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Al Towijry M, Alanazi AMM, Eldesoky F, Alharthi YH, Albalawi IAS. Epidermolysis Bullosa Simplex With Dystonin Gene Mutation: First Reported Case in Saudi Arabia. Cureus 2023; 15:e43206. [PMID: 37692655 PMCID: PMC10487254 DOI: 10.7759/cureus.43206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2023] [Indexed: 09/12/2023] Open
Abstract
We report a case of a 3-year-old Saudi female patient as the first case reported in Saudi Arabia who is homozygous for dystonin c.3370C>T, p.(Gln1124*). At the age of 3 months, the girl started to develop numerous vesicles and bullae involving the dorsum of the feet that were not on a pressure site, with remission and aggravation, but she had no mucosal lesions or nail affection. The patient was diagnosed with epidermolysis bullosa simplex.
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Affiliation(s)
| | | | - Fatma Eldesoky
- Department of Dermatology, King Salman Armed Forces Hospital, Tabuk, SAU
| | - Yousef H Alharthi
- Department of Dermatology, King Salman Armed Forces Hospital, Tabuk, SAU
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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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Epidermolysis Bullosa—A Different Genetic Approach in Correlation with Genetic Heterogeneity. Diagnostics (Basel) 2022; 12:diagnostics12061325. [PMID: 35741135 PMCID: PMC9222206 DOI: 10.3390/diagnostics12061325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/23/2022] [Accepted: 05/25/2022] [Indexed: 11/17/2022] Open
Abstract
Epidermolysis bullosa is a heterogeneous group of rare genetic disorders characterized by mucocutaneous fragility and blister formation after minor friction or trauma. There are four major epidermolysis bullosa types based on the ultrastructural level of tissue cleavage: simplex, junctional, dystrophic, and Kindler epidermolysis bullosa. They are caused by mutations in genes that encode the proteins that are part of the hemidesmosomes and focal adhesion complex. Some of these disorders can be associated with extracutaneous manifestations, which are sometimes fatal. They are inherited in an autosomal recessive or autosomal dominant manner. This review is focused on the phenomena of heterogeneity (locus, allelic, mutational, and clinical) in epidermolysis bullosa, and on the correlation genotype–phenotype.
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Xu X, Zhao J, Wang C, Qu X, Ran M, Ye F, Shen M, Wang K, Zhang Q. Case Report: De novo KLHL24 Gene Pathogenic Variants in Chinese Twin Boys With Epidermolysis Bullosa Simplex. Front Genet 2021; 12:729628. [PMID: 34804116 PMCID: PMC8602111 DOI: 10.3389/fgene.2021.729628] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/15/2021] [Indexed: 11/13/2022] Open
Abstract
Objectives: The aim of this study was to determine the molecular etiology and clinical manifestations of a pair of Chinese twins affected with epidermolysis bullosa simplex. Pediatricians should pay attention to the early genetic diagnosis of this disease. Methods: Histopathological examination of HE-stained skin, electron microscopy of biopsied normal skin, and whole-exome sequencing was performed to assess pathogenicity and conservation of detected mutations. Two years later, the cutaneous and extracutaneous manifestations of the twins were comprehensively evaluated. Results: A de novo pathogenic variant c.2T>C (p.M1T) in KLHL24 (NM_017,644) was identified in both twins. The characteristics of extensive skin defects on the extremities at birth and the tendency to lesson with increasing age were confirmed. No positive sensitive markers, such as B-type natriuretic peptide, cardiac troponin I, for cardiac dysfunction were detected. Conclusions: The de novo pathogenic variants c.2T>C (p.M1T) in KLHL24 (NM_017,644) contributes to the development of epidermolysis bullosa. Genetic diagnosis at birth or early infancy can better predict the disease prognosis and guide the treatment.
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Affiliation(s)
- Xiaojing Xu
- Department of Pediatrics, China-Japan Friendship Hospital, Beijing, China
| | - Juan Zhao
- Department of Pediatrics, China-Japan Friendship Hospital, Beijing, China
| | - Chao Wang
- Department of Pediatrics, China-Japan Friendship Hospital, Beijing, China
| | - Xiaoxuan Qu
- Department of Pediatrics, China-Japan Friendship Hospital, Beijing, China
| | - Menglong Ran
- Department of Dermatology and Venereology, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Beijing, China
| | - Fang Ye
- Department of Pediatrics, China-Japan Friendship Hospital, Beijing, China
| | - Ming Shen
- Department of Pediatrics, China-Japan Friendship Hospital, Beijing, China
| | - Kundi Wang
- Department of Pediatrics, China-Japan Friendship Hospital, Beijing, China
| | - Qi Zhang
- Department of Pediatrics, China-Japan Friendship Hospital, Beijing, China
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Kiritsi D, Tsakiris L, Schauer F. Plectin in Skin Fragility Disorders. Cells 2021; 10:cells10102738. [PMID: 34685719 PMCID: PMC8534787 DOI: 10.3390/cells10102738] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 11/16/2022] Open
Abstract
Plectin is a multi-faceted, 500 kDa-large protein, which due to its expression in different isoforms and distinct organs acts diversely as a cytoskeletal crosslinker and signaling scaffold. It functions as a mediator of keratinocyte mechanical stability in the skin, primarily through linking intermediate filaments to hemidesmosomes. Skin fragility may occur through the presence of mutations in the gene encoding for plectin, PLEC, or through the presence of autoantibodies against the molecule. Below, we review the cutaneous manifestations of plectinopathies as well as their systemic involvement in specific disease subtypes. We summarize the known roles of plectin in keratinocytes and fibroblasts and provide an outlook on future perspectives for plectin-associated skin disorders.
