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1.
Genome Res ; 2024 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-39472019

RESUMO

Rare or de novo structural variation, primarily in the form of copy number variants, is detected in 5%-10% of autism spectrum disorder (ASD) families. While complex structural variants involving duplications can generally be detected using microarray or short-read genome sequencing (GS), these methods frequently fail to characterize breakpoints at nucleotide resolution, requiring additional molecular methods for validation and fine-mapping. Here, we use Oxford Nanopore Technologies PromethION long-read GS to characterize complex genomic rearrangements (CGRs) involving large duplications that segregate with ASD in five families. In total, we investigated 13 CGR carriers and were able to resolve all breakpoint junctions at nucleotide resolution. While all breakpoints were identified, the precise genomic architecture of one rearrangement remained unresolved with three different potential structures. The findings in two families include potential fusion genes formed through duplication rearrangements, involving IL1RAPL1-DMD and SUPT16H-CHD8 In two of the families originating from the same geographical region, an identical rearrangement involving ANK2 was identified, which likely represents a founder variant. In addition, we analyze methylation status directly from the long-read data, allowing us to assess the activity of rearranged genes and regulatory regions. Investigation of methylation across the CGRs reveals aberrant methylation status in carriers across a rearrangement affecting the CREBBP locus. In aggregate, our results demonstrate the utility of nanopore sequencing to pinpoint CGRs associated with ASD in five unrelated families, and highlight the importance of a gene-centric description of disease-associated complex chromosomal rearrangements.

2.
Genome Res ; 2024 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-39472022

RESUMO

Clinical genetic laboratories often require a comprehensive analysis of chromosomal rearrangements/structural variants (SVs), from large events like translocations and inversions to supernumerary ring/marker chromosomes and small deletions or duplications. Understanding the complexity of these events and their clinical consequences requires pinpointing breakpoint junctions and resolving the derivative chromosome structure. This task often surpasses the capabilities of short-read sequencing technologies. In contrast, long-read sequencing techniques present a compelling alternative for clinical diagnostics. Here, Genomic Medicine Sweden-Rare Diseases has explored the utility of HiFi Revio long-read genome sequencing (lrGS) for digital karyotyping of SVs nationwide. The 16 samples from 13 families were collected from all Swedish healthcare regions. Prior investigations had identified 16 SVs, ranging from simple to complex rearrangements, including inversions, translocations, and copy number variants. We have established a national pipeline and a shared variant database for variant calling and filtering. Using lrGS, 14 of the 16 known SVs are detected. Of these, 13 are mapped at nucleotide resolution, and one complex rearrangement is only visible by read depth. Two Chromosome 21 rearrangements, one mosaic, remain undetected. Average read lengths are 8.3-18.8 kb with coverage exceeding 20× for all samples. De novo assembly results in a limited number of phased contigs per individual (N50 6-86 Mb), enabling direct characterization of the chromosomal rearrangements. In a national pilot study, we demonstrate the utility of HiFi Revio lrGS for analyzing chromosomal rearrangements. Based on our results, we propose a 5-year plan to expand lrGS use for rare disease diagnostics in Sweden.

3.
Int J Mol Sci ; 25(12)2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38928350

RESUMO

The COVID-19 pandemic highlighted the need for a rapid, convenient, and scalable diagnostic method for detecting a novel pathogen amidst a global pandemic. While command-line interface tools offer automation for SARS-CoV-2 Oxford Nanopore Technology sequencing data analysis, they are inapplicable to users with limited programming skills. A solution is to establish such automated workflows within a graphical user interface software. We developed two workflows in the software Geneious Prime 2022.1.1, adapted for data obtained from the Midnight and Artic's nCoV-2019 sequencing protocols. Both workflows perform trimming, read mapping, consensus generation, and annotation on SARS-CoV-2 Nanopore sequencing data. Additionally, one workflow includes phylogenetic assignment using the bioinformatic tools pangolin and Nextclade as plugins. The basic workflow was validated in 2020, adhering to the requirements of the European Centre for Disease Prevention and Control for SARS-CoV-2 sequencing and analysis. The enhanced workflow, providing phylogenetic assignment, underwent validation at Uppsala University Hospital by analysing 96 clinical samples. It provided accurate diagnoses matching the original results of the basic workflow while also reducing manual clicks and analysis time. These bioinformatic workflows streamline SARS-CoV-2 Nanopore data analysis in Geneious Prime, saving time and manual work for operators lacking programming knowledge.


