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Dangreau L, Hosen MJ, De Zaeytijd J, Leroy BP, Coucke PJ, Vanakker OM. Gonadal Mosaicism as a Rare Inheritance Pattern in Recessive Genodermatoses: Report of Two Cases with Pseudoxanthoma Elasticum and Literature Review. Curr Issues Mol Biol 2024; 46:9998-10007. [PMID: 39329949 DOI: 10.3390/cimb46090597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2024] [Revised: 08/30/2024] [Accepted: 09/07/2024] [Indexed: 09/28/2024] Open
Abstract
Germline mosaicism in autosomal recessive disorders is considered a rare disease mechanism with important consequences for diagnosis and patient counseling. In this report, we present two families with PXE in which paternal germline mosaicism for an ABCC6 whole-gene deletion was observed. The first family further illustrates the clinical challenges in PXE, with a typical PXE retinopathy in an apparently heterozygous carrier parent. A systematic review of the literature on gonadal mosaicism in autosomal recessive genodermatoses revealed 16 additional patients. As in most reported families, segregation analysis data are not mentioned, and this may still be an underrepresentation. Though rare, the possibility of germline mosaicism emphasizes the need for variant verification in parents and sibs of a newly diagnosed proband, as it has significant implications for genetic counseling and management.
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Affiliation(s)
- Lisa Dangreau
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, 9000 Ghent, Belgium
| | - Mohammad J Hosen
- Department of Genetic Engineering and Biotechnology, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
| | - Julie De Zaeytijd
- Department of Ophthalmology, Ghent University Hospital, 9000 Ghent, Belgium
| | - Bart P Leroy
- Department of Ophthalmology, Ghent University Hospital, 9000 Ghent, Belgium
- Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Paul J Coucke
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, 9000 Ghent, Belgium
| | - Olivier M Vanakker
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, 9000 Ghent, Belgium
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Vahidnezhad H, Youssefian L, Harvey N, Tavasoli AR, Saeidian AH, Sotoudeh S, Varghaei A, Mahmoudi H, Mansouri P, Mozafari N, Zargari O, Zeinali S, Uitto J. Mutation update: The spectra of PLEC sequence variants and related plectinopathies. Hum Mutat 2022; 43:1706-1731. [PMID: 35815343 PMCID: PMC9771971 DOI: 10.1002/humu.24434] [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: 05/02/2022] [Revised: 06/23/2022] [Accepted: 07/07/2022] [Indexed: 01/24/2023]
Abstract
Plectin, encoded by PLEC, is a cytoskeletal linker of intermediate filaments expressed in many cell types. Plectin consists of three main domains that determine its functionality: the N-terminal domain, the Rod domain, and the C-terminal domain. Molecular defects of PLEC correlating with the functional aspects lead to a group of rare heritable disorders, plectinopathies. These multisystem disorders include an autosomal dominant form of epidermolysis bullosa simplex (EBS-Ogna), limb-girdle muscular dystrophy (LGMD), aplasia cutis congenita (ACC), and an autosomal recessive form of EBS, which may associate with muscular dystrophy (EBS-MD), pyloric atresia (EBS-PA), and/or congenital myasthenic syndrome (EBS-MyS). In this study, genotyping of over 600 Iranian patients with epidermolysis bullosa by next-generation sequencing identified 15 patients with disease-causing PLEC variants. This mutation update analyzes the clinical spectrum of PLEC in our cohort and in the literature and demonstrates the relationship between PLEC genotype and phenotypic manifestations. This study has integrated our seven novel PLEC variants and phenotypic findings with previously published data totaling 116 variants to provide the most complete overview of pathogenic PLEC variants and related disorders.
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Affiliation(s)
- Hassan Vahidnezhad
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
| | - Leila Youssefian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
| | - Nailah Harvey
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
- Philadelphia College of Osteopathic Medicine, Philadelphia, Pennsylvania, USA
| | - Ali Reza Tavasoli
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
- Pediatric Neurology Division, Children’s Medical Center, Pediatric Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Hossein Saeidian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
| | - Soheila Sotoudeh
- Department of Dermatology, Children’s Medical Center, Pediatric Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Aida Varghaei
- Department of Dermatology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Hamidreza Mahmoudi
- Department of Dermatology, Razi Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Parvin Mansouri
- Skin and Stem Cell Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Nikoo Mozafari
- Skin Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | | | - Jouni Uitto
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA
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Zrelski MM, Kustermann M, Winter L. Muscle-Related Plectinopathies. Cells 2021; 10:2480. [PMID: 34572129 PMCID: PMC8466646 DOI: 10.3390/cells10092480] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 12/23/2022] Open
Abstract
Plectin is a giant cytoskeletal crosslinker and intermediate filament stabilizing protein. Mutations in the human plectin gene (PLEC) cause several rare diseases that are grouped under the term plectinopathies. The most common disorder is autosomal recessive disease epidermolysis bullosa simplex with muscular dystrophy (EBS-MD), which is characterized by skin blistering and progressive muscle weakness. Besides EBS-MD, PLEC mutations lead to EBS with nail dystrophy, EBS-MD with a myasthenic syndrome, EBS with pyloric atresia, limb-girdle muscular dystrophy type R17, or EBS-Ogna. In this review, we focus on the clinical and pathological manifestations caused by PLEC mutations on skeletal and cardiac muscle. Skeletal muscle biopsies from EBS-MD patients and plectin-deficient mice revealed severe dystrophic features with variation in fiber size, degenerative myofibrillar changes, mitochondrial alterations, and pathological desmin-positive protein aggregates. Ultrastructurally, PLEC mutations lead to a disorganization of myofibrils and sarcomeres, Z- and I-band alterations, autophagic vacuoles and cytoplasmic bodies, and misplaced and degenerating mitochondria. We also summarize a variety of genetically manipulated mouse and cell models, which are either plectin-deficient or that specifically lack a skeletal muscle-expressed plectin isoform. These models are powerful tools to study functional and molecular consequences of PLEC defects and their downstream effects on the skeletal muscle organization.
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Affiliation(s)
| | | | - Lilli Winter
- Center for Anatomy and Cell Biology, Neuromuscular Research Department, Medical University of Vienna, 1090 Vienna, Austria; (M.M.Z.); (M.K.)
