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Elitt MS, Tesar PJ. Pelizaeus-Merzbacher disease: on the cusp of myelin medicine. Trends Mol Med 2024; 30:459-470. [PMID: 38582621 PMCID: PMC11081862 DOI: 10.1016/j.molmed.2024.03.005] [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: 01/02/2024] [Revised: 03/05/2024] [Accepted: 03/08/2024] [Indexed: 04/08/2024]
Abstract
Pelizaeus-Merzbacher disease (PMD) is caused by mutations in the proteolipid protein 1 (PLP1) gene encoding proteolipid protein (PLP). As a major component of myelin, mutated PLP causes progressive neurodegeneration and eventually death due to severe white matter deficits. Medical care has long been limited to symptomatic treatments, but first-in-class PMD therapies with novel mechanisms now stand poised to enter clinical trials. Here, we review PMD disease mechanisms and outline rationale for therapeutic interventions, including PLP1 suppression, cell transplantation, iron chelation, and intracellular stress modulation. We discuss available preclinical data and their implications on clinical development. With several novel treatments on the horizon, PMD is on the precipice of a new era in the diagnosis and treatment of patients suffering from this debilitating disease.
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Affiliation(s)
- Matthew S Elitt
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Paul J Tesar
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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2
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Ghasemi A, Sadr Z, Babanejad M, Rohani M, Alavi A. Copy Number Variations in Hereditary Spastic Paraplegia-Related Genes: Evaluation of an Iranian Hereditary Spastic Paraplegia Cohort and Literature Review. Mol Syndromol 2023; 14:477-484. [PMID: 38058755 PMCID: PMC10697729 DOI: 10.1159/000531507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 06/07/2023] [Indexed: 12/08/2023] Open
Abstract
Introduction In human genetic disorders, copy number variations (CNVs) are considered a considerable underlying cause. CNVs are generally detected by array-based methods but can also be discovered by read-depth analysis of whole-exome sequencing (WES) data. We performed WES-based CNV identification in a cohort of 35 Iranian families with hereditary spastic paraplegia (HSP) patients. Methods Thirty-five patients whose routine single-nucleotide variants (SNVs) and insertion/deletion analyses from exome data were unrevealing underwent a pipeline of CNV analysis using the read-depth detection method. Subsequently, a comprehensive search about the existence of CNVs in all 84 known HSP-causing genes was carried out in all reported HSP cases, so far. Results and Discussion CNV analysis of exome data indicated that 1 patient harbored a heterozygous deletion in exon 17 of the SPAST gene. Multiplex ligation-dependent probe amplification analysis confirmed this deletion in the proband and his affected father. Literature review demonstrated that, to date, pathogenic CNVs have been identified in 30 out of 84 HSP-causing genes (∼36%). However, CNVs in only 17 of these genes were specifically associated with the HSP phenotype. Among them, CNVs were more common in L1CAM, PLP1, SPAST, SPG7, SPG11, and REEP1 genes. The identification of the CNV in 1 of our patients suggests that WES allows the detection of both SNVs and CNVs from a single method without additional costs and execution time. However, because of intrinsic issues of WES in the detection of large rearrangements, it may not yet be exploited to replace the CNV detection methods in standard clinical practice.
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Affiliation(s)
- Aida Ghasemi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Zahra Sadr
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mojgan Babanejad
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mohammad Rohani
- Department of Neurology, Iran University of Medical Sciences, Hazrat Rasool Hospital, Tehran, Iran
| | - Afagh Alavi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- Neuromuscular Research Center, Tehran University of Medical Sciences, Tehran, Iran
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Zhou X, Wang Y, He R, Liu Z, Xu Q, Guo J, Yan X, Li J, Tang B, Zeng S, Sun Q. Microdeletion in distal PLP1 enhancers causes hereditary spastic paraplegia 2. Ann Clin Transl Neurol 2023; 10:1590-1602. [PMID: 37475517 PMCID: PMC10502680 DOI: 10.1002/acn3.51848] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/22/2023] Open
Abstract
OBJECTIVES Hereditary spastic paraplegia (HSP) is a genetically heterogeneous disease caused by over 70 genes, with a significant number of patients still genetically unsolved. In this study, we recruited a suspected HSP family characterized by spasticity, developmental delay, ataxia and hypomyelination, and intended to reveal its molecular etiology by whole exome sequencing (WES) and long-read sequencing (LRS) analyses. METHODS WES was performed on 13 individuals of the family to identify the causative mutations, including analyses of SNVs (single-nucleotide variants) and CNVs (copy number variants). Accurate circular consensus (CCS) long-read sequencing (LRS) was used to verify the findings of CNV analysis from WES. RESULTS SNVs analysis identified a missense variant c.195G>T (p.E65D) of MORF4L2 at Xq22.2 co-segregating in this family from WES data. Further CNVs analysis revealed a microdeletion, which was adjacent to the MORF4L2 gene, also co-segregating in this family. LRS verified this microdeletion and confirmed the deletion range (chrX: 103,690,507-103,715,018, hg38) with high resolution at nucleotide level accuracy. INTERPRETATIONS In this study, we identified an Xq22.2 microdeletion (about 24.5 kb), which contains distal enhancers of the PLP1 gene, as a likely cause of SPG2 in this family. The lack of distal enhancers may result in transcriptional repression of PLP1 in oligodendrocytes, potentially affecting its role in the maintenance of myelin, and causing SPG2 phenotype. This study has highlighted the importance of noncoding genomic alterations in the genetic etiology of SPG2.
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Affiliation(s)
- Xun Zhou
- Department of Geriatric Neurology, Xiangya HospitalCentral South UniversityChangshaChina
| | - Yige Wang
- Department of Neurology, Xiangya HospitalCentral South UniversityChangshaChina
| | - Runcheng He
- Department of Neurology, Xiangya HospitalCentral South UniversityChangshaChina
| | - Zhenhua Liu
- Department of Neurology, Xiangya HospitalCentral South UniversityChangshaChina
- National Clinical Research Center for Geriatric Disorders, Xiangya HospitalCentral South UniversityChangshaChina
- Key Laboratory of Hunan Province in Neurodegenerative DisordersCentral South UniversityChangshaChina
| | - Qian Xu
- Department of Neurology, Xiangya HospitalCentral South UniversityChangshaChina
- National Clinical Research Center for Geriatric Disorders, Xiangya HospitalCentral South UniversityChangshaChina
- Key Laboratory of Hunan Province in Neurodegenerative DisordersCentral South UniversityChangshaChina
| | - Jifeng Guo
- Department of Neurology, Xiangya HospitalCentral South UniversityChangshaChina
- National Clinical Research Center for Geriatric Disorders, Xiangya HospitalCentral South UniversityChangshaChina
- Key Laboratory of Hunan Province in Neurodegenerative DisordersCentral South UniversityChangshaChina
| | - Xinxiang Yan
- Department of Neurology, Xiangya HospitalCentral South UniversityChangshaChina
- National Clinical Research Center for Geriatric Disorders, Xiangya HospitalCentral South UniversityChangshaChina
| | - Jinchen Li
- Department of Geriatric Neurology, Xiangya HospitalCentral South UniversityChangshaChina
- Department of Neurology, Xiangya HospitalCentral South UniversityChangshaChina
- National Clinical Research Center for Geriatric Disorders, Xiangya HospitalCentral South UniversityChangshaChina
- Center for Medical Genetics, School of Life SciencesCentral South UniversityChangshaChina
| | - Beisha Tang
- Department of Geriatric Neurology, Xiangya HospitalCentral South UniversityChangshaChina
- Department of Neurology, Xiangya HospitalCentral South UniversityChangshaChina
- National Clinical Research Center for Geriatric Disorders, Xiangya HospitalCentral South UniversityChangshaChina
- Key Laboratory of Hunan Province in Neurodegenerative DisordersCentral South UniversityChangshaChina
| | - Sheng Zeng
- Department of Geriatrics, The Second Xiangya HospitalCentral South UniversityChangshaChina
| | - Qiying Sun
- Department of Geriatric Neurology, Xiangya HospitalCentral South UniversityChangshaChina
- National Clinical Research Center for Geriatric Disorders, Xiangya HospitalCentral South UniversityChangshaChina
- Key Laboratory of Hunan Province in Neurodegenerative DisordersCentral South UniversityChangshaChina
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Rogac M, Kovanda A, Lovrečić L, Peterlin B. Optical genome mapping in an atypical Pelizaeus-Merzbacher prenatal challenge. Front Genet 2023; 14:1173426. [PMID: 37560384 PMCID: PMC10407396 DOI: 10.3389/fgene.2023.1173426] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 07/14/2023] [Indexed: 08/11/2023] Open
Abstract
Pathogenic genetic variants represent a challenge in prenatal counseling, especially when clinical presentation in familial carriers is atypical. We describe a prenatal case involving a microarray-detected duplication of PLP1 which causes X-linked Pelizaeus-Merzbacher disease, a progressive hypomyelinating leukodystrophy. Because of atypical clinical presentation in an older male child, the duplication was examined using a novel technology, optical genome mapping, and was found to be an inverted duplication, which has not been previously described. Simultaneously, segregation analysis identified another healthy adult male carrier of this unique structural rearrangement. The novel PLP1 structural variant was reclassified, and a healthy boy was delivered. In conclusion, we suggest that examining structural variants with novel methods is warranted especially in cases with atypical clinical presentation and may in these cases lead to improved prenatal and postnatal genetic counseling.
