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Casamassa A, Ferrari D, Gelati M, Carella M, Vescovi AL, Rosati J. A Link between Genetic Disorders and Cellular Impairment, Using Human Induced Pluripotent Stem Cells to Reveal the Functional Consequences of Copy Number Variations in the Central Nervous System-A Close Look at Chromosome 15. Int J Mol Sci 2020; 21:ijms21051860. [PMID: 32182809 PMCID: PMC7084702 DOI: 10.3390/ijms21051860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 12/28/2022] Open
Abstract
Recent cutting-edge human genetics technology has allowed us to identify copy number variations (CNVs) and has provided new insights for understanding causative mechanisms of human diseases. A growing number of studies show that CNVs could be associated with physiological mechanisms linked to evolutionary trigger, as well as to the pathogenesis of various diseases, including cancer, autoimmune disease and mental disorders such as autism spectrum disorders, schizophrenia, intellectual disabilities or attention-deficit/hyperactivity disorder. Their incomplete penetrance and variable expressivity make diagnosis difficult and hinder comprehension of the mechanistic bases of these disorders. Additional elements such as co-presence of other CNVs, genomic background and environmental factors are involved in determining the final phenotype associated with a CNV. Genetically engineered animal models are helpful tools for understanding the behavioral consequences of CNVs. However, the genetic background and the biology of these animal model systems have sometimes led to confusing results. New cellular models obtained through somatic cellular reprogramming technology that produce induced pluripotent stem cells (iPSCs) from human subjects are being used to explore the mechanisms involved in the pathogenic consequences of CNVs. Considering the vast quantity of CNVs found in the human genome, we intend to focus on reviewing the current literature on the use of iPSCs carrying CNVs on chromosome 15, highlighting advantages and limits of this system with respect to mouse model systems.
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Affiliation(s)
- Alessia Casamassa
- Cellular Reprogramming Unit, Fondazione IRCCS Casa Sollievo della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, Foggia, Italy;
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania Luigi Vanvitelli, Viale Abramo Lincoln 5, 81100 Caserta, Italy
| | - Daniela Ferrari
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy;
| | - Maurizio Gelati
- Fondazione IRCCS Casa Sollievo della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, Foggia, Italy; (M.G.); (M.C.)
| | - Massimo Carella
- Fondazione IRCCS Casa Sollievo della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, Foggia, Italy; (M.G.); (M.C.)
| | - Angelo Luigi Vescovi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy;
- Fondazione IRCCS Casa Sollievo della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, Foggia, Italy; (M.G.); (M.C.)
- Correspondence: (A.L.V.); (J.R.)
| | - Jessica Rosati
- Cellular Reprogramming Unit, Fondazione IRCCS Casa Sollievo della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, Foggia, Italy;
- Correspondence: (A.L.V.); (J.R.)
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Yamamoto-Shimojima K, Imaizumi T, Aoki Y, Inoue K, Kaname T, Okuno Y, Muramatsu H, Kato K, Yamamoto T. Elucidation of the pathogenic mechanism and potential treatment strategy for a female patient with spastic paraplegia derived from a single-nucleotide deletion in PLP1. J Hum Genet 2019; 64:665-671. [PMID: 31004103 DOI: 10.1038/s10038-019-0600-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/24/2019] [Accepted: 04/04/2019] [Indexed: 11/09/2022]
Abstract
Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive disorder caused by abnormalities in the gene PLP1. Most females harboring heterozygous PLP1 abnormalities are basically asymptomatic. However, as a result of abnormal patterns of X-chromosome inactivation, it is possible for some female carriers to be symptomatic. Whole-exome sequencing of a female patient with unknown spastic paraplegia was performed to obtain a molecular diagnosis. As a result, a de novo heterozygous single-nucleotide deletion in PLP1 [NM_000533.5(PLP1_v001):c.783del; p.Thr262Leufs*20] was identified. RNA sequencing was performed in a patient-derived lymphoblastoid cell line, confirming mono-allelic expression of the mutated allele and abnormal inactivation of the wild-type allele. The patient-derived lymphoblastoid cell line was then treated with VX680 or 5azadC, which resulted in restored expression of the wild-type allele. These two agents thus have the potential to reverse inappropriately-skewed inactivation of the X-chromosome.
