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Frommherz L, Krause A, Kopp J, Hotz A, Hübner S, Reimer-Taschenbrecker A, Casetti F, Zirn B, Fischer J, Has C. High rate of self-improving phenotypes in children with non-syndromic congenital ichthyosis: case series from south-western Germany. J Eur Acad Dermatol Venereol 2021; 35:2293-2299. [PMID: 34273205 DOI: 10.1111/jdv.17524] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 07/02/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Non-syndromic congenital ichthyosis describes a heterogeneous group of hereditary skin disorders associated with erythroderma and scaling at birth. Although both severe and mild courses are known, the prediction of the natural history in clinical practice may be challenging. OBJECTIVES To determine clinical course and genotype-phenotype correlations in children affected by non-syndromic congenital ichthyosis in a case series from south-western Germany. METHODS We performed a retrospective observational study of 32 children affected by non-syndromic congenital ichthyoses seen in our genodermatosis clinic between 2011 and 2020. Follow-ups included assessment of weight and severity of skin involvement utilizing a modified Ichthyosis Area Severity Index (mIASI). mIASI was calculated as a sum comprising the previously published IASI score and an additional novel score to evaluate palmoplantar involvement. Linear regression was assessed using Pearson correlation, and statistical analysis was performed using the Wilcoxon-Mann-Whitney test. RESULTS This study included 23 patients with autosomal recessive congenital ichthyosis, seven with keratinopathic ichthyosis and two with harlequin ichthyosis. Cutaneous manifestations improved in more than 70% of the children during the follow-up. Especially in patients with mutations in ALOXE3 and ALOX12B, mIASI scores dropped significantly. The most common phenotype observed in this study was designated 'mild fine scaling ichthyosis'. Severe palmoplantar involvement occurred in patients with KRT1 and ABCA12 mutations; most patients demonstrated hyperlinearity as a sign of dryness and scaling. Weight was mainly in the normal range and negatively correlated with the severity of skin involvement. CONCLUSIONS Congenital ichthyosis that self-improves and evolves with mild fine scaling ichthyosis was the most common phenotype observed in our patients. This type might be underdiagnosed if the genetic diagnosis is not performed in the first year of life. mIASI is an easy and fast instrument for scoring disease severity and adding additional points for palmoplantar involvement might be valuable.
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Affiliation(s)
- L Frommherz
- Faculty of Medicine, Department of Dermatology, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany.,Department of Dermatology and Allergy, University Hospital, LMU Munich, Munich, Germany
| | - A Krause
- Faculty of Medicine, Department of Dermatology, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - J Kopp
- Institute of Human Genetics, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - A Hotz
- Institute of Human Genetics, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - S Hübner
- Faculty of Medicine, Department of Dermatology, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - A Reimer-Taschenbrecker
- Faculty of Medicine, Department of Dermatology, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - F Casetti
- Faculty of Medicine, Department of Dermatology, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - B Zirn
- Genetikum® Stuttgart, Genetic Counselling and Diagnostics, Stuttgart, Germany
| | - J Fischer
- Institute of Human Genetics, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - C Has
- Faculty of Medicine, Department of Dermatology, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
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2
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Koller U, Bauer JW. Gene Replacement Therapies for Genodermatoses: A Status Quo. Front Genet 2021; 12:658295. [PMID: 33995490 PMCID: PMC8120236 DOI: 10.3389/fgene.2021.658295] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/17/2021] [Indexed: 11/29/2022] Open
Abstract
Epidermolysis bullosa (EB) is a genodermatosis, characterized by the formation of extended blisters and lesions on the skin and mucous membranes upon minimal mechanical trauma. The disease is caused by mutations in genes encoding proteins that are essential for skin stability. Functional impairment, reduction, or absence of one of these proteins results in skin fragility due to reduced connectivity between dermis and epidermis. Currently, gene therapy represents the only treatment option with the potential to cure this severe blistering skin disease. Two promising forms of gene therapy are potentially feasible for EB: gene replacement and genome editing. While genome editing for genodermatoses remains at the preclinical stage, gene replacement approaches are clinically advanced and have been applied already to a small number of patients with junctional and dystrophic forms of EB. Here, the viral transduction of the “wild-type” transgene into skin stem cells, followed by autologous grafting of corrected epidermal sheets, led to the regeneration of stable skin. Recent developments regarding designer nuclease-based gene editing strategies enable the establishment of alternative options to restore the gene function in genodermatoses. This is particularly true in cases wherein genetic constellation hinders gene therapy-based gene replacement.
