Project description:Identifying causes of sporadic intellectual disability remains a considerable medical challenge. Here, we demonstrate that null mutations in the NONO gene, a member of the Drosophila Behavior Human Splicing (DBHS) protein family, are a novel cause of X-linked syndromic intellectual disability. Comparing humans to Nono-deficient mice revealed related behavioral and craniofacial anomalies, as well as global transcriptional dysregulation. Nono-deficient mice also showed deregulation of a large number of synaptic transcripts, causing a disorganization of inhibitory synapses, with impaired postsynaptic scaffolding of gephyrin. Alteration of gephyrin clustering could be rescued by over-expression of Gabra2 in NONO-compromised neurons. These findings link NONO to intellectual disability and first highlight the key role of DBHS proteins in functional organization of GABAergic synapses.
Project description:Identifying causes of sporadic intellectual disability remains a considerable medical challenge. Here, we demonstrate that null mutations in the NONO gene, a member of the Drosophila Behavior Human Splicing (DBHS) protein family, are a novel cause of X-linked syndromic intellectual disability. Comparing humans to Nono-deficient mice revealed related behavioral and craniofacial anomalies, as well as global transcriptional dysregulation. Nono-deficient mice also showed deregulation of a large number of synaptic transcripts, causing a disorganization of inhibitory synapses, with impaired postsynaptic scaffolding of gephyrin. Alteration of gephyrin clustering could be rescued by over-expression of Gabra2 in NONO-compromised neurons. These findings link NONO to intellectual disability and first highlight the key role of DBHS proteins in functional organization of GABAergic synapses.
Project description:Potocki-Shaffer syndrome (PSS) is a rare contiguous gene deletion syndrome marked by haploinsufficiency of genes in chromosomal region 11p11.2p12. Approximately 50 cases of PSS have been reported; however, a syndrome with a PSS-like clinical phenotype caused by 11p11.12p12 duplication has not yet been reported. We first report the 11p11.12p12 duplication in a family with intellectual disability and craniofacial anomalies. 11p11.12p12 duplication syndrome was identified by karyotype analysis. Next-generation sequencing (NGS) analysis clarified the location of the chromosomal variations, which was confirmed by chromosome microarray analysis (CMA). Whole-exome sequencing (WES) was performed to exclude single nucleotide variations (SNVs). The raw data of NGS analysis and WES have been submitted to SRA, the accession number is PRJNA713823.
Project description:Identifying causes of sporadic intellectual disability remains a considerable medical challenge. Here, we demonstrate that null mutations in the NONO gene, a member of the Drosophila Behavior Human Splicing (DBHS) protein family, are a novel cause of X-linked syndromic intellectual disability. Comparing humans to Nono-deficient mice revealed related behavioral and craniofacial anomalies, as well as global transcriptional dysregulation. Nono-deficient mice also showed deregulation of a large number of synaptic transcripts, causing a disorganization of inhibitory synapses, with impaired postsynaptic scaffolding of gephyrin. Alteration of gephyrin clustering could be rescued by over-expression of Gabra2 in NONO-compromised neurons. These findings link NONO to intellectual disability and first highlight the key role of DBHS proteins in functional organization of GABAergic synapses.
Project description:Intellectual disability (ID) is a clinically important disease and a most prevalent neurodevelopmental disorder. The etiology and pathogenesis of ID are poorly recognized. Exome sequencing revealed a homozygous missense mutation in the POLR3B gene in a consanguineous family with three Intellectual disability with craniofacal anomalies patients. POLR3B gene encoding the second largest subunit of RNA polymerase III. To explore how genetic variants alter cell expression in ID patients, RNA sequencing on blood samples was performed and to obtain insights into the biological pathways influenced by POLR3B mutation, we applied our RNA-Seq data to several gene ontology programs such as ToppGene, Enrichr, KEGG. We detected a significant decrease expression of several spliceosomal RNAs, ribosomal proteins and transcription factors in our ID patients. We hypothesize that POLR3B mutation dysregulates the expression of some important transcription factors, ribosomal and spliceosomal genes and impairments in protein synthesis and splicing mediated in part by transcription factors such as FOXC2, GATA1, .. contribute to impaired neuronal function and concurrence of intellectual disability and craniofacial anomalies in our patients. Our study highlights the emerging role of spliceosome and ribosomal proteins in intellectual disability.
