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Gao Y, Zhang Q, Zhang S, Yang L, Liu Y, Liu Y, Wang T. A Connexin Gene (GJB3) Mutation in a Chinese Family With Erythrokeratodermia Variabilis, Ichthyosis and Nonsyndromic Hearing Loss: Case Report and Mutations Update. Front Genet 2022; 13:797124. [PMID: 35677558 PMCID: PMC9168653 DOI: 10.3389/fgene.2022.797124] [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: 11/20/2021] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Gap junctions formed by connexins are channels on cytoplasm functioning in ion recycling and homeostasis. Some members of connexin family including connexin 31 are significant components in human skin and cochlea. In clinic, mutations of connexin 31 have been revealed as the cause of a rare hereditary skin disease called erythrokeratodermia variabilis (EKV) and non-syndromic hearing loss (NSHL).Objective: To determine the underlying genetic cause of EKV, ichthyosis and NSHL in three members of a Chinese pedigree and skin histologic characteristics of the EKV patient.Methods: By performing whole exome sequencing (WES), Sanger sequencing and skin biopsy, we demonstrate a Chinese pedigree carrying a mutation of GJB3 with three patients separately diagnosed with EKV, ichthyosis and NSHL.Results: The proband, a 6-year-old Chinese girl, presented with demarcated annular red-brown plaques and hyperkeratotic scaly patches on her trunk and limbs. Her mother has ichthyosis with hyperkeratosis and geographic tongue while her younger brother had NSHL since birth. Mutation analysis revealed all of them carried a heterozygous missense mutation c.293G>A of GJB3. Skin biopsy showed many grain cells with dyskeratosis in the granular layer. Acanthosis, papillomatosis, and a mild superficial perivascular lymphocytic infiltrate were observed.Conclusion: A mutation of GJB3 associated with EKV, ichthyosis and NSHL is reported in this case. The daughter with EKV and the son with NSHL in this Chinese family inherited the mutation from their mother with ichthyosis. The variation of clinical features may involve with genetic, epigenetic and environmental factors.
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Affiliation(s)
- Yajuan Gao
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, National Clinical Research Center for Dermatologic and Immunologic Diseases, Beijing, China
| | - Qianli Zhang
- Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shiyu Zhang
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, National Clinical Research Center for Dermatologic and Immunologic Diseases, Beijing, China
| | - Lu Yang
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, National Clinical Research Center for Dermatologic and Immunologic Diseases, Beijing, China
| | - Yaping Liu
- Department of Medical Genetics and National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- *Correspondence: Yaping Liu, ; Yuehua Liu, ; Tao Wang,
| | - Yuehua Liu
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, National Clinical Research Center for Dermatologic and Immunologic Diseases, Beijing, China
- *Correspondence: Yaping Liu, ; Yuehua Liu, ; Tao Wang,
| | - Tao Wang
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, National Clinical Research Center for Dermatologic and Immunologic Diseases, Beijing, China
- *Correspondence: Yaping Liu, ; Yuehua Liu, ; Tao Wang,
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Interrogation of Carboxy-Terminus Localized GJA1 Variants Associated with Erythrokeratodermia Variabilis et Progressiva. Int J Mol Sci 2022; 23:ijms23010486. [PMID: 35008913 PMCID: PMC8745721 DOI: 10.3390/ijms23010486] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/17/2021] [Accepted: 12/24/2021] [Indexed: 02/04/2023] Open
Abstract
Although inherited GJA1 (encoding Cx43) gene mutations most often lead to oculodentodigital dysplasia and related disorders, four variants have been linked to erythrokeratodermia variabilis et progressiva (EKVP), a skin disorder characterized by erythematous and hyperkeratotic lesions. While two autosomal-dominant EKVP-linked GJA1 mutations have been shown to lead to augmented hemichannels, the consequence(s) of keratinocytes harboring a de novo P283L variant alone or in combination with a de novo T290N variant remain unknown. Interestingly, these variants reside within or adjacent to a carboxy terminus polypeptide motif that has been shown to be important in regulating the internalization and degradation of Cx43. Cx43-rich rat epidermal keratinocytes (REKs) or Cx43-ablated REKs engineered to express fluorescent protein-tagged P283L and/or T290N variants formed prototypical gap junctions at cell-cell interfaces similar to wildtype Cx43. Dye coupling and dye uptake studies further revealed that each variant or a combination of both variants formed functional gap junction channels, with no evidence of augmented hemichannel function or induction of cell death. Tracking the fate of EKVP-associated variants in the presence of the protein secretion blocker brefeldin A, or an inhibitor of protein synthesis cycloheximide, revealed that P283L or the combination of P283L and T290N variants either significantly extended Cx43 residency on the cell surface of keratinocytes or delayed its degradation. However, caution is needed in concluding that this modest change in the Cx43 life cycle is sufficient to cause EKVP, or whether an additional underlying mechanism or another unidentified gene mutation is contributing to the pathogenesis found in patients. This question will be resolved if further patients are identified where whole exome sequencing reveals a Cx43 P283L variant alone or, in combination with a T290N variant, co-segregates with EKVP across several family generations.
