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1.
Nat Commun ; 11(1): 5236, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-33067431

RESUMO

The etiology of major neurodevelopmental disorders such as schizophrenia and autism is unclear, with evidence supporting a combination of genetic factors and environmental insults, including viral infection during pregnancy. Here we utilized a mouse model of maternal immune activation (MIA) with the viral mimic PolyI:C infection during early gestation. We investigated the transcriptional changes in the brains of mouse fetuses following MIA during the prenatal period, and evaluated the behavioral and biochemical changes in the adult brain. The results reveal an increase in RNA editing levels and dysregulation in brain development-related gene pathways in the fetal brains of MIA mice. These MIA-induced brain editing changes are not observed in adulthood, although MIA-induced behavioral deficits are observed. Taken together, our findings suggest that MIA induces transient dysregulation of RNA editing at a critical time in brain development.


Assuntos
Transtornos do Neurodesenvolvimento/etiologia , Transtornos do Neurodesenvolvimento/genética , Complicações na Gravidez/imunologia , Gravidez/imunologia , Efeitos Tardios da Exposição Pré-Natal/genética , Edição de RNA , Animais , Comportamento Animal , Encéfalo/crescimento & desenvolvimento , Encéfalo/imunologia , Encéfalo/metabolismo , Modelos Animais de Doenças , Feminino , Imunidade Materno-Adquirida , Camundongos , Camundongos Endogâmicos C57BL , Transtornos do Neurodesenvolvimento/imunologia , Transtornos do Neurodesenvolvimento/psicologia , Poli I-C/efeitos adversos , Poli I-C/imunologia , Complicações na Gravidez/etiologia , Complicações na Gravidez/genética , Efeitos Tardios da Exposição Pré-Natal/imunologia , Efeitos Tardios da Exposição Pré-Natal/psicologia
2.
Nat Commun ; 11(1): 4932, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-33004838

RESUMO

Most genes associated with neurodevelopmental disorders (NDDs) were identified with an excess of de novo mutations (DNMs) but the significance in case-control mutation burden analysis is unestablished. Here, we sequence 63 genes in 16,294 NDD cases and an additional 62 genes in 6,211 NDD cases. By combining these with published data, we assess a total of 125 genes in over 16,000 NDD cases and compare the mutation burden to nonpsychiatric controls from ExAC. We identify 48 genes (25 newly reported) showing significant burden of ultra-rare (MAF < 0.01%) gene-disruptive mutations (FDR 5%), six of which reach family-wise error rate (FWER) significance (p < 1.25E-06). Among these 125 targeted genes, we also reevaluate DNM excess in 17,426 NDD trios with 6,499 new autism trios. We identify 90 genes enriched for DNMs (FDR 5%; e.g., GABRG2 and UIMC1); of which, 61 reach FWER significance (p < 3.64E-07; e.g., CASZ1). In addition to doubling the number of patients for many NDD risk genes, we present phenotype-genotype correlations for seven risk genes (CTCF, HNRNPU, KCNQ3, ZBTB18, TCF12, SPEN, and LEO1) based on this large-scale targeted sequencing effort.


Assuntos
Predisposição Genética para Doença , Transtornos do Neurodesenvolvimento/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fator de Ligação a CCCTC/genética , Estudos de Casos e Controles , Estudos de Coortes , Análise Mutacional de DNA , Proteínas de Ligação a DNA/genética , Feminino , Estudos de Associação Genética , Ribonucleoproteínas Nucleares Heterogêneas Grupo U/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Canal de Potássio KCNQ3/genética , Masculino , Mutação , Proteínas de Ligação a RNA/genética , Proteínas Repressoras/genética , Fatores de Transcrição/genética
3.
Neuron ; 107(6): 1000-1013, 2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32970995

RESUMO

Human organoid models of the central nervous system, including the neural retina, are providing unprecedented opportunities to explore human neurodevelopment and neurodegeneration in controlled culture environments. In this Perspective, we discuss how the single-cell multi-omic toolkit has been used to identify features and limitations of brain and retina organoids and how these tools can be deployed to study congenital brain malformations and vision disorders in organoids. We also address how to improve brain and retina organoid protocols to revolutionize in vitro disease modeling.