Assuntos
COVID-19 , Biologia Computacional , Pandemias , Filogenia , SARS-CoV-2 , Software , SARS-CoV-2/genética , COVID-19/epidemiologia , COVID-19/virologia , Humanos , Biologia Computacional/métodos , Fluxo de Trabalho , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Interface Usuário-Computador , Sequenciamento por Nanoporos/métodos
4.
RNA ; 26(11): 1654-1666, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32763916

RESUMO

The deamination of adenosine to inosine at the wobble position of tRNA is an essential post-transcriptional RNA modification required for wobble decoding in bacteria and eukaryotes. In humans, the wobble inosine modification is catalyzed by the heterodimeric ADAT2/3 complex. Here, we describe novel pathogenic ADAT3 variants impairing adenosine deaminase activity through a distinct mechanism that can be corrected through expression of the heterodimeric ADAT2 subunit. The variants were identified in a family in which all three siblings exhibit intellectual disability linked to biallelic variants in the ADAT3 locus. The biallelic ADAT3 variants result in a missense variant converting alanine to valine at a conserved residue or the introduction of a premature stop codon in the deaminase domain. Fibroblast cells derived from two ID-affected individuals exhibit a reduction in tRNA wobble inosine levels and severely diminished adenosine tRNA deaminase activity. Notably, the ADAT3 variants exhibit impaired interaction with the ADAT2 subunit and alterations in ADAT2-dependent nuclear localization. Based upon these findings, we find that tRNA adenosine deaminase activity and wobble inosine modification can be rescued in patient cells by overexpression of the ADAT2 catalytic subunit. These results uncover a key role for the inactive ADAT3 deaminase domain in proper assembly with ADAT2 and demonstrate that ADAT2/3 nuclear import is required for maintaining proper levels of the wobble inosine modification in tRNA.


Assuntos
Adenosina Desaminase/genética , Adenosina Desaminase/metabolismo , Deficiência Intelectual/genética , Mutação de Sentido Incorreto , RNA de Transferência/química , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Transporte Ativo do Núcleo Celular , Adenosina/metabolismo , Adenosina Desaminase/química , Adolescente , Sítios de Ligação , Células Cultivadas , Criança , Pré-Escolar , Códon de Terminação , Feminino , Predisposição Genética para Doença , Humanos , Inosina/metabolismo , Deficiência Intelectual/metabolismo , Masculino , Linhagem , Domínios Proteicos , Proteínas de Ligação a RNA/química , Sequenciamento do Exoma
5.
Int J Mol Sci ; 23(16)2022 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-36012658

RESUMO

Balanced structural variants, such as reciprocal translocations, are sometimes hard to detect with sequencing, especially when the breakpoints are located in repetitive or insufficiently mapped regions of the genome. In such cases, long-range information is required to resolve the rearrangement, identify disrupted genes and, in symptomatic carriers, pinpoint the disease-causing mechanisms. Here, we report an individual with autism, epilepsy and osteoporosis and a de novo balanced reciprocal translocation: t(17;19) (p13;p11). The genomic DNA was analyzed by short-, linked- and long-read genome sequencing, as well as optical mapping. Transcriptional consequences were assessed by transcriptome sequencing of patient-specific neuroepithelial stem cells derived from induced pluripotent stem cells (iPSC). The translocation breakpoints were only detected by long-read sequencing, the first on 17p13, located between exon 1 and exon 2 of MINK1 (Misshapen-like kinase 1), and the second in the chromosome 19 centromere. Functional validation in induced neural cells showed that MINK1 expression was reduced by >50% in the patient's cells compared to healthy control cells. Furthermore, pathway analysis revealed an enrichment of changed neural pathways in the patient's cells. Altogether, our multi-omics experiments highlight MINK1 as a candidate monogenic disease gene and show the advantages of long-read genome sequencing in capturing centromeric translocations.