Project description:Intellectual disability is a neurodevelopmental disorder that affects 2-3% of the general population. Syndromic forms of intellectual disability frequently have a genetic basis and are often accompanied by additional developmental anomalies. Pathogenic variants in components of TATA-binding protein associated factors (TAFs) have recently been identified in a subset of patients with intellectual disability, craniofacial hypoplasia, and congenital heart disease. This syndrome has been termed as a TAFopathy and includes mutations in TATA binding protein (TBP), TAF1, TAF2, and TAF6. The underlying mechanism by which TAFopathies give rise to neurodevelopmental, craniofacial, and cardiac abnormalities remains to be defined. Through a forward genetic screen in zebrafish, we have recovered a recessive mutant phenotype characterized by craniofacial hypoplasia, ventricular hypoplasia, heart failure at 96 hours post-fertilization and lethality, and show it is caused by a nonsense mutation in taf5. CRISPR/CAS9 mediated gene editing revealed that these defects where phenocopied by mutations in taf1 and taf5. Mechanistically, taf5-/- zebrafish displayed misregulation in metabolic gene expression and metabolism as evidenced by RNA sequencing, respiration assays, and metabolite studies. Collectively, these findings suggest that the TAF complex may contribute to neurologic, craniofacial, and cardiac development through regulation of metabolism.
Project description:Here we describe an interstitial pure duplication of 19p13.3 that was initially considered as a de novo alteration, in a patient with intellectual disability studied by array-CGH. The finding of the same chromosomal alteration in a first-degree cousin of this patient led us to investigate the presence of insertional translocations. An intrachromosomal insertional translocation was found in at least three generations. Three intellectually disabled patients with the same duplication and multiples abortions among translocation carrier family members were found. A review of other published cases has allowed us to find three other cases with a similar pure duplication and some clinical findings present in all patients as intrauterine growth retardation, microcephaly, motor and speech delay, moderate to severe intellectual disability and dysmorphic features. These findings allow us to suggest the existence of a new microduplication syndrome in chromosomal region 19p13.3.
Project description:Here we describe an interstitial pure duplication of 19p13.3 that was initially considered as a de novo alteration, in a patient with intellectual disability studied by array-CGH. The finding of the same chromosomal alteration in a first-degree cousin of this patient led us to investigate the presence of insertional translocations. An intrachromosomal insertional translocation was found in at least three generations. Three intellectually disabled patients with the same duplication and multiples abortions among translocation carrier family members were found. A review of other published cases has allowed us to find three other cases with a similar pure duplication and some clinical findings present in all patients as intrauterine growth retardation, microcephaly, motor and speech delay, moderate to severe intellectual disability and dysmorphic features. These findings allow us to suggest the existence of a new microduplication syndrome in chromosomal region 19p13.3. Whole genome array-CGH was performed on Agilent oligo-chip 44K (human genome CGH microarray G4410B from Agilent Technologies, Palo Alto, CA) as recommended. The patientsM-bM-^@M-^Y DNA samples were tested against a pool of 10 sex-matched normal DNA samples, all of them (patients and normal controls) from our geographical area. Scanned images were quantified using Agilent Feature Extraction Software (v9.0). The results were analyzed using Agilent Genomic Workbench software. Annotations have been obtained from UCSC (http://genome.ucsc.edu) based on human genome build GRCh37/hg19.
Project description:Intellectual disability is a common condition that carries lifelong severe medical and developmental consequences. The causes of intellectual disability (ID) remain unknown for the majority of patients due to the extensive clinical and genetic heterogeneity of this disorder. De novo mutations may play an important role in ID as most individuals with ID present as isolated cases without family history and/or clear syndromic indication. In addition, the involvement of such mutations have recently been demonstrated in a small number of individuals with ID. Here we evaluate the diagnostic potential and role of de novo mutations in a cohort of 100 patients with ID of unknown cause using family-based exome sequencing. Single end short-read (50 bp) SOLiD 4 sequencing data for 300 individuals, constituting 100 patient-parent trios. For more details please read; http://www.nejm.org/doi/full/10.1056/NEJMoa1206524. Dataset is created by RUNMC (Radboud University, Nijmegen Medical Center), partner of Geuvadis consortium (http://www.geuvadis.org).