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Affiliation(s)
- Mihael Rogac
- Clinical Institute of Genomic Medicine, University Medical Center Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Anja Kovanda
- Clinical Institute of Genomic Medicine, University Medical Center Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Luca Lovrečić
- Clinical Institute of Genomic Medicine, University Medical Center Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Borut Peterlin
- Clinical Institute of Genomic Medicine, University Medical Center Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Avramouli A, Krokidis MG, Exarchos TP, Vlamos P. In Silico Structural Analysis Predicting the Pathogenicity of PLP1 Mutations in Multiple Sclerosis. Brain Sci 2022; 13:brainsci13010042. [PMID: 36672024 PMCID: PMC9856082 DOI: 10.3390/brainsci13010042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
The X chromosome gene PLP1 encodes myelin proteolipid protein (PLP), the most prevalent protein in the myelin sheath surrounding the central nervous system. X-linked dysmyelinating disorders such as Pelizaeus-Merzbacher disease (PMD) or spastic paraplegia type 2 (SPG2) are typically caused by point mutations in PLP1. Nevertheless, numerous case reports have shown individuals with PLP1 missense point mutations which also presented clinical symptoms and indications that were consistent with the diagnostic criteria of multiple sclerosis (MS), a disabling disease of the brain and spinal cord with no current cure. Computational structural biology methods were used to assess the impact of these mutations on the stability and flexibility of PLP structure in order to determine the role of PLP1 mutations in MS pathogenicity. The analysis showed that most of the variants can alter the functionality of the protein structure such as R137W variants which results in loss of helix and H140Y which alters the ordered protein interface. In silico genomic methods were also performed to predict the significance of these mutations associated with impairments in protein functionality and could suggest a better definition for therapeutic strategies and clinical application in MS patients.
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Duan R, Ji H, Yan H, Wang J, Zhang Y, Zhang Q, Li D, Cao B, Gu Q, Wu Y, Jiang Y, Li M, Wang J. Genotype-phenotype correlation and natural history analyses in a Chinese cohort with pelizaeus-merzbacher disease. Orphanet J Rare Dis 2022; 17:137. [PMID: 35346287 PMCID: PMC8962489 DOI: 10.1186/s13023-022-02267-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 02/20/2022] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The natural history and genotype-phenotype correlation of Pelizaeus-Merzbacher disease (PMD) of Chinese patients has been rarely reported. METHOD Patients who met the criteria for PMD were enrolled in our study. Genomic analysis was conducted by multiplex ligation probe amplification (MLPA) and Sanger or whole-exome sequencing (WES). Natural history differences and genotype-phenotype correlations were analyzed. RESULT A total of 111 patients were enrolled in our follow-up study. The median follow-up interval was 53 m (1185). Among PMD patients, developmental delay was the most common sign, and nystagmus and hypotonia were the most common initial symptoms observed. A total of 78.4% of the patients were able to control their head, and 72.1% could speak words. However, few of the patients could stand (9.0%) or walk (4.5%) by themselves. Nystagmus improved in more than half of the patients, and hypotonia sometimes deteriorated to movement disorders. More PLP1 point mutations patients were categorized into severe group, while more patients with PLP1 duplications were categorized into mild group (p < 0.001). Compared to patients in mild groups, those in the severe group had earlier disease onset and had acquired fewer skills at a later age. CONCLUSION PMD patients have early disease onset with nystagmus and hypotonia followed by decreased nystagmus and movement disorders, such as spasticit. Patients with PLP1 duplication were more likely to be categorized into the mild group, whereas patients with point mutations were more likely to be categorized into the severe group.
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Affiliation(s)
- Ruoyu Duan
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Haoran Ji
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Huifang Yan
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Junyu Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Yu Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Qian Zhang
- Department of Children's Development and Rehabilitation, Peking University First Hospital, Beijing, 100034, China
| | - Dongxiao Li
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Binbin Cao
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Qiang Gu
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Ming Li
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China. .,Department of Children's Development and Rehabilitation, Peking University First Hospital, Beijing, 100034, China.
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China.
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7
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Sherman LS, Su W, Johnson AL, Peterson SM, Cullin C, Lavinder T, Ferguson B, Lewis AD. A novel non-human primate model of Pelizaeus-Merzbacher disease. Neurobiol Dis 2021; 158:105465. [PMID: 34364975 DOI: 10.1016/j.nbd.2021.105465] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 07/06/2021] [Accepted: 08/02/2021] [Indexed: 11/30/2022] Open
Abstract
Pelizaeus-Merzbacher disease (PMD) is a severe hypomyelinating disorder of the central nervous system (CNS) linked to mutations in the proteolipid protein-1 (PLP1) gene. Although there are multiple animal models of PMD, few of them fully mimic the human disease. Here, we report three spontaneous cases of male neonatal rhesus macaques with the clinical symptoms of hypomyelinating disease, including intention tremors, progressively worsening motor dysfunction, and nystagmus. These animals demonstrated a paucity of CNS myelination accompanied by reactive astrogliosis, and a lack of PLP1 expression throughout white matter. Genetic analysis revealed that these animals were related to one another and that their parents carried a rare, hemizygous missense variant in exon 5 of the PLP1 gene. These animals therefore represent the first reported non-human primate model of PMD, providing a novel and valuable opportunity for preclinical studies that aim to promote myelination in pediatric hypomyelinating diseases.
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Affiliation(s)
- Larry S Sherman
- Divisions of Neuroscience Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, United States of America; Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR, United States of America.
| | - Weiping Su
- Divisions of Neuroscience Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, United States of America
| | - Amanda L Johnson
- Divisions of Comparative Medicine Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, United States of America
| | - Samuel M Peterson
- Divisions of Genetics, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, United States of America
| | - Cassandra Cullin
- Divisions of Comparative Medicine Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, United States of America
| | - Tiffany Lavinder
- Divisions of Comparative Medicine Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, United States of America
| | - Betsy Ferguson
- Divisions of Genetics, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, United States of America
| | - Anne D Lewis
- Divisions of Comparative Medicine Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, United States of America.