Assuntos
Transtorno Autístico , Epilepsia , Osteoporose , Proteínas Serina-Treonina Quinases , Transtorno Autístico/genética , Mapeamento Cromossômico , Epilepsia/genética , Humanos , Osteoporose/genética , Proteínas Serina-Treonina Quinases/genética , Translocação Genética
6.
BMC Bioinformatics ; 22(1): 110, 2021 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-33676405

RESUMO

BACKGROUND: Machine learning involves strategies and algorithms that may assist bioinformatics analyses in terms of data mining and knowledge discovery. In several applications, viz. in Life Sciences, it is often more important to understand how a prediction was obtained rather than knowing what prediction was made. To this end so-called interpretable machine learning has been recently advocated. In this study, we implemented an interpretable machine learning package based on the rough set theory. An important aim of our work was provision of statistical properties of the models and their components. RESULTS: We present the R.ROSETTA package, which is an R wrapper of ROSETTA framework. The original ROSETTA functions have been improved and adapted to the R programming environment. The package allows for building and analyzing non-linear interpretable machine learning models. R.ROSETTA gathers combinatorial statistics via rule-based modelling for accessible and transparent results, well-suited for adoption within the greater scientific community. The package also provides statistics and visualization tools that facilitate minimization of analysis bias and noise. The R.ROSETTA package is freely available at https://github.com/komorowskilab/R.ROSETTA . To illustrate the usage of the package, we applied it to a transcriptome dataset from an autism case-control study. Our tool provided hypotheses for potential co-predictive mechanisms among features that discerned phenotype classes. These co-predictors represented neurodevelopmental and autism-related genes. CONCLUSIONS: R.ROSETTA provides new insights for interpretable machine learning analyses and knowledge-based systems. We demonstrated that our package facilitated detection of dependencies for autism-related genes. Although the sample application of R.ROSETTA illustrates transcriptome data analysis, the package can be used to analyze any data organized in decision tables.


Assuntos
Algoritmos , Aprendizado de Máquina , Estudos de Casos e Controles , Biologia Computacional , Mineração de Dados
7.
Hum Genet ; 140(5): 775-790, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33315133

RESUMO

Chromoanagenesis is a genomic event responsible for the formation of complex structural chromosomal rearrangements (CCRs). Germline chromoanagenesis is rare and the majority of reported cases are associated with an affected phenotype. Here, we report a healthy female carrying two de novo CCRs involving chromosomes 4, 19, 21 and X and chromosomes 7 and 11, respectively, with a total of 137 breakpoint junctions (BPJs). We characterized the CCRs using a hybrid-sequencing approach, combining short-read sequencing, nanopore sequencing, and optical mapping. The results were validated using multiple cytogenetic methods, including fluorescence in situ hybridization, spectral karyotyping, and Sanger sequencing. We identified 137 BPJs, which to our knowledge is the highest number of reported breakpoint junctions in germline chromoanagenesis. We also performed a statistical assessment of the positioning of the breakpoints, revealing a significant enrichment of BPJ-affecting genes (96 intragenic BPJs, 26 genes, p < 0.0001), indicating that the CCRs formed during active transcription of these genes. In addition, we find that the DNA fragments are unevenly and non-randomly distributed across the derivative chromosomes indicating a multistep process of scattering and re-joining of DNA fragments. In summary, we report a new maximum number of BPJs (137) in germline chromoanagenesis. We also show that a hybrid sequencing approach is necessary for the correct characterization of complex CCRs. Through in-depth statistical assessment, it was found that the CCRs most likely was formed through an event resembling chromoplexy-a catastrophic event caused by erroneous transcription factor binding.


