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Dai N, Groenendyk J, Michalak M. Interplay between myotubularins and Ca 2+ homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119739. [PMID: 38710289 DOI: 10.1016/j.bbamcr.2024.119739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/08/2024]
Abstract
The myotubularin family, encompassing myotubularin 1 (MTM1) and 14 myotubularin-related proteins (MTMRs), represents a conserved group of phosphatases featuring a protein tyrosine phosphatase domain. Nine members are characterized by an active phosphatase domain C(X)5R, dephosphorylating the D3 position of PtdIns(3)P and PtdIns(3,5)P2. Mutations in myotubularin genes result in human myopathies, and several neuropathies including X-linked myotubular myopathy and Charcot-Marie-Tooth type 4B. MTM1, MTMR6 and MTMR14 also contribute to Ca2+ signaling and Ca2+ homeostasis that play a key role in many MTM-dependent myopathies and neuropathies. Here we explore the evolving roles of MTM1/MTMRs, unveiling their influence on critical aspects of Ca2+ signaling pathways.
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Affiliation(s)
- Ning Dai
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Jody Groenendyk
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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2
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Zhang J, Tao P, Deuitch NT, Yu X, Askentijevich I, Zhou Q. Proteasome-Associated Syndromes: Updates on Genetics, Clinical Manifestations, Pathogenesis, and Treatment. J Clin Immunol 2024; 44:88. [PMID: 38578475 DOI: 10.1007/s10875-024-01692-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 03/15/2024] [Indexed: 04/06/2024]
Abstract
The ubiquitin-proteasome system (UPS) has a critical role in post-translational protein modification that is essential for the maintenance of all cellular functions, including immune responses. The proteasome complex is ubiquitously expressed and is responsible for degradation of short-lived structurally abnormal, misfolded and not-needed proteins that are targeted for degradation via ubiquitin conjugation. Over the last 14 years, an increasing number of human diseases have been linked to pathogenic variants in proteasome subunits and UPS regulators. Defects of the proteasome complex or its chaperons - which have a regulatory role in the assembly of the proteasome - disrupt protein clearance and cellular homeostasis, leading to immune dysregulation, severe inflammation, and neurodevelopmental disorders in humans. Proteasome-associated diseases have complex inheritance, including monogenic, digenic and oligogenic disorders and can be dominantly or recessively inherited. In this review, we summarize the current known genetic causes of proteasomal disease, and discuss the molecular pathogenesis of these conditions based on the function and cellular expression of mutated proteins in the proteasome complex.
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Affiliation(s)
- Jiahui Zhang
- Department of Rheumatology, The Second Affiliated Hospital, Zhejiang University School of Medicine, and Liangzhu Laboratory, Zhejiang University, Hangzhou, China
- National Clinical Research Center for Kidney Diseases, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Panfeng Tao
- Department of Rheumatology, The Second Affiliated Hospital, Zhejiang University School of Medicine, and Liangzhu Laboratory, Zhejiang University, Hangzhou, China.
| | - Natalie T Deuitch
- Inflammatory Disease Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Xiaomin Yu
- Department of Rheumatology, The Second Affiliated Hospital, Zhejiang University School of Medicine, and Liangzhu Laboratory, Zhejiang University, Hangzhou, China.
| | - Ivona Askentijevich
- Inflammatory Disease Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Qing Zhou
- Department of Rheumatology, The Second Affiliated Hospital, Zhejiang University School of Medicine, and Liangzhu Laboratory, Zhejiang University, Hangzhou, China.