Assuntos
Genômica/métodos , Transtornos do Neurodesenvolvimento/metabolismo , Organoides/metabolismo , Cultura Primária de Células/métodos , Análise de Célula Única/métodos , Transtornos da Visão/metabolismo , Humanos , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/patologia , Organoides/crescimento & desenvolvimento , Organoides/patologia , Transtornos da Visão/genética , Transtornos da Visão/patologia
4.
PLoS Genet ; 16(9): e1009017, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32925911

RESUMO

Interpreting rare variants remains a challenge in personal genomics, especially for disorders with several causal genes and for genes that cause multiple disorders. ZNF423 encodes a transcriptional regulatory protein that intersects several developmental pathways. ZNF423 has been implicated in rare neurodevelopmental disorders, consistent with midline brain defects in Zfp423-mutant mice, but pathogenic potential of most patient variants remains uncertain. We engineered ~50 patient-derived and small deletion variants into the highly-conserved mouse ortholog and examined neuroanatomical measures for 791 littermate pairs. Three substitutions previously asserted pathogenic appeared benign, while a fourth was effectively null. Heterozygous premature termination codon (PTC) variants showed mild haploabnormality, consistent with loss-of-function intolerance inferred from human population data. In-frame deletions of specific zinc fingers showed mild to moderate abnormalities, as did low-expression variants. These results affirm the need for functional validation of rare variants in biological context and demonstrate cost-effective modeling of neuroanatomical abnormalities in mice.


Assuntos
Defeitos do Tubo Neural/genética , Proteínas/genética , Alelos , Animais , Encéfalo/patologia , Encefalopatias/genética , Modelos Animais de Doenças , Feminino , Frequência do Gene/genética , Genômica , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Malformações do Sistema Nervoso/genética , Transtornos do Neurodesenvolvimento/genética , Proteínas/metabolismo , Fatores de Transcrição/genética , Dedos de Zinco
5.
Am J Hum Genet ; 107(3): 555-563, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32758449

RESUMO

Helsmoortel-Van der Aa syndrome (HVDAS) is a neurodevelopmental condition associated with intellectual disability/developmental delay, autism spectrum disorder, and multiple medical comorbidities. HVDAS is caused by mutations in activity-dependent neuroprotective protein (ADNP). A recent study identified genome-wide DNA methylation changes in 22 individuals with HVDAS, adding to the group of neurodevelopmental disorders with an epigenetic signature. This methylation signature segregated those with HVDAS into two groups based on the location of the mutations. Here, we conducted an independent study on 24 individuals with HVDAS and replicated the existence of the two mutation-dependent episignatures. To probe whether the two distinct episignatures correlate with clinical outcomes, we used deep behavioral and neurobiological data from two prospective cohorts of individuals with a genetic diagnosis of HVDAS. We found limited phenotypic differences between the two HVDAS-affected groups and no evidence that individuals with more widespread methylation changes are more severely affected. Moreover, in spite of the methylation changes, we observed no profound alterations in the blood transcriptome of individuals with HVDAS. Our data warrant caution in harnessing methylation signatures in HVDAS as a tool for clinical stratification, at least with regard to behavioral phenotypes.


Assuntos
Transtorno do Espectro Autista/genética , Proteínas de Homeodomínio/genética , Deficiência Intelectual/genética , Proteínas do Tecido Nervoso/genética , Transtornos do Neurodesenvolvimento/genética , Transtorno do Espectro Autista/patologia , Criança , Metilação de DNA/genética , Deficiências do Desenvolvimento/genética , Deficiências do Desenvolvimento/patologia , Epigênese Genética/genética , Feminino , Humanos , Deficiência Intelectual/patologia , Masculino , Mutação/genética , Transtornos do Neurodesenvolvimento/patologia , Fenótipo , Transcriptoma/genética
6.
Am J Hum Genet ; 107(2): 311-324, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32738225

RESUMO

Aminoacyl-tRNA synthetases (ARSs) are ubiquitous, ancient enzymes that charge amino acids to cognate tRNA molecules, the essential first step of protein translation. Here, we describe 32 individuals from 21 families, presenting with microcephaly, neurodevelopmental delay, seizures, peripheral neuropathy, and ataxia, with de novo heterozygous and bi-allelic mutations in asparaginyl-tRNA synthetase (NARS1). We demonstrate a reduction in NARS1 mRNA expression as well as in NARS1 enzyme levels and activity in both individual fibroblasts and induced neural progenitor cells (iNPCs). Molecular modeling of the recessive c.1633C>T (p.Arg545Cys) variant shows weaker spatial positioning and tRNA selectivity. We conclude that de novo and bi-allelic mutations in NARS1 are a significant cause of neurodevelopmental disease, where the mechanism for de novo variants could be toxic gain-of-function and for recessive variants, partial loss-of-function.