Assuntos
Quebra Cromossômica , Rearranjo Gênico/genética , Translocação Genética/genética , Cromossomos/genética , Análise Citogenética , Feminino , Humanos , Hibridização in Situ Fluorescente , Sequenciamento Completo do Genoma
8.
Genet Med ; 23(5): 888-899, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33597769

RESUMO

PURPOSE: Postsynaptic density protein-95 (PSD-95), encoded by DLG4, regulates excitatory synaptic function in the brain. Here we present the clinical and genetic features of 53 patients (42 previously unpublished) with DLG4 variants. METHODS: The clinical and genetic information were collected through GeneMatcher collaboration. All the individuals were investigated by local clinicians and the gene variants were identified by clinical exome/genome sequencing. RESULTS: The clinical picture was predominated by early onset global developmental delay, intellectual disability, autism spectrum disorder, and attention deficit-hyperactivity disorder, all of which point to a brain disorder. Marfanoid habitus, which was previously suggested to be a characteristic feature of DLG4-related phenotypes, was found in only nine individuals and despite some overlapping features, a distinct facial dysmorphism could not be established. Of the 45 different DLG4 variants, 39 were predicted to lead to loss of protein function and the majority occurred de novo (four with unknown origin). The six missense variants identified were suggested to lead to structural or functional changes by protein modeling studies. CONCLUSION: The present study shows that clinical manifestations associated with DLG4 overlap with those found in other neurodevelopmental disorders of synaptic dysfunction; thus, we designate this group of disorders as DLG4-related synaptopathy.


Assuntos
Transtorno do Espectro Autista , Encefalopatias , Deficiência Intelectual , Transtornos do Neurodesenvolvimento , Transtorno do Espectro Autista/diagnóstico , Transtorno do Espectro Autista/genética , Encéfalo , Proteína 4 Homóloga a Disks-Large/genética , Humanos , Transtornos do Neurodesenvolvimento/diagnóstico , Transtornos do Neurodesenvolvimento/genética , Fenótipo
9.
BMC Biotechnol ; 19(1): 31, 2019 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-31164119

RESUMO

BACKGROUND: Copy number variation (CNV) plays an important role in human genetic diversity and has been associated with multiple complex disorders. Here we investigate a CNV on chromosome 10q11.22 that spans NPY4R, the gene for the appetite-regulating pancreatic polypeptide receptor Y4. This genomic region has been challenging to map due to multiple repeated elements and its precise organization has not yet been resolved. Previous studies using microarrays were interpreted to show that the most common copy number was 2 per genome. RESULTS: We have investigated 18 individuals from the 1000 Genomes project using the well-established method of read depth analysis and the new droplet digital PCR (ddPCR) method. We find that the most common copy number for NPY4R is 4. The estimated number of copies ranged from three to seven based on read depth analyses with Control-FREEC and CNVnator, and from four to seven based on ddPCR. We suggest that the difference between our results and those published previously can be explained by methodological differences such as reference gene choice, data normalization and method reliability. Three high-quality archaic human genomes (two Neanderthal and one Denisova) display four copies of the NPY4R gene indicating that a duplication occurred prior to the human-Neanderthal/Denisova split. CONCLUSIONS: We conclude that ddPCR is a sensitive and reliable method for CNV determination, that it can be used for read depth calibration in CNV studies based on already available whole-genome sequencing data, and that further investigation of NPY4R copy number variation and its consequences are necessary due to the role of Y4 receptor in food intake regulation.


Assuntos
Variações do Número de Cópias de DNA/genética , Dosagem de Genes , Reação em Cadeia da Polimerase/métodos , Receptores de Neuropeptídeo Y/genética , Análise de Sequência de DNA/métodos , Genoma Humano/genética , Genômica/métodos , Humanos , Reprodutibilidade dos Testes
10.
Hum Mutat ; 39(9): 1262-1272, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29932473

RESUMO

Amplification of DNA is required as a mandatory step during library preparation in most targeted sequencing protocols. This can be a critical limitation when targeting regions that are highly repetitive or with extreme guanine-cytosine (GC) content, including repeat expansions associated with human disease. Here, we used an amplification-free protocol for targeted enrichment utilizing the CRISPR/Cas9 system (No-Amp Targeted sequencing) in combination with single molecule, real-time (SMRT) sequencing for studying repeat elements in the huntingtin (HTT) gene, where an expanded CAG repeat is causative for Huntington disease. We also developed a robust data analysis pipeline for repeat element analysis that is independent of alignment of reads to a reference genome. The method was applied to 11 diagnostic blood samples, and for all 22 alleles the resulting CAG repeat count agreed with previous results based on fragment analysis. The amplification-free protocol also allowed for studying somatic variability of repeat elements in our samples, without the interference of PCR stutter. In summary, with No-Amp Targeted sequencing in combination with our analysis pipeline, we could accurately study repeat elements that are difficult to investigate using PCR-based methods.


