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Yasarbas SS, Inal E, Yildirim MA, Dubrac S, Lamartine J, Mese G. Connexins in epidermal health and diseases: insights into their mutations, implications, and therapeutic solutions. Front Physiol 2024; 15:1346971. [PMID: 38827992 PMCID: PMC11140265 DOI: 10.3389/fphys.2024.1346971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 04/15/2024] [Indexed: 06/05/2024] Open
Abstract
The epidermis, the outermost layer of the skin, serves as a protective barrier against external factors. Epidermal differentiation, a tightly regulated process essential for epidermal homeostasis, epidermal barrier formation and skin integrity maintenance, is orchestrated by several players, including signaling molecules, calcium gradient and junctional complexes such as gap junctions (GJs). GJ proteins, known as connexins facilitate cell-to-cell communication between adjacent keratinocytes. Connexins can function as either hemichannels or GJs, depending on their interaction with other connexons from neighboring keratinocytes. These channels enable the transport of metabolites, cAMP, microRNAs, and ions, including Ca2+, across cell membranes. At least ten distinct connexins are expressed within the epidermis and mutations in at least five of them has been linked to various skin disorders. Connexin mutations may cause aberrant channel activity by altering their synthesis, their gating properties, their intracellular trafficking, and the assembly of hemichannels and GJ channels. In addition to mutations, connexin expression is dysregulated in other skin conditions including psoriasis, chronic wound and skin cancers, indicating the crucial role of connexins in skin homeostasis. Current treatment options for conditions with mutant or altered connexins are limited and primarily focus on symptom management. Several therapeutics, including non-peptide chemicals, antibodies, mimetic peptides and allele-specific small interfering RNAs are promising in treating connexin-related skin disorders. Since connexins play crucial roles in maintaining epidermal homeostasis as shown with linkage to a range of skin disorders and cancer, further investigations are warranted to decipher the molecular and cellular alterations within cells due to mutations or altered expression, leading to abnormal proliferation and differentiation. This would also help characterize the roles of each isoform in skin homeostasis, in addition to the development of innovative therapeutic interventions. This review highlights the critical functions of connexins in the epidermis and the association between connexins and skin disorders, and discusses potential therapeutic options.
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Affiliation(s)
- S. Suheda Yasarbas
- Izmir Institute of Technology, Faculty of Science, Department of Molecular Biology and Genetics, Izmir, Turkiye
| | - Ece Inal
- Izmir Institute of Technology, Faculty of Science, Department of Molecular Biology and Genetics, Izmir, Turkiye
| | - M. Azra Yildirim
- Izmir Institute of Technology, Faculty of Science, Department of Molecular Biology and Genetics, Izmir, Turkiye
| | - Sandrine Dubrac
- Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Innsbruck, Austria
| | - Jérôme Lamartine
- Skin Functional Integrity Group, Laboratory for Tissue Biology and Therapeutics Engineering (LBTI) CNRS UMR5305, University of Lyon, Lyon, France
| | - Gulistan Mese
- Izmir Institute of Technology, Faculty of Science, Department of Molecular Biology and Genetics, Izmir, Turkiye
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2
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Mc Lean K, Bignotti S, Callea M, Cammarata-Scalisi F, Steger B, Armstrong D, Lagan M, Sinton J, Semeraro F, Kaye SB, Romano V, Willoughby CE. Ocular phenotype and therapeutic interventions in keratitis-ichthyosis-deafness (KID) syndrome. Ophthalmic Genet 2024; 45:16-22. [PMID: 37755702 DOI: 10.1080/13816810.2023.2258218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 09/07/2023] [Indexed: 09/28/2023]
Abstract