Assuntos
Aspartato-tRNA Ligase/genética , Mutação com Ganho de Função/genética , Mutação com Perda de Função/genética , Transtornos do Neurodesenvolvimento/genética , Aminoacil-RNA de Transferência/genética , Alelos , Aminoacil-tRNA Sintetases/genética , Linhagem Celular , Feminino , Predisposição Genética para Doença/genética , Humanos , Masculino , Linhagem , RNA de Transferência/genética , Células-Tronco/fisiologia
7.
BMC Med Genet ; 21(1): 158, 2020 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-32746809

RESUMO

BACKGROUND: Okur-Chung neurodevelopmental syndrome (OCNDS) and tricho-rhino-phalangeal syndrome type I (TRPSI) are rare Mendelian diseases. OCNDS is caused by CSNK2A1 gene variants and TRPSI is caused by the TRPS1gene. However, to have two Mendelian diseases in one patient is even rarer. CASE PRESENTATION: A 6-year-10-month-old boy characterized by special facial features, short stature and mental retardation was referred to our pediatric endocrinology department. Whole-exome sequencing (WES) was done to detect the molecular basis of his disease. This patient was confirmed to carry two variants in the CSNK2A1 gene and one in the TRPS1 gene. The variant in the CSNK2A1 gene was vertically transmitted from his father, and the variant in TRPS1 gene from his mother. These two variants are classified as pathogenic and the causes of the presentation in this child. This patient's father and mother have subsequently been diagnosed as having OCNDS and TRPSI respectively. CONCLUSION: This is the first reported case of a dual molecular diagnosis of tricho-rhino-phalangeal syndrome type I and Okur-Chung neurodevelopmental syndrome in the same patient. This patient is the first published example of vertical transmission of this recurrent CSN2A1 variant from parent to child. A novel variant in the TRPS1 gene that is pathogenic was also identified. In conclusion, identification of the variants in this patient expands the phenotypes and molecular basis of dual Mendelian diseases.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Dedos/anormalidades , Doenças do Cabelo/genética , Síndrome de Langer-Giedion/genética , Transtornos do Neurodesenvolvimento/genética , Nariz/anormalidades , Sequência de Bases , Criança , Feminino , Humanos , Masculino , Linhagem
8.
Am J Hum Genet ; 107(3): 499-513, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32721402

RESUMO

Signal transduction through the RAF-MEK-ERK pathway, the first described mitogen-associated protein kinase (MAPK) cascade, mediates multiple cellular processes and participates in early and late developmental programs. Aberrant signaling through this cascade contributes to oncogenesis and underlies the RASopathies, a family of cancer-prone disorders. Here, we report that de novo missense variants in MAPK1, encoding the mitogen-activated protein kinase 1 (i.e., extracellular signal-regulated protein kinase 2, ERK2), cause a neurodevelopmental disease within the RASopathy phenotypic spectrum, reminiscent of Noonan syndrome in some subjects. Pathogenic variants promote increased phosphorylation of the kinase, which enhances translocation to the nucleus and boosts MAPK signaling in vitro and in vivo. Two variant classes are identified, one of which directly disrupts binding to MKP3, a dual-specificity protein phosphatase negatively regulating ERK function. Importantly, signal dysregulation driven by pathogenic MAPK1 variants is stimulus reliant and retains dependence on MEK activity. Our data support a model in which the identified pathogenic variants operate with counteracting effects on MAPK1 function by differentially impacting the ability of the kinase to interact with regulators and substrates, which likely explains the minor role of these variants as driver events contributing to oncogenesis. After nearly 20 years from the discovery of the first gene implicated in Noonan syndrome, PTPN11, the last tier of the MAPK cascade joins the group of genes mutated in RASopathies.


Assuntos
Carcinogênese/genética , Proteína Quinase 1 Ativada por Mitógeno/genética , Transtornos do Neurodesenvolvimento/genética , Síndrome de Noonan/genética , Pré-Escolar , Feminino , Humanos , Sistema de Sinalização das MAP Quinases/genética , Masculino , Mutação de Sentido Incorreto/genética , Transtornos do Neurodesenvolvimento/patologia , Síndrome de Noonan/fisiopatologia , Fenótipo , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Transdução de Sinais , Sequenciamento Completo do Exoma , Proteínas ras/genética
9.
Nat Commun ; 11(1): 3358, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620757

RESUMO

Neurodevelopmental disorders have a heritable component and are associated with region specific alterations in brain anatomy. However, it is unclear how genetic risks for neurodevelopmental disorders are translated into spatially patterned brain vulnerabilities. Here, we integrated cortical neuroimaging data from patients with neurodevelopmental disorders caused by genomic copy number variations (CNVs) and gene expression data from healthy subjects. For each of the six investigated disorders, we show that spatial patterns of cortical anatomy changes in youth are correlated with cortical spatial expression of CNV genes in neurotypical adults. By transforming normative bulk-tissue cortical expression data into cell-type expression maps, we link anatomical change maps in each analysed disorder to specific cell classes as well as the CNV-region genes they express. Our findings reveal organizing principles that regulate the mapping of genetic risks onto regional brain changes in neurogenetic disorders. Our findings will enable screening for candidate molecular mechanisms from readily available neuroimaging data.