Assuntos
Genoma Humano/genética , Proteína Huntingtina/genética , Doença de Huntington/genética , Expansão das Repetições de Trinucleotídeos/genética , Alelos , Ataxina-10/genética , Proteína C9orf72/genética , Sistemas CRISPR-Cas/genética , Proteína do X Frágil da Deficiência Intelectual/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Doença de Huntington/patologia , RNA Guia de Cinetoplastídeos/genética , Análise de Sequência de DNA
11.
Am J Med Genet B Neuropsychiatr Genet ; 177(1): 10-20, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28990276

RESUMO

Intellectual Disability (ID) is a clinically heterogeneous condition that affects 2-3% of population worldwide. In recent years, exome sequencing has been a successful strategy for studies of genetic causes of ID, providing a growing list of both candidate and validated ID genes. In this study, exome sequencing was performed on 28 ID patients in 27 patient-parent trios with the aim to identify de novo variants (DNVs) in known and novel ID associated genes. We report the identification of 25 DNVs out of which five were classified as pathogenic or likely pathogenic. Among these, a two base pair deletion was identified in the PUF60 gene, which is one of three genes in the critical region of the 8q24.3 microdeletion syndrome (Verheij syndrome). Our result adds to the growing evidence that PUF60 is responsible for the majority of the symptoms reported for carriers of a microdeletion across this region. We also report variants in several genes previously not associated with ID, including a de novo missense variant in NAA15. We highlight NAA15 as a novel candidate ID gene based on the vital role of NAA15 in the generation and differentiation of neurons in neonatal brain, the fact that the gene is highly intolerant to loss of function and coding variation, and previously reported DNVs in neurodevelopmental disorders.


Assuntos
Deficiência Intelectual/genética , Acetiltransferase N-Terminal A/genética , Acetiltransferase N-Terminal E/genética , Fatores de Processamento de RNA/genética , Proteínas Repressoras/genética , Exoma , Humanos , Deficiência Intelectual/metabolismo , Mutação , Acetiltransferase N-Terminal A/metabolismo , Acetiltransferase N-Terminal E/metabolismo , Transtornos do Neurodesenvolvimento/genética , Fatores de Processamento de RNA/metabolismo , Proteínas Repressoras/metabolismo , Sequenciamento do Exoma/métodos
12.
Hum Mutat ; 38(10): 1394-1401, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28581210

RESUMO

Glycosylphosphatidylinositol (GPI) is a glycolipid that tethers more than 150 different proteins to the cell surface. Aberrations in biosynthesis of GPI anchors cause congenital disorders of glycosylation with clinical features including intellectual disability (ID), seizures, and facial dysmorphism. Here, we present two siblings with ID, cerebellar hypoplasia, cerebellar ataxia, early-onset seizures, and minor facial dysmorphology. Using exome sequencing, we identified a homozygous nonsense variant (NM_001127178.1:c.1640G>A, p.Trp547*) in the gene Phosphatidylinositol Glycan Anchor Biosynthesis, Class G (PIGG) in both the patients. Variants in several other GPI anchor synthesis genes lead to a reduced expression of GPI-anchored proteins (GPI-APs) that can be measured by flow cytometry. No significant differences in GPI-APs could be detected in patient granulocytes, consistent with recent findings. However, fibroblasts showed a reduced global level of GPI anchors and of specific GPI-linked markers. These findings suggest that fibroblasts might be more sensitive to pathogenic variants in GPI synthesis pathway and are well suited to screen for GPI-anchor deficiencies. Based on genetic and functional evidence, we confirm that pathogenic variants in PIGG cause an ID syndrome, and we find that loss of function of PIGG is associated with GPI deficiency.