BACKGROUND To report ocular manifestations, clinical course, and therapeutic management of patients with molecular genetically confirmed keratitis-ichthyosis-deafness syndrome. METHODS Four patients, aged 19 to 46, with keratitis-ichthyosis-deafness syndrome from across the UK were recruited for a general and ocular examination and GJB2 (Cx26) mutational analysis. The ocular examination included best-corrected visual acuity, slit-lamp bio-microscopy, and ocular surface assessment. Mutational analysis of the coding region of GJB2 (Cx26) was performed by bidirectional Sanger sequencing. RESULTS All four individuals had the characteristic systemic features of keratitis-ichthyosis-deafness syndrome. Each patient was found to have a missense mutation, resulting in the substitution of aspartic acid with asparagine at codon 50 (p.D50N). Main ophthalmic features were vascularizing keratopathy, ocular surface disease, hyperkeratotic lid lesions, recurrent epithelial defects, and corneal stromal scarring. One patient had multiple surgical procedures, including superficial keratectomies and lamellar keratoplasty, which failed to prevent severe visual loss. In contrast, oral therapy with ketoconazole stabilized the corneal and skin disease in two other patients with keratitis-ichthyosis-deafness syndrome. The patient who underwent intracorneal bevacizumab injection showed a marked reduction in corneal vascularization following a single application. CONCLUSIONS Keratitis-ichthyosis-deafness syndrome is a rare ectodermal dysplasia caused by heterozygous mutations in GJB2 (Cx26) with a severe, progressive vascularizing keratopathy. Oral ketoconazole therapy may offer benefit in stabilizing the corneal and skin disease.
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Affiliation(s)
- Keri Mc Lean
- Department of Corneal and External Eye Diseases, St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK
- Department of Eye and Vision Science, Institute of Life Course and Medical Science, University of Liverpool, Liverpool, UK
| | - Stefano Bignotti
- Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, Ophthalmology Clinic, University of Brescia, Brescia, Italy
| | - Michele Callea
- Pediatric Dentistry and Special Dental Care Unit, Meyer Children's University Hospital IRCCS, Florence, Italy
| | | | - Bernhard Steger
- Department of Ophthalmology, Medical University of Innsbruck, Innsbruck, Austria
| | - David Armstrong
- Department of Ophthalmology, Royal Victoria Hospital, Belfast, UK
| | - Maeve Lagan
- Department of Ophthalmology, Royal Victoria Hospital, Belfast, UK
| | - Janet Sinton
- Department of Ophthalmology, Altnagelvin Area Hospital, Londonderry, UK
| | - Francesco Semeraro
- Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, Ophthalmology Clinic, University of Brescia, Brescia, Italy
| | - Stephen B Kaye
- Department of Corneal and External Eye Diseases, St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK
- Department of Eye and Vision Science, Institute of Life Course and Medical Science, University of Liverpool, Liverpool, UK
| | - Vito Romano
- Department of Corneal and External Eye Diseases, St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK
- Department of Eye and Vision Science, Institute of Life Course and Medical Science, University of Liverpool, Liverpool, UK
- Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, Ophthalmology Clinic, University of Brescia, Brescia, Italy
| | - Colin E Willoughby
- Department of Corneal and External Eye Diseases, St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK
- Department of Ophthalmology, Medical University of Innsbruck, Innsbruck, Austria
- Genomic Medicine, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
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3
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López-Sundh AE, Escribano-Palomino E, Feito-Rodríguez M, Tenorio J, Brizzi ME, Krasnovska Zayets K, Servera-Negra G, de Lucas-Laguna R. Keratitis-ichthyosis-deafness syndrome with lethal p.Ala88Val variant and severe hypercalcemia. Am J Med Genet A 2023; 191:253-258. [PMID: 36286624 DOI: 10.1002/ajmg.a.63005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 07/03/2022] [Accepted: 08/27/2022] [Indexed: 12/14/2022]
Abstract
Keratitis-ichthyosis-deafness (KID) syndrome is a rare genetic disease caused by pathogenic variants in connexin 26 (gene GJB2), which is part of the transmembrane channels of the epithelia. Connexin 26 is expressed mainly in the cornea, the sensory epithelium of the inner ear, and in the skin keratinocytes, which are the three main target organs in KID syndrome. Approximately a dozen pathogenic variants have been described to date, including some lethal forms. Patients with lethal pathogenic variants present with severe symptoms from birth and die from sepsis during the first year of life. We present a premature female patient with KID syndrome carrying the lethal p.Ala88Val pathogenic variant in GJB2. In addition to the respiratory distress associated with this variant, our patient presented severe hypercalcemia of unexplained origin refractory to treatment. This abnormality has not been reported earlier in other patients with KID syndrome with the same variant.