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Charfeddine C, Laroussi N, Mkaouar R, Jouini R, Khayat O, Redissi A, Mosbah A, Dallali H, Chedly Debbiche A, Zaouak A, Fenniche S, Abdelhak S, Hammami-Ghorbel H. Expanding the clinical phenotype associated with NIPAL4 mutation: Study of a Tunisian consanguineous family with erythrokeratodermia variabilis-Like Autosomal Recessive Congenital Ichthyosis. PLoS One 2021; 16:e0258777. [PMID: 34669720 PMCID: PMC8528321 DOI: 10.1371/journal.pone.0258777] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 10/05/2021] [Indexed: 11/19/2022] Open
Abstract
Erythrokeratodermia variabilis (EKV) is a rare disorder of cornification usually associated with dominant mutations in the GJB3 and GJB4 genes encoding connexins (Cx)31 and 30.3. Genetic heterogeneity of EKV has already been suggested. We investigated at the clinical and genetic level a consanguineous Tunisian family with 2 sisters presenting an autosomal recessive form of EKV to better characterize this disease. Mutational analysis initially screened the connexin genes and Whole-exome sequencing (WES) was performed to identify the molecular aetiology of the particular EKV phenotype in the proband. Migratory shaped erythematous areas are the initial presenting sign followed by relatively stable hyperkeratotic plaques are the two predominates characteristics in both patients. However, remarkable variability of morphological and dominating features of the disease were observed between patients. In particular, the younger sister (proband) exhibited ichthyosiform-like appearance suggesting Autosomal Recessive Congenital Ichthyosis (ARCI) condition. No causative mutations were detected in the GJB3 and GJB4 genes. WES results revealed a novel missense homozygous mutation in NIPAL4 gene (c.835C>G, p.Pro279Ala) in both patients. This variant is predicted to be likely pathogenic. In addition, in silico analysis of the mutated 3D domain structure predicted that this variant would result in NIPA4 protein destabilization and Mg2+ transport perturbation, pointing out the potential role of NIPAL4 gene in the development and maintenance of the barrier function of the epidermis. Taken togheter, these results expand the clinical phenotype associated with NIPAL4 mutation and reinforce our hypothesis of NIPAL4 as the main candidate gene for the EKV-like ARCI phenotype.
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Affiliation(s)
- Cherine Charfeddine
- University Tunis El Manar, Institut Pasteur de Tunis, Biomedical Genomics and Oncogenetics Laboratory, LR20IPT05, Tunis, Tunisia
- Université de la Manouba, Institut de Biotechnologie de Sidi Thabet, Ariana, Tunisia
- * E-mail:
| | - Nadia Laroussi
- University Tunis El Manar, Institut Pasteur de Tunis, Biomedical Genomics and Oncogenetics Laboratory, LR20IPT05, Tunis, Tunisia
| | - Rahma Mkaouar
- University Tunis El Manar, Institut Pasteur de Tunis, Biomedical Genomics and Oncogenetics Laboratory, LR20IPT05, Tunis, Tunisia
| | - Raja Jouini
- Department of Pathology, Habib Thameur Hospital, Tunis, Tunisia
| | - Olfa Khayat
- Department of Pathology, Habib Thameur Hospital, Tunis, Tunisia
| | - Aladin Redissi
- BVBGR-LR11ES31, ISBST, Université de la Manouba, Institut de Biotechnologie de Sidi Thabet, Ariana, Tunisia
| | - Amor Mosbah
- BVBGR-LR11ES31, ISBST, Université de la Manouba, Institut de Biotechnologie de Sidi Thabet, Ariana, Tunisia
| | - Hamza Dallali
- University Tunis El Manar, Institut Pasteur de Tunis, Biomedical Genomics and Oncogenetics Laboratory, LR20IPT05, Tunis, Tunisia
| | | | - Anissa Zaouak
- Department of Dermatology, Genodermatosis and Cancers Laboratory LR12SP03, Habib Thameur Hospital, Tunis, Tunisia
| | - Sami Fenniche
- Department of Dermatology, Genodermatosis and Cancers Laboratory LR12SP03, Habib Thameur Hospital, Tunis, Tunisia
| | - Sonia Abdelhak
- University Tunis El Manar, Institut Pasteur de Tunis, Biomedical Genomics and Oncogenetics Laboratory, LR20IPT05, Tunis, Tunisia
| | - Houda Hammami-Ghorbel
- Department of Dermatology, Genodermatosis and Cancers Laboratory LR12SP03, Habib Thameur Hospital, Tunis, Tunisia
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Li C, Liang J, Chen P, Zeng K, Xue R, Tian X, Liang L, Wang Q, Shi M, Zhang X. Two de novo GJA1 mutation in two sporadic patients with erythrokeratodermia variabilis et progressiva. Mol Genet Genomic Med 2019; 7:e670. [PMID: 30924322 PMCID: PMC6565561 DOI: 10.1002/mgg3.670] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/02/2019] [Accepted: 03/04/2019] [Indexed: 01/05/2023] Open
Abstract