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Yang X, Li D, Tu C, He W, Meng L, Tan YQ, Lu G, Du J, Zhang Q. Novel variants of the PCCB gene in Chinese patients with propionic acidemia. Clin Chim Acta 2021; 519:18-25. [PMID: 33798502 DOI: 10.1016/j.cca.2021.03.019] [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: 02/22/2021] [Accepted: 03/20/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND AND AIMS Propionic acidemia (PA) is an autosomal recessive metabolic disorder caused by a deficiency of propionyl-CoA carboxylase and mutations in the PCCA and PCCB genes. In this study, we investigated the clinical characteristics of individuals with PA and conducted genetic analyses to provide new genetic evidence for the diagnosis of PA. MATERIALS AND METHODS We conducted whole-exome sequencing and Sanger sequencing in four individuals with PA from three unrelated Chinese families. We also performed a structural analysis of the PCCB protein variants. Couples from the three families included in our study underwent in vitro fertilization with preimplantation genetic testing. RESULTS We found five variants of PCCB. These biallelic variants were inherited from heterozygous parental carriers and were located in the functional domain, absent in human population genome datasets, and predicted to be deleterious. These findings indicate that the variants might be responsible for the clinical features observed in these particular patients with PA. Through successful embryo transfer and implantation, one of the couples fortunately gave birth to a healthy child. CONCLUSION Overall, our study can expand the mutation spectrum of PCCB and provide useful information for the prenatal diagnosis of PA and genetic counseling for affected individuals.
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Affiliation(s)
- Xiaoxuan Yang
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Dongyan Li
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Chaofeng Tu
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China; Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Wenbing He
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China; Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Lanlan Meng
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Yue-Qiu Tan
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China; Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Guangxiu Lu
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Juan Du
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China; Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.
| | - Qianjun Zhang
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China; Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.
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Yuan SM, Zhang YN, Du J, Li W, Tu CF, Meng LL, Lin G, Lu GX, Tan YQ. Phenotypic and molecular characteristics of androgen insensitivity syndrome patients. Asian J Androl 2019; 20:473-478. [PMID: 29785970 PMCID: PMC6116692 DOI: 10.4103/aja.aja_17_18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Androgen insensitivity syndrome (AIS), an X-linked recessive genetic disorder of sex development, is caused by mutations in the androgen receptor (AR) gene, and is characterized by partial or complete inability of specific tissues to respond to androgens in individuals with the 46, XY karyotype. This study aimed to investigate AR gene mutations and to characterize genotype–phenotype correlations. Ten patients from unrelated families, aged 2–31 years, were recruited in the study. Based on karyotype, altered hormone profile, and clinical manifestations, nine patients were preliminarily diagnosed with complete AIS and one with partial AIS. Genetic analysis of AR gene revealed the existence of 10 different mutations, of which five were novel (c.2112 C>G[p.S704R], c.2290T>A[p.Y764N], c.2626C>T[p.Q876X], c.933dupC[p.K313Qfs*28], and c.1067delC[p.A356Efs*123]); the other five were previously reported (c.1789G>A[p.A597T], c.2566C>T[p.R856C], c.2668G>A[p.V890M], c.2679C>T[p.P893L], and c.1605C>G[p.Y535X]). Regarding the distribution of these mutations, 60.0% were clustered in the ligand-binding domain of AR gene. Exons 1 and 8 of AR gene each accounted for 30.0% (3/10) of all mutations. Most of the truncation mutations were in exon 1 and missense mutations were mainly located in exons 4–8. Our study expands the spectrum of AR gene mutations and confirms the usefulness of AR gene sequencing to support a diagnosis of AIS and to enable prenatal or antenatal screening.
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Affiliation(s)
- Shi-Min Yuan
- Reproductive and Genetic Hospital of Citic-Xiangya, Changsha 410078, China
| | - Ya-Nan Zhang
- Maternal and Child Health Hospital of Hunan Province, Changsha 410078, China
| | - Juan Du
- Reproductive and Genetic Hospital of Citic-Xiangya, Changsha 410078, China.,Institute of Reproduction and Stem Cell Engineering, Central South University, Changsha 410078, China
| | - Wen Li
- Reproductive and Genetic Hospital of Citic-Xiangya, Changsha 410078, China.,Institute of Reproduction and Stem Cell Engineering, Central South University, Changsha 410078, China
| | - Chao-Feng Tu
- Institute of Reproduction and Stem Cell Engineering, Central South University, Changsha 410078, China
| | - Lan-Lan Meng
- Reproductive and Genetic Hospital of Citic-Xiangya, Changsha 410078, China
| | - Ge Lin
- Reproductive and Genetic Hospital of Citic-Xiangya, Changsha 410078, China.,Institute of Reproduction and Stem Cell Engineering, Central South University, Changsha 410078, China
| | - Guang-Xiu Lu
- Reproductive and Genetic Hospital of Citic-Xiangya, Changsha 410078, China.,Institute of Reproduction and Stem Cell Engineering, Central South University, Changsha 410078, China
| | - Yue-Qiu Tan
- Reproductive and Genetic Hospital of Citic-Xiangya, Changsha 410078, China.,Institute of Reproduction and Stem Cell Engineering, Central South University, Changsha 410078, China
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Zhong J, Chen G, Dang Y, Liao H, Zhang J, Lan D. Novel compound heterozygous PLEC mutations lead to early‑onset limb‑girdle muscular dystrophy 2Q. Mol Med Rep 2017; 15:2760-2764. [PMID: 28447722 DOI: 10.3892/mmr.2017.6309] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 01/12/2017] [Indexed: 11/05/2022] Open
Abstract
Limb-girdle muscular dystrophy 2Q (LGMD2Q) is a specific mutation in the plectin (PLEC1) gene at chromosome 8q24.3. In the present study, targeted sequencing using a muscle disease gene panel was performed in a patient with muscular dystrophy. The family members were confirmed by Sanger sequencing. The PolyPhen‑2, SIFT and MutationTaster tools were used to predicted the possible effect of the mutations. Immunocytochemistry was used to visualize and localize the plectin protein within the gastrocnemius. Novel compound heterozygous mutations c.5995C>T (p.Arg1999Trp) and c.9940T>A (p.Phe3314 Ile) in the PLEC gene were identified to be the genetic cause of LGMD2Q in this family. These variants were absent in 200 normal controls. Furthermore, defects in the plectin protein within the gastrocnemius were determined using immunocytochemistry. To the best of our knowledge, the present study provides the second report on plectin‑associated LGMD2Q without other symptoms, although the genotype identified was novel. The missense mutations in the proband were considered to be an explanation for the symptom. These findings extend current knowledge of the mutation spectrum of the PLEC gene associated with LGMD2Q.