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Lee SJ, Kim TY, Hong S, Byun J, Cho SR. Pelizaeus-Merzbacher Disease with PLP1 Exon 1 Duplication, Previously Misdiagnosed as Cerebral Palsy: a Case Report. BRAIN & NEUROREHABILITATION 2021; 14:e20. [PMID: 36743429 PMCID: PMC9879495 DOI: 10.12786/bn.2021.14.e20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 11/08/2022] Open
Abstract
Pelizaeus-Merzbacher disease (PMD) is a X-linked recessive disorder with dysmyelination in central nervous system caused by proteolipid protein 1 (PLP1) gene mutation. We report a case of PMD with PLP1 exon 1 duplication, previously misdiagnosed as cerebral palsy (CP). A 25-year-old male previously diagnosed as CP visited our clinic with progressive weakness and spasticity of bilateral lower limbs. Next generation sequencing revealed hemizygous duplication of exon 1 in PLP1. Additionally, multiplex ligation-dependent probe amplification assay of the patient's mother showed the same mutation, which could finally confirm the diagnosis as PMD. This patient received comprehensive rehabilitation program, and helped the patient to achieve functional improvement. Proper diagnosis and therapeutic plan will be needed for the patients with PMD, before diagnosing CP rashly.
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Affiliation(s)
- Su Ji Lee
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Tae Yong Kim
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Seungbeen Hong
- Department of Physical Medicine and Rehabilitation, National Health Insurance Service Ilsan Hospital, Goyang, Korea
| | - Justin Byun
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea.,Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea
| | - Sung-Rae Cho
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea.,Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
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Lee JM, Kim A, Lee YJ, Kwack M. Symptomatic female spastic paraplegia patient with a novel heterozygous variant of the PLP1 gene. Ann Indian Acad Neurol 2021; 24:958-960. [PMID: 35359527 PMCID: PMC8965957 DOI: 10.4103/aian.aian_793_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/02/2020] [Accepted: 09/03/2020] [Indexed: 11/08/2022] Open
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Abstract
Hypomyelinating leukodystrophies constitute a subset of genetic white matter disorders characterized by a primary lack of myelin deposition. Most patients with severe hypomyelination present in infancy or early childhood and develop severe neurological deficits, but the clinical presentation can also be mild with onset of symptoms in adolescence or adulthood. MRI can be used to visualize the process of myelination in detail, and MRI pattern recognition can provide a clinical diagnosis in many patients. Next-generation sequencing provides a definitive diagnosis in 80-90% of patients. Genes associated with hypomyelination include those that encode structural myelin proteins but also many that encode proteins involved in RNA translation and some lysosomal proteins. The precise pathomechanisms remain to be elucidated. Improved understanding of the process of myelination, the metabolic axonal support functions of myelin and the proposed contribution of myelin to CNS plasticity provide possible explanations as to why almost all patients with hypomyelination experience slow clinical decline after a long phase of stability. In this Review, we provide an overview of the hypomyelinating leukodystrophies, the advances in our understanding of myelin biology and of the genes involved in these disorders, and the insights these advances have provided into their clinical presentations and evolution.
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Lyahyai J, Ouled Amar Bencheikh B, Elalaoui SC, Mansouri M, Boualla L, DIonne-Laporte A, Spiegelman D, Dion PA, Cossette P, Rouleau GA, Sefiani A. Exome sequencing reveals a novel PLP1 mutation in a Moroccan family with connatal Pelizaeus-Merzbacher disease: a case report. BMC Pediatr 2018; 18:90. [PMID: 29486744 PMCID: PMC5830319 DOI: 10.1186/s12887-018-1063-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 02/15/2018] [Indexed: 11/20/2022] Open
Abstract
Background Epilepsy regroups a common and diverse set of chronic neurological disorders that are characterized by spontaneous, unprovoked, and recurrent epileptic seizures. Epilepsies have a highly heterogeneous background with a strong genetic contribution and various mode of inheritance. X-linked epilepsy usually manifests as part of a syndrome or epileptic encephalopathy. The variability of clinical manifestations of X-linked epilepsy may be attributed to several factors including the causal genetic mutation, making diagnosis, genetic counseling and treatment decisions difficult. We report the description of a Moroccan family referred to our genetic department with X-linked epileptic seizures as the only initial diagnosis. Case presentation Knowing the new contribution of Next-Generation Sequencing (NGS) for clinical investigation, and given the heterogeneity of this group of disorders we performed a Whole-Exome Sequencing (WES) analysis and co-segregation study in several members of this large family. We detected a novel pathogenic PLP1 missense mutation c.251C > A (p.Ala84Asp) allowing us to make a diagnosis of Pelizaeus-Merzbacher Disease for this family. Conclusion This report extends the spectrum of PLP1 mutations and highlights the diagnostic utility of NGS to investigate this group of heterogeneous disorders.
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Tantzer S, Sperle K, Kenaley K, Taube J, Hobson GM. Morpholino Antisense Oligomers as a Potential Therapeutic Option for the Correction of Alternative Splicing in PMD, SPG2, and HEMS. MOLECULAR THERAPY. NUCLEIC ACIDS 2018; 12:420-432. [PMID: 30195779 PMCID: PMC6036941 DOI: 10.1016/j.omtn.2018.05.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 05/22/2018] [Indexed: 01/10/2023]
Abstract
DNA variants of the proteolipid protein 1 gene (PLP1) that shift PLP1/DM20 alternative splicing away from the PLP1 form toward DM20 cause the allelic X-linked leukodystrophies Pelizaeus-Merzbacher disease (PMD), spastic paraplegia 2 (SPG2), and hypomyelination of early myelinating structures (HEMS). We designed a morpholino oligomer (MO-PLP) to block use of the DM20 5' splice donor site, thereby shifting alternative splicing toward the PLP1 5' splice site. Treatment of an immature oligodendrocyte cell line with MO-PLP significantly shifted alternative splicing toward PLP1 expression from the endogenous gene and from transfected human minigene splicing constructs harboring patient variants known to reduce the amount of the PLP1 spliced product. Additionally, a single intracerebroventricular injection of MO-PLP into the brains of neonatal mice, carrying a deletion of an intronic splicing enhancer identified in a PMD patient that reduces the Plp1 spliced form, corrected alternative splicing at both RNA and protein levels in the CNS. The effect lasted to post-natal day 90, well beyond the early post-natal spike in myelination and PLP production. Further, the single injection produced a sustained reduction of inflammatory markers in the brains of the mice. Our results suggest that morpholino oligomers have therapeutic potential for the treatment of PMD, SPG2, and HEMS.
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Affiliation(s)
- Stephanie Tantzer
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
| | - Karen Sperle
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
| | - Kaitlin Kenaley
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA; Department of Pediatrics/Neonatology, Christiana Care Health System, Newark, DE 19713, USA
| | - Jennifer Taube
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, 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.
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13
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Margraf RL, Durtschi J, Krock B, Newcomb TM, Bonkowsky JL, Voelkerding KV, Bayrak-Toydemir P, Lutz RE, Swoboda KJ. Novel PLP1 Mutations Identified With Next-Generation Sequencing Expand the Spectrum of PLP1-Associated Leukodystrophy Clinical Phenotypes. Child Neurol Open 2018; 5:2329048X18789282. [PMID: 30046645 PMCID: PMC6056774 DOI: 10.1177/2329048x18789282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 06/12/2018] [Indexed: 11/30/2022] Open
Abstract
Next-generation sequencing was performed for 2 families with an undiagnosed neurologic disease. Analysis revealed X-linked mutations in the proteolipid protein 1 (PLP1) gene, which is associated with X-linked Pelizaeus-Merzbacher disease and Spastic Paraplegia type 2. In family A, the novel PLP1 missense mutation c.617T>A (p.M206K) was hemizygous in the 2 affected male children and heterozygous in the mother. In family B, the novel de novoPLP1 frameshift mutation c.359_369del (p.G120fs) was hemizygous in the affected male child. Although PLP1 mutations have been reported to cause an increasingly wide range of phenotypes inclusive of the dystonia, spastic paraparesis, motor neuronopathy, and leukodystrophy observed in our patients, atypical features included the cerebrospinal fluid deficiency of neurotransmitter and pterin metabolites and the delayed appearance of myelin abnormalities on neuroimaging studies. Next-generation sequencing studies provided a diagnosis for these families with complex leukodystrophy disease phenotypes, which expanded the spectrum of PLP1-associated leukodystrophy clinical phenotypes.