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Affiliation(s)
- Keiko Yamamoto-Shimojima
- Japan Society for the Promotion of Science (RPD), Tokyo, 160-8582, Japan.,Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, 162-8666, Japan.,Tokyo Women's Medical University, Institute of Integrated Medical Sciences, Tokyo, 162-8666, Japan
| | - Taichi Imaizumi
- Department of Gene Medicine, Graduate school of Medicine, Tokyo Women's Medical University, Tokyo, 162-8666, Japan.,Department of Pediatrics, St. Marianna University School of Medicine, Kawasaki, 216-8511, Japan
| | - Yusuke Aoki
- Department of Neurology, Aichi Children's Health and Medical Center, Aichi, 474-8710, Japan
| | - Ken Inoue
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, 187-0031, Japan
| | - Tadashi Kaname
- Department of Genome Medicine, National Center for Child Health and Development, Tokyo, 157-8535, Japan
| | - Yusuke Okuno
- Center for Advanced Medicine and Clinical Research, Department of Advanced Medicine, Nagoya University Hospital, Nagoya, 466-8560, Japan
| | - Hideki Muramatsu
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8560, Japan
| | - Kohji Kato
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8560, Japan
| | - Toshiyuki Yamamoto
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, 162-8666, Japan. .,Tokyo Women's Medical University, Institute of Integrated Medical Sciences, Tokyo, 162-8666, Japan. .,Department of Gene Medicine, Graduate school of Medicine, Tokyo Women's Medical University, Tokyo, 162-8666, Japan.
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Shimada S, Hirasawa K, Takeshita A, Nakatsukasa H, Yamamoto-Shimojima K, Imaizumi T, Nagata S, Yamamoto T. Novel compound heterozygous EPG5 mutations consisted with a missense mutation and a microduplication in the exon 1 region identified in a Japanese patient with Vici syndrome. Am J Med Genet A 2018; 176:2803-2807. [PMID: 30152144 DOI: 10.1002/ajmg.a.40500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 07/11/2018] [Accepted: 07/14/2018] [Indexed: 01/27/2023]
Abstract
Vici syndrome is a rare, autosomal recessive, multisystem disorder, characterized by agenesis of the corpus callosum, cataracts, psychomotor delay, cardiomyopathy, hypopigmentation, and recurrent infections. Mutations in the ectopic P-granules autophagy protein 5 homolog gene (EPG5), which encodes a key autophagy regulator, are responsible for this syndrome. A 3-year-old Japanese girl manifesting similar symptoms to those found in patients with Vici syndrome showed intractable diarrhea, rather than immunodeficiency. Whole exome sequencing identified only a heterozygous variant in EPG5, NM_020964.2(EPG5):c.3389A > C (p.His1130Pro), which was inherited from her mother. Sequencing analyses of the EPG5 messenger RNA showed only an altered nucleotide "C" at position, c.3389, indicating decreased expression of the wild-type allele. Microarray-based comparative genomic hybridization revealed a de novo microduplication in the exon 1 region. Large exon deletions and duplications of EPG5 have never been reported so far. This was considered the cause of the decreased expression of the wild-type allele. In conclusion, we successfully identified novel compound heterozygous mutations in EPG5 in a patient who was clinically considered to have Vici syndrome.
