translation efficiency. This assay successfully enriched for elements that alter reporter translation, identifying over 100 potentially functional mutations. Studies in patient-derived cell lines further confirmed these mutations alter protein production in individuals in autism, including for multiple genes known to cause of syndromic forms autism, suggesting a diagnosis for these individual patients. Since UTR function varies by cell type, we further optimized this high throughput assay to enable assessment of mutations in neurons of the living brain. Neurons demonstrate profoundly different principles of regulation by 5'UTRs, consistent with more robust mechanism for reducing impact of 5'UTR RNA structure. Overall our results highlight a new approach for assessing the impact of 5’UTR across cell types and suggest some cases of neurodevelopmental disorder may be caused by such variants.
Project description:The cohesin complex is a large evolutionary conserved functional unit which plays an essential role in DNA repair and replication, chromosome segregation and gene expression. It consists of four core proteins, SMC1A, SMC3, RAD21, and STAG1/2, and by proteins regulating the interaction between the complex and the chromosomes. Mutations in the genes coding for these proteins have been demonstrated to cause multisystem developmental disorders known as "cohesinopathies". The most frequent and well recognized among these distinctive clinical conditions are the Cornelia de Lange syndrome (CdLS, OMIM 122470) and Roberts syndrome (OMIM 268300). STAG1 belongs to the STAG subunit of the core cohesin complex, along with five other subunits. Pathogenic variants in STAG1 gene have recently been reported to cause an emerging syndromic form of neurodevelopmental disorder that is to date poorly characterized. Here, we describe a 5 year old female patient with neurodevelopmental delay, mild intellectual disability, dysmorphic features and congenital anomalies, in which next generation sequencing analysis allowed us to identify a novel pathogenic variation c.2769_2770del p.(Ile924Serfs*8) in STAG1 gene, which result to be de novo. The variant has never been reported before in medical literature and is absent in public databases. Thus, it is useful to expand the molecular spectrum of clinically relevant alterations of STAG1 and their phenotypic consequences.
Project description:Purpose: MBD5-Associated Neurodevelopmental Disorder (MAND) is an Autism Spectrum Disorder (ASD) disorder characterized by intellectual disability, motor delay, severe speech impairment and autism-like behavioral problems. The role of MBD5 in neurodevelopmental function remains largely undefined. In this study, we explored the neurodevelopmental phenotype of 2q23.1 deletion syndrome through creating neuronal progenitor stem cells (NPC) derived from 2q23.1 patients and conducting RNA-seq to identify the contributory altered gene and to expand our knowledge about gene network differences and possible interactions between the related disease pathways and ASD. Methods: Primary skin fibroblasts from three MAND patients and four control cases were converted into induced pluripotent stem cell (iPSC) lines by transient transfections of episomal plasmids. Directed differentiation of these iPSC to NPC was accomplished with monolayer culture protocol for two weeks. Results: The RNA-seq analysis identified 498 genome-wide significant (q < 0.05) differentially expressed gene in the patients derived NPC lines as a consequence of reduced MBD5 dosage. 25 ASD associated genes were included in the differentially expressed gene list. On the top of the list, FOXG1 expression is significantly (P < 0.0001) increased in the patient derived NPC samples. The differentially expressed gene list was highly overlapped with the SFARI autism gene set, identifying biological processes that are implicating neurological phenotype and ASD such as central nervous system development, neuron differentiation, and regulation of neurogenesis. The findings of the transcriptome deviation in early neuronal stage of MAND can provide potential connection to the overlapping neurocognitive and neuropsychiatric phenotypes associated with growing risk factors, such as other chromatin modifiers and epigenetic factors that link to ASD. Such in vitro models can nurture hypotheses toward therapeutic interventions.