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Affiliation(s)
- Rebecca L Margraf
- ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, Salt Lake City, UT, USA
| | - Jacob Durtschi
- ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, Salt Lake City, UT, USA
| | - Bryan Krock
- ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, Salt Lake City, UT, USA
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Tara M Newcomb
- Pediatric Motor Disorders Research Program, Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Joshua L Bonkowsky
- Division of Pediatric Neurology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Karl V Voelkerding
- ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, Salt Lake City, UT, USA
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Pinar Bayrak-Toydemir
- ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories, Salt Lake City, UT, USA
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Richard E Lutz
- Department of Endocrinology, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Genetics, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kathryn J Swoboda
- Pediatric Motor Disorders Research Program, Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT, USA
- Division of Pediatric Neurology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
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14
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Velasco Parra HM, Maradei Anaya SJ, Acosta Guio JC, Arteaga Diaz CE, Prieto Rivera JC. Clinical and mutational spectrum of Colombian patients with Pelizaeus Merzbacher Disease. Colomb Med (Cali) 2018; 49:182-187. [PMID: 30104812 PMCID: PMC6084915 DOI: 10.25100/cm.v49i2.2522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 05/25/2017] [Accepted: 11/02/2017] [Indexed: 11/11/2022] Open
Abstract
CASE PRESENTATION Pelizaeus Merzbacher Disease (PMD) is an X-linked developmental defect of myelination that causes childhood chronic spastic encephalopathy. Its genetic etiology can be either a duplication (or other gene dosage alterations) or a punctual mutation at the PLP1 locus. Clinically, it presents with developmental delay, nystagmus and, spasticity, supported by neuroimaging in which the defect of myelination is evident. We present a series of seven Colombian patients diagnosed with this leucodystrophy, describing their genotypic and phenotypic characteristics and heterogeneity. CLINICAL FINDINGS All patients included were male, 6 months to 16 years of age. Mean age at onset of symptoms was 8 months. Mean age at diagnosis was 5 years 5 months, being classic PMD most frequently diagnosed, as compared to the connatal phenotype. All cases had a primary diagnosis of developmental delay on 100%, and in 28.7% of cases, early onset nystagmus was described. 85.7% of patients had spasticity, 71.4% cerebellar signs, 57.0% hypotonia, and 28.5% had an abnormal movement disorder. Only three patients were able to achieve gait, though altered. In the two patients who had a diagnosis of connatal PMD maturational ages in danger zones according to the WHO Abbreviated Scale of Psychosocial Development were documented. All cases had abnormalities in neuroimages. MOLECULAR ANALYSIS AND RESULTS Molecular studies were used in the majority of the cases to confirm the diagnosis (85.7 %). For two cases molecular confirmation was not considered necessary given their affected male brothers had already been tested. PLP1 gene dosage alterations (duplications) were found in 28.5 % of the patients (two siblings), whereas three different single nucleotide variants were detected. CLINICAL RELEVANCE According to these findings, as authors we propose the diagnostic algorithm in Colombian population to begin on a high clinical suspicion, followed by paraclinical extension, moving on to the molecular confirmation by using approaches to simultaneously sequence the PLP1 gene in order to detect point mutations and in/dels and performing a copy number variation analysis for the detection of gene dosage alterations.
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Affiliation(s)
- Harvy Mauricio Velasco Parra
- Maestria en Genética Humana, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia
- Hospital Militar Central, Bogotá, Colombia
- Instituto de Ortopedia Infantil Roosevelt, Bogotá, Colombia
| | | | - Johanna Carolina Acosta Guio
- Maestria en Genética Humana, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia
- Instituto de Ortopedia Infantil Roosevelt, Bogotá, Colombia
| | | | - Juan Carlos Prieto Rivera
- Genetica Medica, Facultad de Medicina, Pontificia Universidad Javeriana. Bogotá, Colombia
- Hospital La Victoria, Bogotá, Colombia
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15
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Osório MJ, Goldman SA. Neurogenetics of Pelizaeus-Merzbacher disease. HANDBOOK OF CLINICAL NEUROLOGY 2018; 148:701-722. [PMID: 29478609 DOI: 10.1016/b978-0-444-64076-5.00045-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Pelizaeus-Merzbacher disease (PMD) is an X-linked disorder caused by mutations in the PLP1 gene, which encodes the proteolipid protein of myelinating oligodendroglia. PMD exhibits phenotypic variability that reflects its considerable genotypic heterogeneity, but all forms of the disease result in central hypomyelination associated with early neurologic dysfunction, progressive deterioration, and ultimately death. PMD has been classified into three major subtypes, according to the age of presentation: connatal PMD, classic PMD, and transitional PMD, combining features of both connatal and classic forms. Two other less severe phenotypes were subsequently described, including the spastic paraplegia syndrome and PLP1-null disease. These disorders may be associated with duplications, as well as with point, missense, and null mutations within the PLP1 gene. A number of clinically similar Pelizaeus-Merzbacher-like disorders (PMLD) are considered in the differential diagnosis of PMD, the most prominent of which is PMLD-1, caused by misexpression of the GJC2 gene encoding connexin-47. No effective therapy for PMD exists. Yet, as a relatively pure central nervous system hypomyelinating disorder, with limited involvement of the peripheral nervous system and little attendant neuronal pathology, PMD is an attractive therapeutic target for neural stem cell and glial progenitor cell transplantation, efforts at which are now underway in a number of centers internationally.
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Affiliation(s)
- M Joana Osório
- Center for Translational Neuromedicine and Department of Neurology, University of Rochester Medical Center, Rochester, NY, United States; Center for Translational Neuromedicine, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark
| | - Steven A Goldman
- Center for Translational Neuromedicine and Department of Neurology, University of Rochester Medical Center, Rochester, NY, United States; Center for Translational Neuromedicine, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark.
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16
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Labonne JDJ, Graves TD, Shen Y, Jones JR, Kong IK, Layman LC, Kim HG. A microdeletion at Xq22.2 implicates a glycine receptor GLRA4 involved in intellectual disability, behavioral problems and craniofacial anomalies. BMC Neurol 2016; 16:132. [PMID: 27506666 PMCID: PMC4979147 DOI: 10.1186/s12883-016-0642-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 07/20/2016] [Indexed: 12/03/2022] Open
Abstract
Background Among the 21 annotated genes at Xq22.2, PLP1 is the only known gene involved in Xq22.2 microdeletion and microduplication syndromes with intellectual disability. Using an atypical microdeletion, which does not encompass PLP1, we implicate a novel gene GLRA4 involved in intellectual disability, behavioral problems and craniofacial anomalies. Case presentation We report a female patient (DGDP084) with a de novo Xq22.2 microdeletion of at least 110 kb presenting with intellectual disability, motor delay, behavioral problems and craniofacial anomalies. While her phenotypic features such as cognitive impairment and motor delay show overlap with Pelizaeus-Merzbacher disease (PMD) caused by PLP1 mutations at Xq22.2, this gene is not included in our patient’s microdeletion and is not dysregulated by a position effect. Because the microdeletion encompasses only three genes, GLRA4, MORF4L2 and TCEAL1, we investigated their expression levels in various tissues by RT-qPCR and found that all three genes were highly expressed in whole human brain, fetal brain, cerebellum and hippocampus. When we examined the transcript levels of GLRA4, MORF4L2 as well as TCEAL1 in DGDP084′s family, however, only GLRA4 transcripts were reduced in the female patient compared to her healthy mother. This suggests that GLRA4 is the plausible candidate gene for cognitive impairment, behavioral problems and craniofacial anomalies observed in DGDP084. Importantly, glycine receptors mediate inhibitory synaptic transmission in the brain stem as well as the spinal cord, and are known to be involved in syndromic intellectual disability. Conclusion We hypothesize that GLRA4 is involved in intellectual disability, behavioral problems and craniofacial anomalies as the second gene identified for X-linked syndromic intellectual disability at Xq22.2. Additional point mutations or intragenic deletions of GLRA4 as well as functional studies are needed to further validate our hypothesis. Electronic supplementary material The online version of this article (doi:10.1186/s12883-016-0642-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jonathan D J Labonne
- Department of Obstetrics & Gynecology, Section of Reproductive Endocrinology, Infertility & Genetics, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA, 30912, USA.,Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA, 30912, USA
| | - Tyler D Graves
- Department of Obstetrics & Gynecology, Section of Reproductive Endocrinology, Infertility & Genetics, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA, 30912, USA
| | - Yiping Shen
- Department of Laboratory Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | | | - Il-Keun Kong
- Department of Animal Science, Division of Applied Life Science (BK21plus), Institute of Agriculture and Life Science, Gyeongsang National University, Jinju, Gyeongsangnam-do, South Korea
| | - Lawrence C Layman
- Department of Obstetrics & Gynecology, Section of Reproductive Endocrinology, Infertility & Genetics, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA, 30912, USA.,Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA, 30912, USA.,Neuroscience Program, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Hyung-Goo Kim
- Department of Obstetrics & Gynecology, Section of Reproductive Endocrinology, Infertility & Genetics, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA, 30912, USA. .,Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA, 30912, USA.