Assuntos
Córtex Cerebral/patologia , Variações do Número de Cópias de DNA , Predisposição Genética para Doença , Transtornos do Neurodesenvolvimento/genética , Adolescente , Adulto , Mapeamento Encefálico , Córtex Cerebral/citologia , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/crescimento & desenvolvimento , Criança , Estudos de Coortes , Feminino , Perfilação da Expressão Gênica , Genoma Humano , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos do Neurodesenvolvimento/diagnóstico , Transtornos do Neurodesenvolvimento/patologia , Neuroimagem , Neurônios/metabolismo , Neurônios/patologia , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Análise Espacial , Adulto Jovem
10.
Am J Hum Genet ; 107(2): 352-363, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32693025

RESUMO

MORC2 encodes an ATPase that plays a role in chromatin remodeling, DNA repair, and transcriptional regulation. Heterozygous variants in MORC2 have been reported in individuals with autosomal-dominant Charcot-Marie-Tooth disease type 2Z and spinal muscular atrophy, and the onset of symptoms ranges from infancy to the second decade of life. Here, we present a cohort of 20 individuals referred for exome sequencing who harbor pathogenic variants in the ATPase module of MORC2. Individuals presented with a similar phenotype consisting of developmental delay, intellectual disability, growth retardation, microcephaly, and variable craniofacial dysmorphism. Weakness, hyporeflexia, and electrophysiologic abnormalities suggestive of neuropathy were frequently observed but were not the predominant feature. Five of 18 individuals for whom brain imaging was available had lesions reminiscent of those observed in Leigh syndrome, and five of six individuals who had dilated eye exams had retinal pigmentary abnormalities. Functional assays revealed that these MORC2 variants result in hyperactivation of epigenetic silencing by the HUSH complex, supporting their pathogenicity. The described set of morphological, growth, developmental, and neurological findings and medical concerns expands the spectrum of genetic disorders resulting from pathogenic variants in MORC2.


Assuntos
Adenosina Trifosfatases/genética , Anormalidades Craniofaciais/genética , Transtornos do Crescimento/genética , Mutação/genética , Transtornos do Neurodesenvolvimento/genética , Fatores de Transcrição/genética , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Doenças Genéticas Inatas/genética , Heterozigoto , Humanos , Lactente , Deficiência Intelectual/genética , Masculino , Microcefalia/genética , Pessoa de Meia-Idade , Fenótipo , Adulto Jovem
11.
Am J Hum Genet ; 107(3): 544-554, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32730804

RESUMO

RNA polymerase II interacts with various other complexes and factors to ensure correct initiation, elongation, and termination of mRNA transcription. One of these proteins is SR-related CTD-associated factor 4 (SCAF4), which is important for correct usage of polyA sites for mRNA termination. Using exome sequencing and international matchmaking, we identified nine likely pathogenic germline variants in SCAF4 including two splice-site and seven truncating variants, all residing in the N-terminal two thirds of the protein. Eight of these variants occurred de novo, and one was inherited. Affected individuals demonstrated a variable neurodevelopmental disorder characterized by mild intellectual disability, seizures, behavioral abnormalities, and various skeletal and structural anomalies. Paired-end RNA sequencing on blood lymphocytes of SCAF4-deficient individuals revealed a broad deregulation of more than 9,000 genes and significant differential splicing of more than 2,900 genes, indicating an important role of SCAF4 in mRNA processing. Knockdown of the SCAF4 ortholog CG4266 in the model organism Drosophila melanogaster resulted in impaired locomotor function, learning, and short-term memory. Furthermore, we observed an increased number of active zones in larval neuromuscular junctions, representing large glutamatergic synapses. These observations indicate a role of CG4266 in nervous system development and function and support the implication of SCAF4 in neurodevelopmental phenotypes. In summary, our data show that heterozygous, likely gene-disrupting variants in SCAF4 are causative for a variable neurodevelopmental disorder associated with impaired mRNA processing.