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3
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Job F, Mai C, Villavicencio-Lorini P, Herfurth J, Neuhaus H, Hoffmann K, Pfirrmann T, Hollemann T. OTUD3: A Lys6 and Lys63 specific deubiquitinase in early vertebrate development. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194901. [PMID: 36503125 DOI: 10.1016/j.bbagrm.2022.194901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/17/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022]
Abstract
Ubiquitination and deubiquitylation regulate essential cellular processes and involve hundreds of sequentially acting enzymes, many of which are barely understood. OTUD3 is an evolutionarily highly conserved deubiquitinase involved in many aspects of cellular homeostasis. However, its biochemical properties and physiological role during development are poorly understood. Here, we report on the expression of OTUD3 in human tissue samples where it appears prominently in those of neuronal origin. In cells, OTUD3 is present in the cytoplasm where it can bind to microtubules. Interestingly, we found that OTUD3 cleaves preferentially at K6 and K63, i.e., poly-ubiquitin linkages that are not primarily involved in protein degradation. We employed Xenopus embryos to study the consequences of suppressing otud3 function during early neural development. We found that Otud3 deficiency led to impaired formation of cranial and particularly of cranial neural crest-derived structures as well as movement defects. Thus, OTUD3 appears as a neuronally enriched deubiquitinase that is involved in the proper development of the neural system.
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Affiliation(s)
- Florian Job
- Martin-Luther-University Halle-Wittenberg, Institute for Physiological Chemistry, 06114 Halle, Germany; Martin-Luther-University Halle-Wittenberg, Institute of Human Genetics, 06114 Halle, Germany
| | - Carolin Mai
- Martin-Luther-University Halle-Wittenberg, Institute for Physiological Chemistry, 06114 Halle, Germany
| | | | - Juliane Herfurth
- Martin-Luther-University Halle-Wittenberg, Institute for Physiological Chemistry, 06114 Halle, Germany
| | - Herbert Neuhaus
- Martin-Luther-University Halle-Wittenberg, Institute for Physiological Chemistry, 06114 Halle, Germany
| | - Katrin Hoffmann
- Martin-Luther-University Halle-Wittenberg, Institute of Human Genetics, 06114 Halle, Germany
| | - Thorsten Pfirrmann
- Martin-Luther-University Halle-Wittenberg, Institute for Physiological Chemistry, 06114 Halle, Germany; Department of Medicine, Health and Medical University, 14471 Potsdam, Germany
| | - Thomas Hollemann
- Martin-Luther-University Halle-Wittenberg, Institute for Physiological Chemistry, 06114 Halle, Germany.
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4
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Impaired OTUD7A-dependent Ankyrin regulation mediates neuronal dysfunction in mouse and human models of the 15q13.3 microdeletion syndrome. Mol Psychiatry 2023; 28:1747-1769. [PMID: 36604605 DOI: 10.1038/s41380-022-01937-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 12/15/2022] [Accepted: 12/19/2022] [Indexed: 01/07/2023]
Abstract
Copy number variations (CNVs) are associated with psychiatric and neurodevelopmental disorders (NDDs), and most, including the recurrent 15q13.3 microdeletion disorder, have unknown disease mechanisms. We used a heterozygous 15q13.3 microdeletion mouse model and patient iPSC-derived neurons to reveal developmental defects in neuronal maturation and network activity. To identify the underlying molecular dysfunction, we developed a neuron-specific proximity-labeling proteomics (BioID2) pipeline, combined with patient mutations, to target the 15q13.3 CNV genetic driver OTUD7A. OTUD7A is an emerging independent NDD risk gene with no known function in the brain, but has putative deubiquitinase function. The OTUD7A protein-protein interaction network included synaptic, axonal, and cytoskeletal proteins and was enriched for ASD and epilepsy risk genes (Ank3, Ank2, SPTAN1, SPTBN1). The interactions between OTUD7A and Ankyrin-G (Ank3) and Ankyrin-B (Ank2) were disrupted by an epilepsy-associated OTUD7A L233F variant. Further investigation of Ankyrin-G in mouse and human 15q13.3 microdeletion and OTUD7AL233F/L233F models revealed protein instability, increased polyubiquitination, and decreased levels in the axon initial segment, while structured illumination microscopy identified reduced Ankyrin-G nanodomains in dendritic spines. Functional analysis of human 15q13.3 microdeletion and OTUD7AL233F/L233F models revealed shared and distinct impairments to axonal growth and intrinsic excitability. Importantly, restoring OTUD7A or Ankyrin-G expression in 15q13.3 microdeletion neurons led to a reversal of abnormalities. These data reveal a critical OTUD7A-Ankyrin pathway in neuronal development, which is impaired in the 15q13.3 microdeletion syndrome, leading to neuronal dysfunction. Furthermore, our study highlights the utility of targeting CNV genes using cell type-specific proteomics to identify shared and unexplored disease mechanisms across NDDs.