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17
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Xie H, Feng H, Ji J, Wu Y, Kou L, Li D, Ji H, Wu X, Niu Z, Wang J, Jiang Y. Identification and functional study of novel PLP1 mutations in Chinese patients with Pelizaeus-Merzbacher disease. Brain Dev 2015; 37:797-802. [PMID: 25491635 DOI: 10.1016/j.braindev.2014.11.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 11/23/2014] [Accepted: 11/25/2014] [Indexed: 01/01/2023]
Abstract
PURPOSE Pelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive hypomyelination disorder characterized by nystagmus, ataxia, impaired motor development, and progressive spasticity. Identification of proteolipid protein 1 (PLP1) mutations in Chinese patients with Pelizaeus-Merzbacher disease (PMD) and confirmation of the biological impacts of the identified mutations are the aims of this study. METHODS An analysis of clinical materials and a follow-up study were conducted for the patients with PMD. Sequencing and immunofluorescence were applied for molecular analysis of the causative gene PLP1. RESULTS We identified PLP1 mutations in seven male patients with PMD. Three novel missense mutations (c.353C>G, p.T118R; c.623G>T, p.G208V; c.709T>G, p.F237V) and three reported missense mutations (c.467C>T, p.T156I; c.517C>T, p.P173S; c.646C>T, p.P216S) of PLP1 were identified from seven Chinese PMD patients. The three mutations (F237V in patient 2, P216S in patient 5 and T156I in patient 6) were de novo. Mutant proteins were trapped in the lumen of endoplasmic reticulum. CONCLUSION We have identified six pathogenic mutations, enriching the specific spectrum of missense mutations in the patients with PMD. The six PLP1 mutations are probably pathogenic. By reviewing the known PLP1 mutations, we have preliminarily revealed the position of missense mutation may be associated with the severity of PMD.
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Affiliation(s)
- Han Xie
- Department of Pediatrics, Peking University First Hospital, 100034 Beijing, China
| | - Hongchun Feng
- Department of Pediatrics, Peking University First Hospital, 100034 Beijing, China; Department of Neurology, Xi'an North Hospital, 710043 Xi'an, Shaanxi, China
| | - Jinhua Ji
- Department of Pediatrics, Peking University First Hospital, 100034 Beijing, China; Department of Neurology, Shanxi Medical University First Hospital, 030001 Taiyuan, Shanxi, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, 100034 Beijing, China
| | - Liping Kou
- Department of Pediatrics, Peking University First Hospital, 100034 Beijing, China; Department of Neurology, Shanxi Medical University First Hospital, 030001 Taiyuan, Shanxi, China
| | - Dongxiao Li
- Department of Pediatrics, Peking University First Hospital, 100034 Beijing, China
| | - Haoran Ji
- Department of Pediatrics, Peking University First Hospital, 100034 Beijing, China
| | - Xiru Wu
- Department of Pediatrics, Peking University First Hospital, 100034 Beijing, China
| | - Zhengping Niu
- Department of Neurology, Shanxi Medical University First Hospital, 030001 Taiyuan, Shanxi, China
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, 100034 Beijing, China.
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, 100034 Beijing, China.
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18
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Kevelam SH, Taube JR, van Spaendonk RML, Bertini E, Sperle K, Tarnopolsky M, Tonduti D, Valente EM, Travaglini L, Sistermans EA, Bernard G, Catsman-Berrevoets CE, van Karnebeek CDM, Østergaard JR, Friederich RL, Fawzi Elsaid M, Schieving JH, Tarailo-Graovac M, Orcesi S, Steenweg ME, van Berkel CGM, Waisfisz Q, Abbink TEM, van der Knaap MS, Hobson GM, Wolf NI. Altered PLP1 splicing causes hypomyelination of early myelinating structures. Ann Clin Transl Neurol 2015; 2:648-61. [PMID: 26125040 PMCID: PMC4479525 DOI: 10.1002/acn3.203] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/03/2015] [Accepted: 03/12/2015] [Indexed: 12/19/2022] Open
Abstract
Objective The objective of this study was to investigate the genetic etiology of the X-linked disorder “Hypomyelination of Early Myelinating Structures” (HEMS). Methods We included 16 patients from 10 families diagnosed with HEMS by brain MRI criteria. Exome sequencing was used to search for causal mutations. In silico analysis of effects of the mutations on splicing and RNA folding was performed. In vitro gene splicing was examined in RNA from patients’ fibroblasts and an immortalized immature oligodendrocyte cell line after transfection with mutant minigene splicing constructs. Results All patients had unusual hemizygous mutations of PLP1 located in exon 3B (one deletion, one missense and two silent), which is spliced out in isoform DM20, or in intron 3 (five mutations). The deletion led to truncation of PLP1, but not DM20. Four mutations were predicted to affect PLP1/DM20 alternative splicing by creating exonic splicing silencer motifs or new splice donor sites or by affecting the local RNA structure of the PLP1 splice donor site. Four deep intronic mutations were predicted to destabilize a long-distance interaction structure in the secondary PLP1 RNA fragment involved in regulating PLP1/DM20 alternative splicing. Splicing studies in fibroblasts and transfected cells confirmed a decreased PLP1/DM20 ratio. Interpretation Brain structures that normally myelinate early are poorly myelinated in HEMS, while they are the best myelinated structures in Pelizaeus–Merzbacher disease, also caused by PLP1 alterations. Our data extend the phenotypic spectrum of PLP1-related disorders indicating that normal PLP1/DM20 alternative splicing is essential for early myelination and support the need to include intron 3 in diagnostic sequencing.