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Affiliation(s)
- Shino Shimada
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
- Institute for Integrated Medical Sciences, Tokyo Women's Medical University, Tokyo, Japan
| | - Kyoko Hirasawa
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
| | - Akiko Takeshita
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
| | | | - Keiko Yamamoto-Shimojima
- Institute for Integrated Medical Sciences, Tokyo Women's Medical University, Tokyo, Japan
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Taichi Imaizumi
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Satoru Nagata
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
| | - Toshiyuki Yamamoto
- Institute for Integrated Medical Sciences, Tokyo Women's Medical University, Tokyo, Japan
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
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Anderson RH, Francis KR. Modeling rare diseases with induced pluripotent stem cell technology. Mol Cell Probes 2018; 40:52-59. [PMID: 29307697 PMCID: PMC6033695 DOI: 10.1016/j.mcp.2018.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/22/2017] [Accepted: 01/02/2018] [Indexed: 12/18/2022]
Abstract
Rare diseases, in totality, affect a significant proportion of the population and represent an unmet medical need facing the scientific community. However, the treatment of individuals affected by rare diseases is hampered by poorly understood mechanisms preventing the development of viable therapeutics. The discovery and application of cellular reprogramming to create novel induced pluripotent stem cell models of rare diseases has revolutionized the rare disease community. Through developmental and functional analysis of differentiated cell types, these stem cell models carrying patient-specific mutations have become an invaluable tool for rare disease research. In this review article, we discuss the reprogramming of samples from individuals affected with rare diseases to induced pluripotent stem cells, current and future applications for this technology, and how integration of genome editing to rare disease research will help to improve our understanding of disease pathogenesis and lead to patient therapies.
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Affiliation(s)
- Ruthellen H Anderson
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD, USA; Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA
| | - Kevin R Francis
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD, USA; Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA.
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Gillentine MA, Yin J, Bajic A, Zhang P, Cummock S, Kim JJ, Schaaf CP. Functional Consequences of CHRNA7 Copy-Number Alterations in Induced Pluripotent Stem Cells and Neural Progenitor Cells. Am J Hum Genet 2017; 101:874-887. [PMID: 29129316 DOI: 10.1016/j.ajhg.2017.09.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 09/27/2017] [Indexed: 01/08/2023] Open
Abstract
Copy-number variants (CNVs) of chromosome 15q13.3 manifest clinically as neuropsychiatric disorders with variable expressivity. CHRNA7, encoding for the α7 nicotinic acetylcholine receptor (nAChR), has been suggested as a candidate gene for the phenotypes observed. Here, we used induced pluripotent stem cells (iPSCs) and neural progenitor cells (NPCs) derived from individuals with heterozygous 15q13.3 deletions and heterozygous 15q13.3 duplications to investigate the CHRNA7-dependent molecular consequences of the respective CNVs. Unexpectedly, both deletions and duplications lead to decreased α7 nAChR-associated calcium flux. For deletions, this decrease in α7 nAChR-dependent calcium flux is expected due to haploinsufficiency of CHRNA7. For duplications, we found that increased expression of CHRNA7 mRNA is associated with higher expression of nAChR-specific and resident ER chaperones, indicating increased ER stress. This is likely a consequence of inefficient chaperoning and accumulation of α7 subunits in the ER, as opposed to being incorporated into functional α7 nAChRs at the cell membrane. Here, we showed that α7 nAChR-dependent calcium signal cascades are downregulated in both 15q13.3 deletion and duplication NPCs. While it may seem surprising that genomic changes in opposite direction have consequences on downstream pathways that are in similar direction, it aligns with clinical data, which suggest that both individuals with deletions and duplications of 15q13.3 manifest neuropsychiatric disease and cognitive deficits.