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Affiliation(s)
| | | | | | - Jair Tenorio
- CIBERER, Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII, Madrid, Spain.,Institute of Medical and Molecular Genetics (INGEMM)-IdiPAZ, Hospital Universitario La Paz-UAMs, Madrid, Spain.,ITHACA, European Reference Network on Rare Congenital Malformations and Rare Intellectual Disability, Paris, France
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4
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Alsabbagh MM. Keratitis-ichthyosis-deafness syndrome: A comprehensive review of cutaneous and systemic manifestations. Pediatr Dermatol 2023; 40:19-27. [PMID: 36444857 DOI: 10.1111/pde.15201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 11/05/2022] [Indexed: 11/30/2022]
Abstract
Keratitis-ichthyosis-deafness syndrome is a rare genetic disease presenting with cutaneous, ocular, and otic defects. This comprehensive review provides insight into the clinical presentations, highlighting the cutaneous manifestations including histopathology and treatment options.
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Affiliation(s)
- Manahel Mahmood Alsabbagh
- Department of Molecular Medicine, Princess Al-Jawhara Center for Molecular Medicine and Inherited Disorders, Arabian Gulf University, Manama, Kingdom of Bahrain
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5
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Al-janabi AM, Ahmmed HS, Al-Khafaji SM. Connexin 26 (GJB2) gene mutations linked with autosomal recessive non-syndromic sensor neural hearing loss in the Iraqi population. J Med Life 2021; 14:841-846. [PMID: 35126756 PMCID: PMC8811675 DOI: 10.25122/jml-2021-0152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/08/2021] [Indexed: 11/19/2022] Open
Abstract
Deafness is a total or partial hearing loss that may appear at any age and with different degrees of severity. Approximately 50% of hearing loss have a genetic origin, and among them, non-syndromic sensorineural deafness represents about 70% of the cases. From them, 80% correspond to autosomal recessive inheritance deafness. Autosomal recessive deafness was not studied enough at the molecular level in Iraq. This study aimed to verify the frequency of three GJB2 mutations in non-syndromic sensorineural deafness in the Iraqi population. The current case-control study was conducted from January 2018 to January 2020. The study included 95 deafness patients (55 males and 40 females) and 110 healthy control group. Age and sex were matched between the two groups. In order to detect c.35delG, 235delC, and 167delT mutations in the GJB2 gene, we employed the PCR-RFLP technique. The c.35delG was the main frequent mutation encountered with the GJB2 gene among patients with autosomal recessive non-syndromic sensorineural hearing loss. Among them, 35 (36.8%) were homozygous, 40 (42.1%) were heterozygous, and 20 (21.1%) were wild genotypes. The second-degree mutation in the GJB2 gene was c.235delC mutation, which from the 95 deaf patients, there were 20 (21.1%) with homozygous, 33 (34.7%) heterozygous, and 42 (44.2%) wild genotypes. None of the 95 deaf patients showed the c.167delT mutation, and no mutations appeared in the control group. Our data concluded that the GJB2 c.35delG and c.235delC gene mutations were the main cause of autosomal recessive non-syndromic sensorineural hearing loss in the Iraqi deaf population.