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Affiliation(s)
- Sietske H Kevelam
- Department of Child Neurology, VU University Medical Center Amsterdam, The Netherlands ; Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - Jennifer R Taube
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children Wilmington, Delaware
| | | | - Enrico Bertini
- Unit for Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Bambino Gesu' Children's Research Hospital, IRCCS Rome, Italy
| | - Karen Sperle
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children Wilmington, Delaware
| | - Mark Tarnopolsky
- Department of Pediatrics, McMaster Children's Hospital Hamilton, Ontario, Canada
| | - Davide Tonduti
- Child Neuropsychiatry Unit, Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy
| | - Enza Maria Valente
- Department of Medicine and Surgery, University of Salerno Salerno, Italy ; CSS-Mendel Institute, IRCCS Casa Sollievo della Sofferenza San Giovanni Rotondo, Italy
| | - Lorena Travaglini
- Unit for Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Bambino Gesu' Children's Research Hospital, IRCCS Rome, Italy
| | - Erik A Sistermans
- Department of Clinical Genetics, VU University Medical Center Amsterdam, The Netherlands
| | - Geneviève Bernard
- Division of Pediatric Neurology, Departments of Pediatrics, Neurology and Neurosurgery, Montreal Children's Hospital, McGill University Health Center Montreal, Quebec, Canada
| | - Coriene E Catsman-Berrevoets
- Department of Pediatric Neurology, Erasmus University Hospital - Sophia Children's Hospital Rotterdam, The Netherlands
| | - Clara D M van Karnebeek
- Division of Biochemical Diseases, Department of Pediatrics, BC Children's Hospital, Centre for Molecular Medicine and Therapeutics, University of British Columbia Vancouver, Canada
| | - John R Østergaard
- Centre for Rare diseases, Department of Paediatrics, Aarhus University Hospital Aarhus, Denmark
| | - Richard L Friederich
- Department of Child Neurology, Kaiser Permanente Pediatric Specialties Roseville, California
| | | | - Jolanda H Schieving
- Department of Child Neurology, Radboud University Medical Center Nijmegen, The Netherlands
| | - Maja Tarailo-Graovac
- Department of Medical Genetics, University of British Colombia Vancouver, Canada
| | - Simona Orcesi
- Child Neurology and Psychiatry Unit, C. Mondino National Neurological Institute Pavia, Italy
| | - Marjan E Steenweg
- Department of Child Neurology, VU University Medical Center Amsterdam, The Netherlands ; Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - Carola G M van Berkel
- Department of Child Neurology, VU University Medical Center Amsterdam, The Netherlands
| | - Quinten Waisfisz
- Department of Clinical Genetics, VU University Medical Center Amsterdam, The Netherlands
| | - Truus E M Abbink
- Department of Child Neurology, VU University Medical Center Amsterdam, The Netherlands ; Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - Marjo S van der Knaap
- Department of Child Neurology, VU University Medical Center Amsterdam, The Netherlands ; Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands ; Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, The Netherlands
| | - Grace M Hobson
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children Wilmington, Delaware ; Department of Biological Sciences, University of Delaware Newark, Delaware ; Department of Pediatrics, Jefferson Medical College, Thomas Jefferson University Philadelphia, Pennsylvania
| | - Nicole I Wolf
- Department of Child Neurology, VU University Medical Center Amsterdam, The Netherlands ; Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
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A novel PLP1 frameshift mutation causing a milder form of Pelizaeus-Merzbacher disease. Brain Dev 2015; 37:455-8. [PMID: 25043250 DOI: 10.1016/j.braindev.2014.06.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/21/2014] [Accepted: 06/25/2014] [Indexed: 01/19/2023]
Abstract
BACKGROUND Pelizaeus-Merzbacher disease (PMD), a hypomyelinating leukodystrophy, and the related but less severe allelic spastic paraplegia 2 (SPG2) are caused by mutations in the proteolipid protein 1 (PLP1) gene. Magnetic resonance imaging (MRI) is pivotal for diagnosing these disorders. The severity of PMD/SPG2 varies, and for a milder form of PMD, there have been some reports of near-normal findings in T1-weighted images but abnormal findings in T2-weighted images. PATIENT We report the case of a 5-year-old boy diagnosed with a milder form of PMD caused by a novel PLP1 mutation in exon 3: c.300delC (p.I100IfsX13). He had delayed development from several months of age and was able to walk with support at 19 months in spite of the spasticity in his lower extremities. Hypomyelination was noted at 12 months by brain MRI. Motor nerve conduction studies showed decreased velocities with reduced amplitudes. Follow-up MRI at 1-year intervals from 18 months until 55 months of age showed gradual myelination progress. DISCUSSION The single nucleotide deletion identified in this patient can cause a frameshift and premature termination of PLP1. Via the nonsense-mediated mRNA decay mechanism of this mutation will result in loss-of-function, leading to a milder form of PMD. The present case is compatible with previously reported cases of milder form of PMD. We incidentally identified progressive myelination in this patient by T1-weighted images obtained by serial MRI. This finding adds to our understanding of the pathological stages of a milder form of PMD.
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Rodriguez E, Sakowski L, Hobson GM, Armani MH, Kreiger PA, Zhu Y, Waldman SA, Shaffer TH. Plp1 gene duplication inhibits airway responsiveness and induces lung inflammation. Pulm Pharmacol Ther 2014; 30:22-31. [PMID: 25445931 DOI: 10.1016/j.pupt.2014.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/26/2014] [Accepted: 10/25/2014] [Indexed: 11/25/2022]
Abstract
Mice with Plp1 gene duplication model the most common form of Pelizaeus-Merzbacher disease (PMD), a CNS disease in which patients may suffer respiratory complications. We hypothesized that affected mice would lack airway responsiveness compared to wild-type and carrier mice during methacholine challenge. Wild-type (n = 10), carrier female (n = 6) and affected male (n = 8) mice were anesthetized-paralyzed, tracheostomized and ventilated. Respiratory mechanics were recorded at baseline and during escalating doses of nebulized methacholine followed by albuterol. Lung resistance (RL) was the primary endpoint. Lung tissues were assayed for inflammatory and histological differences. At baseline, phase angles were higher in carrier and affected mice than wild-type. Dose-response RL curves in affected and carrier mice indicated a lack of methacholine response. Albuterol reduced RL in wild-type and carrier, but not affected mice. Affected mice exhibited lower interleukin (IL)-6 tissue levels and alveolar inflammatory infiltrates. Affected and carrier mice, compared to wild-type, lacked airway reactivity during methacholine challenge, but only affected mice exhibited decreased lung tissue levels of IL-6 and inflammation.
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Affiliation(s)
- Elena Rodriguez
- Alfred I. duPont Hospital for Children, Nemours Lung Center, Wilmington, DE 19803, USA; Alfred I. duPont Hospital for Children, Nemours Biomedical Research, Wilmington, DE 19803, USA; Thomas Jefferson University, Division of Clinical Pharmacology, Dept. of Pharmacology and Experimental Therapeutics, Philadelphia, PA 19107, USA.
| | - Lauren Sakowski
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Wilmington, DE 19803, USA; University of Delaware, Department of Biological Sciences, Newark, DE 19716, USA
| | - Grace M Hobson
- Alfred I. duPont Hospital for Children, Nemours Biomedical Research, Wilmington, DE 19803, USA; Center for Applied Clinical Genomics, Nemours Biomedical Research, Wilmington, DE 19803, USA; University of Delaware, Department of Biological Sciences, Newark, DE 19716, USA; Thomas Jefferson University, Department of Pediatrics, Philadelphia, PA 19107, USA
| | - Milena Hirata Armani
- Alfred I. duPont Hospital for Children, Nemours Lung Center, Wilmington, DE 19803, USA
| | - Portia A Kreiger
- Nemours Alfred I. duPont Hospital for Children, Department of Pathology, Wilmington, DE 19803, USA
| | - Yan Zhu
- Alfred I. duPont Hospital for Children, Nemours Lung Center, Wilmington, DE 19803, USA; Alfred I. duPont Hospital for Children, Nemours Biomedical Research, Wilmington, DE 19803, USA
| | - Scott A Waldman
- Thomas Jefferson University, Division of Clinical Pharmacology, Dept. of Pharmacology and Experimental Therapeutics, Philadelphia, PA 19107, USA
| | - Thomas H Shaffer
- Alfred I. duPont Hospital for Children, Nemours Lung Center, Wilmington, DE 19803, USA; Alfred I. duPont Hospital for Children, Nemours Biomedical Research, Wilmington, DE 19803, USA
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Laššuthová P, Žaliová M, Inoue K, Haberlová J, Sixtová K, Sakmaryová I, Paděrová K, Mazanec R, Zámečník J, Šišková D, Garbern J, Seeman P. Three new PLP1 splicing mutations demonstrate pathogenic and phenotypic diversity of Pelizaeus-Merzbacher disease. J Child Neurol 2014; 29:924-31. [PMID: 23771846 DOI: 10.1177/0883073813492387] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/09/2013] [Indexed: 11/16/2022]
Abstract
Pelizaeus-Merzbacher disease is a severe X-linked disorder of central myelination caused by mutations affecting the proteolipid protein gene. We describe 3 new PLP1 splicing mutations, their effect on splicing and associated phenotypes. Mutation c.453_453+6del7insA affects the exon 3B donor splice site and disrupts the PLP1-transcript without affecting the DM20, was found in a patient with severe Pelizaeus-Merzbacher disease and in his female cousin with early-onset spastic paraparesis. Mutation c.191+1G>A causes exon 2 skipping with a frame shift, is expected to result in a functionally null allele, and was found in a patient with mild Pelizaeus-Merzbacher disease and in his aunt with late-onset spastic paraparesis. Mutation c.696+1G>A utilizes a cryptic splice site in exon 5, causes partial exon 5 skipping and in-frame deletion, and was found in an isolated patient with a severe classical Pelizaeus-Merzbacher. PLP1 splice-site mutations express a variety of disease phenotypes mediated by different molecular pathogenic mechanisms.