Assuntos
Deficiência Intelectual/genética , Transtornos do Neurodesenvolvimento/genética , Convulsões/genética , Fatores de Processamento de Serina-Arginina/genética , Animais , Criança , Drosophila melanogaster/genética , Feminino , Técnicas de Silenciamento de Genes , Variação Genética/genética , Heterozigoto , Humanos , Deficiência Intelectual/fisiopatologia , Locomoção/genética , Masculino , Mutação/genética , Transtornos do Neurodesenvolvimento/fisiopatologia , RNA Polimerase II/genética , Processamento Pós-Transcricional do RNA/genética , RNA Mensageiro/genética , Convulsões/fisiopatologia , Sequenciamento Completo do Exoma
12.
Adv Neurobiol ; 25: 109-153, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32578146

RESUMO

Despite decades of study, elucidation of the underlying etiology of complex developmental disorders such as autism spectrum disorder (ASD), schizophrenia (SCZ), intellectual disability (ID), and bipolar disorder (BPD) has been hampered by the inability to study human neurons, the heterogeneity of these disorders, and the relevance of animal model systems. Moreover, a majority of these developmental disorders have multifactorial or idiopathic (unknown) causes making them difficult to model using traditional methods of genetic alteration. Examination of the brains of individuals with ASD and other developmental disorders in both post-mortem and MRI studies shows defects that are suggestive of dysregulation of embryonic and early postnatal development. For ASD, more recent genetic studies have also suggested that risk genes largely converge upon the developing human cerebral cortex between weeks 8 and 24 in utero. Yet, an overwhelming majority of studies in autism rodent models have focused on postnatal development or adult synaptic transmission defects in autism related circuits. Thus, studies looking at early developmental processes such as proliferation, cell migration, and early differentiation, which are essential to build the brain, are largely lacking. Yet, interestingly, a few studies that did assess early neurodevelopment found that alterations in brain structure and function associated with neurodevelopmental disorders (NDDs) begin as early as the initial formation and patterning of the neural tube. By the early to mid-2000s, the derivation of human embryonic stem cells (hESCs) and later induced pluripotent stem cells (iPSCs) allowed us to study living human neural cells in culture for the first time. Specifically, iPSCs gave us the unprecedented ability to study cells derived from individuals with idiopathic disorders. Studies indicate that iPSC-derived neural cells, whether precursors or "matured" neurons, largely resemble cortical cells of embryonic humans from weeks 8 to 24. Thus, these cells are an excellent model to study early human neurodevelopment, particularly in the context of genetically complex diseases. Indeed, since 2011, numerous studies have assessed developmental phenotypes in neurons derived from individuals with both genetic and idiopathic forms of ASD and other NDDs. However, while iPSC-derived neurons are fetal in nature, they are post-mitotic and thus cannot be used to study developmental processes that occur before terminal differentiation. Moreover, it is important to note that during the 8-24-week window of human neurodevelopment, neural precursor cells are actively undergoing proliferation, migration, and early differentiation to form the basic cytoarchitecture of the brain. Thus, by studying NPCs specifically, we could gain insight into how early neurodevelopmental processes contribute to the pathogenesis of NDDs. Indeed, a few studies have explored NPC phenotypes in NDDs and have uncovered dysregulations in cell proliferation. Yet, few studies have explored migration and early differentiation phenotypes of NPCs in NDDs. In this chapter, we will discuss cell migration and neurite outgrowth and the role of these processes in neurodevelopment and NDDs. We will begin by reviewing the processes that are important in early neurodevelopment and early cortical development. We will then delve into the roles of neurite outgrowth and cell migration in the formation of the brain and how errors in these processes affect brain development. We also provide review of a few key molecules that are involved in the regulation of neurite outgrowth and migration while discussing how dysregulations in these molecules can lead to abnormalities in brain structure and function thereby highlighting their contribution to pathogenesis of NDDs. Then we will discuss whether neurite outgrowth, migration, and the molecules that regulate these processes are associated with ASD. Lastly, we will review the utility of iPSCs in modeling NDDs and discuss future goals for the study of NDDs using this technology.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Células-Tronco Neurais , Transtornos do Neurodesenvolvimento , Animais , Transtorno do Espectro Autista/genética , Transtorno Autístico/genética , Movimento Celular , Humanos , Transtornos do Neurodesenvolvimento/genética , Crescimento Neuronal
13.
PLoS Genet ; 16(6): e1008792, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32579612