Background Erythrokeratodermia variabilis et progressiva (EKVP, OMIM 133200) is a rare hereditary disorder characterized by varies from transient, fast moving erythema to persistent brown hyperkeratotic plaques. Recently, mutations in the genes gap junction alpha 1 gene (GJA1), GJB3, and GJB4 have been reported to cause EKVP. Here, we report the identification of two de novo missense mutations in the GJA1 gene in two unrelated individuals with EKVP. Methods The patients and his family members were subjected to mutation detection in the candidate gene GJA1, GJB3, and GJB4 by Sanger sequencing. The expression of connexin (Cx) 43 was detected by immunohistochemistry and immunofluorescence (IF) studies in the lesions. Results A 12‐year‐old boy presented with multiple hyperkeratotic plaques on the face, neck, elbows, wrists, limbs, knees, inguinal region, hands, and feet. A 7‐year‐old girl presented with symmetrical erythematous, plaques on the hands, feet, wrists, and ankles. A novel heterozygous missense mutation c.848C > T (p.P283L) in exon 2 of the GJA1 gene was identified in both patients. A novel heterozygous missense mutation c.869C > A (p.T290N) in exon 2 of the GJA1 gene was also identified in the boy. These mutations were not found in the unaffected family members and 100 normal controls. In the patients’ lesions, Cx43 protein was located to the cytomembrane and cytoplasm in the stratum corneum, and granular layer. Compound heterozygous mutations in the boy showed a more severe clinical phenotype and cytoplasmic mislocalization. Conclusions The novel mutations c.848C > T (p.P283L) and c.869C > A(p.T290N) arose de novo and were considered as the cause of two Chinese EKVP. GJA1 P283L and T290N mutations lead to Cx43 protein cytoplasmic mislocalization. Our finding expands the mutant spectrum of GJA1 gene and adds new understanding of the genotype‐phenotype correlation.
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Affiliation(s)
- Changxing Li
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jingyao Liang
- Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou, China
| | - Pingjiao Chen
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Kang Zeng
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Rujun Xue
- Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou, China
| | - Xin Tian
- Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou, China
| | - Liuping Liang
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qi Wang
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Minglan Shi
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xibao Zhang
- Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou, China
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5
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Easton JA, Albuloushi AK, Kamps MAF, Brouns GHMR, Broers JLV, Coull BJ, Oji V, van Geel M, van Steensel MAM, Martin PE. A rare missense mutation in GJB3
(Cx31G45E) is associated with a unique cellular phenotype resulting in necrotic cell death. Exp Dermatol 2018; 28:1106-1113. [DOI: 10.1111/exd.13542] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Jennifer A. Easton
- Department of Dermatology; Maastricht University Medical Centre; Maastricht The Netherlands
- GROW School for Oncology and Developmental Biology; Maastricht University; Maastricht The Netherlands
| | - Ahmad K. Albuloushi
- Department of Life Sciences; School of Health and Life Sciences; Glasgow Caledonian University; Glasgow UK
| | - Miriam A. F. Kamps
- Department of Dermatology; Maastricht University Medical Centre; Maastricht The Netherlands
- GROW School for Oncology and Developmental Biology; Maastricht University; Maastricht The Netherlands
- Department of Genetics and Cell Biology; Maastricht University; Maastricht The Netherlands
| | - Gladys H. M. R. Brouns
- Department of Dermatology; Maastricht University Medical Centre; Maastricht The Netherlands
| | - Jos L. V. Broers
- GROW School for Oncology and Developmental Biology; Maastricht University; Maastricht The Netherlands
- Department of Genetics and Cell Biology; Maastricht University; Maastricht The Netherlands
| | - Barry J. Coull
- Department of Dermatology; Maastricht University Medical Centre; Maastricht The Netherlands
- Division of Biological Chemistry and Drug Discovery; College of Life Sciences; University of Dundee; Dundee UK
| | - Vincent Oji
- Department of Dermatology; University Hospital Münster; Münster Germany
| | - Michel van Geel
- Department of Dermatology; Maastricht University Medical Centre; Maastricht The Netherlands
- GROW School for Oncology and Developmental Biology; Maastricht University; Maastricht The Netherlands
| | - Maurice A. M. van Steensel
- Department of Dermatology; Maastricht University Medical Centre; Maastricht The Netherlands
- GROW School for Oncology and Developmental Biology; Maastricht University; Maastricht The Netherlands
- Skin Research Institute of Singapore; Institute of Medical Biology, Immunos; Singapore
| | - Patricia E. Martin
- Department of Life Sciences; School of Health and Life Sciences; Glasgow Caledonian University; Glasgow UK
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Abou Tayoun AN, Al Turki SH, Oza AM, Bowser MJ, Hernandez AL, Funke BH, Rehm HL, Amr SS. Improving hearing loss gene testing: a systematic review of gene evidence toward more efficient next-generation sequencing-based diagnostic testing and interpretation. Genet Med 2015; 18:545-53. [PMID: 26562227 DOI: 10.1038/gim.2015.141] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 08/27/2015] [Indexed: 12/11/2022] Open
