Browsing by Subject "Exome sequencing"

Now showing 1 - 10 of 12
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    A graph neural network model to estimate cell-wise metabolic flux using single-cell RNA-seq data
    (Cold Spring Harbor Laboratory, 2021) Alghamdi, Norah; Chang, Wennan; Dang, Pengtao; Lu, Xiaoyu; Wan, Changlin; Gampala, Silpa; Huang, Zhi; Wang, Jiashi; Ma, Qin; Zang, Yong; Fishel, Melissa; Cao, Sha; Zhang, Chi; Medical and Molecular Genetics, School of Medicine
    The metabolic heterogeneity and metabolic interplay between cells are known as significant contributors to disease treatment resistance. However, with the lack of a mature high-throughput single-cell metabolomics technology, we are yet to establish systematic understanding of the intra-tissue metabolic heterogeneity and cooperative mechanisms. To mitigate this knowledge gap, we developed a novel computational method, namely, single-cell flux estimation analysis (scFEA), to infer the cell-wise fluxome from single-cell RNA-sequencing (scRNA-seq) data. scFEA is empowered by a systematically reconstructed human metabolic map as a factor graph, a novel probabilistic model to leverage the flux balance constraints on scRNA-seq data, and a novel graph neural network-based optimization solver. The intricate information cascade from transcriptome to metabolome was captured using multilayer neural networks to capitulate the nonlinear dependency between enzymatic gene expressions and reaction rates. We experimentally validated scFEA by generating an scRNA-seq data set with matched metabolomics data on cells of perturbed oxygen and genetic conditions. Application of scFEA on this data set showed the consistency between predicted flux and the observed variation of metabolite abundance in the matched metabolomics data. We also applied scFEA on five publicly available scRNA-seq and spatial transcriptomics data sets and identified context- and cell group-specific metabolic variations. The cell-wise fluxome predicted by scFEA empowers a series of downstream analyses including identification of metabolic modules or cell groups that share common metabolic variations, sensitivity evaluation of enzymes with regards to their impact on the whole metabolic flux, and inference of cell-tissue and cell-cell metabolic communications.
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    Aminoacylation-defective bi-allelic mutations in human EPRS1 associated with psychomotor developmental delay, epilepsy, and deafness
    (Wiley, 2023) Jin, Danni; Wek, Sheree A.; Cordova, Ricardo A.; Wek, Ronald C.; Lacombe, Didier; Michaud, Vincent; Musier-Forsyth, Karin; Biochemistry and Molecular Biology, School of Medicine
    Aminoacyl-tRNA synthetases are enzymes that ensure accurate protein synthesis. Variants of the dual-functional cytoplasmic human glutamyl-prolyl-tRNA synthetase, EPRS1, have been associated with leukodystrophy, diabetes and bone disease. Here, we report compound heterozygous variants in EPRS1 in a 4-year-old female patient presenting with psychomotor developmental delay, seizures and deafness. Functional studies of these two missense mutations support major defects in enzymatic function in vitro and contributed to confirmation of the diagnosis.
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    Enhanced MAPK1 Function Causes a Neurodevelopmental Disorder within the RASopathy Clinical Spectrum
    (Elsevier, 2020-09-03) Motta, Marialetizia; Pannone, Luca; Pantaleoni, Francesca; Bocchinfuso, Gianfranco; Radio, Francesca Clementina; Cecchetti, Serena; Ciolfi, Andrea; Di Rocco, Martina; Elting, Mariet W.; Brilstra, Eva H.; Boni, Stefania; Mazzanti, Laura; Tamburrino, Federica; Walsh, Larry; Payne, Katelyn; Fernández-Jaén, Alberto; Ganapathi, Mythily; Chung, Wendy K.; Grange, Dorothy K.; Dave-Wala, Ashita; Reshmi, Shalini C.; Bartholomew, Dennis W.; Mouhlas, Danielle; Carpentieri, Giovanna; Bruselles, Alessandro; Pizzi, Simone; Bellacchio, Emanuele; Piceci-Sparascio, Francesca; Lißewski, Christina; Brinkmann, Julia; Waclaw, Ronald R.; Waisfisz, Quinten; van Gassen, Koen; Wentzensen, Ingrid M.; Morrow, Michelle M.; Álvarez, Sara; Martínez-García, Mónica; De Luca, Alessandro; Memo, Luigi; Zampino, Giuseppe; Rossi, Cesare; Seri, Marco; Gelb, Bruce D.; Zenker, Martin; Dallapiccola, Bruno; Stella, Lorenzo; Prada, Carlos E.; Martinelli, Simone; Flex, Elisabetta; Tartaglia, Marco; Medical and Molecular Genetics, School of Medicine
    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.