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Jolly LA, Kumar R, Penzes P, Piper M, Gecz J. The DUB Club: Deubiquitinating Enzymes and Neurodevelopmental Disorders. Biol Psychiatry 2022; 92:614-625. [PMID: 35662507 PMCID: PMC10084722 DOI: 10.1016/j.biopsych.2022.03.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/28/2022] [Accepted: 03/28/2022] [Indexed: 02/08/2023]
Abstract
Protein ubiquitination is a widespread, multifunctional, posttranslational protein modification, best known for its ability to direct protein degradation via the ubiquitin proteasome system (UPS). Ubiquitination is also reversible, and the human genome encodes over 90 deubiquitinating enzymes (DUBs), many of which appear to target specific subsets of ubiquitinated proteins. This review focuses on the roles of DUBs in neurodevelopmental disorders (NDDs). We present the current genetic evidence connecting 12 DUBs to a range of NDDs and the functional studies implicating at least 19 additional DUBs as candidate NDD genes. We highlight how the study of DUBs in NDDs offers critical insights into the role of protein degradation during brain development. Because one of the major known functions of a DUB is to antagonize the UPS, loss of function of DUB genes has been shown to culminate in loss of abundance of its protein substrates. The identification and study of NDD DUB substrates in the developing brain is revealing that they regulate networks of proteins that themselves are encoded by NDD genes. We describe the new technologies that are enabling the full resolution of DUB protein networks in the developing brain, with the view that this knowledge can direct the development of new therapeutic paradigms. The fact that the abundance of many NDD proteins is regulated by the UPS presents an exciting opportunity to combat NDDs caused by haploinsufficiency, because the loss of abundance of NDD proteins can be potentially rectified by antagonizing their UPS-based degradation.
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Affiliation(s)
- Lachlan A Jolly
- University of Adelaide and Robinson Research Institute, Adelaide, South Australia, Australia.
| | - Raman Kumar
- University of Adelaide and Robinson Research Institute, Adelaide, South Australia, Australia
| | - Peter Penzes
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Michael Piper
- School of Biomedical Sciences and Queensland Brain Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Jozef Gecz
- University of Adelaide and Robinson Research Institute, Adelaide, South Australia, Australia; South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
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Yuan B, Schulze KV, Assia Batzir N, Sinson J, Dai H, Zhu W, Bocanegra F, Fong CT, Holder J, Nguyen J, Schaaf CP, Yang Y, Bi W, Eng C, Shaw C, Lupski JR, Liu P. Sequencing individual genomes with recurrent genomic disorder deletions: an approach to characterize genes for autosomal recessive rare disease traits. Genome Med 2022; 14:113. [PMID: 36180924 PMCID: PMC9526336 DOI: 10.1186/s13073-022-01113-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 09/02/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND In medical genetics, discovery and characterization of disease trait contributory genes and alleles depends on genetic reasoning, study design, and patient ascertainment; we suggest a segmental haploid genetics approach to enhance gene discovery and molecular diagnostics. METHODS We constructed a genome-wide map for nonallelic homologous recombination (NAHR)-mediated recurrent genomic deletions and used this map to estimate population frequencies of NAHR deletions based on large-scale population cohorts and region-specific studies. We calculated recessive disease carrier burden using high-quality pathogenic or likely pathogenic variants from ClinVar and gnomAD. We developed