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6
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Sánchez-Espino LF, Gil-Téllez CI, Cantú-Reyna C, Martínez-Longoria CA. Ichthyosiform Erythroderma, a Multifaceted Syndromic Entity. Pediatr Rev 2021; 42:112-117. [PMID: 34470889 DOI: 10.1542/pir.2018-0140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Luis F Sánchez-Espino
- Instituto de Seguridad Social para los trabajadores del Estado de Nuevo León (ISSSTELEON), Hospital San José del Tecnológico de Monterrey, Mexico.,Department of Pediatrics, Tecnológico de Monterrey, School of Medicine and Health Science, Mexico
| | - Claudia I Gil-Téllez
- Instituto de Seguridad Social para los trabajadores del Estado de Nuevo León (ISSSTELEON), Hospital San José del Tecnológico de Monterrey, Mexico
| | - Consuelo Cantú-Reyna
- Instituto de Seguridad Social para los trabajadores del Estado de Nuevo León (ISSSTELEON), Hospital San José del Tecnológico de Monterrey, Mexico
| | - César A Martínez-Longoria
- Instituto de Seguridad Social para los trabajadores del Estado de Nuevo León (ISSSTELEON), Hospital San José del Tecnológico de Monterrey, Mexico
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7
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Garcia-Vega L, O’Shaughnessy EM, Albuloushi A, Martin PE. Connexins and the Epithelial Tissue Barrier: A Focus on Connexin 26. BIOLOGY 2021; 10:biology10010059. [PMID: 33466954 PMCID: PMC7829877 DOI: 10.3390/biology10010059] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 12/15/2022]
Abstract
Simple Summary Tissues that face the external environment are known as ‘epithelial tissue’ and form barriers between different body compartments. This includes the outer layer of the skin, linings of the intestine and airways that project into the lumen connecting with the external environment, and the cornea of the eye. These tissues do not have a direct blood supply and are dependent on exchange of regulatory molecules between cells to ensure co-ordination of tissue events. Proteins known as connexins form channels linking cells directly and permit exchange of small regulatory signals. A range of environmental stimuli can dysregulate the level of connexin proteins and or protein function within the epithelia, leading to pathologies including non-healing wounds. Mutations in these proteins are linked with hearing loss, skin and eye disorders of differing severity. As such, connexins emerge as prime therapeutic targets with several agents currently in clinical trials. This review outlines the role of connexins in epithelial tissue and how their dysregulation contributes to pathological pathways. Abstract Epithelial tissue responds rapidly to environmental triggers and is constantly renewed. This tissue is also highly accessible for therapeutic targeting. This review highlights the role of connexin mediated communication in avascular epithelial tissue. These proteins form communication conduits with the extracellular space (hemichannels) and between neighboring cells (gap junctions). Regulated exchange of small metabolites less than 1kDa aide the co-ordination of cellular activities and in spatial communication compartments segregating tissue networks. Dysregulation of connexin expression and function has profound impact on physiological processes in epithelial tissue including wound healing. Connexin 26, one of the smallest connexins, is expressed in diverse epithelial tissue and mutations in this protein are associated with hearing loss, skin and eye conditions of differing severity. The functional consequences of dysregulated connexin activity is discussed and the development of connexin targeted therapeutic strategies highlighted.
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8
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Cammarata-Scalisi F, Willoughby CE, Cárdenas Tadich A, Labrador N, Herrera A, Callea M. Clinical, etiopathogenic, and therapeutic aspects of KID syndrome. Dermatol Ther 2020; 33:e13507. [PMID: 32367610 DOI: 10.1111/dth.13507] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/20/2020] [Accepted: 04/28/2020] [Indexed: 11/26/2022]
Abstract
Keratitis-ichthyosis-deafness (KID syndrome) is a syndromes ichthyoses that is clinically and genetically heterogeneous requiring early and long-term multidisciplinary monitoring of affected individuals. A review of the clinical, etiopathogenic and therapeutic aspects is presented of this rare congenital ectodermal disorder.