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Affiliation(s)
- Jingzi Zhong
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Gang Chen
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Yiwu Dang
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Haixia Liao
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Jiapeng Zhang
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Dan Lan
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
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Kyrova J, Kopeckova L, Buckova H, Mrazova L, Vesely K, Hermanova M, Oslejskova H, Fajkusova L. Epidermolysis bullosa simplex with muscular dystrophy. Review of the literature and a case report. J Dermatol Case Rep 2016; 10:39-48. [PMID: 28400893 DOI: 10.3315/jdcr.2016.1231] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/06/2016] [Indexed: 11/11/2022]
Abstract
BACKGROUND Epidermolysis bullosa simplex associated with muscular dystrophy is a genetic skin disease caused by plectin deficiency. A case of a 19-year-old Czech patient affected with this disease and a review all previously published clinical cases are presented. MAIN OBSERVATIONS In our patient, skin signs of the disease developed after birth. Bilateral ptosis at the age of 8 years was considered as the first specific symptom of muscular dystrophy. Since then, severe scoliosis, urological and psychiatric complication have quickly developed. The signs of plectin deficiency were found by histopathological studies, electron microscopy and antigen mapping of the skin and muscular samples. Two autosomal recessive mutations in the plectin gene leading to premature termination codon were disclosed by mutation analysis. By review of all published clinical cases, 49 patients with this disease were found. 54 different mutations in the plectin gene were published, p.(Arg2319*) in exon 31 being the most frequently found. Median age of muscular dystrophy development was 9.5 years. Hoarseness and respiratory complications were the most often complications beside skin involvement. CONCLUSION Epidermolysis bullosa simplex with muscular dystrophy was diagnosed based on clinical, histopathological (skin and muscle biopsy) and mutation analysis of the plectin gene. Overview of the genetic and clinical characteristic of this disease could be presented by review of all previously published clinical cases.
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Affiliation(s)
- Jana Kyrova
- Department of Pediatric Dermatology, Pediatric Clinic, University Hospital Brno and Masaryk University Brno, Brno, Czech Republic; ; EB Centre Czech Republic, University Hospital Brno and Masaryk University Brno, Brno, Czech Republic
| | - Lenka Kopeckova
- Centre of Molecular Biology and Gene Therapy, University Hospital Brno and Masaryk University Brno, Brno, Czech Republic
| | - Hana Buckova
- Department of Pediatric Dermatology, Pediatric Clinic, University Hospital Brno and Masaryk University Brno, Brno, Czech Republic; ; EB Centre Czech Republic, University Hospital Brno and Masaryk University Brno, Brno, Czech Republic
| | - Lenka Mrazova
- Clinic of Pediatric Neurology, University Hospital and Masaryk University Brno, Brno, Czech Republic
| | - Karel Vesely
- 1st Department of Pathological Anatomy, St. Anne´s University Hospital Brno and Masaryk University Brno, Brno, Czech Republic
| | - Marketa Hermanova
- 1st Department of Pathological Anatomy, St. Anne´s University Hospital Brno and Masaryk University Brno, Brno, Czech Republic
| | - Hana Oslejskova
- Clinic of Pediatric Neurology, University Hospital and Masaryk University Brno, Brno, Czech Republic
| | - Lenka Fajkusova
- Centre of Molecular Biology and Gene Therapy, University Hospital Brno and Masaryk University Brno, Brno, Czech Republic
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Plectin-related skin diseases. J Dermatol Sci 2014; 77:139-45. [PMID: 25530118 DOI: 10.1016/j.jdermsci.2014.11.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 11/05/2014] [Accepted: 11/12/2014] [Indexed: 12/20/2022]
Abstract
Plectin has been characterized as a linker protein that is expressed in many cell types and is distinctive in various isoforms in the N-terminus and around the rod domain due to complicated alternative splicing of PLEC, the gene encoding plectin. Plectin deficiency causes autosomal recessive epidermolysis bullosa simplex (EBS) with involvement of the skin and other organs, such as muscle and gastrointestinal tract, depending on the expression pattern of the defective protein. In addition, a point mutation in the rod domain of plectin leads to autosomal dominant EBS, called as EBS-Ogna. Plectin can be targeted by circulating autoantibodies in subepidermal autoimmune blistering diseases. This review summarizes plectin-related skin diseases, from congenital to autoimmune disorders.
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Charlesworth A, Chiaverini C, Chevrant-Breton J, DelRio M, Diociaiuti A, Dupuis RP, El Hachem M, Le Fiblec B, Sankari-Ho AM, Valhquist A, Wierzbicka E, Lacour JP, Meneguzzi G. Epidermolysis bullosa simplex with PLEC mutations: new phenotypes and new mutations. Br J Dermatol 2013; 168:808-14. [PMID: 23289980 DOI: 10.1111/bjd.12202] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Genetic mutations in the plectin gene (PLEC) cause autosomal recessive forms of epidermolysis bullosa simplex (EBS) associated with either muscular dystrophy (EBS-MD) or pyloric atresia (EBS-PA). Phenotype-genotype analysis has suggested that EBS-MD is due mostly to genetic mutations affecting the central rod domain of plectin, and EBS-PA to mutations outside this domain. OBJECTIVES This study aimed to describe new phenotypes of patients with EBS-MD and EBS-PA, to identify novel PLEC mutations and to establish genotype-phenotype correlations. METHODS Seven patients with a suspicion of EBS linked to PLEC mutations were included. A standardized clinical questionnaire was sent to the physicians in charge of each patient. Immunofluorescence studies of skin biopsies followed by molecular analysis of PLEC were performed in all patients. RESULTS We report the first case of nonlethal EBS-PA improving with age, the first multisystemic involvement in a patient with lethal EBS-PA, and the first patients with EBS-MD with involvement of either the bladder or oesophagus. Eleven novel PLEC mutations are also reported. CONCLUSIONS Our results confirm that EBS-PA is linked to mutations in the distal exons 1-30 and 32 of PLEC. Long-term survival is possible, with skin improvement, but a delayed onset of MD is probable. While EBS-MD is linked to PLEC mutations in all exons, in most cases one of the mutations affects exon 31. The precocity of MD seems to be linked to the type and localization of the PLEC mutation(s), but no correlation with mucosal involvement has been found.