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Affiliation(s)
- Dimitra Kiritsi
- Department of Dermatology, Faculty of Medicine, Medical Center-University of Freiburg, 79104 Freiburg, Germany;
- Correspondence:
| | | | - Franziska Schauer
- Department of Dermatology, Faculty of Medicine, Medical Center-University of Freiburg, 79104 Freiburg, Germany;
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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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Castañón MJ, Wiche G. Identifying Plectin Isoform Functions through Animal Models. Cells 2021; 10:cells10092453. [PMID: 34572100 PMCID: PMC8468861 DOI: 10.3390/cells10092453] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/04/2021] [Accepted: 09/14/2021] [Indexed: 12/12/2022] Open
Abstract
Plectin, a high-molecular-weight cytoskeletal linker protein, binds with high affinity to intermediate filaments of all types and connects them to junctional complexes, organelles, and inner membrane systems. In addition, it interacts with actomyosin structures and microtubules. As a multifunctional protein, plectin has been implicated in several multisystemic diseases, the most common of which is epidermolysis bullosa simplex with muscular dystrophy (EBS-MD). A great part of our knowledge about plectin’s functional diversity has been gained through the analysis of a unique collection of transgenic mice that includes a full (null) knockout (KO), several tissue-restricted and isoform-specific KOs, three double KOs, and two knock-in lines. The key molecular features and pathological phenotypes of these mice will be discussed in this review. In summary, the analysis of the different genetic models indicated that a functional plectin is required for the proper function of striated and simple epithelia, cardiac and skeletal muscle, the neuromuscular junction, and the vascular endothelium, recapitulating the symptoms of humans carrying plectin mutations. The plectin-null line showed severe skin and muscle phenotypes reflecting the importance of plectin for hemidesmosome and sarcomere integrity; whereas the ablation of individual isoforms caused a specific phenotype in myofibers, basal keratinocytes, or neurons. Tissue-restricted ablation of plectin rendered the targeted cells less resilient to mechanical stress. Studies based on animal models other than the mouse, such as zebrafish and C. elegans, will be discussed as well.
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Khan FF, Khan N, Rehman S, Ejaz A, Ali U, Erfan M, Ahmed ZM, Naeem M. Identification and Computational Analysis of Novel Pathogenic Variants in Pakistani Families with Diverse Epidermolysis Bullosa Phenotypes. Biomolecules 2021; 11:620. [PMID: 33921969 PMCID: PMC8143555 DOI: 10.3390/biom11050620] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/15/2021] [Indexed: 12/17/2022] Open
Abstract
Epidermolysis bullosa (EB) includes a group of rare gesnodermatoses that result in blistering and erosions of the skin and mucous membranes. Genetically, pathogenic variants in around 20 genes are known to alter the structural and functional integrity of intraepidermal adhesion and dermo-epidermal anchorage, leading to four different types of EB. Here we report the underlying genetic causes of EB phenotypes segregating in seven large consanguineous families, recruited from different regions of Pakistan. Whole exome sequencing, followed by segregation analysis of candidate variants through Sanger sequencing, identified eight pathogenic variants, including three novel (ITGB4: c.1285G>T, and c.3373G>A; PLEC: c.1828A>G) and five previously reported variants (COL7A1: c.6209G>A, and c.1573C>T; FERMT1: c.676insC; LAMA3: c.151insG; LAMB3: c.1705C>T). All identified variants were either absent or had very low frequencies in the control databases. Our in-silico analyses and 3-dimensional (3D) molecular modeling support the deleterious impact of these variants on the encoded proteins. Intriguingly, we report the first case of a recessively inherited form of rare EBS-Ogna associated with a homozygous variant in the PLEC gene. Our study highlights the clinical and genetic diversity of EB in the Pakistani population and expands the mutation spectrum of EB; it could also be useful for prenatal diagnosis and genetic counseling of the affected families.
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Affiliation(s)
- Fehmida F. Khan
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad 45320, Pakistan; (F.F.K.); (N.K.)
| | - Naima Khan
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad 45320, Pakistan; (F.F.K.); (N.K.)
| | - Sakina Rehman
- Laboratory of Neurogenetics and Translational Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Amir Ejaz
- Army Medical College, Rawalpindi 46000, Pakistan;
| | - Uzma Ali
- Department of Dermatology, Capital Hospital, Islamabad 44000, Pakistan;
| | - Muhammad Erfan
- Department of Dermatology, Federal Government Polyclinic Hospital, Islamabad 44000, Pakistan;
| | - Zubair M. Ahmed
- Laboratory of Neurogenetics and Translational Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Muhammad Naeem
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad 45320, Pakistan; (F.F.K.); (N.K.)