a NIRD (NAHR deletion Impact to Recessive Disease) score for recessive disorders by quantifying the contribution of NAHR deletion to the overall allele load that enumerated all pairwise combinations of disease-causing alleles; we used a Punnett square approach based on an assumption of random mating. Literature mining was conducted to identify all reported patients with defects in a gene with a high NIRD score; meta-analysis was performed on these patients to estimate the representation of NAHR deletions in recessive traits from contemporary human genomics studies. Retrospective analyses of extant clinical exome sequencing (cES) were performed for novel rare recessive disease trait gene and allele discovery from individuals with NAHR deletions. RESULTS We present novel genomic insights regarding the genome-wide impact of NAHR recurrent segmental variants on recessive disease burden; we demonstrate the utility of NAHR recurrent deletions to enhance discovery in the challenging context of autosomal recessive (AR) traits and biallelic variation. Computational results demonstrate new mutations mediated by NAHR, involving recurrent deletions at 30 genomic regions, likely drive recessive disease burden for over 74% of loci within these segmental deletions or at least 2% of loci genome-wide. Meta-analyses on 170 literature-reported patients implicate that NAHR deletions are depleted from the ascertained pool of AR trait alleles. Exome reanalysis of personal genomes from subjects harboring recurrent deletions uncovered new disease-contributing variants in genes including COX10, ERCC6, PRRT2, and OTUD7A. CONCLUSIONS Our results demonstrate that genomic sequencing of personal genomes with NAHR deletions could dramatically improve allele and gene discovery and enhance clinical molecular diagnosis. Moreover, results suggest NAHR events could potentially enable human haploid genetic screens as an approach to experimental inquiry into disease biology.
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Affiliation(s)
- Bo Yuan
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.39382.330000 0001 2160 926XHuman Genome Sequencing Center, Baylor College of Medicine, Houston, TX USA
| | - Katharina V. Schulze
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Nurit Assia Batzir
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Jefferson Sinson
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Hongzheng Dai
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Wenmiao Zhu
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | | | - Chin-To Fong
- grid.412750.50000 0004 1936 9166Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | - Jimmy Holder
- grid.39382.330000 0001 2160 926XDepartment of Pediatrics, Baylor College of Medicine, Houston, TX USA
| | - Joanne Nguyen
- grid.267308.80000 0000 9206 2401Department of Pediatrics, University of Texas Health Science Center, Houston, TX USA
| | - Christian P. Schaaf
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.7700.00000 0001 2190 4373Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Yaping Yang
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Weimin Bi
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Christine Eng
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Chad Shaw
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.21940.3e0000 0004 1936 8278Department of Statistics, Rice University, Houston, TX USA
| | - James R. Lupski
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.39382.330000 0001 2160 926XHuman Genome Sequencing Center, Baylor College of Medicine, Houston, TX USA ,grid.39382.330000 0001 2160 926XDepartment of Pediatrics, Baylor College of Medicine, Houston, TX USA ,grid.416975.80000 0001 2200 2638Texas Children’s Hospital, Houston, TX USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA. .,Baylor Genetics, Houston, TX, USA.