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Affiliation(s)
- Ulrich Koller
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Johann W Bauer
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
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3
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Kocher T, Koller U. Advances in gene editing strategies for epidermolysis bullosa. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 182:81-109. [PMID: 34175052 DOI: 10.1016/bs.pmbts.2020.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Epidermolysis bullosa represents a monogenetic disease comprising a variety of heterogeneous mutations in at least 16 genes encoding structural proteins crucial for skin integrity. Due to well-defined mutations but still lacking causal treatment options for the disease, epidermolysis bullosa represents an ideal candidate for gene therapeutic interventions. Recent developments and improvements in the genome editing field have paved the way for the translation of various gene repair strategies into the clinic. With the ability to accurately predict and monitor targeting events within the human genome, the translation might soon be possible. Here, we describe current advancements in the genome editing field for epidermolysis bullosa, along with a discussion of aspects and strategies for precise and personalized gene editing-based medicine, in order to develop efficient and safe ex vivo as well as in vivo genome editing therapies for epidermolysis bullosa patients in the future.
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Affiliation(s)
- Thomas Kocher
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Ulrich Koller
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University Salzburg, Salzburg, Austria.
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4
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March OP, Kocher T, Koller U. Context-Dependent Strategies for Enhanced Genome Editing of Genodermatoses. Cells 2020; 9:E112. [PMID: 31906492 PMCID: PMC7016731 DOI: 10.3390/cells9010112] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/27/2019] [Accepted: 12/31/2019] [Indexed: 12/17/2022] Open
Abstract
The skin provides direct protection to the human body from assault by the harsh external environment. The crucial function of this organ is significantly disrupted in genodermatoses patients. Genodermatoses comprise a heterogeneous group of largely monogenetic skin disorders, typically involving mutations in genes encoding structural proteins. Therapeutic options for this debilitating group of diseases, including epidermolysis bullosa, primarily consist of wound management. Genome editing approaches co-opt double-strand break repair pathways to introduce desired sequence alterations at specific loci. Rapid advances in genome editing technologies have the potential to propel novel genetic therapies into the clinic. However, the associated phenotypes of many mutations may be treated via several genome editing strategies. Therefore, for potential clinical applications, implementation of efficient approaches based upon mutation, gene and disease context is necessary. Here, we describe current genome editing approaches for the treatment of genodermatoses, along with a discussion of the optimal strategy for each genetic context, in order to achieve enhanced genome editing approaches.
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Affiliation(s)
| | | | - Ulrich Koller
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (O.P.M.); (T.K.)