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Nevin ZS, Factor DC, Karl RT, Douvaras P, Laukka J, Windrem MS, Goldman SA, Fossati V, Hobson GM, Tesar PJ. Modeling the Mutational and Phenotypic Landscapes of Pelizaeus-Merzbacher Disease with Human iPSC-Derived Oligodendrocytes. Am J Hum Genet 2017; 100:617-634. [PMID: 28366443 DOI: 10.1016/j.ajhg.2017.03.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/09/2017] [Indexed: 02/07/2023] Open
Abstract
Pelizaeus-Merzbacher disease (PMD) is a pediatric disease of myelin in the central nervous system and manifests with a wide spectrum of clinical severities. Although PMD is a rare monogenic disease, hundreds of mutations in the X-linked myelin gene proteolipid protein 1 (PLP1) have been identified in humans. Attempts to identify a common pathogenic process underlying PMD have been complicated by an incomplete understanding of PLP1 dysfunction and limited access to primary human oligodendrocytes. To address this, we generated panels of human induced pluripotent stem cells (hiPSCs) and hiPSC-derived oligodendrocytes from 12 individuals with mutations spanning the genetic and clinical diversity of PMD-including point mutations and duplication, triplication, and deletion of PLP1-and developed an in vitro platform for molecular and cellular characterization of all 12 mutations simultaneously. We identified individual and shared defects in PLP1 mRNA expression and splicing, oligodendrocyte progenitor development, and oligodendrocyte morphology and capacity for myelination. These observations enabled classification of PMD subgroups by cell-intrinsic phenotypes and identified a subset of mutations for targeted testing of small-molecule modulators of the endoplasmic reticulum stress response, which improved both morphologic and myelination defects. Collectively, these data provide insights into the pathogeneses of a variety of PLP1 mutations and suggest that disparate etiologies of PMD could require specific treatment approaches for subsets of individuals. More broadly, this study demonstrates the versatility of a hiPSC-based panel spanning the mutational heterogeneity within a single disease and establishes a widely applicable platform for genotype-phenotype correlation and drug screening in any human myelin disorder.
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Affiliation(s)
- Zachary S Nevin
- Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Daniel C Factor
- Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Robert T Karl
- Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | | | - Jeremy Laukka
- Departments of Neurology and Neuroscience, College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA
| | - Martha S Windrem
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Steven A Goldman
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA; Center for Neuroscience, Faculty of Medicine and Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Valentina Fossati
- New York Stem Cell Foundation Research Institute, New York, NY 10032, USA
| | - Grace M Hobson
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA; Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA; Department of Pediatrics, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Paul J Tesar
- Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
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Sabapathy V, Kumar S. hiPSC-derived iMSCs: NextGen MSCs as an advanced therapeutically active cell resource for regenerative medicine. J Cell Mol Med 2016; 20:1571-88. [PMID: 27097531 PMCID: PMC4956943 DOI: 10.1111/jcmm.12839] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 02/14/2016] [Indexed: 12/18/2022] Open
Abstract
Mesenchymal stem cells (MSCs) are being assessed for ameliorating the severity of graft‐versus‐host disease, autoimmune conditions, musculoskeletal injuries and cardiovascular diseases. While most of these clinical therapeutic applications require substantial cell quantities, the number of MSCs that can be obtained initially from a single donor remains limited. The utility of MSCs derived from human‐induced pluripotent stem cells (hiPSCs) has been shown in recent pre‐clinical studies. Since adult MSCs have limited capability regarding proliferation, the quantum of bioactive factor secretion and immunomodulation ability may be constrained. Hence, the alternate source of MSCs is being considered to replace the commonly used adult tissue‐derived MSCs. The MSCs have been obtained from various adult and foetal tissues. The hiPSC‐derived MSCs (iMSCs) are transpiring as an attractive source of MSCs because during reprogramming process, cells undergo rejuvination, exhibiting better cellular vitality such as survival, proliferation and differentiations potentials. The autologous iMSCs could be considered as an inexhaustible source of MSCs that could be used to meet the unmet clinical needs. Human‐induced PSC‐derived MSCs are reported to be superior when compared to the adult MSCs regarding cell proliferation, immunomodulation, cytokines profiles, microenvironment modulating exosomes and bioactive paracrine factors secretion. Strategies such as derivation and propagation of iMSCs in chemically defined culture conditions and use of footprint‐free safer reprogramming strategies have contributed towards the development of clinically relevant cell types. In this review, the role of iPSC‐derived mesenchymal stromal cells (iMSCs) as an alternate source of therapeutically active MSCs has been described. Additionally, we also describe the role of iMSCs in regenerative medical applications, the necessary strategies, and the regulatory policies that have to be enforced to render iMSC's effectiveness in translational medicine.