RESUMO

While rare pathogenic copy-number variants (CNVs) are associated with both neuronal and non-neuronal phenotypes, functional studies evaluating these regions have focused on the molecular basis of neuronal defects. We report a systematic functional analysis of non-neuronal defects for homologs of 59 genes within ten pathogenic CNVs and 20 neurodevelopmental genes in Drosophila melanogaster. Using wing-specific knockdown of 136 RNA interference lines, we identified qualitative and quantitative phenotypes in 72/79 homologs, including 21 lines with severe wing defects and six lines with lethality. In fact, we found that 10/31 homologs of CNV genes also showed complete or partial lethality at larval or pupal stages with ubiquitous knockdown. Comparisons between eye and wing-specific knockdown of 37/45 homologs showed both neuronal and non-neuronal defects, but with no correlation in the severity of defects. We further observed disruptions in cell proliferation and apoptosis in larval wing discs for 23/27 homologs, and altered Wnt, Hedgehog and Notch signaling for 9/14 homologs, including AATF/Aatf, PPP4C/Pp4-19C, and KIF11/Klp61F. These findings were further supported by tissue-specific differences in expression patterns of human CNV genes, as well as connectivity of CNV genes to signaling pathway genes in brain, heart and kidney-specific networks. Our findings suggest that multiple genes within each CNV differentially affect both global and tissue-specific developmental processes within conserved pathways, and that their roles are not restricted to neuronal functions.


Assuntos
Variações do Número de Cópias de DNA , Proteínas de Drosophila/genética , Regulação da Expressão Gênica no Desenvolvimento , Transtornos do Neurodesenvolvimento/genética , Animais , Olho Composto de Artrópodes/embriologia , Olho Composto de Artrópodes/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Especificidade de Órgãos , Receptores Notch/genética , Receptores Notch/metabolismo , Transdução de Sinais , Asas de Animais/embriologia , Asas de Animais/metabolismo , Proteínas Wnt/genética , Proteínas Wnt/metabolismo
14.
Nat Commun ; 11(1): 2990, 2020 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-32533064

RESUMO

Structural variants (SVs) contribute to many disorders, yet, functionally annotating them remains a major challenge. Here, we integrate SVs with RNA-sequencing from human post-mortem brains to quantify their dosage and regulatory effects. We show that genic and regulatory SVs exist at significantly lower frequencies than intergenic SVs. Functional impact of copy number variants (CNVs) stems from both the proportion of genic and regulatory content altered and loss-of-function intolerance of the gene. We train a linear model to predict expression effects of rare CNVs and use it to annotate regulatory disruption of CNVs from 14,891 independent genome-sequenced individuals. Pathogenic deletions implicated in neurodevelopmental disorders show significantly more extreme regulatory disruption scores and if rank ordered would be prioritized higher than using frequency or length alone. This work shows the deleteriousness of regulatory SVs, particularly those altering CTCF sites and provides a simple approach for functionally annotating the regulatory consequences of CNVs.


Assuntos
Encéfalo/metabolismo , Variações do Número de Cópias de DNA , Regulação da Expressão Gênica , Variação Genética , Genoma Humano/genética , Autopsia/métodos , Encéfalo/patologia , Feminino , Perfilação da Expressão Gênica/métodos , Humanos , Masculino , Transtornos do Neurodesenvolvimento/genética , Análise de Sequência de RNA/métodos
15.
Cytogenet Genome Res ; 160(6): 321-328, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32535594

RESUMO

Balanced chromosomal rearrangements are usually associated with a normal phenotype, although in some individuals, phenotypic alterations are observed. In these patients, molecular characterization of the breakpoints can reveal the pathogenic mechanism, providing the annotation of disease-associated loci and a better genotype-phenotype correlation. In this study, we describe a patient with a balanced reciprocal translocation between 4q27 and 7p22 associated with neurodevelopmental delay. We performed cytogenetic evaluation, next-generation sequencing of microdissected derivative chromosomes, and Sanger sequencing of the junction points to define the translocation's breakpoints at base pair resolution. We found that the PCDH10 and TNRC18 genes were disrupted by the breakpoints at chromosomes 4 and 7, respectively, with the formation of chimeric genes at the junction points. Gene expression studies in the patient's peripheral blood showed reduced expression of TNRC18, a gene with unknown function and clinical significance. PCDH10 plays a role in the development of the nervous system and might be involved with the patient's neurodevelopmental delay. In this study, the full molecular characterization of the junction points was shown as an efficient tool for fine breakpoint mapping in balanced translocations in order to unmask gene disruptions and investigate the potential pathogenic role of the disrupted genes.