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Abstract
Epidermolysis bullosa (EB) is an inherited, heterogeneous group of rare genetic dermatoses characterized by mucocutaneous fragility and blister formation, inducible by often minimal trauma. A broad phenotypic spectrum has been described, with potentially severe extracutaneous manifestations, morbidity and mortality. Over 30 subtypes are recognized, grouped into four major categories, based predominantly on the plane of cleavage within the skin and reflecting the underlying molecular abnormality: EB simplex, junctional EB, dystrophic EB and Kindler EB. The study of EB has led to seminal advances in our understanding of cutaneous biology. To date, pathogenetic mutations in 16 distinct genes have been implicated in EB, encoding proteins influencing cellular integrity and adhesion. Precise diagnosis is reliant on correlating clinical, electron microscopic and immunohistological features with mutational analyses. In the absence of curative treatment, multidisciplinary care is targeted towards minimizing the risk of blister formation, wound care, symptom relief and specific complications, the most feared of which - and also the leading cause of mortality - is squamous cell carcinoma. Preclinical advances in cell-based, protein replacement and gene therapies are paving the way for clinical successes with gene correction, raising hopes amongst patients and clinicians worldwide.
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Mohammed F, Trieber C, Overduin M, Chidgey M. Molecular mechanism of intermediate filament recognition by plakin proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118801. [PMID: 32712070 DOI: 10.1016/j.bbamcr.2020.118801] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/15/2020] [Accepted: 07/20/2020] [Indexed: 12/26/2022]
Abstract
The plakin family of cytolinkers interacts with intermediate filaments (IFs) through plakin repeat domain (PRD) and linker modules. Recent structure/function studies have established the molecular basis of envoplakin-PRD and periplakin-linker interactions with vimentin. Both plakin modules share a broad basic groove which recognizes acidic rod elements on IFs, a mechanism that is applicable to other plakin family members. This review postulates a universal IF engagement mechanism that illuminates the specific effects of pathogenic mutations associated with diseases including arrhythmogenic right ventricular cardiomyopathy, and reveals how diverse plakin proteins offer tailored IF tethering to ensure stable, dynamic and regulated cellular structures.
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Affiliation(s)
- Fiyaz Mohammed
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham B15 2TT, UK.
| | - Catharine Trieber
- Department of Biochemistry, Faculty of Medicine and Dentistry, 474 Medical Sciences Building, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
| | - Michael Overduin
- Department of Biochemistry, Faculty of Medicine and Dentistry, 474 Medical Sciences Building, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
| | - Martyn Chidgey
- Institute of Clinical Sciences, University of Birmingham, Birmingham B15 2TT, UK.
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Mariath LM, Santin JT, Schuler-Faccini L, Kiszewski AE. Inherited epidermolysis bullosa: update on the clinical and genetic aspects. An Bras Dermatol 2020; 95:551-569. [PMID: 32732072 PMCID: PMC7563003 DOI: 10.1016/j.abd.2020.05.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/17/2020] [Indexed: 12/14/2022] Open
Abstract
Inherited epidermolysis bullosa is a group of genetic diseases characterized by skin fragility and blistering on the skin and mucous membranes in response to minimal trauma. Epidermolysis bullosa is clinically and genetically very heterogeneous, being classified into four main types according to the layer of skin in which blistering occurs: epidermolysis bullosa simplex (intraepidermal), junctional epidermolysis bullosa (within the lamina lucida of the basement membrane), dystrophic epidermolysis bullosa (below the basement membrane), and Kindler epidermolysis bullosa (mixed skin cleavage pattern). Furthermore, epidermolysis bullosa is stratified into several subtypes, which consider the clinical characteristics, the distribution of the blisters, and the severity of cutaneous and extracutaneous signs. Pathogenic variants in at least 16 genes that encode proteins essential for the integrity and adhesion of skin layers have already been associated with different subtypes of epidermolysis bullosa. The marked heterogeneity of the disease, which includes phenotypes with a broad spectrum of severity and many causal genes, hinders its classification and diagnosis. For this reason, dermatologists and geneticists regularly review and update the classification criteria. This review aimed to update the state of the art on inherited epidermolysis bullosa, with a special focus on the associated clinical and genetic aspects, presenting data from the most recent reclassification consensus, published in 2020.
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Affiliation(s)
- Luiza Monteavaro Mariath
- Postgraduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Juliana Tosetto Santin
- Postgraduate Program in Child and Adolescent Health, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Dermatology Service, Santa Casa de Misericórdia de Porto Alegre/Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil
| | | | - Ana Elisa Kiszewski
- Dermatology Service, Santa Casa de Misericórdia de Porto Alegre/Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil; Department of Clinical Medicine, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil; Pediatric Dermatology Unit, Santa Casa de Misericórdia de Porto Alegre/Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil.