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Affiliation(s)
- Vikram Sabapathy
- Center for Stem Cell Research, A Unit of inStem Bengaluru, Christian Medical College, Vellore, Tamil Nadu, India
| | - Sanjay Kumar
- Center for Stem Cell Research, A Unit of inStem Bengaluru, Christian Medical College, Vellore, Tamil Nadu, India
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Osaka H, Inoue K. Pathophysiology and emerging therapeutic strategies in Pelizaeus–Merzbacher disease. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1106315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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CHCHD2 is down-regulated in neuronal cells differentiated from iPS cells derived from patients with lissencephaly. Genomics 2015; 106:196-203. [DOI: 10.1016/j.ygeno.2015.07.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 06/17/2015] [Accepted: 07/01/2015] [Indexed: 12/20/2022]
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A de novo TUBB4A mutation in a patient with hypomyelination mimicking Pelizaeus-Merzbacher disease. Brain Dev 2015; 37:281-5. [PMID: 24974158 DOI: 10.1016/j.braindev.2014.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/02/2014] [Accepted: 05/02/2014] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Hypomyelinating leukoencephalopathy is a heterogeneous disorder caused by mutations in several-different genes. Clinical entity of hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) is one of them. METHOD A male patient showed pendular nystagmus, infantile hypotonia, an abnormal pattern of brain auditory evoked potential, and hypomyelination on brain magnetic resonance imaging, which suggested Pelizaeus-Merzbacher disease (PMD) as the candidate diagnosis; however, no abnormality was found in the proteolipid protein 1 gene (PLP1) that is responsible for PMD. Whole exome sequencing was performed to identify pathogenic mutations in this patient. RESULTS A de novo mutation was identified in the tubulin 4a gene (TUBB4A), which has been recently reported to be associated with H-ABC. Although the patient did not show any neurological features suggesting H-ABC, such as extrapyramidal or cerebellar signs, radiological findings demonstrated the finding of cerebellar atrophy at the age of 36months. CONCLUSION This study suggested us the difficulty of clinical diagnosis for H-ABC early in the life of the patient, which makes predication of prognosis and genetic counseling difficult.
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Torii T, Miyamoto Y, Yamauchi J, Tanoue A. Pelizaeus-Merzbacher disease: cellular pathogenesis and pharmacologic therapy. Pediatr Int 2014; 56:659-66. [PMID: 25040584 DOI: 10.1111/ped.12450] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 06/30/2014] [Accepted: 07/07/2014] [Indexed: 01/18/2023]
Abstract
Pelizaeus-Merzbacher disease (PMD) is a rare leukodystrophy that causes severe dysmyelination in the central nervous system in infancy and early childhood. Many previous studies showed that various proteolipid protein 1 (plp1) mutations, including duplications, point mutations, and deletions, lead to oligodendrocyte dysfunction in patients with PMD. PMD onset and clinical severity range widely, depending on the type of plp1 mutation. Patients with PMD exhibit a delayed mental and physical development phenotype, but specific pharmacological therapy and clinical treatment for PMD are not yet well established. This review describes PMD pathology and establishment of new clinical treatment for PMD. These findings support the development of a new therapy for PMD and these treatments may improve the quality of life in patients with PMD.