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    Familial Autonomic Ganglionopathy Caused by Rare CHRNA3 Genetic Variants
    (Wolters Kluwer, 2021) Shibao, Cyndya A.; Joos, Karen; Phillips, John A., III.; Cogan, Joy; Newman, John H.; Hamid, Rizwan; Meiler, Jens; Capra, John; Sheehan, Jonathan; Vetrini, Francesco; Yang, Yaping; Black, Bonnie; Diedrich, André; Roberston, David; Biaggioni, Italo; Medical and Molecular Genetics, School of Medicine
    Objective: To determine the molecular basis of a new monogenetic recessive disorder that results in familial autonomic ganglionopathy with diffuse autonomic failure. Methods: Two adult siblings from one family (I-4 and I-5) and another participant from a second family (II-3) presented with severe neurogenic orthostatic hypotension (nOH), small nonreactive pupils, and constipation. All 3 affected members had low norepinephrine levels and diffuse panautonomic failure. Results: Whole exome sequencing of DNA from I-4 and I-5 showed compound heterozygosity for c.907_908delCT (p.L303Dfs*115)/c.688 G>A (p.D230N) pathologic variants in the acetylcholine receptor, neuronal nicotinic, α3 subunit gene (CHRNA3). II-3 from the second family was homozygous for the same frameshift (fs) variant (p.L303Dfs*115//p.L303Dfs*115). CHRNA3 encodes a critical subunit of the nicotinic acetylcholine receptors (nAChRs) responsible for fast synaptic transmission in the autonomic ganglia. The fs variant is clearly pathogenic and the p.D230N variant is predicted to be damaging (SIFT)/probably damaging (PolyPhen2). The p.D230N variant lies on the interface between CHRNA3 and other nAChR subunits based on structural modeling and is predicted to destabilize the nAChR pentameric complex. Conclusions: We report a novel genetic disease that affected 3 individuals from 2 unrelated families who presented with severe nOH, miosis, and constipation. These patients had rare pathologic variants in the CHRNA3 gene that cosegregate with and are predicted to be the likely cause of their diffuse panautonomic failure.
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    Functional Dysregulation of CDC42 Causes Diverse Developmental Phenotypes
    (Elsevier, 2018-02-01) Martinelli, Simone; Krumbach, Oliver H.F.; Pantaleoni, Francesca; Coppola, Simona; Amin, Ehsan; Pannone, Luca; Nouri, Kazem; Farina, Luciapia; Dvorsky, Radovan; Lepri, Francesca; Bucholzer, Marcel; Konopatzki, Raphael; Walsh, Laurence; Payne, Katelyn; Pierpont, Mary Ella; Vergano, Samantha Schrier; Langley, Katherine G.; Larsen, Douglas; Farwell, Kelly D.; Tang, Sha; Mroske, Cameron; Gallotta, Ivan; Schiavi, Elia Di; della Monica, Matteo; Lugli, Licia; Rossi, Cesare; Seri, Marco; Cocchi, Guido; Henderson, Lindsay; Baskin, Berivan; Alders, Mariëlle; Mendoza-Londono, Roberto; Dupuis, Lucie; Nickerson, Deborah A.; Chong, Jessica X.; Meeks, Naomi; Brown, Kathleen; Causey, Tahnee; Cho, Megan T.; Demuth, Stephanie; Digilio, Maria Cristina; Gelb, Bruce D.; Bamshad, Michael J.; Zenker, Martin; Ahmadian, Mohammad Reza; Hennekam, Raoul C.; Tartaglia, Marco; Mirzaa, Ghayda M.; Neurology, School of Medicine
    Exome sequencing has markedly enhanced the discovery of genes implicated in Mendelian disorders, particularly for individuals in whom a known clinical entity could not be assigned. This has led to the recognition that phenotypic heterogeneity resulting from allelic mutations occurs more commonly than previously appreciated. Here, we report that missense variants in CDC42, a gene encoding a small GTPase functioning as an intracellular signaling node, underlie a clinically heterogeneous group of phenotypes characterized by variable growth dysregulation, facial dysmorphism, and neurodevelopmental, immunological, and hematological anomalies, including a phenotype resembling Noonan syndrome, a developmental disorder caused by dysregulated RAS signaling. In silico, in vitro, and in vivo analyses demonstrate that mutations variably perturb CDC42 function by altering the switch between the active and inactive states of the GTPase and/or affecting CDC42 interaction with effectors, and differentially disturb cellular and developmental processes. These findings reveal the remarkably variable impact that dominantly acting CDC42 mutations have on cell function and development, creating challenges in syndrome definition, and exemplify the importance of functional profiling for syndrome recognition and delineation.