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Affiliation(s)
- Petra Laššuthová
- Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic
| | - Markéta Žaliová
- Department of Paediatric Haematology and Oncology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic
| | - Ken Inoue
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Jana Haberlová
- Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic
| | - Klára Sixtová
- Department of Paediatric Neurology, Thomayer's Hospital, Prague, Czech Republic
| | - Iva Sakmaryová
- Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic
| | - Kateřina Paděrová
- Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic
| | - Radim Mazanec
- Department of Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic
| | - Josef Zámečník
- Department of Pathology and Molecular Medicine, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic
| | - Dana Šišková
- Department of Paediatric Neurology, Thomayer's Hospital, Prague, Czech Republic
| | - Jim Garbern
- Department of Neurology and Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA
| | - Pavel Seeman
- Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic
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22
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Taube JR, Sperle K, Banser L, Seeman P, Cavan BCV, Garbern JY, Hobson GM. PMD patient mutations reveal a long-distance intronic interaction that regulates PLP1/DM20 alternative splicing. Hum Mol Genet 2014; 23:5464-78. [PMID: 24890387 DOI: 10.1093/hmg/ddu271] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Alternative splicing of the proteolipid protein 1 gene (PLP1) produces two forms, PLP1 and DM20, due to alternative use of 5' splice sites with the same acceptor site in intron 3. The PLP1 form predominates in central nervous system RNA. Mutations that reduce the ratio of PLP1 to DM20, whether mutant or normal protein is formed, result in the X-linked leukodystrophy Pelizaeus-Merzbacher disease (PMD). We investigated the ability of sequences throughout PLP1 intron 3 to regulate alternative splicing using a splicing minigene construct transfected into the oligodendrocyte cell line, Oli-neu. Our data reveal that the alternative splice of PLP1 is regulated by a long-distance interaction between two highly conserved elements that are separated by 581 bases within the 1071-base intron 3. Further, our data suggest that a base-pairing secondary structure forms between these two elements, and we demonstrate that mutations of either element designed to destabilize the secondary structure decreased the PLP1/DM20 ratio, while swap mutations designed to restore the structure brought the PLP1/DM20 ratio to near normal levels. Sequence analysis of intron 3 in families with clinical symptoms of PMD who did not have coding-region mutations revealed mutations that segregated with disease in three families. We showed that these patient mutations, which potentially destabilize the secondary structure, also reduced the PLP1/DM20 ratio. This is the first report of patient mutations causing disease by disruption of a long-distance intronic interaction controlling alternative splicing. This finding has important implications for molecular diagnostics of PMD.
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Affiliation(s)
- Jennifer R Taube
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
| | - Karen Sperle
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
| | - Linda Banser
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
| | - Pavel Seeman
- Department of Child Neurology, DNA Laboratory, 2nd School of Medicine, Charles University and University Hospital Motol, 150 06 Prague 5, Czech Republic
| | | | - James Y Garbern
- Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642, 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 and Department of Pediatrics, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
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23
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Matsufuji M, Osaka H, Gotoh L, Shimbo H, Takashima S, Inoue K. Partial PLP1 deletion causing X-linked dominant spastic paraplegia type 2. Pediatr Neurol 2013; 49:477-81. [PMID: 24095575 DOI: 10.1016/j.pediatrneurol.2013.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 07/01/2013] [Accepted: 07/13/2013] [Indexed: 12/23/2022]
Abstract
BACKGROUND Proteolipid protein 1 gene (PLP1) mutations result in a continuum of neurological findings characterized by X-linked hypomyelinating leukodystrophies of the central nervous system, from mild spastic paraplegia type 2 to severe Pelizaeus-Merzbacher disease. PATIENTS We report spastic paraplegia type 2 in three individuals in one family. A 29-year-old man developed progressive spastic quadriplegia from early childhood with dysarthria, ataxia, dysphagia, and intellectual delay, but he displayed no nystagmus. His mother developed adult-onset mild spastic diplegia with dementia developing in later life, whereas his sister exhibited spastic diplegia from childhood, complicated by motor developmental delay and dysphagia. All three individuals had initially mild but progressive neurological phenotypes, no nystagmus, normal brainstem auditory-evoked potentials, and demyelinating peripheral neuropathy, but with varying clinical severity. RESULTS A 33-kb deletion encompassing exon 2 to 7 of PLP1 was identified in all three patients. Cloning of the junction fragment of the genomic recombination revealed a short palindromic sequence at the distal breakpoint, potentially facilitating a double-strand deoxyribonucleic acid break, followed by nonhomologous end joining. X-inactivation study and sequencing of the undeleted PLP1 alleles failed to explain the differences in severity between the two female patients. CONCLUSIONS PLP1 partial deletion is a rare cause of spastic paraplegia type 2 and exhibits X-linked dominant inheritance with variable expressivity.
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Affiliation(s)
- Mayumi Matsufuji
- Yanagawa Institute for Developmental Disabilities, Fukuoka, Japan.
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24
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Noetzli L, Sanz PG, Brodsky GL, Hinckley JD, Giugni JC, Giannaula RJ, Gonzalez-Alegre P, Di Paola J. A novel mutation in PLP1 causes severe hereditary spastic paraplegia type 2. Gene 2013; 533:447-50. [PMID: 24103481 DOI: 10.1016/j.gene.2013.09.076] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/18/2013] [Accepted: 09/22/2013] [Indexed: 01/10/2023]
Abstract
Hereditary spastic paraplegia (HSP) type 2 is a proteolipid protein (PLP1)-related genetic disorder that is characterized by dysmyelination of the central nervous system resulting primarily in limb spasticity, cognitive impairment, nystagmus, and spastic urinary bladder of varying severity. Previously reported PLP1 mutations include duplications, point mutations, or whole gene deletions with a continuum of phenotypes ranging from severe Pelizaeus-Merzbacher disease (PMD) to uncomplicated HSP type 2. In this manuscript we report a novel PLP1 missense mutation (c.88G>C) in a family from Argentina. This mutation is in a highly conserved transmembrane domain of PLP1 and the mutant protein was found to be retained in the endoplasmic reticulum when expressed in vitro. Due to the variable expressivity that characterizes these disorders our report contributes to the knowledge of genotype-phenotype correlations of PLP1-related disorders.