Assuntos
Caderinas/genética , Pontos de Quebra do Cromossomo , Cromossomos Humanos Par 4/genética , Cromossomos Humanos Par 7/genética , Transtornos do Neurodesenvolvimento/genética , Translocação Genética/genética , Adulto , Sequência de Bases , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Deficiência Intelectual/genética , Deficiência Intelectual/psicologia , Transtornos do Neurodesenvolvimento/psicologia
16.
Mol Pharmacol ; 98(3): 192-202, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32580997

RESUMO

Neuronal voltage-gated potassium channels (Kv) are critical regulators of electrical activity in the central nervous system. Mutations in the KCNQ (Kv7) ion channel family are linked to epilepsy and neurodevelopmental disorders. These channels underlie the neuronal "M-current" and cluster in the axon initial segment to regulate the firing of action potentials. There is general consensus that KCNQ channel assembly and heteromerization are controlled by C-terminal helices. We identified a pediatric patient with neurodevelopmental disability, including autism traits, inattention and hyperactivity, and ataxia, who carries a de novo frameshift mutation in KCNQ3 (KCNQ3-FS534), leading to truncation of ∼300 amino acids in the C terminus. We investigated possible molecular mechanisms of channel dysfunction, including haplo-insufficiency or a dominant-negative effect caused by the assembly of truncated KCNQ3 and functional KCNQ2 subunits. We also used a recently recognized property of the KCNQ2-specific activator ICA-069673 to identify assembly of heteromeric channels. ICA-069673 exhibits a functional signature that depends on the subunit composition of KCNQ2/3 channels, allowing us to determine whether truncated KCNQ3 subunits can assemble with KCNQ2. Our findings demonstrate that although the KCNQ3-FS534 mutant does not generate functional channels on its own, large C-terminal truncations of KCNQ3 (including the KCNQ3-FS534 mutation) assemble efficiently with KCNQ2 but fail to promote or stabilize KCNQ2/KCNQ3 heteromeric channel expression. Therefore, the frequent assumption that pathologies linked to KCNQ3 truncations arise from haplo-insufficiency should be reconsidered in some cases. Subtype-specific channel activators like ICA-069673 are a reliable tool to identify heteromeric assembly of KCNQ2 and KCNQ3. SIGNIFICANCE STATEMENT: Mutations that truncate the C terminus of neuronal Kv7/KCNQ channels are linked to a spectrum of seizure disorders. One role of the multifunctional KCNQ C terminus is to mediate subtype-specific assembly of heteromeric KCNQ channels. This study describes the use of a subtype-specific Kv7 activator to assess assembly of heteromeric KCNQ2/KCNQ3 (Kv7.2/Kv7.3) channels and demonstrates that large disease-linked and experimentally generated C-terminal truncated KCNQ3 mutants retain the ability to assemble with KCNQ2.


Assuntos
Mutação da Fase de Leitura , Canal de Potássio KCNQ2/metabolismo , Canal de Potássio KCNQ3/química , Canal de Potássio KCNQ3/metabolismo , Transtornos do Neurodesenvolvimento/genética , Animais , Criança , Humanos , Canal de Potássio KCNQ2/química , Canal de Potássio KCNQ3/genética , Masculino , Modelos Moleculares , Conformação Proteica , Multimerização Proteica , Estabilidade Proteica , Estrutura Secundária de Proteína , Xenopus laevis
17.
Neuron ; 107(1): 22-37, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32559416

RESUMO

Neuronal SNAREs and their key regulators together drive synaptic vesicle exocytosis and synaptic transmission as a single integrated membrane fusion machine. Human pathogenic mutations have now been reported for all eight core components, but patients are diagnosed with very different neurodevelopmental syndromes. We propose to unify these syndromes, based on etiology and mechanism, as "SNAREopathies." Here, we review the strikingly diverse clinical phenomenology and disease severity and the also remarkably diverse genetic mechanisms. We argue that disease severity generally scales with functional redundancy and, conversely, that the large effect of mutations in some SNARE genes is the price paid for extensive integration and exceptional specialization. Finally, we discuss how subtle differences in components being rate limiting in different types of neurons helps to explain the main symptoms.


Assuntos
Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/fisiopatologia , Proteínas SNARE/fisiologia , Humanos , Mutação
18.
Am J Hum Genet ; 107(1): 164-172, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32553196