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    Importance of genetic evaluation and testing in pediatric cardiomyopathy
    (Baishideng, 2014-11-26) Tariq, Muhammad; Ware, Stephanie M.; Pediatrics, School of Medicine
    Pediatric cardiomyopathies are clinically heterogeneous heart muscle disorders that are responsible for significant morbidity and mortality. Phenotypes include hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, left ventricular noncompaction and arrhythmogenic right ventricular cardiomyopathy. There is substantial evidence for a genetic contribution to pediatric cardiomyopathy. To date, more than 100 genes have been implicated in cardiomyopathy, but comprehensive genetic diagnosis has been problematic because of the large number of genes, the private nature of mutations, and difficulties in interpreting novel rare variants. This review will focus on current knowledge on the genetic etiologies of pediatric cardiomyopathy and their diagnostic relevance in clinical settings. Recent developments in sequencing technologies are greatly impacting the pace of gene discovery and clinical diagnosis. Understanding the genetic basis for pediatric cardiomyopathy and establishing genotype-phenotype correlations may help delineate the molecular and cellular events necessary to identify potential novel therapeutic targets for heart muscle dysfunction in children.
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    Missense variants in TAF1 and developmental phenotypes: Challenges of determining pathogenicity
    (Wiley, 2019-10-23) Cheng, Hanyin; Capponi, Simona; Wakeling, Emma; Marchi, Elaine; Li, Quan; Zhao, Mengge; Weng, Chunhua; Piatek, Stefan G.; Ahlfors, Helena; Kleyner, Robert; Rope, Alan; Lumaka, Aimé; Lukusa, Prosper; Devriendt, Koenraad; Vermeesch, Joris; Posey, Jennifer E.; Palmer, Elizabeth E.; Murray, Lucinda; Leon, Eyby; Diaz, Jullianne; Worgan, Lisa; Mallawaarachchi, Amali; Vogt, Julie; de Munnik, Sonja A.; Dreyer, Lauren; Baynam, Gareth; Ewans, Lisa; Stark, Zornitza; Lunke, Sebastian; Gonçalves, Ana R.; Soares, Gabriela; Oliveira, Jorge; Fassi, Emily; Willing, Marcia; Waugh, Jeff L.; Faivre, Laurence; Riviere, Jean-Baptiste; Moutton, Sebastien; Mohammed, Shehla; Payne, Katelyn; Walsh, Laurence; Begtrup, Amber; Guillen Sacoto, Maria J.; Douglas, Ganka; Alexander, Nora; Buckley, Michael F.; Mark, Paul R.; Adès, Lesley C.; Sandaradura, Sarah A.; Lupski, James R.; Roscioli, Tony; Agrawal, Pankaj B.; Kline, Antonie D.; Wang, Kai; Timmers, T. Marc; Lyon, Gholson J.; Neurology, School of Medicine
    We recently described a new neurodevelopmental syndrome (TAF1/MRXS33 intellectual disability syndrome) (MIM# 300966) caused by pathogenic variants involving the X-linked gene TAF1, which participates in RNA polymerase II transcription. The initial study reported eleven families, and the syndrome was defined as presenting early in life with hypotonia, facial dysmorphia, and developmental delay that evolved into intellectual disability (ID) and/or autism spectrum disorder (ASD). We have now identified an additional 27 families through a genotype-first approach. Familial segregation analysis, clinical phenotyping, and bioinformatics were capitalized on to assess potential variant pathogenicity, and molecular modelling was performed for those variants falling within structurally characterized domains of TAF1. A novel phenotypic clustering approach was also applied, in which the phenotypes of affected individuals were classified using 51 standardized Human Phenotype Ontology (HPO) terms. Phenotypes associated with TAF1 variants show considerable pleiotropy and clinical variability, but prominent among previously unreported effects were brain morphological abnormalities, seizures, hearing loss, and heart malformations. Our allelic series broadens the phenotypic spectrum of TAF1/MRXS33 intellectual disability syndrome and the range of TAF1 molecular defects in humans. It also illustrates the challenges for determining the pathogenicity of inherited missense variants, particularly for genes mapping to chromosome X.