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Mishra A, Prabha PK, Singla R, Kaur G, Sharma AR, Joshi R, Suroy B, Medhi B. Epigenetic Interface of Autism Spectrum Disorders (ASDs): Implications of Chromosome 15q11-q13 Segment. ACS Chem Neurosci 2022; 13:1684-1696. [PMID: 35635007 DOI: 10.1021/acschemneuro.2c00060] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Autism spectrum disorders (ASDs) are multifactorial in nature and include both genetic and environmental factors. The increasing evidence advocates an important role of epigenetics in ASD etiology. One of the most common forms of epigenetic changes observed in the case of neurodevelopmental disorders is imprinting which is tightly regulated by developmental and tissue-specific mechanisms. Interestingly, many of these disorders that demonstrate autism-like phenotypes at varying degrees have found involvement of chromosome 15q11-q13 segment. Numerous studies demonstrate occurrence of ASD in the presence of chromosomal abnormalities located mainly in Chr15q11-q13 region. Several plausible candidate genes associated with ASD are in this chromosomal segment, including gamma aminobutyric acid A (GABAA) receptor genes GABRB3, GABRA5 and GABRG3, UBE3A, ATP 10A, MKRN3, ZNF, MAGEL2, Necdin (NDN), and SNRPN. The main objective of this review is to highlight the contribution of epigenetic modulations in chromosome 15q11-q13 segment toward the genetic etiology and pathophysiology of ASD. The present review reports the abnormalities in epigenetic regulation on genes and genomic regions located on chromosome 15 in relation to either syndromic (15q11-q13 maternal duplication) or nonsyndromic forms of ASD. Furthermore, studies reviewed in this article demonstrate conditions in which epigenetic dysregulation has been found to be a pathological factor for ASD development, thereby supporting a role for epigenetics in the multifactorial etiologies of ASD. Also, on the basis of the evidence found so far, we strongly emphasize the need to develop future therapeutic strategies as well as screening procedures for ASD that target mechanisms involving genes located on the chromosomal 15q11-q13 segment.
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Affiliation(s)
- Abhishek Mishra
- Dept. of Pharmacology, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh 160012, India
| | - Praisy K Prabha
- Dept. of Pharmacology, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh 160012, India
| | - Rubal Singla
- Dept. of Pharmacology, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh 160012, India
| | - Gurjeet Kaur
- Dept. of Pharmacology, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh 160012, India
| | - Amit Raj Sharma
- Dept. of Neurology, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh 160012, India
| | - Rupa Joshi
- Dept. of Pharmacology, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh 160012, India
| | - Benjamin Suroy
- Dept. of Pharmacology, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh 160012, India
| | - Bikash Medhi
- Dept. of Pharmacology, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh 160012, India
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Fielder SM, Rosenfeld JA, Burrage LC, Emrick L, Lalani S, Attali R, Bembenek JN, Hoang H, Baldridge D, Silverman GA, Schedl T, Pak SC. Functional analysis of a novel de novo variant in PPP5C associated with microcephaly, seizures, and developmental delay. Mol Genet Metab 2022; 136:65-73. [PMID: 35361529 DOI: 10.1016/j.ymgme.2022.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/13/2022] [Indexed: 11/27/2022]
Abstract
We describe a proband evaluated through the Undiagnosed Diseases Network (UDN) who presented with microcephaly, developmental delay, and refractory epilepsy with a de novo p.Ala47Thr missense variant in the protein phosphatase gene, PPP5C. This gene has not previously been associated with a Mendelian disease, and based on the population database, gnomAD, the gene has a low tolerance for loss-of-function variants (pLI = 1, o/e = 0.07). We functionally evaluated the PPP5C variant in C. elegans by knocking the variant into the orthologous gene, pph-5, at the corresponding residue, Ala48Thr. We employed assays in three different biological processes where pph-5 was known to function through opposing the activity of genes, mec-15 and sep-1. We demonstrated that, in contrast to control animals, the pph-5 Ala48Thr variant suppresses the neurite growth phenotype and the GABA signaling defects of mec-15 mutants, and the embryonic lethality of sep-1 mutants. The Ala48Thr variant did not display dominance and behaved similarly to the reference pph-5 null, indicating that the variant is likely a strong hypomorph or complete loss-of-function. We conclude that pph-5 Ala48Thr is damaging in C. elegans. By extension in the proband, PPP5C p.Ala47Thr is likely damaging, the de novo dominant presentation is consistent with haplo-insufficiency, and the PPP5C variant is likely responsible for one or more of the proband's phenotypes.
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Affiliation(s)
- Sara M Fielder
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Lisa Emrick
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Seema Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Ruben Attali
- Genomic Research Department, Emedgene Technologies, 6744332 Tel Aviv, Israel
| | - Joshua N Bembenek
- Department of Obstetrics and Gynecology, C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Hieu Hoang
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Dustin Baldridge
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Gary A Silverman
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Tim Schedl
- Department of Genetics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Stephen C Pak
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA.