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Affiliation(s)
- A Charlesworth
- French Centre for Hereditary Epidermolysis Bullosa, Archet 2 Hospital, Nice, France
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Winter L, Wiche G. The many faces of plectin and plectinopathies: pathology and mechanisms. Acta Neuropathol 2013; 125:77-93. [PMID: 22864774 DOI: 10.1007/s00401-012-1026-0] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 07/12/2012] [Accepted: 07/23/2012] [Indexed: 12/20/2022]
Abstract
Plectin, a giant multifunctional cytolinker protein, plays a crucial role in stabilizing and orchestrating intermediate filament networks in cells. Mutations in the human plectin gene result in multiple diseases manifesting with muscular dystrophy, skin blistering, and signs of neuropathy. The most common disease caused by plectin deficiency is epidermolysis bullosa simplex (EBS)-MD, a rare autosomal-recessive skin blistering disorder with late-onset muscular dystrophy. EBS-MD patients and plectin-deficient mice display pathologic desmin-positive protein aggregates, degenerated myofibrils, and mitochondrial abnormalities, the hallmarks of myofibrillar myopathies. In addition to EBS-MD, plectin mutations have been shown to cause EBS-MD with a myasthenic syndrome, limb-girdle muscular dystrophy type 2Q, EBS with pyloric atresia, and EBS-Ogna. This review focuses on clinical and pathological manifestations of these plectinopathies. It addresses especially plectin's role in skeletal muscle, where a loss of muscle fiber integrity and profound changes of myofiber cytoarchitecture are observed in its absence. Furthermore, the highly complex genetic and molecular structure of plectin is discussed; a high number of differentially spliced exons give rise to a variety of different isoforms, which fulfill distinct functions in different cell types and tissues. Plectin's abilities to act as a dynamic organizer of intermediate filament networks and to interact with a multitude of different interaction partners are the basis for its function as a scaffolding platform for proteins involved in signaling. Finally, the article addresses a series of genetically manipulated mouse lines that were generated to serve as powerful models to study functional and molecular consequences of plectin gene defects.
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Affiliation(s)
- Lilli Winter
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9, 1030 Vienna, Austria
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11
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Celik C, Uysal H, Heper AO, Karaoglan B. Epidermolysis bullosa simplex associated with muscular dystrophy and cardiac involvement. J Clin Neuromuscul Dis 2012; 6:157-61. [PMID: 19078768 DOI: 10.1097/01.cnd.0000159779.32828.e7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We report a new clinical variant of epidermolysis bullosa simplex with muscular dystrophy (EBS-MD) that was associated with cardiac involvement. A 33-year-old patient had atrial fibrillation, pericardial effusion, and hypokinetic left ventricular cardiac walls. The muscle biopsy material revealed diffuse endomysial fibrosis and small atrophic muscle fibers with rounded contours. A positive desmin expression with abnormal localization in the subsarcolemmal groups was observed. We concluded that patients with EBS-MD should be investigated carefully when there are associated cardiac findings.
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Affiliation(s)
- Canan Celik
- From the Departments of *Physical Medicine and Rehabilitation and daggerNeurology, Ankara Physical Medicine and Rehabilitation Education and Research Hospital, Ankara, Turkey; and the Departments of double daggerPathology and section signPhysical Medicine and Rehabilitation, Gazi University Medicine, School of Medicine, Ankara, Turkey
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Selcen D, Juel VC, Hobson-Webb LD, Smith EC, Stickler DE, Bite AV, Ohno K, Engel AG. Myasthenic syndrome caused by plectinopathy. Neurology 2011; 76:327-36. [PMID: 21263134 DOI: 10.1212/wnl.0b013e31820882bd] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Plectin crosslinks intermediate filaments to their targets in different tissues. Defects in plectin cause epidermolysis bullosa simplex (EBS), muscular dystrophy (MD), and sometimes pyloric atresia. Association of EBS with a myasthenic syndrome (MyS) was documented in a single patient in 1999. OBJECTIVES To analyze the clinical, structural, and genetic aspects of a second and fatal case of EBS associated with a MyS and search for the genetic basis of the disease in a previously reported patient with EBS-MD-MyS. METHODS Clinical observations; histochemical, immunocytochemical, and electron microscopy studies of skeletal muscle and neuromuscular junction; and mutation analysis. RESULTS An African American man had EBS since early infancy, and progressive muscle weakness, hyperCKemia, and myasthenic symptoms refractory to therapy since age 3 years. Eventually he became motionless and died at age 42 years. At age 15 years, he had a marked EMG decrement, and a reduced miniature endplate potential amplitude. The myopathy was associated with dislocated muscle fiber organelles, structurally abnormal nuclei, focal plasmalemmal defects, and focal calcium ingress into muscle fibers. The neuromuscular junctions showed destruction of the junctional folds, and remodeling. Mutation analysis demonstrated a known p.Arg2319X and a novel c.12043dupG mutation in PLEC1. The EBS-MD-MyS patient reported in 1999 also carried c.12043dupG and a novel p.Gln2057X mutation. The novel mutations were absent in 200 Caucasian and 100 African American subjects. CONCLUSIONS The MyS in plectinopathy is attributed to destruction of the junctional folds and the myopathy to defective anchoring of muscle fiber organelles and defects in sarcolemmal integrity.