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Affiliation(s)
- Leila Noetzli
- Department of Pediatrics, University of Colorado Denver School of Medicine, USA; Human Medical Genetics and Genomics Program, University of Colorado Denver School of Medicine, USA
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25
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Regis S, Corsolini F, Grossi S, Tappino B, Cooper DN, Filocamo M. Restoration of the normal splicing pattern of the PLP1 gene by means of an antisense oligonucleotide directed against an exonic mutation. PLoS One 2013; 8:e73633. [PMID: 24019930 PMCID: PMC3760819 DOI: 10.1371/journal.pone.0073633] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 07/30/2013] [Indexed: 11/19/2022] Open
Abstract
An exonic missense mutation, c.436C>G, in the PLP1 gene of a patient affected by the hypomyelinating leukodystrophy, Pelizaeus–Merzbacher disease, has previously been found to be responsible for the alteration of the canonical alternative splicing profile of the PLP1 gene leading to the loss of the longer PLP isoform. Here we show that the presence of the c.436C>G mutation served to introduce regulatory motifs that appear to be responsible for the perturbed splicing pattern that led to loss of the major PLP transcript. With the aim of disrupting the interaction between the PLP1 splicing regulatory motifs and their cognate splicing factors, we designed an antisense oligonucleotide-based in vitro correction protocol that successfully restored PLP transcript production in oligodendrocyte precursor cells.
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Affiliation(s)
- Stefano Regis
- Centro di Diagnostica Genetica e Biochimica delle Malattie Metaboliche, Istituto G. Gaslini, Genova, Italy
| | - Fabio Corsolini
- Centro di Diagnostica Genetica e Biochimica delle Malattie Metaboliche, Istituto G. Gaslini, Genova, Italy
| | - Serena Grossi
- Centro di Diagnostica Genetica e Biochimica delle Malattie Metaboliche, Istituto G. Gaslini, Genova, Italy
| | - Barbara Tappino
- Centro di Diagnostica Genetica e Biochimica delle Malattie Metaboliche, Istituto G. Gaslini, Genova, Italy
| | - David N. Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Mirella Filocamo
- Centro di Diagnostica Genetica e Biochimica delle Malattie Metaboliche, Istituto G. Gaslini, Genova, Italy
- * E-mail:
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26
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Biancheri R, Grossi S, Regis S, Rossi A, Corsolini F, Rossi DP, Cavalli P, Severino M, Filocamo M. Further genotype–phenotype correlation emerging from two families with
PLP1
exon 4 skipping. Clin Genet 2013; 85:267-72. [DOI: 10.1111/cge.12154] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/26/2013] [Accepted: 03/26/2013] [Indexed: 02/03/2023]
Affiliation(s)
| | - Serena Grossi
- UOSD Centro di diagnostica genetica e biochimica delle malattie metaboliche
| | - Stefano Regis
- UOSD Centro di diagnostica genetica e biochimica delle malattie metaboliche
| | - Andrea Rossi
- Pediatric Neuroradiology UnitIstituto G. Gaslini Genova Italy
| | - Fabio Corsolini
- UOSD Centro di diagnostica genetica e biochimica delle malattie metaboliche
| | | | - Pietro Cavalli
- Servizio di GeneticaIstituti Ospedalieri di Cremona Cremona Italy
| | | | - Mirella Filocamo
- UOSD Centro di diagnostica genetica e biochimica delle malattie metaboliche
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27
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Martínez-Montero P, Muñoz-Calero M, Vallespín E, Campistol J, Martorell L, Ruiz-Falcó MJ, Santana A, Pons R, Dinopoulos A, Sierra C, Nevado J, Molano J. PLP1gene analysis in 88 patients with leukodystrophy. Clin Genet 2013; 84:566-71. [DOI: 10.1111/cge.12103] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 01/16/2013] [Accepted: 01/16/2013] [Indexed: 01/11/2023]
Affiliation(s)
| | - M Muñoz-Calero
- INGEMM, IdIPAZ, CIBERER; Hospital Universitario La Paz; Madrid Spain
| | - E Vallespín
- INGEMM, IdIPAZ, CIBERER; Hospital Universitario La Paz; Madrid Spain
| | | | - L Martorell
- Molecular Genetics Unit; Hospital Sant Joan de Deu; Barcelona Spain
| | - MJ Ruiz-Falcó
- Neurology Service; Hospital Infantil Universitario Niño Jesús; Madrid Spain
| | - A Santana
- Genetics Unit; C. U. Insular Materno Infantil; Las Palmas de Gran Canaria Spain
| | - R Pons
- Paediatric Neurology Service; University of Athens; "Attiko" University Hospital Athens; Athens Greece
| | - A Dinopoulos
- Paediatric Neurology Service; University of Athens; "Attiko" University Hospital Athens; Athens Greece
| | - C Sierra
- Paediatric Neurology Service; Complejo Hospitalario de Jaén; Jaén Spain
| | - J Nevado
- INGEMM, IdIPAZ, CIBERER; Hospital Universitario La Paz; Madrid Spain
| | - J Molano
- INGEMM, IdIPAZ, CIBERER; Hospital Universitario La Paz; Madrid Spain
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28
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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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29
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Kitsiou-Tzeli S, Konstantinidou A, Sofocleous C, Kosma K, Syrmou A, Giannikou K, Sifakis S, Makrythanasis P, Tzetis M. Familial Pelizaeus-Merzbacher disease caused by a 320.6-kb Xq22.2 duplication and the pathological findings of a male fetus. ACTA ACUST UNITED AC 2012; 94:494-8. [PMID: 22511562 DOI: 10.1002/bdra.23015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 03/09/2012] [Accepted: 03/10/2012] [Indexed: 01/04/2023]
Abstract
BACKGROUND Pelizaeus-Merzbacher disease (PMD) is a recessive, X-linked leukoencephalopathy attributed to impaired myelination during central nervous system development, caused by defects in the proteolipid protein 1 (PLP1) gene. PMD presents clinical variability, ranging from the severe connatal form to the classic form. CASES We report the clinical and molecular findings of two affected males, three carrier females, and an aborted male fetus with familial PMD. The two male probands presented with severe PMD phenotype and intellectual disability. High-resolution oligonucleotide-based array comparative genomic hybridization (aCGH) identified an Xq22.2 duplication of 320.6 kb (102641391-102961998, hg18), including the PLP1 gene and surrounding chromosomal region. Postmortem examination of the aborted fetus at 25 weeks' gestation showed focal subcortical white matter degeneration, focal gliosis, and cerebellar atrophy. CONCLUSIONS Genotype-phenotype correlation is provided. In the connatal form of PMD, leukodystrophy and cerebellar atrophy can occur antenatally and be established at 25 weeks' gestation. The observation of degenerative brain lesions occurring before the onset of subcortical myelination suggests that the PLP1 gene has a more complex role in human brain development, exceeding its structural function in myelin formation.
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30
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An autopsy case of adult-onset hereditary spastic paraplegia type 2 with a novel mutation in exon 7 of the proteolipid protein 1 gene. Acta Neuropathol 2011; 122:775-81. [PMID: 22101368 DOI: 10.1007/s00401-011-0916-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 11/09/2011] [Accepted: 11/12/2011] [Indexed: 01/15/2023]
Abstract
We report an autopsy case of rare adult-onset spastic paraplegia type 2 (SPG2) with a novel missense mutation in exon 7 of the proteolipid protein 1 gene (PLP1). The patient was a 67-year-old man whose elder brother had died of a similar disease with onset in his 40s. Thirty-three years before death at the age of 35, he noticed difficulty in walking. He gradually became abasic over a period of 6 years. He also developed progressive dementia and eventually became bed-ridden by 28 years after onset. At autopsy, gross inspection revealed diffuse, moderate atrophy of the cerebrum with a dilated ventricular system and softening of the white matter throughout the central nervous system (CNS). Histopathologically, the CNS showed widespread myelin pallor in the white matter. By contrast, the gray matter and peripheral nerves were well preserved. Some white matter tracts, including the corticospinal tracts, were preferentially affected, and severe axonal degeneration was observed in these tracts. Genetic analysis revealed a novel mutation, p.Tyr263Cys, in exon 7 of PLP1. This case represents an adult-onset SPG2 patient with one of the oldest ages of onset reported to date. The late onset and long clinical course suggest that this novel mutation does not affect the maturation of oligodendrocytes, but is related to insufficient maintenance of myelin.
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