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Affiliation(s)
- Tomohiro Torii
- Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan
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Involvement of ER stress in dysmyelination of Pelizaeus-Merzbacher Disease with PLP1 missense mutations shown by iPSC-derived oligodendrocytes. Stem Cell Reports 2014; 2:648-61. [PMID: 24936452 PMCID: PMC4050482 DOI: 10.1016/j.stemcr.2014.03.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 03/20/2014] [Accepted: 03/20/2014] [Indexed: 01/22/2023] Open
Abstract
Pelizaeus-Merzbacher disease (PMD) is a form of X-linked leukodystrophy caused by mutations in the proteolipid protein 1 (PLP1) gene. Although PLP1 proteins with missense mutations have been shown to accumulate in the rough endoplasmic reticulum (ER) in disease model animals and cell lines transfected with mutant PLP1 genes, the exact pathogenetic mechanism of PMD has not previously been clarified. In this study, we established induced pluripotent stem cells (iPSCs) from two PMD patients carrying missense mutation and differentiated them into oligodendrocytes in vitro. In the PMD iPSC-derived oligodendrocytes, mislocalization of mutant PLP1 proteins to the ER and an association between increased susceptibility to ER stress and increased numbers of apoptotic oligodendrocytes were observed. Moreover, electron microscopic analysis demonstrated drastically reduced myelin formation accompanied by abnormal ER morphology. Thus, this study demonstrates the involvement of ER stress in pathogenic dysmyelination in the oligodendrocytes of PMD patients with the PLP1 missense mutation. Modeling Pelizaeus-Merzbacher disease (PMD) using iPSC-derived oligodendrocytes Increased ER stress involved in the apoptosis of PMD iPSC-derived oligodendrocytes Abnormal myelin structures and ER morphologies in PMD iPSC-derived oligodendrocytes Models for the pathophysiology of dysmyelinating disorders
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Shimojima K, Shimada S, Tamasaki A, Akaboshi S, Komoike Y, Saito A, Furukawa T, Yamamoto T. Novel compound heterozygous mutations of POLR3A revealed by whole-exome sequencing in a patient with hypomyelination. Brain Dev 2014; 36:315-21. [PMID: 23694757 DOI: 10.1016/j.braindev.2013.04.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 04/16/2013] [Accepted: 04/23/2013] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Congenital white matter disorders are a heterogeneous group of hypomyelination disorders affecting the white matter of the brain. Recently, mutations in the genes encoding the subunits of RNA polymerase III (Pol III), POLR3A and POLR3B, have been identified as new genetic causes for hypomyelinating disorders. METHOD Whole-exome sequencing was applied to identify responsible gene mutations in a 29-year-old female patient showing hypomyelination of unknown cause. To investigate the pathological mechanism underlying the hypomyelination in this patient, the expression level of 7SL RNA, a transcriptional target of Pol III, was analyzed in cultured skin fibroblasts derived from the patient with POLR3A mutations. RESULTS Novel compound heterozygous mutations of POLR3A were identified in the patient, who started to show cerebellar signs at 3 years, lost ambulation at 7 years, and became bedridden at 18 years. Brain magnetic resonance imaging showed severe volume loss in the brainstem, the cerebellum, and the white matter associated with hypomyelination. In addition to hypodontia and hypogonadism, she showed many pituitary hormone-related deficiencies. The expression level of 7SL RNA in cultured skin fibroblasts derived from this patient showed no significant abnormality. CONCLUSION The many pituitary hormone-related deficiencies identified in this patient may be an essential finding for the Pol III-related leukodystrophies spectrum. Further investigation is needed for a better understanding of the disease mechanism.
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Affiliation(s)
- Keiko Shimojima
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo 162-8666, Japan
| | - Shino Shimada
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo 162-8666, Japan; Department of Pediatrics, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Akiko Tamasaki
- Division of Child Neurology, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan
| | - Shinjiro Akaboshi
- Department of Pediatrics, National Hospital Organization Tottori Medical Center, Tottori 689-0203, Japan
| | - Yuta Komoike
- Department of Hygiene and Public Health, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | | | - Toru Furukawa
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo 162-8666, Japan
| | - Toshiyuki Yamamoto
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo 162-8666, Japan.