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Affiliation(s)
- D Selcen
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
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13
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Natsuga K, Nishie W, Akiyama M, Nakamura H, Shinkuma S, McMillan JR, Nagasaki A, Has C, Ouchi T, Ishiko A, Hirako Y, Owaribe K, Sawamura D, Bruckner-Tuderman L, Shimizu H. Plectin expression patterns determine two distinct subtypes of epidermolysis bullosa simplex. Hum Mutat 2010; 31:308-16. [PMID: 20052759 DOI: 10.1002/humu.21189] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Plectin is a cytoskeletal linker protein that has a dumbbell-like structure with a long central rod and N- and C-terminal globular domains. Mutations in the gene encoding plectin (PLEC1) cause two distinct autosomal recessive subtypes of epidermolysis bullosa (EB): EB simplex with muscular dystrophy (EBS-MD), and EB simplex with pyloric atresia (EBS-PA). Here, we demonstrate that normal human fibroblasts express two different plectin isoforms including full-length and rodless forms of plectin. We performed detailed analysis of plectin expression patterns in six EBS-MD and three EBS-PA patients. In EBS-PA, expression of all plectin domains was found to be markedly attenuated or completely lost; in EBS-MD, the expression of the N- and C-terminal domains of plectin remained detectable, although the expression of rod domains was absent or markedly reduced. Our data suggest that loss of the full-length plectin isoform with residual expression of the rodless plectin isoform leads to EBS-MD, and that complete loss or marked attenuation of full-length and rodless plectin expression underlies the more severe EBS-PA phenotype. These results also clearly account for the majority of EBS-MD PLEC1 mutation restriction within the large exon 31 that encodes the plectin rod domain, whereas EBS-PA PLEC1 mutations are generally outside exon 31.
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Affiliation(s)
- Ken Natsuga
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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14
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Chiavérini C, Charlesworth A, Meneguzzi G, Lacour JP, Ortonne JP. Epidermolysis bullosa simplex with muscular dystrophy. Dermatol Clin 2010; 28:245-55, viii. [PMID: 20447487 DOI: 10.1016/j.det.2010.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Epidermolysis bullosa simplex (EBS) is an inherited skin disorder characterized by separation of the epidermis from the underlying dermis, with the cleavage plane lying within the basal-cell layer of the epithelium. The major clinical subtypes of EBS have a dominant inheritance and have been associated with genetic defects in specific domains of keratins K5 and K14 that result in abnormal organization of the keratin network and cell disruption. Autosomal recessive forms of EBS associated with extracutaneous manifestations, such as muscular dystrophy (MIM 226670) or pyloric atresia (MIM 612138), have been linked to genetic mutations in the gene for plectin (PLEC). PLEC mutations have also been found in 2 families with the rare dominant Ogna form of EBS. This article reviews current knowledge on EBS.
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Affiliation(s)
- C Chiavérini
- French Reference Center of Hereditary Epidermolysis Bullosa, Nice, France.
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15
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16
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Rezniczek GA, Walko G, Wiche G. Plectin gene defects lead to various forms of epidermolysis bullosa simplex. Dermatol Clin 2010; 28:33-41. [PMID: 19945614 DOI: 10.1016/j.det.2009.10.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Plectin is an important organizer of the keratin filament cytoskeleton in basal keratinocytes. It is essential for anchoring these filaments to the extracellular matrix via hemidesmosomal integrins. Loss of plectin or incorrect function of the protein due to mutations in its gene can lead to various forms of the skin blistering disease, epidermolysis bullosa simplex. Severity and subtype of the disease is dependent on the specific mutation and can be associated with (late-onset) muscular dystrophy or pyloric atresia. Mouse models mimicking the human phenotypes allow detailed study of plectin function.
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Affiliation(s)
- Günther A Rezniczek
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr.-Bohr-Gasse 9, 1030 Vienna, Austria
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17
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Muscular Integrity—A Matter of Interlinking Distinct Structures via Plectin. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 642:165-75. [DOI: 10.1007/978-0-387-84847-1_12] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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18
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Abu Sa'd J, Indelman M, Pfendner E, Falik-Zaccai TC, Mizrachi-Koren M, Shalev S, Ben Amitai D, Raas-Rothshild A, Adir-Shani A, Borochowitz ZU, Gershoni-Baruch R, Khayat M, Landau D, Richard G, Bergman R, Uitto J, Kanaan M, Sprecher E. Molecular epidemiology of hereditary epidermolysis bullosa in a Middle Eastern population. J Invest Dermatol 2006; 126:777-81. [PMID: 16439963 DOI: 10.1038/sj.jid.5700163] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Epidermolysis bullosa (EB) encompasses a large group of inherited blistering skin disorders caused by mutations in at least 10 genes. Numerous studies, mainly performed in European and US families with EB, have revealed a number of characteristic epidemiological and genetic features, which form the basis for current diagnostic and counseling strategies. However, little is currently known about the molecular epidemiology of EB in Middle East populations. In the present study, we assessed 55 EB families for pathogenic sequence alterations in the 10 genes known to be associated with EB. Our results show unique EB subtype distribution and patterns of inheritance in our cohort. We also failed to detect recurrent mutations frequently encountered in Europe and the US, and did not consistently observe genotype-phenotype correlations formerly established in Western populations. Thus, the molecular epidemiology of EB in the Middle East is significantly different from that previously delineated in Europe and the US. Our data raise the possibility that similar differences may also be found in other genetically heterogeneous groups of disorders, and indicate the need for population-specific diagnostic and management approaches.