Assuntos
Ataxia Cerebelar/genética , Cerebelo/anormalidades , Glicosilfosfatidilinositóis/genética , Deficiência Intelectual/genética , Malformações do Sistema Nervoso/genética , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Ataxia Cerebelar/fisiopatologia , Cerebelo/fisiopatologia , Criança , Pré-Escolar , Deficiências do Desenvolvimento/genética , Deficiências do Desenvolvimento/fisiopatologia , Feminino , Citometria de Fluxo , Expressão Gênica , Glicosilfosfatidilinositóis/química , Glicosilfosfatidilinositóis/deficiência , Humanos , Deficiência Intelectual/fisiopatologia , Masculino , Proteínas de Membrana/genética , Malformações do Sistema Nervoso/fisiopatologia , Linhagem , Fosfotransferases (Aceptor do Grupo Álcool)/química , Convulsões/genética , Convulsões/fisiopatologia , Irmãos , Sequenciamento do Exoma
13.
J Med Genet ; 53(10): 697-704, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27334371

RESUMO

BACKGROUND: De novo mutations are a frequent cause of disorders related to brain development. We report the results of screening patients diagnosed with both epilepsy and intellectual disability (ID) using exome sequencing to identify known and new causative de novo mutations relevant to these conditions. METHODS: Exome sequencing was performed on 39 patient-parent trios to identify de novo mutations. Clinical significance of de novo mutations in genes was determined using the American College of Medical Genetics and Genomics standard guidelines for interpretation of coding variants. Variants in genes of unknown clinical significance were further analysed in the context of previous trio sequencing efforts in neurodevelopmental disorders. RESULTS: In 39 patient-parent trios we identified 29 de novo mutations in coding sequence. Analysis of de novo and inherited variants yielded a molecular diagnosis in 11 families (28.2%). In combination with previously published exome sequencing results in neurodevelopmental disorders, our analysis implicates HECW2 as a novel candidate gene in ID and epilepsy. CONCLUSIONS: Our results support the use of exome sequencing as a diagnostic approach for ID and epilepsy, and confirm previous results regarding the importance of de novo mutations in this patient group. The results also highlight the utility of network analysis and comparison to previous large-scale studies as strategies to prioritise candidate genes for further studies. This study adds knowledge to the increasingly growing list of causative and candidate genes in ID and epilepsy and highlights HECW2 as a new candidate gene for neurodevelopmental disorders.


Assuntos
Epilepsia/metabolismo , Deficiência Intelectual/metabolismo , Mutação , Ubiquitina-Proteína Ligases/genética , Análise Mutacional de DNA , Epilepsia/genética , Exoma , Feminino , Humanos , Deficiência Intelectual/genética , Masculino , Síndrome
14.
Hum Mutat ; 37(9): 964-75, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27328812

RESUMO

Chromatin-remodeling factors are required for a wide range of cellular and biological processes including development and cognition, mainly by regulating gene expression. As these functions would predict, deregulation of chromatin-remodeling factors causes various disease syndromes, including neurodevelopmental disorders. Recent reports have linked mutations in several genes coding for chromatin-remodeling factors to intellectual disability (ID). Here, we used exome sequencing and identified a nonsynonymous de novo mutation in BAZ1A (NM_182648.2:c.4043T > G, p.Phe1348Cys), encoding the ATP-utilizing chromatin assembly and remodeling factor 1 (ACF1), in a patient with unexplained ID. ACF1 has been previously reported to bind to the promoter of the vitamin D receptor (VDR)-regulated genes and suppress their expression. Our results show that the patient displays decreased binding of ACF1 to the promoter of the VDR-regulated gene CYP24A1. Using RNA sequencing, we find that the mutation affects the expression of genes involved in several pathways including vitamin D metabolism, Wnt signaling and synaptic formation. RNA sequencing of BAZ1A knockdown cells and Baz1a knockout mice revealed that BAZ1A carry out distinctive functions in different tissues. We also demonstrate that BAZ1A depletion influence the expression of genes important for nervous system development and function. Our data point to an important role for BAZ1A in neurodevelopment, and highlight a possible link for BAZ1A to ID.