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Affiliation(s)
| | | | | | | | - Adriana Herrera
- Ophthalmology Unit, University of Los Andes, Mérida, Venezuela
| | - Michele Callea
- Unit of Dentistry, Bambino Gesù Children' Hospital, IRCCS, Rome, Italy
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9
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Korolenkova MV, Dmitrieva NA, Babichenko II, Gusova YV, Poberezhnaya AA. [Oral manifestations of KID syndrome: rare clinical case]. STOMATOLOGII︠A︡ 2019; 98:93-95. [PMID: 31513158 DOI: 10.17116/stomat20199804193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The paper presents a rare clinical case of an infant with KID (Keratitis, Ichthyosis, Deafness) syndrome (about 100 patients reported so far) admitted for histological verification of oral mucosa lesions. Disease pathogenesis defines inadequate reparation and skin and mucosa innate immunity defect leading to higher incidence of bacterial and fungal infections, so the 4-years old girl received treatment for vegetating candidiasis of the oral mucosa for several weeks with no clinical improvement. Initial examination showed that the oral lesions resulted from sharp edges of severely affected carious teeth. Histological study of multifocal biopsy revealed pyogenic granulomas and no signs of SCC. Teeth extraction and symptomatic treatment leaded to significant clinical improvement and some remained mucosal changes may be attributed to syndrome manifestations.
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Affiliation(s)
- M V Korolenkova
- Central Research Institute of Dentistry and Maxillofacial Surgery, Moscow, Russia
| | - N A Dmitrieva
- Central Research Institute of Dentistry and Maxillofacial Surgery, Moscow, Russia
| | - I I Babichenko
- Central Research Institute of Dentistry and Maxillofacial Surgery, Moscow, Russia
| | - Yu V Gusova
- Central Research Institute of Dentistry and Maxillofacial Surgery, Moscow, Russia
| | - A A Poberezhnaya
- Central Research Institute of Dentistry and Maxillofacial Surgery, Moscow, Russia
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10
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Sayeb M, Riahi Z, Laroussi N, Bonnet C, Romdhane L, Mkaouar R, Zaouak A, Marrakchi J, Abdessalem G, Messaoud O, Bouchniba O, Ghilane N, Mokni M, Besbes G, Yacoub‐Youssef H, Petit C, Abdelhak S. A Tunisian family with a novel mutation in the gene
CYP
4F22
for lamellar ichthyosis and co‐occurrence of hearing loss in a child due to mutation in the
SLC
26A4
gene. Int J Dermatol 2019; 58:1439-1443. [DOI: 10.1111/ijd.14452] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 03/06/2019] [Accepted: 03/11/2019] [Indexed: 12/30/2022]
Affiliation(s)
- Marwa Sayeb
- Laboratory of Biomedical Genomics and Oncogenetics (LR11IPT05) University of Tunis El Manar Pasteur Institut of Tunis Tunis Tunisia
| | - Zied Riahi
- Laboratory of Biomedical Genomics and Oncogenetics (LR11IPT05) University of Tunis El Manar Pasteur Institut of Tunis Tunis Tunisia
- INSERM UMRS 1120 Vision Institut Paris France
- University of Paris VI UPMC Sorbonnes Paris France
| | - Nadia Laroussi
- Laboratory of Biomedical Genomics and Oncogenetics (LR11IPT05) University of Tunis El Manar Pasteur Institut of Tunis Tunis Tunisia
| | - Crystel Bonnet
- INSERM UMRS 1120 Vision Institut Paris France
- University of Paris VI UPMC Sorbonnes Paris France
| | - Lilia Romdhane
- Laboratory of Biomedical Genomics and Oncogenetics (LR11IPT05) University of Tunis El Manar Pasteur Institut of Tunis Tunis Tunisia
- Department of Biology Faculty of Science of Bizerte Université Tunis Carthage ZarzounaTunisia
| | - Rahma Mkaouar
- Laboratory of Biomedical Genomics and Oncogenetics (LR11IPT05) University of Tunis El Manar Pasteur Institut of Tunis Tunis Tunisia
| | - Anissa Zaouak
- Department of Dermatology Habib Thameur Hospital TunisTunisia
| | | | - Ghaith Abdessalem
- Laboratory of Biomedical Genomics and Oncogenetics (LR11IPT05) University of Tunis El Manar Pasteur Institut of Tunis Tunis Tunisia
| | - Olfa Messaoud
- Laboratory of Biomedical Genomics and Oncogenetics (LR11IPT05) University of Tunis El Manar Pasteur Institut of Tunis Tunis Tunisia
| | - Oussema Bouchniba
- Departement of Biochemistry Habib Bourguiba Hospital MedenineTunisia
| | - Nacer Ghilane
- Departement of Biochemistry Habib Bourguiba Hospital MedenineTunisia
| | - Mourad Mokni
- Department of Dermatology CHU La Rabta Tunis Tunis Tunisia
| | - Ghazi Besbes
- Department of Otorhinolaryngology CHU La Rabta TunisTunisia
| | - Houda Yacoub‐Youssef
- Laboratory of Biomedical Genomics and Oncogenetics (LR11IPT05) University of Tunis El Manar Pasteur Institut of Tunis Tunis Tunisia
| | - Christine Petit
- INSERM UMRS 1120 Vision Institut Paris France
- University of Paris VI UPMC Sorbonnes Paris France
- Unité de Génétique et Physiologie de l'Audition Institut Pasteur Paris France
- Collège de France Paris France
| | - Sonia Abdelhak
- Laboratory of Biomedical Genomics and Oncogenetics (LR11IPT05) University of Tunis El Manar Pasteur Institut of Tunis Tunis Tunisia