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Affiliation(s)
- Judeh Abu Sa'd
- Department of Life Sciences, Bethlehem University, Palestinian Authority, Haifa, Israel
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19
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Abrahamsberg C, Fuchs P, Osmanagic-Myers S, Fischer I, Propst F, Elbe-Bürger A, Wiche G. Targeted ablation of plectin isoform 1 uncovers role of cytolinker proteins in leukocyte recruitment. Proc Natl Acad Sci U S A 2005; 102:18449-54. [PMID: 16344482 PMCID: PMC1317913 DOI: 10.1073/pnas.0505380102] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Plectin, a typical cytolinker protein, is essential for skin and skeletal muscle integrity. It stabilizes cells mechanically, regulates cytoskeleton dynamics, and serves as a scaffolding platform for signaling molecules. A variety of isoforms expressed in different tissues and cell types account for this versatility. To uncover the role of plectin 1, the major isoform expressed in tissues of mesenchymal origin, against the background of all other variants, we raised plectin isoform 1-specific antibodies and generated isoform-deficient mice. In contrast to plectin-null mice (lacking all plectin isoforms), which die shortly after birth because of severe skin blistering, plectin isoform 1-deficient mice were viable at birth, had a normal lifespan, and did not display the skin blistering phenotype. However, dermal fibroblasts isolated from plectin 1-deficient mice exhibited abnormalities in their actin cytoskeleton and impaired migration potential. Similarly, plectin 1-deficient T cells isolated from nymph nodes showed diminished chemotactic migration in vitro. Most strikingly, in vivo we found that leukocyte infiltration during wound healing was reduced in the mutant mice. These data show a specific role of a cytolinker protein in immune cell motility. Single isoform-deficient mice thus represent a powerful tool to unravel highly specific functions of plectin variants.
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Affiliation(s)
- Christina Abrahamsberg
- Department of Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 4, Dr. Bohrgasse 9, A-1030 Vienna, Austria
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20
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Pfendner E, Rouan F, Uitto J. Progress in epidermolysis bullosa: the phenotypic spectrum of plectin mutations. Exp Dermatol 2005; 14:241-9. [PMID: 15810881 DOI: 10.1111/j.0906-6705.2005.00324.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Plectin, a large multidomain adhesive protein with versatile binding functions, is expressed in a number of tissues and cell types. In the skin, plectin is a critical component of hemidesmosomes, interacting with keratin intermediate filaments and beta4 integrin. Mutations in the plectin gene (PLEC1) result in fragility of skin, demonstrating blister formation at the level of hemidesmosomes. These blistering disorders belong to the spectrum of epidermolysis bullosa (EB) phenotypes, and three distinct variants because of plectin mutations have been identified. First, EB with muscular dystrophy, an autosomal recessive syndrome, is frequently caused by premature termination codon-causing mutations leading to the absence of plectin both in the skin and in the muscle. Second, a heterozygous missense mutation (R2110W) in PLEC1 has been documented in patients with EB simplex of the Ogna type, a rare autosomal dominant disorder. Finally, recent studies have disclosed plectin mutations in patients with EB with pyloric atresia, an autosomal recessive syndrome, frequently with lethal consequences. Collectively, these observations attest to the phenotypic spectrum of plectin mutations, and provide the basis for accurate genetic counselling with prognostic implications, as well as for prenatal diagnosis in families at the risk of recurrence of the disease.
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Affiliation(s)
- E Pfendner
- Department of Dermatology and Cutaneous Biology, Jefferson Medical College, and DebRA Molecular Diagnostics Laboratory, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
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21
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Abstract
Epidermolysis bullosa with pyloric atresia (EB-PA), manifesting with neonatal blistering and gastric anomalies, is known to be caused by mutations in the hemidesmosomal genes ITGA6 and ITGB4, which encode the alpha6 and beta4 integrin polypeptides, respectively. As part of our molecular diagnostics program, we have now encountered four families with EB-PA in which no mutations could be identified in these two genes. Instead, PCR amplification followed by heteroduplex scanning and/or direct nucleotide sequencing revealed homozygous mutations in the plectin gene (PLEC1), encoding another hemidesmosomal protein previously linked to EB with muscular dystrophy. Our findings provide evidence for additional molecular heterogeneity in EB, and emphasize the importance of screening EB-PA patients not only for alpha6beta4 integrin but also for plectin deficiency.
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Affiliation(s)
- Ellen Pfendner
- Department of Dermatology and Cutaneous Biology, Jefferson Medical College, Philadelphia, Pennsylvania, USA
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22
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Takahashi Y, Rouan F, Uitto J, Ishida-Yamamoto A, Iizuka H, Owaribe K, Tanigawa M, Ishii N, Yasumoto S, Hashimoto T. Plectin deficient epidermolysis bullosa simplex with 27-year-history of muscular dystrophy. J Dermatol Sci 2004; 37:87-93. [PMID: 15659326 DOI: 10.1016/j.jdermsci.2004.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2004] [Revised: 11/12/2004] [Accepted: 11/16/2004] [Indexed: 11/20/2022]
Abstract
BACKGROUND Epidermolysis bullosa simplex associated with muscular dystrophy is caused by plectin deficiency. OBJECTIVE To report clinical, immunohistochemical, ultrastructural and molecular features of a 52-year-old Japanese patient affected with this disease, whose muscular disease had been followed-up for 27 years. METHODS We performed histopathological study, immunofluorescence, electron microscopic study and mutation detection analysis for plectin. RESULTS The patient developed blisters and erosions followed by nail deformity on the traumatized regions from birth. The skin lesions were continuously developed to date. The histopathological study showed subepidermal blister. Electron microscopic study showed blister formation inside the basal cells at the level just above the attachment plaque of hemidesmosome. Immunofluorescence showed complete loss of staining to plectin. The mutation analysis using protein truncation test and DNA sequencing revealed a C-to-T transition at nucleotide position 7006 of the plectin cDNA sequence, which lead a novel homozygous nonsense mutation (R2319X). CONCLUSION From the above results, the diagnosis of epidermolysis bullosa simplex associated with muscular dystrophy was made. Slight muscular dystrophy was noticed at the age of 25 years. The muscular dystrophy gradually progressed and she could not walk at the age of 46 years. However, she can still breathe and swallow by herself. This is the patient of this disease with the longest follow-up, and may indicate the slow progress of muscular condition of this disease.