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12
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Xing G, Xiong WC, Mei L. Rapsyn as a signaling and scaffolding molecule in neuromuscular junction formation and maintenance. Neurosci Lett 2020; 731:135013. [DOI: 10.1016/j.neulet.2020.135013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 04/23/2020] [Indexed: 12/20/2022]
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13
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Has C, Liu L, Bolling MC, Charlesworth AV, El Hachem M, Escámez MJ, Fuentes I, Büchel S, Hiremagalore R, Pohla-Gubo G, van den Akker PC, Wertheim-Tysarowska K, Zambruno G. Clinical practice guidelines for laboratory diagnosis of epidermolysis bullosa. Br J Dermatol 2019; 182:574-592. [PMID: 31090061 PMCID: PMC7064925 DOI: 10.1111/bjd.18128] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2019] [Indexed: 02/06/2023]
Abstract
Linked Comment: https://doi.org/10.1111/bjd.18377. https://doi.org/10.1111/bjd.18829 available online
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Affiliation(s)
- C Has
- Department of Dermatology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - L Liu
- Viapath, St Thomas' Hospital, London, U.K
| | - M C Bolling
- Department of Dermatology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - A V Charlesworth
- Centre de Reference des Maladies Rares de la Peau et des Muqueuses d'Origine Génétique, L'Archet Hôpital, Nice, France
| | - M El Hachem
- Dermatology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - M J Escámez
- Bioengineering Department at Universidad Carlos III de Madrid (UC3M), Regenerative Medicine Unit at CIEMAT - U714 CIBER on Rare Diseases (ISCIII), Instituto de Investigación Sanitaria Fundación Jiménez Diaz (IISFJD), Madrid, Spain
| | - I Fuentes
- Fundación DEBRA Chile, Santiago, Chile.,Centro de Genética y Genómica, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - S Büchel
- Department of Dermatology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - R Hiremagalore
- Adjunct Faculty, Centre for Human Genetics and Department of Dermatology and Pediatrics, Manipal Hospital, Bengaluru, India
| | - G Pohla-Gubo
- EB House Austria, Department of Dermatology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - P C van den Akker
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | | | - G Zambruno
- Dermatology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
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Mariath LM, Santin JT, Frantz JA, Doriqui MJR, Kiszewski AE, Schuler-Faccini L. An overview of the genetic basis of epidermolysis bullosa in Brazil: discovery of novel and recurrent disease-causing variants. Clin Genet 2019; 96:189-198. [PMID: 31001817 DOI: 10.1111/cge.13555] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/01/2019] [Accepted: 04/17/2019] [Indexed: 12/23/2022]
Abstract
Epidermolysis bullosa (EB) is a genodermatosis that encompasses a group of clinically and genetically heterogeneous disorders classified in four major types: EB simplex (EBS), junctional EB (JEB), dystrophic EB (DEB) and Kindler syndrome. Our aim was to characterize recurrent and novel mutations associated to EB in a sample of Brazilian patients. Eighty-seven patients (25 EBS, 4 JEB and 58 DEB) were studied. We performed a next-generation sequencing-based multigene panel through ion torrent technology including 11 genes: KRT5, KRT14, PLEC, TGM5, LAMA3, LAMB3, LAMC2, COL17A1, ITGB4, COL7A1, and FERMT1. A total of 72 different pathogenic or likely pathogenic variants were identified, 32 of them are novel. The causal variant was detected in 82 patients (efficiency of 94.3%). Pathogenic variants in the residue 125 of KRT14 were identified in 32% of all EBS patients. In DEB patients, four COL7A1 variants were quite frequent, some of them clustered in specific Brazilian regions. Our study extends the spectrum of known mutations in EB and describes, for the first time, the genetic profile of EB patients from Brazil.
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Affiliation(s)
- Luiza M Mariath
- Postgraduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Juliana T Santin
- Postgraduate Program in Child and Adolescent Health, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Jeanine A Frantz
- Faculty of Medicine, Universidade Regional de Blumenau, Blumenau, Brazil.,Board of Directors, DEBRA Brasil (Epidermolysis Bullosa Research Association of Brazil), Blumenau, Brazil
| | - Maria J R Doriqui
- Section of Medical Genetics, Hospital Infantil Dr. Juvêncio Mattos, São Luís, Brazil
| | - Ana E Kiszewski
- Section of Dermatology, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil.,Section of Pediatric Dermatology, Hospital da Criança Santo Antônio, Irmandade da Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, Brazil
| | - Lavínia Schuler-Faccini
- Postgraduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Department of Genetics, Instituto Nacional de Ciência e Tecnologia de Genética Médica Populacional (INaGeMP), Porto Alegre, Brazil
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15
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No major role for rare plectin variants in arrhythmogenic right ventricular cardiomyopathy. PLoS One 2018; 13:e0203078. [PMID: 30161220 PMCID: PMC6117038 DOI: 10.1371/journal.pone.0203078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/14/2018] [Indexed: 11/19/2022] Open
Abstract
Aims Likely pathogenic/pathogenic variants in genes encoding desmosomal proteins play an important role in the pathophysiology of arrhythmogenic right ventricular cardiomyopathy (ARVC). However, for a substantial proportion of ARVC patients, the genetic substrate remains unknown. We hypothesized that plectin, a cytolinker protein encoded by the PLEC gene, could play a role in ARVC because it has been proposed to link the desmosomal protein desmoplakin to the cytoskeleton and therefore has a potential function in the desmosomal structure. Methods We screened PLEC in 359 ARVC patients and compared the frequency of rare coding PLEC variants (minor allele frequency [MAF] <0.001) between patients and controls. To assess the frequency of rare variants in the control population, we evaluated the rare coding variants (MAF <0.001) found in the European cohort of the Exome Aggregation Database. We further evaluated plectin localization by immunofluorescence in a subset of patients with and without a PLEC variant. Results Forty ARVC patients carried one or more rare PLEC variants (11%, 40/359). However, rare variants also seem to occur frequently in the control population (18%, 4754/26197 individuals). Nor did we find a difference in the prevalence of rare PLEC variants in ARVC patients with or without a desmosomal likely pathogenic/pathogenic variant (14% versus 8%, respectively). However, immunofluorescence analysis did show decreased plectin junctional localization in myocardial tissue from 5 ARVC patients with PLEC variants. Conclusions Although PLEC has been hypothesized as a promising candidate gene for ARVC, our current study did not show an enrichment of rare PLEC variants in ARVC patients compared to controls and therefore does not support a major role for PLEC in this disorder. Although rare PLEC variants were associated with abnormal localization in cardiac tissue, the confluence of data does not support a role for plectin abnormalities in ARVC development.