Assuntos
Deficiência Intelectual/genética , Sistema Nervoso/crescimento & desenvolvimento , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Substituição de Aminoácidos , Animais , Linhagem Celular , Proteínas Cromossômicas não Histona , Exoma , Redes Reguladoras de Genes , Humanos , Camundongos , Regiões Promotoras Genéticas , Receptores de Calcitriol/metabolismo , Análise de Sequência de DNA , Análise de Sequência de RNA , Potenciais Sinápticos , Distribuição Tecidual , Via de Sinalização Wnt
15.
Nature ; 464(7289): 704-12, 2010 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-19812545

RESUMO

Structural variations of DNA greater than 1 kilobase in size account for most bases that vary among human genomes, but are still relatively under-ascertained. Here we use tiling oligonucleotide microarrays, comprising 42 million probes, to generate a comprehensive map of 11,700 copy number variations (CNVs) greater than 443 base pairs, of which most (8,599) have been validated independently. For 4,978 of these CNVs, we generated reference genotypes from 450 individuals of European, African or East Asian ancestry. The predominant mutational mechanisms differ among CNV size classes. Retrotransposition has duplicated and inserted some coding and non-coding DNA segments randomly around the genome. Furthermore, by correlation with known trait-associated single nucleotide polymorphisms (SNPs), we identified 30 loci with CNVs that are candidates for influencing disease susceptibility. Despite this, having assessed the completeness of our map and the patterns of linkage disequilibrium between CNVs and SNPs, we conclude that, for complex traits, the heritability void left by genome-wide association studies will not be accounted for by common CNVs.


Assuntos
Variações do Número de Cópias de DNA/genética , Predisposição Genética para Doença/genética , Genoma Humano/genética , Mutagênese/genética , Duplicação Gênica , Estudo de Associação Genômica Ampla , Genótipo , Haplótipos/genética , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único/genética , Grupos Raciais/genética , Reprodutibilidade dos Testes
16.
Twin Res Hum Genet ; 19(2): 97-103, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26899349

RESUMO

Monozygotic (MZ) twins stem from the same single fertilized egg and therefore share all their inherited genetic variation. This is one of the unequivocal facts on which genetic epidemiology and twin studies are based. To what extent this also implies that MZ twins share genotypes in adult tissues is not precisely established, but a common pragmatic assumption is that MZ twins are 100% genetically identical also in adult tissues. During the past decade, this view has been challenged by several reports, with observations of differences in post-zygotic copy number variations (CNVs) between members of the same MZ pair. In this study, we performed a systematic search for differences of CNVs within 38 adult MZ pairs who had been misclassified as dizygotic (DZ) twins by questionnaire-based assessment. Initial scoring by PennCNV suggested a total of 967 CNV discordances. The within-pair correlation in number of CNVs detected was strongly dependent on confidence score filtering and reached a plateau of r = 0.8 when restricting to CNVs detected with confidence score larger than 50. The top-ranked discordances were subsequently selected for validation by quantitative polymerase chain reaction (qPCR), from which one single ~120kb deletion in NRXN1 on chromosome 2 (bp 51017111-51136802) was validated. Despite involving an exon, no sign of cognitive/mental consequences was apparent in the affected twin pair, potentially reflecting limited or lack of expression of the transcripts containing this exon in nerve/brain.


Assuntos
Moléculas de Adesão Celular Neuronais/genética , Variações do Número de Cópias de DNA/genética , Proteínas do Tecido Nervoso/genética , Gêmeos Monozigóticos/genética , Proteínas de Ligação ao Cálcio , Cognição/fisiologia , Feminino , Genoma Humano , Genótipo , Humanos , Masculino , Moléculas de Adesão de Célula Nervosa , Inquéritos e Questionários , Gêmeos Dizigóticos/genética
17.
Nucleic Acids Res ; 42(Database issue): D986-92, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24174537

RESUMO

Over the past decade, the Database of Genomic Variants (DGV; http://dgv.tcag.ca/) has provided a publicly accessible, comprehensive curated catalogue of structural variation (SV) found in the genomes of control individuals from worldwide populations. Here, we describe updates and new features, which have expanded the utility of DGV for both the basic research and clinical diagnostic communities. The current version of DGV consists of 55 published studies, comprising >2.5 million entries identified in >22,300 genomes. Studies included in DGV are selected from the accessioned data sets in the archival SV databases dbVar (NCBI) and DGVa (EBI), and then further curated for accuracy and validity. The core visualization tool (gbrowse) has been upgraded with additional functions to facilitate data analysis and comparison, and a new query tool has been developed to provide flexible and interactive access to the data. The content from DGV is regularly incorporated into other large-scale genome reference databases and represents a standard data resource for new product and database development, in particular for copy number variation testing in clinical labs. The accurate cataloguing of variants in DGV will continue to enable medical genetics and genome sequencing research.