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5
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Frommherz L, Küsel J, Zimmer A, Fischer J, Has C. Withdrawn:
Skin fragility caused by biallelic
KRT10
mutations: an intriguing form of self‐improving epidermolytic ichthyosis. Br J Dermatol 2019; 182:780-785. [DOI: 10.1111/bjd.18325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2019] [Indexed: 12/20/2022]
Affiliation(s)
- L. Frommherz
- Department of Dermatology Medical Center – University of Freiburg Faculty of Medicine Hauptstraße 7 79104 Freiburg Germany
| | - J. Küsel
- Institute of Human Genetics Medical Center – University of Freiburg Faculty of Medicine Hauptstraße 7 79104 Freiburg Germany
| | - A. Zimmer
- Institute of Human Genetics Medical Center – University of Freiburg Faculty of Medicine Hauptstraße 7 79104 Freiburg Germany
| | - J. Fischer
- Institute of Human Genetics Medical Center – University of Freiburg Faculty of Medicine Hauptstraße 7 79104 Freiburg Germany
| | - C. Has
- Department of Dermatology Medical Center – University of Freiburg Faculty of Medicine Hauptstraße 7 79104 Freiburg Germany
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6
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Gene Editing–Mediated Disruption of Epidermolytic Ichthyosis–Associated KRT10 Alleles Restores Filament Stability in Keratinocytes. J Invest Dermatol 2019; 139:1699-1710.e6. [DOI: 10.1016/j.jid.2019.03.1146] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/27/2019] [Accepted: 03/04/2019] [Indexed: 12/28/2022]
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7
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Vodo D, Sarig O, Peled A, Samuelov L, Malchin N, Grafi-Cohen M, Sprecher E. Recessive epidermolytic ichthyosis results from loss of keratin 10 expression, regardless of the mutation location. Clin Exp Dermatol 2017; 43:187-190. [DOI: 10.1111/ced.13324] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2017] [Indexed: 12/01/2022]
Affiliation(s)
- D. Vodo
- Department of Dermatology; Tel-Aviv Sourasky Medical Center; Tel-Aviv Israel
- Department of Human Molecular Genetics; Sackler Faculty of Medicine; Tel-Aviv University; Tel-Aviv Israel
| | - O. Sarig
- Department of Dermatology; Tel-Aviv Sourasky Medical Center; Tel-Aviv Israel
| | - A. Peled
- Department of Dermatology; Tel-Aviv Sourasky Medical Center; Tel-Aviv Israel
- Department of Human Molecular Genetics; Sackler Faculty of Medicine; Tel-Aviv University; Tel-Aviv Israel
| | - L. Samuelov
- Department of Dermatology; Tel-Aviv Sourasky Medical Center; Tel-Aviv Israel
| | - N. Malchin
- Department of Dermatology; Tel-Aviv Sourasky Medical Center; Tel-Aviv Israel
| | - M. Grafi-Cohen
- Department of Dermatology; Tel-Aviv Sourasky Medical Center; Tel-Aviv Israel
| | - E. Sprecher
- Department of Dermatology; Tel-Aviv Sourasky Medical Center; Tel-Aviv Israel
- Department of Human Molecular Genetics; Sackler Faculty of Medicine; Tel-Aviv University; Tel-Aviv Israel
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8
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Al Raddadi AA, Habibullah TH, Abdelaal AM, Felimban AM, Al Raddadi HA, Satti MB. Epidermolytic Ichthyosis without Keratin 1 or 10 Mutations: A Case Report. SAUDI JOURNAL OF MEDICINE AND MEDICAL SCIENCES 2017; 6:36-39. [PMID: 30787815 PMCID: PMC6196674 DOI: 10.4103/1658-631x.220800] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this paper, the authors report a case of an 11-year-old boy with epidermolytic ichthyosis who presented with multiple scattered erosions and typical hyperkeratotic plaques over the face, upper and lower extremities, the trunk, palms and soles. Family history revealed an affected older male sibling and an affected first-degree female relative. In addition, there was a positive history of generations of consanguinity in the patient's family pedigree, increasing the probability of an autosomal recessive inheritance. The clinical diagnosis was confirmed by histopathology; however, mutations in the keratin 1 and 10 genes were absent. This case report addresses the importance of establishing correct diagnosis and mode of inheritance, with literature review of genetic mutations, possible differential diagnosis and the most common and successful treatment modalities for epidermolytic ichthyosis.