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16
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Abstract
Skin fragility refers to a large group of conditions in which the ability of the skin to provide protection against trivial mechanical trauma is diminished, resulting in the formation of blisters, erosions, wounds, or scars. Acquired and physiological skin fragility is common; genetic disorders are rare but give insight into the molecular mechanisms ensuring skin stability. The paradigm is represented by inherited epidermolysis bullosa. This review is focused on recent advances in understanding the molecular basis of genetic skin fragility, including emerging concepts, controversies, unanswered questions, and opinions of the author. In spite of the advanced knowledge on the genetic causes of skin fragility, the molecular pathology is still expanding. Open questions in understanding the molecular basis of genetic skin fragility are the following: what are the causes of phenotypes which remain genetically unsolved, and what are the molecular modifiers which might explain phenotypic differences among individuals with similar mutations? New mutational mechanisms and new genes have recently been discovered and are briefly described here. Comprehensive next-generation sequencing-based genetic testing improved mutation detection and facilitated the identification of the genetic basis of unclear and new phenotypes. Characterization of the biochemical and cell biological consequences of the genetic variants is challenging and laborious but may represent the basis for personalized therapeutic approaches. Molecular modifiers of skin fragility have been uncovered in particular animal and genetic models but not in larger cohorts of patients. This scientific progress is the basis for revisions of the epidermolysis bullosa classification and for innovative therapeutic approaches designed for this intractable condition.
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Affiliation(s)
- Cristina Has
- Department of Dermatology and Venerology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstrasse 7, DE-79104, Freiburg, Germany
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17
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Has C, Schumann H, Leppert J, He Y, Hartmann B, Hausser I, Kohlhase J. Monoallelic Large Intragenic KRT5 Deletions Account for Genetically Unsolved Cases of Epidermolysis Bullosa Simplex. J Invest Dermatol 2017; 137:2231-2234. [PMID: 28576738 DOI: 10.1016/j.jid.2017.05.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 04/25/2017] [Accepted: 05/19/2017] [Indexed: 10/19/2022]
Affiliation(s)
- Cristina Has
- Department of Dermatology, Medical Center-University of Freiburg, Freiburg, Faculty of Medicine, University of Freiburg, Frieburg, Germany.
| | - Hauke Schumann
- Department of Dermatology, Medical Center-University of Freiburg, Freiburg, Faculty of Medicine, University of Freiburg, Frieburg, Germany
| | - Juna Leppert
- Department of Dermatology, Medical Center-University of Freiburg, Freiburg, Faculty of Medicine, University of Freiburg, Frieburg, Germany
| | - Yinghong He
- Department of Dermatology, Medical Center-University of Freiburg, Freiburg, Faculty of Medicine, University of Freiburg, Frieburg, Germany
| | | | - Ingrid Hausser
- Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany
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18
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Mauldin EA, Wang P, Olivry T, Henthorn PS, Casal ML. Epidermolysis bullosa simplex in sibling Eurasier dogs is caused by a PLEC non-sense variant. Vet Dermatol 2017; 28:10-e3. [PMID: 27878870 PMCID: PMC5324056 DOI: 10.1111/vde.12394] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND Plectin, a large linker protein found in many tissues, acts to connect components of the cytoskeleton to each other. In the epidermis, plectin binds keratin intermediate filaments to hemidesmosomes. A deficiency of plectin in the skin leads to blister formation in the basal layer and the disease epidermolysis bullosa simplex (EBS). HYPOTHESIS/OBJECTIVES To describe a novel blistering disease that arose spontaneously in a litter of puppies. ANIMALS Two female and one male 20-day-old Eurasier puppies, from a litter of six, were presented for evaluation of failure to thrive and then euthanized due to poor prognosis. The puppies had ulcers on the lips, tongue, nasal planum, paw pads and abdomen. RESULTS Immunolabelling on frozen skin for basement membrane proteins revealed patchy and weak to absent staining for plectin as compared with strong linear staining in normal dogs. Ultrastructurally, hemidesmosomes were irregularly shaped and had loss of distinction between inner and outer plaques. Pedigree analysis supported an autosomal recessive mode of inheritance. A premature stop codon was discovered in exon 27 of PLEC that resulted in the production of a severely truncated protein. CONCLUSION The study describes the first documented spontaneous EBS associated with a PLEC variant in domestic animals.