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9
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Takahashi Y, Date H, Oi H, Adachi T, Imanishi N, Kimura E, Takizawa H, Kosugi S, Matsumoto N, Kosaki K, Matsubara Y, Mizusawa H. Six years' accomplishment of the Initiative on Rare and Undiagnosed Diseases: nationwide project in Japan to discover causes, mechanisms, and cures. J Hum Genet 2022; 67:505-513. [PMID: 35318459 PMCID: PMC9402437 DOI: 10.1038/s10038-022-01025-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/07/2022] [Accepted: 02/07/2022] [Indexed: 11/09/2022]
Abstract
The identification of causative genetic variants for hereditary diseases has revolutionized clinical medicine and an extensive collaborative framework with international cooperation has become a global trend to understand rare disorders. The Initiative on Rare and Undiagnosed Diseases (IRUD) was established in Japan to provide accurate diagnosis, discover causes, and ultimately provide cures for rare and undiagnosed diseases. The fundamental IRUD system consists of three pillars: IRUD diagnostic coordination, analysis centers (IRUD-ACs), and a data center (IRUD-DC). IRUD diagnostic coordination consists of clinical centers (IRUD-CLs) and clinical specialty subgroups (IRUD-CSSs). In addition, the IRUD coordinating center (IRUD-CC) manages the entire IRUD system and temporarily operates the IRUD resource center (IRUD-RC). By the end of March 2021, 6301 pedigrees consisting of 18,136 individuals were registered in the IRUD. The whole-exome sequencing method was completed in 5136 pedigrees, and a final diagnosis was established in 2247 pedigrees (43.8%). The total number of aberrated genes and pathogenic variants was 657 and 1718, among which 1113 (64.8%) were novel. In addition, 39 novel disease entities or phenotypes with 41 aberrated genes were identified. The 6-year endeavor of IRUD has been an overwhelming success, establishing an all-Japan comprehensive diagnostic and research system covering all geographic areas and clinical specialties/subspecialties. IRUD has accurately diagnosed diseases, identified novel aberrated genes or disease entities, discovered many candidate genes, and enriched phenotypic and pathogenic variant databases. Further promotion of the IRUD is essential for determining causes and developing cures for rare and undiagnosed diseases.
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Affiliation(s)
- Yuji Takahashi
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Hidetoshi Date
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Hideki Oi
- Department of Clinical Data Science, Clinical Research and Education Promotion Division, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Takeya Adachi
- Keio Frontier Research & Education Collaborative Square (K-FRECS) at Tonomachi, Keio University, Kawasaki, Japan.,Department of Medical Regulatory Science, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Kyoto, Japan.,Japan Agency for Medical Research and Development (AMED), Tokyo, Japan
| | - Noriaki Imanishi
- Japan Agency for Medical Research and Development (AMED), Tokyo, Japan.,Department of Research Promotion and Management, National Cerebral and Cardiovascular Center, Suita, Japan
| | - En Kimura
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Kodaira, Japan.,Japan Agency for Medical Research and Development (AMED), Tokyo, Japan.,Astellas Pharma Incorporated, Tokyo, Japan
| | - Hotake Takizawa
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Kodaira, Japan.,Japan Agency for Medical Research and Development (AMED), Tokyo, Japan
| | - Shinji Kosugi
- Department of Medical Ethics/Medical Genetics, Kyoto University School of Public Health, Kyoto, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | | | | | - Hidehiro Mizusawa
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Kodaira, Japan.