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Rahman R, Sharma I, Gahlot LK, Hasija Y. DermaGene and VitmiRS: a comprehensive systems analysis of genetic dermatological disorders. BIOMEDICAL DERMATOLOGY 2018. [DOI: 10.1186/s41702-018-0028-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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12
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Mittal R, Patel AP, Nguyen D, Pan DR, Jhaveri VM, Rudman JR, Dharmaraja A, Yan D, Feng Y, Chapagain P, Lee DJ, Blanton SH, Liu XZ. Genetic basis of hearing loss in Spanish, Hispanic and Latino populations. Gene 2018; 647:297-305. [PMID: 29331482 PMCID: PMC5806531 DOI: 10.1016/j.gene.2018.01.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 01/02/2018] [Accepted: 01/06/2018] [Indexed: 12/13/2022]
Abstract
Hearing loss (HL) is the most common neurosensory disorder affecting humans. The screening, prevention and treatment of HL require a better understanding of the underlying molecular mechanisms. Genetic predisposition is one of the most common factors that leads to HL. Most HL studies include few Spanish, Hispanic and Latino participants, leaving a critical gap in our understanding about the prevalence, impact, unmet health care needs, and genetic factors associated with hearing impairment among Spanish, Hispanic and Latino populations. The few studies which have been performed show that the gene variants commonly associated with HL in non-Spanish and non-Hispanic populations are infrequently responsible for hearing impairment in Spanish as well as Hispanic and Latino populations (hereafter referred to as Hispanic). To design effective screening tools to detect HL in Spanish and Hispanic populations, studies must be conducted to determine the gene variants that are most commonly associated with hearing impairment in this racial/ethnic group. In this review article, we summarize gene variants and loci associated with HL in Spanish and Hispanic populations. Identifying new genetic variants associated with HL in Spanish and Hispanic populations will pave the way to develop effective screening tools and therapeutic strategies for HL.
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Affiliation(s)
- Rahul Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Amit P Patel
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Desiree Nguyen
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Debbie R Pan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Vasanti M Jhaveri
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jason R Rudman
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Arjuna Dharmaraja
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Denise Yan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Yong Feng
- Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, China
| | - Prem Chapagain
- Department of Physics and Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - David J Lee
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Susan H Blanton
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA; Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Xue Zhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, China; Tsinghua University School of Medicine, Beijing 10084, China; Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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13
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Chen L, Su D, Li S, Guan L, Shi C, Li D, Hu S, Ma X. The connexin 46 mutant (V44M) impairs gap junction function causing congenital cataract. J Genet 2017; 96:969-976. [PMID: 29321356 DOI: 10.1007/s12041-017-0861-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Connexin 46 (Cx46) is important for gap junction channels formation which plays crucial role in the preservation of lens homeostasis and transparency. Previously, we have identified a missense mutation (p.V44M) of Cx46 in a congenital cataract family. This study aims at dissecting the potential pathogenesis of the causative mutant of cataract. Plasmids carrying wild-type (wt) and mutant (V44M) of Cx46 were constructed and expressed in Hela cells respectively.Western blotting and fluorescence microscopy were applied to analyse the expression and subcellular localization of recombinant proteins, respectively. Scrape loading dye transfer experiment was performed to detect the transfer capability of gap junction channels among cells expressed V44Mmutant. The results demonstrated that in transfected Hela cells, both wt-Cx46 and Cx46 V44M were localized abundantly in the plasma membrane. No significant difference was found between the protein expressions of the two types of Cx46. The fluorescent localization assay revealed the plaque formation, significantly reduced in the cells expressing Cx46 V44M. Immunoblotting analysis demonstrated that formation of Triton X-100 insoluble complex decreased obviously in mutant Cx46. Additionally, the scrape-loading dye-transfer experiment showed a lower dye diffusion distance of Cx46 V44M cells, which indicates that the gap junction intercellular communication activity was aberrant. Human Cx46 V44M mutant causing cataracts result in abnormally decreased formation of gap junction plaques and impaired gap junction channel function.