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Affiliation(s)
- Elizabeth A. Mauldin
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3900 Delancey Street, Philadelphia, PA 19104, USA
| | - Ping Wang
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3900 Delancey Street, Philadelphia, PA 19104, USA
| | - Thierry Olivry
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, 1052 William Moore Drive, Raleigh, NC 27606, USA
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27695, USA
| | - Paula S. Henthorn
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, 3900 Delancey Street, Philadelphia, PA 19104, USA
| | - Margret L. Casal
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, 3900 Delancey Street, Philadelphia, PA 19104, USA
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He Y, Maier K, Leppert J, Hausser I, Schwieger-Briel A, Weibel L, Theiler M, Kiritsi D, Busch H, Boerries M, Hannula-Jouppi K, Heikkilä H, Tasanen K, Castiglia D, Zambruno G, Has C. Monoallelic Mutations in the Translation Initiation Codon of KLHL24 Cause Skin Fragility. Am J Hum Genet 2016; 99:1395-1404. [PMID: 27889062 DOI: 10.1016/j.ajhg.2016.11.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 11/07/2016] [Indexed: 11/28/2022] Open
Abstract
The genetic basis of epidermolysis bullosa, a group of genetic disorders characterized by the mechanically induced formation of skin blisters, is largely known, but a number of cases still remain genetically unsolved. Here, we used whole-exome and targeted sequencing to identify monoallelic mutations, c.1A>G and c.2T>C, in the translation initiation codon of the gene encoding kelch-like protein 24 (KLHL24) in 14 individuals with a distinct skin-fragility phenotype and skin cleavage within basal keratinocytes. Remarkably, mutation c.1A>G occurred de novo and was recurrent in families originating from different countries. The striking similarities of the clinical features of the affected individuals point to a unique and very specific pathomechanism. We showed that mutations in the translation initiation codon of KLHL24 lead to the usage of a downstream translation initiation site with the same reading frame and formation of a truncated polypeptide. The pathobiology was examined in keratinocytes and fibroblasts of the affected individuals and via expression of mutant KLHL24, and we found mutant KLHL24 to be associated with abnormalities of intermediate filaments in keratinocytes and fibroblasts. In particular, KLHL24 mutations were associated with irregular and fragmented keratin 14. Recombinant overexpression of normal KLHL24 promoted keratin 14 degradation, whereas mutant KLHL24 showed less activity than the normal molecule. These findings identify KLHL24 mutations as a cause of skin fragility and identify a role for KLHL24 in maintaining the balance between intermediate filament stability and degradation required for skin integrity.
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Affiliation(s)
- Yinghong He
- Department of Dermatology, University Medical Center Freiburg, Freiburg 79104, Germany
| | - Kristin Maier
- Department of Dermatology, University Medical Center Freiburg, Freiburg 79104, Germany
| | - Juna Leppert
- Department of Dermatology, University Medical Center Freiburg, Freiburg 79104, Germany
| | - Ingrid Hausser
- Department of Pathology, University of Heidelberg, Heidelberg 69120, Germany
| | - Agnes Schwieger-Briel
- Department of Paediatric Dermatology, University Children's Hospital Zurich, Zurich 8091, Switzerland; Department of Dermatology, University Hospital Zurich, Zurich 8091, Switzerland
| | - Lisa Weibel
- Department of Paediatric Dermatology, University Children's Hospital Zurich, Zurich 8091, Switzerland; Department of Dermatology, University Hospital Zurich, Zurich 8091, Switzerland
| | - Martin Theiler
- Department of Paediatric Dermatology, University Children's Hospital Zurich, Zurich 8091, Switzerland; Department of Dermatology, University Hospital Zurich, Zurich 8091, Switzerland
| | - Dimitra Kiritsi
- Department of Dermatology, University Medical Center Freiburg, Freiburg 79104, Germany
| | - Hauke Busch
- Systems Biology of the Cellular Microenvironment Group, Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University Freiburg, Freiburg 79104, Germany; German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Comprehensive Cancer Center Freiburg, Freiburg 79106, Germany
| | - Melanie Boerries
- Systems Biology of the Cellular Microenvironment Group, Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University Freiburg, Freiburg 79104, Germany; German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Comprehensive Cancer Center Freiburg, Freiburg 79106, Germany
| | - Katariina Hannula-Jouppi
- Department of Dermatology and Allergology, University of Helsinki and Helsinki University Hospital, Helsinki 00014, Finland; Folkhälsan Institute of Genetics, University of Helsinki, Helsinki 00014, Finland
| | - Hannele Heikkilä
- Department of Dermatology and Allergology, University of Helsinki and Helsinki University Hospital, Helsinki 00014, Finland
| | - Kaisa Tasanen
- Department of Dermatology, PEDEGO Research Unit, Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu 90014, Finland
| | - Daniele Castiglia
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico, Rome 00167, Italy
| | - Giovanna Zambruno
- Genetic and Rare Diseases Research Area, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome 00165, Italy
| | - Cristina Has
- Department of Dermatology, University Medical Center Freiburg, Freiburg 79104, Germany.