Abstract
PURPOSE With next generation sequencing technology improvement and cost reductions, it has become technically feasible to sequence a large number of genes in one diagnostic test. This is especially relevant for diseases with large genetic and/or phenotypic heterogeneity, such as hearing loss. However, variant interpretation remains the major bottleneck. This is further exacerbated by the lack in the clinical genetics community of consensus criteria for defining the evidence necessary to include genes on targeted disease panels or in genomic reports, and the consequent risk of reporting variants in genes with no relevance to disease. METHODS We describe a systematic evidence-based approach for assessing gene-disease associations and for curating relevant genes for different disease aspects, including mode of inheritance, phenotypic severity, and mutation spectrum. RESULTS By applying this approach to clinically available hearing loss gene panels with a total of 163 genes, we show that a significant number (45%) of genes lack sufficient evidence of association with disease and thus are expected to increase uncertainty and patient anxiety, in addition to intensifying the interpretation burden. Information about all curated genes is summarized. Our retrospective analysis of 539 hearing loss cases tested by our previous OtoGenomeV2 panel demonstrates the impact of including genes with weak disease association in laboratory wet-bench and interpretation processes. CONCLUSION Our study is, to our knowledge, the first to highlight the urgent need for defining the clinical validity of gene-disease relationships for more efficient and accurate clinical testing and reporting.Genet Med 18 6, 545-553.
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Affiliation(s)
- Ahmad N Abou Tayoun
- Genetics Training Program, Harvard Medical School, Cambridge, Massachusetts, USA.,Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA.,Division of Genomic Diagnostics, The Children's Hospital of Philadelphia, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Saeed H Al Turki
- Genetics Training Program, Harvard Medical School, Cambridge, Massachusetts, USA
| | - Andrea M Oza
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA
| | - Mark J Bowser
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA
| | - Amy L Hernandez
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA
| | - Birgit H Funke
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA.,Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Heidi L Rehm
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA.,Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Sami S Amr
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA.,Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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7
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Tang C, Chen X, Chi J, Yang D, Liu S, Liu M, Pan Q, Fan J, Wang D, Zhang Z. Pathogenic Cx31 is un/misfolded to cause skin abnormality via a Fos/JunB-mediated mechanism. Hum Mol Genet 2015; 24:6054-65. [DOI: 10.1093/hmg/ddv317] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 07/31/2015] [Indexed: 01/29/2023] Open
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Otaguchi R, Kawakami T, Matsuoka M, Kimura S, Soma Y, Matsuda M, Hamada T, Hashimoto T. A sporadic elder case of erythrokeratodermia variabilis with a single base-pair transversion in GJB3 gene successfully treated with systemic vitamin A derivative. J Dermatol 2014; 41:1016-8. [PMID: 25297803 DOI: 10.1111/1346-8138.12628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Risako Otaguchi
- Department of Dermatology, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan
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Scott CA, Tattersall D, O'Toole EA, Kelsell DP. Connexins in epidermal homeostasis and skin disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1952-61. [DOI: 10.1016/j.bbamem.2011.09.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 08/30/2011] [Accepted: 09/06/2011] [Indexed: 12/20/2022]
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10