Assuntos
Bases de Dados de Ácidos Nucleicos , Genoma Humano , Variação Estrutural do Genoma , Doença/genética , Humanos , Internet
18.
Nat Genet ; 39(7 Suppl): S7-15, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17597783

RESUMO

There has been an explosion of data describing newly recognized structural variants in the human genome. In the flurry of reporting, there has been no standard approach to collecting the data, assessing its quality or describing identified features. This risks becoming a rampant problem, in particular with respect to surveys of copy number variation and their application to disease studies. Here, we consider the challenges in characterizing and documenting genomic structural variants. From this, we derive recommendations for standards to be adopted, with the aim of ensuring the accurate presentation of this form of genetic variation to facilitate ongoing research.


Assuntos
Variação Genética , Genoma Humano , Bases de Dados Genéticas/normas , Dosagem de Genes , Genômica/normas , Genômica/tendências , Humanos , Controle de Qualidade , Terminologia como Assunto
19.
Nat Genet ; 39(3): 319-28, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17322880

RESUMO

Autism spectrum disorders (ASDs) are common, heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome heterogeneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1,181 [corrected] families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamate-related genes as promising candidates for contributing to ASDs.


Assuntos
Transtorno Autístico/genética , Aberrações Cromossômicas , Mapeamento Cromossômico , Ligação Genética , Predisposição Genética para Doença , Testes Genéticos/métodos , Transtorno Autístico/diagnóstico , Família , Feminino , Variação Genética , Humanos , Escore Lod , Masculino , Fatores de Risco
20.
Hum Mol Genet ; 22(7): 1373-82, 2013 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-23321059

RESUMO

Linkage, association and expression studies previously pointed to the human QKI, KH domain containing, RNA-binding (QKI) as a candidate gene for schizophrenia. Functional studies of the mouse orthologue Qk focused mainly on its role in oligodendrocyte development and myelination, while its function in astroglia remained unexplored. Here, we show that QKI is highly expressed in human primary astrocytes and that its splice forms encode proteins targeting different subcellular localizations. Uncovering the role of QKI in astrocytes is of interest in light of growing evidence implicating astrocyte dysfunction in the pathogenesis of several disorders of the central nervous system. We selectively silenced QKI splice variants in human primary astrocytes and used RNA sequencing to identify differential expression and splice variant composition at the genome-wide level. We found that an mRNA expression of Glial fibrillary acidic protein (GFAP), encoding a major component of astrocyte intermediate filaments, was down-regulated after QKI7 splice variant silencing. Moreover, we identified a potential QKI-binding site within the 3' untranslated region of human GFAP. This sequence was not conserved between mice and humans, raising the possibility that GFAP is a target for QKI in humans but not rodents. Haloperidol treatment of primary astrocytes resulted in coordinated increases in QKI7 and GFAP expression. Taken together, our results provide the first link between QKI and GFAP, two genes with alterations previously observed independently in schizophrenic patients. Our findings for QKI, together with its well-known role in myelination, suggest that QKI is a hub regulator of glia function in humans.


Assuntos
Astrócitos/metabolismo , Regulação da Expressão Gênica , Proteína Glial Fibrilar Ácida/genética , Proteínas de Ligação a RNA/fisiologia , Sequência de Aminoácidos , Antipsicóticos/farmacologia , Células Cultivadas , Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Proteína Glial Fibrilar Ácida/metabolismo , Haloperidol/farmacologia , Humanos , Dados de Sequência Molecular , Cultura Primária de Células , Domínios e Motivos de Interação entre Proteínas , Isoformas de Proteínas/fisiologia , Transporte Proteico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , Proteínas de Ligação a RNA/química , Esquizofrenia/metabolismo , Análise de Sequência de RNA , Transcriptoma
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