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20
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A PLEC Isoform Identified in Skin, Muscle, and Heart. J Invest Dermatol 2016; 137:518-522. [PMID: 27769846 DOI: 10.1016/j.jid.2016.09.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 08/08/2016] [Accepted: 09/05/2016] [Indexed: 11/21/2022]
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21
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Salas PJ, Forteza R, Mashukova A. Multiple roles for keratin intermediate filaments in the regulation of epithelial barrier function and apico-basal polarity. Tissue Barriers 2016; 4:e1178368. [PMID: 27583190 PMCID: PMC4993576 DOI: 10.1080/21688370.2016.1178368] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/05/2016] [Accepted: 04/07/2016] [Indexed: 12/27/2022] Open
Abstract
As multicellular organisms evolved a family of cytoskeletal proteins, the keratins (types I and II) expressed in epithelial cells diversified in more than 20 genes in vertebrates. There is no question that keratin filaments confer mechanical stiffness to cells. However, such a number of genes can hardly be explained by evolutionary advantages in mechanical features. The use of transgenic mouse models has revealed unexpected functional relationships between keratin intermediate filaments and intracellular signaling. Accordingly, loss of keratins or mutations in keratins that cause or predispose to human diseases, result in increased sensitivity to apoptosis, regulation of innate immunity, permeabilization of tight junctions, and mistargeting of apical proteins in different epithelia. Precise mechanistic explanations for these phenomena are still lacking. However, immobilization of membrane or cytoplasmic proteins, including chaperones, on intermediate filaments (“scaffolding”) appear as common molecular mechanisms and may explain the need for so many different keratin genes in vertebrates.
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Affiliation(s)
- Pedro J Salas
- Department of Cell Biology, Miller School of Medicine, University of Miami , Miami, FL, USA
| | - Radia Forteza
- Department of Cell Biology, Miller School of Medicine, University of Miami , Miami, FL, USA
| | - Anastasia Mashukova
- Department of Cell Biology, Miller School of Medicine, University of Miami, Miami, FL, USA; Department of Physiology, Nova Southeastern University, Fort Lauderdale, FL, USA
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22
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Abstract
Epidermolysis bullosa simplex (EBS) belongs to a family of genetic conditions that cause the skin to be fragile and to blister easily. Although most of the genes involved are known, the molecular mechanisms underlying keratin aggregation remain obscure. In this issue of the Journal, Bohnekamp et al. report on a novel EBS model that is based on the de novo formation of keratin filaments in "keratin null flies."
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23
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Gostyńska KB, Nijenhuis M, Lemmink H, Pas HH, Pasmooij AMG, Lang KK, Castañón MJ, Wiche G, Jonkman MF. Mutation in exon 1a of PLEC, leading to disruption of plectin isoform 1a, causes autosomal-recessive skin-only epidermolysis bullosa simplex. Hum Mol Genet 2015; 24:3155-62. [PMID: 25712130 DOI: 10.1093/hmg/ddv066] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 02/13/2015] [Indexed: 01/07/2023] Open
Abstract
PLEC, the gene encoding the cytolinker protein plectin, has eight tissue-specific isoforms in humans, arising by alternate splicing of the first exon. To date, all PLEC mutations that cause epidermolysis bullosa simplex (EBS) were found in exons common to all isoforms. Due to the ubiquitous presence of plectin in mammalian tissues, EBS from recessive plectin mutations is always associated with extracutaneous involvement including muscular dystrophy, pyloric atresia and cardiomyopathy. We studied a consanguineous family with sisters having isolated blistering suggesting EBS. Skin disease started with foot blisters at walking age and became generalized at puberty while sparing mucous membranes. DNA sequencing revealed a homozygous nonsense mutation (c.46C>T; p.Arg16X) in the first exon of the plectin variant encoding plectin isoform 1a (P1a). Immunofluorescence antigen mapping, transmission electron microscopy, western blot analysis and qRT-PCR were performed on patient skin and cultured keratinocytes, control myocardium and striated muscle samples. We found hypoplastic hemidesmosomes and intra-epidermal 'pseudo-junctional' cleavage fitting EBS. Screening for cardiomyopathy and muscle dystrophy showed no abnormalities. We report the first cases of autosomal-recessive EBS from P1a deficiency affecting skin, while mucous membranes, heart and muscle are spared. The dominant expression of the P1a isoform in epidermal basal cell layer and cultured keratinocytes suggests that mutations in the first exon of isoform 1a cause skin-only EBS without extracutaneous involvement. Our study characterizes yet another of the eight isoforms of plectin and adds a tissue-specific phenotype to the spectrum of 'plectinopathies' produced by mutations of unique first exons of this gene.