RESUMO

CNOT1 is a member of the CCR4-NOT complex, which is a master regulator, orchestrating gene expression, RNA deadenylation, and protein ubiquitination. We report on 39 individuals with heterozygous de novo CNOT1 variants, including missense, splice site, and nonsense variants, who present with a clinical spectrum of intellectual disability, motor delay, speech delay, seizures, hypotonia, and behavioral problems. To link CNOT1 dysfunction to the neurodevelopmental phenotype observed, we generated variant-specific Drosophila models, which showed learning and memory defects upon CNOT1 knockdown. Introduction of human wild-type CNOT1 was able to rescue this phenotype, whereas mutants could not or only partially, supporting our hypothesis that CNOT1 impairment results in neurodevelopmental delay. Furthermore, the genetic interaction with autism-spectrum genes, such as ASH1L, DYRK1A, MED13, and SHANK3, was impaired in our Drosophila models. Molecular characterization of CNOT1 variants revealed normal CNOT1 expression levels, with both mutant and wild-type alleles expressed at similar levels. Analysis of protein-protein interactions with other members indicated that the CCR4-NOT complex remained intact. An integrated omics approach of patient-derived genomics and transcriptomics data suggested only minimal effects on endonucleolytic nonsense-mediated mRNA decay components, suggesting that de novo CNOT1 variants are likely haploinsufficient hypomorph or neomorph, rather than dominant negative. In summary, we provide strong evidence that de novo CNOT1 variants cause neurodevelopmental delay with a wide range of additional co-morbidities. Whereas the underlying pathophysiological mechanism warrants further analysis, our data demonstrate an essential and central role of the CCR4-NOT complex in human brain development.


Assuntos
Deficiências do Desenvolvimento/genética , Expressão Gênica/genética , Transtornos do Neurodesenvolvimento/genética , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , RNA/genética , Receptores CCR4/genética , Fatores de Transcrição/genética , Alelos , Feminino , Variação Genética/genética , Haploinsuficiência/genética , Heterozigoto , Humanos , Masculino , Malformações do Sistema Nervoso/genética , Fenótipo , Estabilidade Proteica
19.
Nat Commun ; 11(1): 2755, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32488011

RESUMO

Fragile X Syndrome results from a loss of Fragile X Mental Retardation Protein (FMRP). We now show that FMRP is a member of a Cav3-Kv4 ion channel complex that is known to regulate A-type potassium current in cerebellar granule cells to produce mossy fiber LTP. Mossy fiber LTP is absent in Fmr1 knockout (KO) mice but is restored by FMRP(1-297)-tat peptide. This peptide further rapidly permeates the blood-brain barrier to enter cells across the cerebellar-cortical axis that restores the balance of protein translation for at least 24 h and transiently reduces elevated levels of activity of adult Fmr1 KO mice in the Open Field Test. These data reveal that FMRP(1-297)-tat can improve function from the levels of protein translation to synaptic efficacy and behaviour in a model of Fragile X syndrome, identifying a potential therapeutic strategy for this genetic disorder.


Assuntos
Proteína do X Frágil de Retardo Mental/metabolismo , Síndrome do Cromossomo X Frágil/metabolismo , Canais Iônicos/metabolismo , Animais , Encéfalo/patologia , Modelos Animais de Doenças , Proteína do X Frágil de Retardo Mental/genética , Síndrome do Cromossomo X Frágil/genética , Síndrome do Cromossomo X Frágil/patologia , Masculino , Camundongos , Camundongos Knockout , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/metabolismo , Transtornos do Neurodesenvolvimento/patologia , Plasticidade Neuronal/genética , Plasticidade Neuronal/fisiologia , Neurônios/metabolismo , Biossíntese de Proteínas
20.
Neuron ; 107(1): 52-64.e7, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32362337

RESUMO

At neuronal synapses, synaptotagmin-1 (syt1) acts as a Ca2+ sensor that synchronizes neurotransmitter release with Ca2+ influx during action potential firing. Heterozygous missense mutations in syt1 have recently been associated with a severe but heterogeneous developmental syndrome, termed syt1-associated neurodevelopmental disorder. Well-defined pathogenic mechanisms, and the basis for phenotypic heterogeneity in this disorder, remain unknown. Here, we report the clinical, physiological, and biophysical characterization of three syt1 mutations from human patients. Synaptic transmission was impaired in neurons expressing mutant variants, which demonstrated potent, graded dominant-negative effects. Biophysical interrogation of the mutant variants revealed novel mechanistic features concerning the cooperative action, and functional specialization, of the tandem Ca2+-sensing domains of syt1. These mechanistic studies led to the discovery that a clinically approved K+ channel antagonist is able to rescue the dominant-negative heterozygous phenotype. Our results establish a molecular cause, basis for phenotypic heterogeneity, and potential treatment approach for syt1-associated neurodevelopmental disorder.


Assuntos
Transtornos do Neurodesenvolvimento/genética , Neurônios/fisiologia , Transmissão Sináptica/genética , Sinaptotagmina I/genética , 4-Aminopiridina/farmacologia , Animais , Células Cultivadas , Humanos , Camundongos , Transtornos do Neurodesenvolvimento/fisiopatologia , Neurônios/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/farmacologia , Transmissão Sináptica/efeitos dos fármacos , Sinaptotagmina I/química
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