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Affiliation(s)
- Ali A Al Raddadi
- Department of Medicine, Section of Dermatology, King Abdulaziz Medical City, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Kingdom of Saudi Arabia
| | - Taha H Habibullah
- Department of Medicine, Section of Dermatology, King Abdulaziz Medical City, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Kingdom of Saudi Arabia
| | - Ahmed M Abdelaal
- Department of Pathology, King Abdulaziz Medical City, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Kingdom of Saudi Arabia
| | - Angie M Felimban
- Department of Medicine, Section of Dermatology, King Abdulaziz Medical City, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Kingdom of Saudi Arabia
| | - Hosam A Al Raddadi
- Department of Medicine, Section of Dermatology, King Abdulaziz Medical City, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Kingdom of Saudi Arabia
| | - Mohamed B Satti
- Department of Pathology, King Abdulaziz Medical City, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Kingdom of Saudi Arabia
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9
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Takeichi T, Akiyama M. Inherited ichthyosis: Non-syndromic forms. J Dermatol 2016; 43:242-51. [DOI: 10.1111/1346-8138.13243] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 10/25/2015] [Indexed: 11/25/2022]
Affiliation(s)
- Takuya Takeichi
- Department of Dermatology; Nagoya University Graduate School of Medicine; Nagoya Japan
| | - Masashi Akiyama
- Department of Dermatology; Nagoya University Graduate School of Medicine; Nagoya Japan
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10
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Gutierrez JA, Hannoush ZC, Vargas LG, Momany A, Garcia CC, Murray JC, Dunnwald M. A Novel non-sense Mutation in Keratin 10 Causes a Familial Case of Recessive Epidermolytic Ichthyosis. Mol Genet Genomic Med 2013; 1:108-112. [PMID: 23957016 PMCID: PMC3744379 DOI: 10.1002/mgg3.6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Epidermolytic ichthyosis (EI) is a rare skin disorder characterized by generalized erythroderma and cutaneous blistering at birth, which is substituted by hyperkeratosis later in life. It is caused by autosomal dominant mutations in highly conserved regions of KRT1 and KRT10. To date, only four mutations with autosomal recessive inheritance of EI have been described in consanguineous families. All of them affect the 2B domain of KRT10. In the present study, we describe four patients with EI (including one lethal case) born from unaffected parents in a consanguineous family of a native Venezuelan community. The objective of this study was to characterize the clinical, genetic, and morphological aspects of the disease in this family, as well as understand its functional implications. Genomic DNA was sequenced for KRT10 and KRT1. Immunofluoresence for keratin expression was performed on cutaneous biopsies. After examination of cutaneous biopsies histology, our results showed hyperkeratosis and acantholysis with an expanded granular layer. Sequencing of KRT10 demonstrated a nonsense mutation (p.Tyr282Ter.) corresponding to the 1B domain of the protein in patients and a heterozygous pattern in other family members, resulting in complete absence of K10. The loss of K10 was compensated by upregulation of K14 and K17. In conclusion, this novel mutation in KRT10 is the first recessive genetic variation that is not located in the so called “hot spot” for recessive EI, suggesting that other areas of the gene are also susceptible for such mutations.
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Affiliation(s)
- Jeydith A Gutierrez
- Internal Medicine Department, Carver College of Medicine, University of IowaIowa City, Iowa
| | - Zeina C Hannoush
- Escuela de Medicina Luis Razetti, Universidad Central de VenezuelaCaracas, Venezuela
| | - Luis G Vargas
- Escuela de Medicina Luis Razetti, Universidad Central de VenezuelaCaracas, Venezuela
| | - Allison Momany
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa City, Iowa
| | - Carmen C Garcia
- Cátedra de Patología General y Fisiopatología, Instituto de Medicina Experimental, Universidad Central de Venezuela (UCV)Caracas, Venezuela
| | - Jeffrey C Murray
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa City, Iowa
| | - Martine Dunnwald
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa City, Iowa
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11
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Bowden PE. Gene therapy for keratin genodermatoses: striving forward but obstacles persist. J Invest Dermatol 2011; 131:1403-5. [PMID: 21673708 DOI: 10.1038/jid.2011.121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
D'Alessandro and colleagues have investigated stress responses in keratinocyte cell lines lacking keratin 14 (K14-null mutation). In this issue, they describe the use of this model to assess the extent of phenotypic rescue achievable by wild-type K14 in the absence of a dominant negative mutation. This work provides proof that, in principle, transfection of wild-type K14 on a null background can significantly normalize the cell and reduce stress responses. However, hurdles to gene therapy in vivo persist because the majority of patients with keratin genodermatoses have heterozygous dominant negative mutations, which are more disruptive than those of the null state. Although correction in the laboratory is now relatively routine, gene delivery to the skin of patients and stable correction of mutations remain major challenges.