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Yamamoto T, Shimada S, Shimojima K. Fiber-fluorescence in situ hybridization analyses as a diagnostic application for orientation of microduplications. World J Med Genet 2013; 3:5-8. [DOI: 10.5496/wjmg.v3.i2.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 05/14/2013] [Accepted: 06/04/2013] [Indexed: 02/06/2023] Open
Abstract
Microduplications are normally invisible under microscopy and were not recognized before chromosomal microarray testing was available. Although it is difficult to confirm the orientation of duplicated segments by standard fluorescence in situ hybridization (FISH), our data indicates that fiber-FISH analysis has the potential to reveal the orientation of duplicated and triplicated segments of chromosomes. Recurrent microduplications reciprocal to microdeletions show tandem orientations of the duplicated segments, which is consistent with a non-allelic homologous recombination mechanism. Several random duplications showed tandem configurations and inverted duplications are rare. Further analysis is required to fully elucidate the basic mechanisms underlying such duplications/triplications.
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Yamamoto T, Matsuo M, Shimada S, Sangu N, Shimojima K, Aso S, Saito K. De novo triplication of 11q12.3 in a patient with developmental delay and distinctive facial features. Mol Cytogenet 2013; 6:15. [PMID: 23552394 PMCID: PMC3626894 DOI: 10.1186/1755-8166-6-15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 03/01/2013] [Indexed: 01/08/2023] Open
Abstract
Background Triplication is a rare chromosomal anomaly. We identified a de novo triplication of 11q12.3 in a patient with developmental delay, distinctive facial features, and others. In the present study, we discuss the mechanism of triplications that are not embedded within duplications and potential genes which may contribute to the phenotype. Results The identified triplication of 11q12.3 was 557 kb long and not embedded within the duplicated regions. The aberrant region was overlapped with the segment reported to be duplicated in 2 other patients. The common phenotypic features in the present patient and the previously reported patient were brain developmental delay, finger abnormalities (including arachnodactuly, camptodactyly, brachydactyly, clinodactyly, and broad thumbs), and preauricular pits. Conclusions Triplications that are not embedded within duplicated regions are rare and sometimes observed as the consequence of non-allelic homologous recombination. The de novo triplication identified in the present study is novel and not embedded within the duplicated region. In the 11q12.3 region, many copy number variations were observed in the database. This may be the trigger of this rare triplication. Because the shortest region of overlap contained 2 candidate genes, STX5 and CHRM1, which show some relevance to neuronal functions, we believe that the genomic copy number gains of these genes may be responsible for the neurological features seen in these patients.
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Affiliation(s)
- Toshiyuki Yamamoto
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, 8-1 Kawada-cho, Shinjuku-ward, Tokyo, 162-8666, Japan.
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Yamamoto T, Shimojima K. Pelizaeus-Merzbacher disease as a chromosomal disorder. Congenit Anom (Kyoto) 2013; 53:3-8. [PMID: 23480352 DOI: 10.1111/cga.12005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 11/04/2012] [Indexed: 12/29/2022]
Abstract
Pelizaeus-Merzbacher disease (PMD) is a congenital hypomyelination disorder caused by alterations affecting the proteolipid protein 1 gene (PLP1) located on Xq22.2. Generally, patients with PLP1 missense mutations show the most severe form of PMD (connatal form); however, two-thirds of patients with PMD carry PLP1 duplications and present typical manifestations of the disorder, recognized as the classical form. Other rare PLP1 abnormalities have been also identified, including X-chromosome translocations, triplications, and a partial duplication, all involving PLP1. The genomic structure of the distal end of the PLP1 locus, characterized by repeated genomic segments, contributes to the chromosomal rearrangements around PLP1 and the manifestation of PMD. Thus, PMD is recognized as a chromosomal disorder.
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Affiliation(s)
- Toshiyuki Yamamoto
- Institute for Integrated Medical Sciences, Tokyo Women's Medical University, Tokyo, Japan.
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Patient-derived iPS cells for unveiling the molecular pathology of Pelizaeus-Merzbacher disease: a commentary on 'Reduced PLP1 expression in induced pluripotent stem cells derived from a Pelizaeus-Merzbacher disease patient with a partial PLP1 duplication'. J Hum Genet 2012; 57:553-4. [PMID: 22786577 DOI: 10.1038/jhg.2012.85] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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