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Disruption of the Ubiquitin-Proteasome System and Elevated Endoplasmic Reticulum Stress in Epilepsy. Biomedicines 2022; 10:biomedicines10030647. [PMID: 35327449 PMCID: PMC8945847 DOI: 10.3390/biomedicines10030647] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/05/2022] [Accepted: 03/07/2022] [Indexed: 02/06/2023] Open
Abstract
The epilepsies are a broad group of conditions characterized by repeated seizures, and together are one of the most common neurological disorders. Additionally, epilepsy is comorbid with many neurological disorders, including lysosomal storage diseases, syndromic intellectual disability, and autism spectrum disorder. Despite the prevalence, treatments are still unsatisfactory: approximately 30% of epileptic patients do not adequately respond to existing therapeutics, which primarily target ion channels. Therefore, new therapeutic approaches are needed. Disturbed proteostasis is an emerging mechanism in epilepsy, with profound effects on neuronal health and function. Proteostasis, the dynamic balance of protein synthesis and degradation, can be directly disrupted by epilepsy-associated mutations in various components of the ubiquitin-proteasome system (UPS), or impairments can be secondary to seizure activity or misfolded proteins. Endoplasmic reticulum (ER) stress can arise from failed proteostasis and result in neuronal death. In light of this, several treatment modalities that modify components of proteostasis have shown promise in the management of neurological disorders. These include chemical chaperones to assist proper folding of proteins, inhibitors of overly active protein degradation, and enhancers of endogenous proteolytic pathways, such as the UPS. This review summarizes recent work on the pathomechanisms of abnormal protein folding and degradation in epilepsy, as well as treatment developments targeting this area.
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Chen CH, Cheng MC, Hu TM, Ping LY. Chromosomal Microarray Analysis as First-Tier Genetic Test for Schizophrenia. Front Genet 2021; 12:620496. [PMID: 34659328 PMCID: PMC8517076 DOI: 10.3389/fgene.2021.620496] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 09/20/2021] [Indexed: 01/07/2023] Open
Abstract
Schizophrenia is a chronic, devastating mental disorder with complex genetic components. Given the advancements in the molecular genetic research of schizophrenia in recent years, there is still a lack of genetic tests that can be used in clinical settings. Chromosomal microarray analysis (CMA) has been used as first-tier genetic testing for congenital abnormalities, developmental delay, and autism spectrum disorders. This study attempted to gain some experience in applying chromosomal microarray analysis as a first-tier genetic test for patients with schizophrenia. We consecutively enrolled patients with schizophrenia spectrum disorder from a clinical setting and conducted genome-wide copy number variation (CNV) analysis using a chromosomal microarray platform. We followed the 2020 “Technical Standards for the interpretation and reporting of constitutional copy-number variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics (ACMG) and the Clinical Genome Resource (ClinGen)” to interpret the clinical significance of CNVs detected from patients. We recruited a total of 60 patients (36 females and 24 males) into this study. We detected three pathogenic CNVs and one likely pathogenic CNV in four patients, respectively. The detection rate was 6.7% (4/60, 95% CI: 0.004–0.13), comparable with previous studies in the literature. Also, we detected thirteen CNVs classified as uncertain clinical significance in nine patients. Detecting these CNVs can help establish the molecular genetic diagnosis of schizophrenia patients and provide helpful information for genetic counseling and clinical management. Also, it can increase our understanding of the pathogenesis of schizophrenia. Hence, we suggest CMA is a valuable genetic tool and considered first-tier genetic testing for schizophrenia spectrum disorders in clinical settings.