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Affiliation(s)
- Paul E Bowden
- Department of Dermatology and Wound Healing, School of Medicine, Cardiff University, Heath Park, Cardiff, UK.
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12
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Arin MJ, Oji V, Emmert S, Hausser I, Traupe H, Krieg T, Grimberg G. Expanding the keratin mutation database: novel and recurrent mutations and genotype-phenotype correlations in 28 patients with epidermolytic ichthyosis. Br J Dermatol 2011; 164:442-7. [PMID: 21271994 DOI: 10.1111/j.1365-2133.2010.10096.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Epidermolytic ichthyosis (EI) is a hereditary keratinization disorder caused by mutations in the keratin 1 (KRT1) or keratin 10 (KRT10) genes. In most cases of severe EI, heterozygous single point mutations are found at the highly conserved helix boundary motifs of KRT1 and KRT10 that play a critical role in filament formation. The presence of palmoplantar keratoderma suggests KRT1 mutations, whereas KRT10 mutations in most instances give rise to the nonpalmoplantar variants. OBJECTIVES To identify the underlying mutations in patients with EI and to correlate genotype and phenotype. METHODS Mutation analysis was performed in 28 patients with EI by direct sequencing of KRT1 and KRT10 genes. RESULTS We identified 14 different mutations, of which four have not been published previously. CONCLUSIONS Identification of novel mutations and genotype-phenotype correlations in EI allows improved understanding of disease pathogenesis as well as better patient management.
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Affiliation(s)
- M J Arin
- Department of Dermatology, University of Cologne, Kerpener Strasse 62, 50931 Cologne, Germany.
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13
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Chamcheu JC, Pihl-Lundin I, Mouyobo CE, Gester T, Virtanen M, Moustakas A, Navsaria H, Vahlquist A, Törmä H. Immortalized keratinocytes derived from patients with epidermolytic ichthyosis reproduce the disease phenotype: a useful in vitro model for testing new treatments. Br J Dermatol 2011; 164:263-72. [PMID: 20977447 DOI: 10.1111/j.1365-2133.2010.10092.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Epidermolytic ichthyosis (EI) is a skin fragility disorder caused by mutations in genes encoding suprabasal keratins 1 and 10. While the aetiology of EI is known, model systems are needed for pathophysiological studies and development of novel therapies. OBJECTIVES To generate immortalized keratinocyte lines from patients with EI for studies of EI cell pathology and the effects of chemical chaperones as putative therapies. METHODS We derived keratinocytes from three patients with EI and one healthy control and established immortalized keratinocytes using human papillomavirus 16-E6/E7. Growth and differentiation characteristics, ability to regenerate organotypic epidermis, keratin expression, formation of cytoskeletal aggregates, and responses to heat shock and chemical chaperones were assessed. RESULTS The cell lines EH11 (K1_p.Val176_Lys197del), EH21 (K10_p.156Arg>Gly), EH31 (K10_p.Leu161_Asp162del) and NKc21 (wild-type) currently exceed 160 population doublings and differentiate when exposed to calcium. At resting state, keratin aggregates were detected in 9% of calcium-differentiated EH31 cells, but not in any other cell line. Heat stress further increased this proportion to 30% and also induced aggregates in 3% of EH11 cultures. Treatment with trimethylamine N-oxide and 4-phenylbutyrate (4-PBA) reduced the fraction of aggregate-containing cells and affected the mRNA expression of keratins 1 and 10 while 4-PBA also modified heat shock protein 70 (HSP70) expression. Furthermore, in situ proximity ligation assay suggested a colocalization between HSP70 and keratins 1 and 10. Reconstituted epidermis from EI cells cornified but EH21 and EH31 cells produced suprabasal cytolysis, closely resembling the in vivo phenotype. CONCLUSIONS These immortalized cell lines represent a useful model for studying EI biology and novel therapies.