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Affiliation(s)
- Lijuan Chen
- Department of Ophthalmology, Hongqi Hospital of Mudanjiang Medical College, Mudanjiang 157000, Heilongjiang Province, People's Republic of China.
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Gudmundsson S, Wilbe M, Ekvall S, Ameur A, Cahill N, Alexandrov LB, Virtanen M, Hellström Pigg M, Vahlquist A, Törmä H, Bondeson ML. Revertant mosaicism repairs skin lesions in a patient with keratitis-ichthyosis-deafness syndrome by second-site mutations in connexin 26. Hum Mol Genet 2017; 26:1070-1077. [PMID: 28158657 PMCID: PMC5409067 DOI: 10.1093/hmg/ddx017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 12/30/2016] [Indexed: 01/21/2023] Open
Abstract
Revertant mosaicism (RM) is a naturally occurring phenomenon where the pathogenic effect of a germline mutation is corrected by a second somatic event. Development of healthy-looking skin due to RM has been observed in patients with various inherited skin disorders, but not in connexin-related disease. We aimed to clarify the underlying molecular mechanisms of suspected RM in the skin of a patient with keratitis-ichthyosis-deafness (KID) syndrome. The patient was diagnosed with KID syndrome due to characteristic skin lesions, hearing deficiency and keratitis. Investigation of GJB2 encoding connexin (Cx) 26 revealed heterozygosity for the recurrent de novo germline mutation, c.148G > A, p.Asp50Asn. At age 20, the patient developed spots of healthy-looking skin that grew in size and number within widespread erythrokeratodermic lesions. Ultra-deep sequencing of two healthy-looking skin biopsies identified five somatic nonsynonymous mutations, independently present in cis with the p.Asp50Asn mutation. Functional studies of Cx26 in HeLa cells revealed co-expression of Cx26-Asp50Asn and wild-type Cx26 in gap junction channel plaques. However, Cx26-Asp50Asn with the second-site mutations identified in the patient displayed no formation of gap junction channel plaques. We argue that the second-site mutations independently inhibit Cx26-Asp50Asn expression in gap junction channels, reverting the dominant negative effect of the p.Asp50Asn mutation. To our knowledge, this is the first time RM has been reported to result in the development of healthy-looking skin in a patient with KID syndrome.
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Affiliation(s)
- Sanna Gudmundsson
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Maria Wilbe
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Sara Ekvall
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Adam Ameur
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Nicola Cahill
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Ludmil B Alexandrov
- Theoretical Biology and Biophysics (T-6), Los Alamos National Laboratory, Los Alamos, NM, USA and
| | - Marie Virtanen
- Department of Medical Sciences, Dermatology, Uppsala University, Uppsala, Sweden
| | - Maritta Hellström Pigg
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Anders Vahlquist
- Department of Medical Sciences, Dermatology, Uppsala University, Uppsala, Sweden
| | - Hans Törmä
- Department of Medical Sciences, Dermatology, Uppsala University, Uppsala, Sweden
| | - Marie-Louise Bondeson
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
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