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Affiliation(s)
- Chia-Hsiang Chen
- Department of Psychiatry, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department and Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Min-Chih Cheng
- Department of Psychiatry, Yuli Branch, Taipei Veterans General Hospital, Hualien, Taiwan
| | - Tsung-Ming Hu
- Department of Psychiatry, Yuli Branch, Taipei Veterans General Hospital, Hualien, Taiwan
| | - Lieh-Yung Ping
- Department of Psychiatry, Yuli Branch, Taipei Veterans General Hospital, Hualien, Taiwan
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12
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Yamada M, Suzuki H, Shima T, Uehara T, Kosaki K. A patient with compound heterozygosity of SMPD4: Another example of utility of exome-based copy number analysis in autosomal recessive disorders. Am J Med Genet A 2021; 188:613-617. [PMID: 34622574 DOI: 10.1002/ajmg.a.62535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 09/25/2021] [Indexed: 11/11/2022]
Abstract
For the efficient diagnosis of rare and undiagnosed diseases, the parallel detection of copy number variants (CNVs) and single nucleotide variants using exome analysis is required. Recently, our group reported the usefulness of a program called EXCAVATOR2, which screens for CNVs from aligned exome data in bam format. This method is expected to contribute to the identification of structural variants and to improve the diagnosis rate, especially for the diagnosis of autosomal recessive disease, when a conventional exome analysis identifies a pathogenic variant in one allele but not the other. Here we report a 2-year-old Japanese boy with an undiagnosed disease. He had severe neonatal asphyxia, severe intellectual disability, intractable seizures, cerebellar and brainstem hypoplasia and dysmorphic features including a prominent supraorbital ridge, thin upper lip, and prominent antihelix. An exome analysis reinforced with a copy number analysis using the EXCAVATOR2 method revealed that the patient had a hemizygous variant in chr2(GRCh37):g.130925108G>A, NM_017951.4 c.832C>T, p.(Arg278*) in SMPD4 that was derived from his father and a deletion of SMPD4 derived from his mother. The presence of the deletion spanning SMPD4 was confirmed by short-read and long-read whole-genome sequencing. The successful diagnosis of this reported patient demonstrates the diagnostic utility of EXCAVATOR2 and overcomes the weakness of exome analysis for the detection of autosomal recessive diseases in nonconsanguineous families, significantly impacting genetic counseling for family planning.
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Affiliation(s)
- Mamiko Yamada
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Taiki Shima
- Department of Pediatrics, Juntendo University Urayasu Hospital, Chiba, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan.,Department of Pediatrics, Central Hospital, Aichi Developmental Disability Center, Aichi, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
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13
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OTUD6B-associated intellectual disability: novel variants and genetic exclusion of retinal degeneration as part of a refined phenotype. J Hum Genet 2021; 67:55-64. [PMID: 34354232 DOI: 10.1038/s10038-021-00966-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/11/2021] [Accepted: 07/23/2021] [Indexed: 11/08/2022]
Abstract
Biallelic pathogenic variants of OTUD6B have recently been described to cause intellectual disability (ID) with seizures. Here, we report the clinical and molecular characterization of five additional patients (from two unrelated Egyptian families) with ID due to homozygous OTUD6B variants. In Family I, the two affected brothers had additional retinal degeneration, a symptom not yet reported in OTUD6B-related ID. Whole-exome sequencing (WES) identified a novel nonsense variant in OTUD6B (c.271C>T, p.(Gln91Ter)), but also a nonsense variant in RP1L1 (c.5959C>T, p.(Gln1987Ter)), all in homozygous state. Biallelic pathogenic variants in RP1L1 cause autosomal recessive retinitis pigmentosa type 88 (RP88). Thus, RP1L1 dysfunction likely accounts for the visual phenotype in this family with two simultaneous autosomal recessive disorders. In Family II, targeted sequencing revealed a novel homozygous missense variant (c.767G>T, p.(Gly256Val)), confirming the clinically suspected OTUD6B-related ID. Consistent with the clinical variability in previously reported OTUD6B patients, our patients showed inter- and intrafamilial differences with regard to the clinical and brain imaging findings. Interestingly, various orodental features were present including macrodontia, dental crowding, abnormally shaped teeth, and thick alveolar ridges. Broad distal phalanges (especially the thumbs and halluces) with prominent interphalangeal joints and fetal pads were recognized in all patients and hence considered pathognomonic. Our study extends the spectrum of the OTUD6B-associated phenotype. Retinal degeneration, albeit present in both patients from Family I, was shown to be unrelated to OTUD6B, demonstrating the need for in-depth analysis of WES data in consanguineous families to uncover simultaneous autosomal recessive disorders.
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