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Affiliation(s)
- J C Chamcheu
- Department of Medical Sciences, Dermatology and Venereology, University Hospital, Uppsala University, SE-751 85 Uppsala, Sweden.
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14
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Keratin gene mutations in disorders of human skin and its appendages. Arch Biochem Biophys 2010; 508:123-37. [PMID: 21176769 DOI: 10.1016/j.abb.2010.12.019] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 12/16/2010] [Indexed: 11/21/2022]
Abstract
Keratins, the major structural protein of all epithelia are a diverse group of cytoskeletal scaffolding proteins that form intermediate filament networks, providing structural support to keratinocytes that maintain the integrity of the skin. Expression of keratin genes is usually regulated by differentiation of the epidermal cells within the stratifying squamous epithelium. Amongst the 54 known functional keratin genes in humans, about 22 different genes including, the cornea, hair and hair follicle-specific keratins have been implicated in a wide range of hereditary diseases. The exact phenotype of each disease usually reflects the spatial expression level and the types of mutated keratin genes, the location of the mutations and their consequences at sub-cellular levels as well as other epigenetic and/or environmental factors. The identification of specific pathogenic mutations in keratin disorders formed the basis of our understanding that led to re-classification, improved diagnosis with prognostic implications, prenatal testing and genetic counseling in severe keratin genodermatoses. Molecular defects in cutaneous keratin genes encoding for keratin intermediate filaments (KIFs) causes keratinocytes and tissue-specific fragility, accounting for a large number of genetic disorders in human skin and its appendages. These diseases are characterized by keratinocytes fragility (cytolysis), intra-epidermal blistering, hyperkeratosis, and keratin filament aggregation in severely affected tissues. Examples include epidermolysis bullosa simplex (EBS; K5, K14), keratinopathic ichthyosis (KPI; K1, K2, K10) i.e. epidermolytic ichthyosis (EI; K1, K10) and ichthyosis bullosa of Siemens (IBS; K2), pachyonychia congenita (PC; K6a, K6b, K16, K17), epidermolytic palmo-plantar keratoderma (EPPK; K9, (K1)), monilethrix (K81, K83, K86), ectodermal dysplasia (ED; K85) and steatocystoma multiplex. These keratins also have been identified to have roles in apoptosis, cell proliferation, wound healing, tissue polarity and remodeling. This review summarizes and discusses the clinical, ultrastructural, molecular genetics and biochemical characteristics of a broad spectrum of keratin-related genodermatoses, with special clinical emphasis on EBS, EI and PC. We also highlight current and emerging model tools for prognostic future therapies. Hopefully, disease modeling and in-depth understanding of the molecular pathogenesis of the diseases may lead to the development of novel therapies for several hereditary cutaneous diseases.
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15
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Covaciu C, Castori M, De Luca N, Ghirri P, Nannipieri A, Ragone G, Zambruno G, Castiglia D. Lethal autosomal recessive epidermolytic ichthyosis due to a novel donor splice-site mutation in KRT10. Br J Dermatol 2010; 162:1384-7. [PMID: 20302579 DOI: 10.1111/j.1365-2133.2010.09665.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Epidermolytic ichthyosis (EI; MIM 113800), previously named bullous congenital ichthyosiform erythroderma or epidermolytic hyperkeratosis, is a rare and clinically variable defect of cornification characterized by generalized erythema, erosions, scaling and easily breaking blisters that become less frequent later in life while hyperkeratosis increases. EI is caused by dominant mutations in either KRT1 or KRT10, encoding keratin 1 (K1) and keratin 10 (K10), respectively. Usually, mutations are missense substitutions into the highly conserved α-helical rod domains of the proteins. However, three inbred pedigrees in which EI is transmitted as a recessive trait due to KRT10 null mutations have been described.
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Affiliation(s)
- C Covaciu
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata-IRCCS, via dei Monti di Creta 104, I-00167 Rome, Italy
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