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    Powerful, scalable and resource-efficient meta-analysis of rare variant associations in large whole genome sequencing studies
    (Springer Nature, 2023) Li, Xihao; Quick, Corbin; Zhou, Hufeng; Gaynor, Sheila M.; Liu, Yaowu; Chen, Han; Selvaraj, Margaret Sunitha; Sun, Ryan; Dey, Rounak; Arnett, Donna K.; Bielak, Lawrence F.; Bis, Joshua C.; Blangero, John; Boerwinkle, Eric; Bowden, Donald W.; Brody, Jennifer A.; Cade, Brian E.; Correa, Adolfo; Cupples, L. Adrienne; Curran, Joanne E.; de Vries, Paul S.; Duggirala, Ravindranath; Freedman, Barry I.; Göring, Harald H. H.; Guo, Xiuqing; Haessler, Jeffrey; Kalyani, Rita R.; Kooperberg, Charles; Kral, Brian G.; Lange, Leslie A.; Manichaikul, Ani; Martin, Lisa W.; McGarvey, Stephen T.; Mitchell, Braxton D.; Montasser, May E.; Morrison, Alanna C.; Naseri, Take; O'Connell, Jeffrey R.; Palmer, Nicholette D.; Peyser, Patricia A.; Psaty, Bruce M.; Raffield, Laura M.; Redline, Susan; Reiner, Alexander P.; Reupena, Muagututi'a Sefuiva; Rice, Kenneth M.; Rich, Stephen S.; Sitlani, Colleen M.; Smith, Jennifer A.; Taylor, Kent D.; Vasan, Ramachandran S.; Willer, Cristen J.; Wilson, James G.; Yanek, Lisa R.; Zhao, Wei; NHLBI Trans-Omics for Precision Medicine (TOPMed) Consortium; TOPMed Lipids Working Group; Rotter, Jerome I.; Natarajan, Pradeep; Peloso, Gina M.; Li, Zilin; Lin, Xihong; Biostatistics and Health Data Science, School of Medicine
    Meta-analysis of whole genome sequencing/whole exome sequencing (WGS/WES) studies provides an attractive solution to the problem of collecting large sample sizes for discovering rare variants associated with complex phenotypes. Existing rare variant meta-analysis approaches are not scalable to biobank-scale WGS data. Here we present MetaSTAAR, a powerful and resource-efficient rare variant meta-analysis framework for large-scale WGS/WES studies. MetaSTAAR accounts for relatedness and population structure, can analyze both quantitative and dichotomous traits and boosts the power of rare variant tests by incorporating multiple variant functional annotations. Through meta-analysis of four lipid traits in 30,138 ancestrally diverse samples from 14 studies of the Trans Omics for Precision Medicine (TOPMed) Program, we show that MetaSTAAR performs rare variant meta-analysis at scale and produces results comparable to using pooled data. Additionally, we identified several conditionally significant rare variant associations with lipid traits. We further demonstrate that MetaSTAAR is scalable to biobank-scale cohorts through meta-analysis of TOPMed WGS data and UK Biobank WES data of ~200,000 samples.