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Torres T, Velho G, Sanches M, Selores M. A case of erythrokeratodermia variabilis with connexin 31 gene mutation (Cx31F137L). Int J Dermatol 2011; 51:494-6. [DOI: 10.1111/j.1365-4632.2010.04640.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Fuchs-Telem D, Pessach Y, Mevorah B, Shirazi I, Sarig O, Sprecher E. Erythrokeratoderma variabilis caused by a recessive mutation in GJB3. Clin Exp Dermatol 2011; 36:406-11. [PMID: 21564177 DOI: 10.1111/j.1365-2230.2010.03986.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Erythrokeratoderma variabilis (EKV) is a rare disorder of cornification usually associated with dominant mutations in the genes GJB3 and GJB4, which code for connexin (Cx)31 and Cx30.3, respectively, and contribute to the formation of functional gap junctions in the epidermis. AIM To identify the molecular basis of recessive EKV in a consanguineous family of Middle Eastern origin. METHODS Direct sequencing and site-directed mutagenesis was used to search for the disease-causing mutation and identify its molecular consequences. RESULTS A novel missense mutation (c.G88A) was found in the human GJB3 gene, resulting in substitution of the amino acid isoleucine for valine at position 30 (p.V30I). Under in vitro conditions, p.V30I prevents Cx31 reaching the cell membrane and taking part in gap-junction formation. CONCLUSIONS Autosomal recessive inheritance should be considered when providing genetic counselling to consanguineous families at risk for EKV.
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Affiliation(s)
- D Fuchs-Telem
- Department of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
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12
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Abstract
BACKGROUND Connexins are a family of transmembrane proteins that are widely expressed in the human body. Connexins play an important role in cell-cell communication and homeostasis in various tissues by forming gap junction channels, which enable a direct passage of ions or metabolites from one cell to another. Twenty-one different connexins are expressed in humans, each having distinct expression patterns and regulation properties. Knowledge on this family of proteins can be gained by making an inventory of mutations and associated diseases in human. DESIGN PubMed and other relevant databases were searched. In addition, key review articles were screened for relevant original publications. Sections of representative organs were photographed and annotated. RESULTS The crucial role of connexins is highlighted by the discovery of mutations in connexin genes which cause a variety of disorders such as myelin-related diseases, skin disorders, hearing loss, congenital cataract, or more complex syndromes such as the oculodendrodigital dysplasia. This review systematically addresses current knowledge on mutations in connexin genes and disease, focusing on the correlation between genetic defects, cellular phenotypes and clinical manifestations. CONCLUSIONS The review of diseases caused by mutations in connexin genes highlights the essential nature of connexin function and intercellular communication in tissue homeostasis.
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Affiliation(s)
- Anna Pfenniger
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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13
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YÜKSEK J, SEZER E, KÖSEOĞLU D, MARKOÇ F, YILDIZ H. Erythrokeratodermia variabilis: Successful treatment with retinoid plus psoralen and ultraviolet A therapy. J Dermatol 2010; 38:725-7. [DOI: 10.1111/j.1346-8138.2010.01058.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Abstract
Tight junctions, gap junctions, adherens junctions, and desmosomes represent intricate structural intercellular channels and bridges that are present in several tissues, including epidermis. Clues to the important function of these units in epithelial cell biology have been gleaned from a variety of studies including naturally occurring and engineered mutations, animal models and other in vitro experiments. In this review, we focus on mutations that have been detected in human diseases. These observations provide intriguing insight into the biological complexities of cell-cell contact and intercellular communication as well as demonstrating the spectrum of inherited human diseases that are associated with mutations in genes encoding the component proteins. Over the last decade or so, human gene mutations have been reported in four tight junction proteins (claudin 1, 14, 16, and zona occludens 2), nine gap junction proteins (connexin 26, 30, 30.3, 31, 32, 40, 43, 46, and 50), one adherens junction protein (P-cadherin) and eight components of desmosomes (plakophilin (PKP) 1 and 2, desmoplakin, plakoglobin--which is also present in adherens junctions, desmoglein (DSG) 1, 2, 4, and corneodesmosin). These discoveries have often highlighted novel or unusual phenotypes, including abnormal skin barrier function, alterations in epidermal differentiation, and developmental anomalies of various ectodermal appendages, especially hair, as well as a range of extracutaneous pathologies. However, this review focuses mainly on inherited disorders of junctions that have an abnormal skin phenotype.
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Affiliation(s)
- Joey E Lai-Cheong
- King's College London, The Guy's, King's College and St Thomas' School of Medicine, Genetic Skin Disease Group, Division of Genetics and Molecular Medicine, St John's Institute of Dermatology, London, UK
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