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Affiliation(s)
- Yoshie Takahashi
- Department of Dermatology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan
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23
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Osmanagic-Myers S, Wiche G. Plectin-RACK1 (receptor for activated C kinase 1) scaffolding: a novel mechanism to regulate protein kinase C activity. J Biol Chem 2004; 279:18701-10. [PMID: 14966116 DOI: 10.1074/jbc.m312382200] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Agonist-induced translocation of protein kinase C (PKC) isozymes is mediated by receptors for the activated form of the kinase, shuttling it from one intracellular site to another and enhancing its catalytic activity. It is however unknown whether the receptors themselves are anchored to certain intracellular structures prior to their engagement with PKC. We show here sequestering of receptor for activated C kinase 1 (RACK1) to the cytoskeleton through the cytoskeletal linker protein plectin during the initial stages of cell adhesion. We found that upon PKC activation, RACK1 was released from the cytoskeleton and transferred to the detergent-soluble cell compartment, where it formed an inducible triple complex with one of the PKC isozymes, PKCdelta, and with plectin. In plectin-deficient cells the cytoskeleton-associated RACK1 fraction was reduced, and the protein was found predominantly at sites to which it normally translocated upon PKC activation. Concomitantly, dislocation of PKCdelta and elevated enzymatic activity were observed in these cells. PKCdelta was also more rapidly degraded, likely due to its overactivation. We propose a previously unrecognized function of plectin as cytoskeletal regulator of PKC signaling, and possibly other signaling events, through sequestration of the scaffolding protein RACK1.
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Affiliation(s)
- Selma Osmanagic-Myers
- Institute of Biochemistry and Molecular Cell Biology, University of Vienna, Vienna Biocenter, Dr. Bohrgasse 9, A-1030 Vienna, Austria
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24
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Charlesworth A, Gagnoux-Palacios L, Bonduelle M, Ortonne JP, De Raeve L, Meneguzzi G. Identification of a Lethal Form of Epidermolysis Bullosa Simplex Associated with a Homozygous Genetic Mutation in Plectin. J Invest Dermatol 2003; 121:1344-8. [PMID: 14675180 DOI: 10.1111/j.1523-1747.2003.12639.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Genetic mutations in plectin, a cytoskeleton linker protein expressed in a large variety of tissues including skin, muscle, and nerves, cause epidermolysis bullosa simplex with muscular dystrophy, a recessive inherited disease characterized by blistering of the skin and late onset of muscular dystrophy, and Ogna epidermolysis bullosa simplex, a rare dominant inherited form of epidermolysis bullosa simplex with no muscular involvement. Here we report a novel homozygous genetic mutation (2727del14) in the plectin gene (PLEC1) associated with a lethal form of recessive inherited epidermolysis bullosa in a consanguineous family with three affected offspring. This new clinical variant of epidermolysis bullosa is characterized by general skin blistering, aplasia cutis of the limbs, developmental complications, and rapid demise after birth. Mutation 2727del14 is the first genetic defect described in PLEC1 that disrupts the plakin domain of plectin. The severe phenotype of the patients may be linked to the role of the N-terminal domain in the function of plectin and develops the understanding of the genotype-phenotype correlations in the genodermatoses affecting the dermal-epidermal junction.
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25
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Mitsuhashi Y, Hashimoto I. Genetic abnormalities and clinical classification of epidermolysis bullosa. Arch Dermatol Res 2003; 295 Suppl 1:S29-33. [PMID: 12677430 DOI: 10.1007/s00403-002-0369-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Genetic abnormalities for different subtypes of epidermolysis bullosa (EB) have been described. In dominant simplex type EB, mutations of the K5 or K14 gene lead to disruption of basal cells and the formation of bullae. The recessive simplex types include EB with muscular dystrophy due to abnormal plectin, EB without muscular dystrophy in patients homozygous for K14 gene abnormalities, and skin fragility syndrome, with formation of acantholytic vesicles within the epidermis due to PKP1 gene mutations. In junctional EB, mutations of the laminin 5, type XVII collagen, and alpha 6 beta 4 integrin genes have been reported. Dystrophic type EB is associated with various abnormalities of the type VII collagen gene. A new classification of EB based on these genetic abnormalities has been proposed. However, some concern has been voiced regarding the clinical utility of a classification based solely on genetic abnormalities. Although the reasons are unclear, identical genetic abnormalities have been known to be associated with different clinical features. A classification including a component based on clinical features would therefore be preferable. This article describes recently discovered genetic abnormalities and offers a new classification scheme for EB.
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Affiliation(s)
- Yoshihiko Mitsuhashi
- Department of Dermatology, Yamagata University School of Medicine, Yamagata, Japan.
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26
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Andrä K, Kornacker I, Jörgl A, Zörer M, Spazierer D, Fuchs P, Fischer I, Wiche G. Plectin-isoform-specific rescue of hemidesmosomal defects in plectin (-/-) keratinocytes. J Invest Dermatol 2003; 120:189-97. [PMID: 12542521 DOI: 10.1046/j.1523-1747.2003.12027.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The various plectin isoforms are among the major crosslinking elements of the cytoskeleton. The importance of plectin in epithelia is convincingly supported by the severe skin blistering observed in plectin-deficient humans and mice. Here, we identified plectin 1a (> 500 kDa), a full length plectin variant containing the sequence encoded by the alternative first exon 1a, as the isoform most prominently expressed in human and mouse keratinocytes. In skin sections and cultured keratinocytes, plectin 1a was shown to colocalize with hemidesmosomal structures. In contrast, a second isoform expressed in epithelia, plectin 1c, differing from 1a merely by a short N-terminal sequence, colocalized with microtubules. Expression of plectin 1a, but not of its N-terminal fragment alone, or of a third alternative full length isoform (plectin 1), restored the reduced number of hemidesmosome-like stable anchoring contacts in cultured plectin-null keratinocytes. Our results show for the first time that different isoforms of a cytolinker protein expressed in one cell type perform distinct functions. Moreover, the identification of plectin 1a as the isoform defects in which cause skin blistering in plectin-related genetic diseases, such as epidermolysis bullosa simplex MD and epidermolysis bullosa simplex Ogna, could have implications for the future development of clinical therapies for patients.