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    Provision and Availability of Genomic Medicine Services in Level IV Neonatal Intensive Care Units
    (Elsevier, 2023) Wojcik, Monica H.; Callahan, Katharine P.; Antoniou, Austin; del Rosario, Maya C.; Brunelli, Luca; ElHassan, Nahed O.; Gogcu, Semsa; Murthy, Karna; Rumpel, Jennifer A.; Wambach, Jennifer A.; Suhrie, Kristen; Fishler, Kristen; Chaudhari, Bimal P.; Pediatrics, School of Medicine
    Purpose: To describe variation in genomic medicine services across level IV neonatal intensive care units (NICUs) in the United States and Canada. Methods: We developed and distributed a novel survey to the 43 level IV NICUs belonging to the Children's Hospitals Neonatal Consortium, requesting a single response per site from a clinician with knowledge of the provision of genomic medicine services. Results: Overall response rate was 74% (32/43). Although chromosomal microarray and exome or genome sequencing (ES or GS) were universally available, access was restricted for 22% (7/32) and 81% (26/32) of centers, respectively. The most common restriction on ES or GS was requiring approval by a specialist (41%, 13/32). Rapid ES/GS was available in 69% of NICUs (22/32). Availability of same-day genetics consultative services was limited (41%, 13/32 sites), and pre- and post-test counseling practices varied widely. Conclusion: We observed large inter-center variation in genomic medicine services across level IV NICUs: most notably, access to rapid, comprehensive genetic testing in time frames relevant to critical care decision making was limited at many level IV Children's Hospitals Neonatal Consortium NICUs despite a significant burden of genetic disease. Further efforts are needed to improve access to neonatal genomic medicine services.
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    Recessive Rare Variants in Deoxyhypusine Synthase, an Enzyme Involved in the Synthesis of Hypusine, Are Associated with a Neurodevelopmental Disorder
    (Elsevier, 2019-02-07) Ganapathi, Mythily; Padgett, Leah R.; Yamada, Kentaro; Devinsky, Orrin; Willaert, Rebecca; Person, Richard; Au, Ping-Yee Billie; Tagoe, Julia; McDonald, Marie; Karlowicz, Danielle; Wolf, Barry; Lee, Joanna; Shen, Yufeng; Okur, Volkan; Deng, Liyong; LeDuc, Charles A.; Wang, Jiayao; Hanner, Ashleigh; Mirmira, Raghavendra G.; Park, Myung Hee; Mastracci, Teresa L.; Chung, Wendy K.; Pediatrics, School of Medicine
    Hypusine is formed post-translationally from lysine and is found in a single cellular protein, eukaryotic translation initiation factor-5A (eIF5A), and its homolog eIF5A2. Biosynthesis of hypusine is a two-step reaction involving the enzymes deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). eIF5A is highly conserved throughout eukaryotic evolution and plays a role in mRNA translation, cellular proliferation, cellular differentiation, and inflammation. DHPS is also highly conserved and is essential for life, as Dhps-null mice are embryonic lethal. Using exome sequencing, we identified rare biallelic, recurrent, predicted likely pathogenic variants in DHPS segregating with disease in five affected individuals from four unrelated families. These individuals have similar neurodevelopmental features that include global developmental delay and seizures. Two of four affected females have short stature. All five affected individuals share a recurrent missense variant (c.518A>G [p.Asn173Ser]) in trans with a likely gene disrupting variant (c.1014+1G>A, c.912_917delTTACAT [p.Tyr305_Ile306del], or c.1A>G [p.Met1?]). cDNA studies demonstrated that the c.1014+1G>A variant causes aberrant splicing. Recombinant DHPS enzyme harboring either the p.Asn173Ser or p.Tyr305_Ile306del variant showed reduced (20%) or absent in vitro activity, respectively. We co-transfected constructs overexpressing HA-tagged DHPS (wild-type or mutant) and GFP-tagged eIF5A into HEK293T cells to determine the effect of these variants on hypusine biosynthesis and observed that the p.Tyr305_Ile306del and p.Asn173Ser variants resulted in reduced hypusination of eIF5A compared to wild-type DHPS enzyme. Our data suggest that rare biallelic variants in DHPS result in reduced enzyme activity that limits the hypusination of eIF5A and are associated with a neurodevelopmental disorder.