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Affiliation(s)
| | | | - Henny Lemmink
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | | | | | - Maria J Castañón
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, Vienna, Austria
| | - Gerhard Wiche
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, Vienna, Austria
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24
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Turcan I, Jonkman MF. Blistering disease: insight from the hemidesmosome and other components of the dermal-epidermal junction. Cell Tissue Res 2014; 360:545-69. [PMID: 25502077 DOI: 10.1007/s00441-014-2021-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Accepted: 09/25/2014] [Indexed: 02/07/2023]
Abstract
The hemidesmosome is a specialized transmembrane complex that mediates the binding of epithelial cells to the underlying basement membrane. In the skin, this multiprotein structure can be regarded as the chief adhesion unit at the site of the dermal-epidermal junction. Focal adhesions are additional specialized attachment structures located between hemidesmosomes. The integrity of the skin relies on well-assembled and functional hemidesmosomes and focal adhesions (also known as integrin adhesomes). However, if these adhesion structures are impaired, e.g., as a result of circulating autoantibodies or inherited genetic mutations, the mechanical strength of the skin is compromised, leading to blistering and/or tissue inflammation. A particular clinical presentation emerges subject to the molecule that is targeted. None of these junctional complexes are simply compounds of adhesion molecules; they also play a significant role in signalling pathways involved in the differentiation and migration of epithelial cells such as during wound healing and in tumour invasion. We summarize current knowledge about hereditary and acquired blistering diseases emerging from pathologies of the hemidesmosome and its neighbouring proteins as components of the dermal-epidermal junction.
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Affiliation(s)
- Iana Turcan
- Centre for Blistering Diseases, Department of Dermatology, University Medical Centre Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands,
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25
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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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26
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Abstract
Genetic skin fragility manifests with diminished resistance of the skin and mucous membranes to external mechanical forces and with skin blistering, erosions, and painful wounds as clinical features. Skin fragility disorders, collectively called epidermolysis bullosa, are caused by mutations in 18 distinct genes that encode proteins involved in epidermal integrity and dermal-epidermal adhesion. The genetic spectrum, along with environmental and genetic modifiers, creates a large number of clinical phenotypes, spanning from minor localized lesions to severe generalized blistering, secondary skin cancer, or early demise resulting from extensive loss of the epidermis. Laboratory investigations of skin fragility have greatly augmented our understanding of genotype-phenotype correlations in epidermolysis bullosa and have also advanced skin biology in general. Current translational research concentrates on the development of biologically valid treatments with therapeutic genes, cells, proteins, or small-molecule compounds in preclinical settings or human pilot trials.
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Affiliation(s)
- Cristina Has
- Department of Dermatology, Medical Center-University of Freiburg, Freiburg 79104, Germany;
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27
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Salam A, Proudfoot LE, McGrath JA. Inherited blistering skin diseases: underlying molecular mechanisms and emerging therapies. Ann Med 2014; 46:49-61. [PMID: 24447048 DOI: 10.3109/07853890.2013.866441] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A key function of human skin is the formation of a structural barrier against the external environment. In part, this is achieved through the formation of a cornified cell envelope derived from a stratified squamous epithelium attached to an epithelial basement membrane. Resilient in health, the structural integrity of skin can become impaired or break down in a collection of inherited skin diseases, referred to as the blistering genodermatoses. These disorders arise from inherited gene mutations in a variety of structural and signalling proteins and manifest clinically as blisters or erosions following minor skin trauma. In some patients, blistering can be severe resulting in significant morbidity. Furthermore, a number of these conditions are associated with debilitating extra-cutaneous manifestations including gastro-intestinal, cardiac, and ocular complications. In recent years, an improved understanding of the molecular basis of the blistering genodermatoses has led to better disease classification and genetic counselling. For patients, this has also advanced translational research with the advent of new clinical trials of gene, protein, cell, drug, and small molecule therapies. Although curing inherited blistering skin diseases still remains elusive, significant improvements in patients' quality of life are already being achieved.
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Affiliation(s)
- Amr Salam
- St John's Institute of Dermatology, King's College London , Floor 9 Tower Wing, Guy's Hospital, Great Maze Pond, London SE1 9RT , UK
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28
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Beyond expectations: novel insights into epidermal keratin function and regulation. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 311:265-306. [PMID: 24952920 DOI: 10.1016/b978-0-12-800179-0.00007-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The epidermis is a stratified epithelium that relies on its cytoskeleton and cell junctions to protect the body against mechanical injury, dehydration, and infections. Keratin intermediate filament proteins are involved in many of these functions by forming cell-specific cytoskeletal scaffolds crucial for the maintenance of cell and tissue integrity. In response to various stresses, the expression and organization of keratins are altered at transcriptional and posttranslational levels to restore tissue homeostasis. Failure to restore tissue homeostasis in the presence of keratin gene mutations results in acute and chronic skin disorders for which currently no rational therapies are available. Here, we review the recent progress on the role of keratins in cytoarchitecture, adhesion, signaling, and inflammation. By focusing on epidermal keratins, we illustrate the contribution of keratin isotypes to differentiated epithelial functions.
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