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Affiliation(s)
- Kerstin Andrä
- Institute of Biochemistry and Molecular Cell Biology, Vienna Biocenter, University of Vienna, Austria
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27
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Schröder R, Kunz WS, Rouan F, Pfendner E, Tolksdorf K, Kappes-Horn K, Altenschmidt-Mehring M, Knoblich R, van der Ven PFM, Reimann J, Fürst DO, Blümcke I, Vielhaber S, Zillikens D, Eming S, Klockgether T, Uitto J, Wiche G, Rolfs A. Disorganization of the desmin cytoskeleton and mitochondrial dysfunction in plectin-related epidermolysis bullosa simplex with muscular dystrophy. J Neuropathol Exp Neurol 2002; 61:520-30. [PMID: 12071635 DOI: 10.1093/jnen/61.6.520] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mutations of the human plectin gene (Plec1) cause autosomal recessive epidermolysis bullosa simplex with muscular dystrophy (EBS-MD). Here, we report on molecular mechanisms leading to severe dystrophic muscle alterations in EBS-MD. Analysis of a 25-yr-old EBS-MD patient carrying a novel homozygous 16-bp insertion mutation (13803ins16/13803ins16) close to the intermediate filament (IF) binding site of plectin showed severe disorganization of the myogenic IF cytoskeleton. Intermyofibrillar and subsarcolemmal accumulations of assembled but highly unordered desmin filaments may be attributed to impaired desmin binding capability of the mutant plectin. This IF pathology was also associated with severe mitochondrial dysfunction, suggesting that the muscle pathology of EBS-MD caused by IF disorganization leads not only to defects in mechanical force transduction but also to metabolic dysfunction. Beyond EBS-MD, our data may contribute to the understanding of other myopathies characterized by sarcoplasmic IF accumulations such as desminopathies or alpha-B-crystallinopathies.
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Affiliation(s)
- Rolf Schröder
- Department of Neurology, University of Bonn, Germany
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28
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Koss-Harnes D, Høyheim B, Anton-Lamprecht I, Gjesti A, Jørgensen RS, Jahnsen FL, Olaisen B, Wiche G, Gedde-Dahl T. A site-specific plectin mutation causes dominant epidermolysis bullosa simplex Ogna: two identical de novo mutations. J Invest Dermatol 2002; 118:87-93. [PMID: 11851880 DOI: 10.1046/j.0022-202x.2001.01591.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Plectin is one of the largest and most versatile cytolinker proteins known. In basal keratinocytes it links the intermediate filament network to cell membrane-associated hemidesmosomes. Several mutations in its gene have been identified that lead to the recessive disease epidermolysis bullosa with muscular dystrophy. We report here a mutation that leads to a dominant form of the disease, epidermolysis bullosa simplex Ogna. We found that the epidermolysis bullosa simplex Ogna phenotype is due to a site-specific missense mutation within plectin's rod domain. Further, we show that epidermolysis bullosa simplex Ogna is not restricted to a single Norwegian kindred as previously believed. A German family with the phenotypic hallmarks of epidermolysis bullosa simplex Ogna was found to carry an identical de novo mutation. These two mutations arose about 200 y apart in time. Consistent with the absence of muscular symptoms in these patients, muscle biopsies from several epidermolysis bullosa simplex Ogna members of the Norwegian kindred showed normal staining patterns using antibodies to plectin. Skin changes in epidermolysis bullosa simplex Ogna patients are documented on the ultrastructural level.
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Affiliation(s)
- Dörte Koss-Harnes
- Department of Dermatology, The National Hospital, University of Oslo, Norway.
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29
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McGrath JA, Eady RA. Recent advances in the molecular basis of inherited skin diseases. ADVANCES IN GENETICS 2001; 43:1-32. [PMID: 11037297 DOI: 10.1016/s0065-2660(01)43002-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Over the last few years the molecular basis of several inherited skin diseases has been delineated. Some discoveries have stemmed from a candidate gene approach using clinical, biochemical, immunohistochemical, and ultrastructural clues, while others have arisen from genetic linkage and positional cloning analyses. Notable advances have included elucidation of specific gene pathology in the major forms of inherited skin fragility, ichthyosis, and keratoderma. These findings have led to a better understanding of the significance of individual structural proteins and regulatory enzymes in keratinocyte adhesion and differentiation. From a clinical perspective, the advances have led to better genetic counseling in many disorders, the development of DNA-based prenatal diagnosis, and a foundation for planning newer forms of treatment, including somatic gene therapy, in selected conditions.
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Affiliation(s)
- J A McGrath
- Department of Cell and Molecular Pathology, St John's Institute of Dermatology, The Guy's, Kings College and St Thomas' Hospital Medical School, St Thomas' Hospital, London, United Kingdom.
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30
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Bauer JW, Rouan F, Kofler B, Rezniczek GA, Kornacker I, Muss W, Hametner R, Klausegger A, Huber A, Pohla-Gubo G, Wiche G, Uitto J, Hintner H. A compound heterozygous one amino-acid insertion/nonsense mutation in the plectin gene causes epidermolysis bullosa simplex with plectin deficiency. THE AMERICAN JOURNAL OF PATHOLOGY 2001; 158:617-25. [PMID: 11159198 PMCID: PMC1850321 DOI: 10.1016/s0002-9440(10)64003-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Plectin is a cytoskeleton linker protein expressed in a variety of tissues including skin, muscle, and nerves. Mutations in its gene are associated with epidermolysis bullosa simplex with late-onset muscular dystrophy. Whereas in most of these patients the pathogenic events are mediated by nonsense-mediated mRNA decay, the consequences of an in-frame mutation are less clear. We analyzed a patient with compound heterozygosity for a 3-bp insertion at position 1287 leading to the insertion of leucine as well as the missense mutation Q1518X leading to a stop codon. The presence of plectin mRNA was demonstrated by a RNase protection assay. However, a marked reduction of plectin protein was found using immunofluorescence microscopy of the patient's skin and Western blot analysis of the patient's cultured keratinocytes. The loss of plectin protein was associated with morphological alterations in plectin-containing structures of the dermo-epidermal junction, in skeletal muscle, and in nerves as detected by electron microscopy. In an in vitro overlay assay using recombinant plectin peptides spanning exons 2 to 15 the insertion of leucine resulted in markedly increased self-aggregation of plectin peptides. These results describe for the first time the functional consequences of an in-frame insertion mutation in humans.
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Affiliation(s)
- J W Bauer
- Department of Dermatology, Children's Hospital Salzburg, Austria.
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