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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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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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Albuloushi A, Lovgren ML, Steel A, Yeoh Y, Waters A, Zamiri M, Martin PE. A heterozygous mutation in GJB2 (Cx26F142L) associated with deafness and recurrent skin rashes results in connexin assembly deficiencies. Exp Dermatol 2020; 29:970-979. [PMID: 32866991 DOI: 10.1111/exd.14187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/11/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022]
Abstract
Mutations in GJB2 encoding Connexin 26 (CX26) are associated with hearing loss and hyperproliferative skin disorders of differing severity including keratitis-ichthyosis-deafness (KID) and Vohwinkel syndrome. A 6-year-old Caucasian girl who presented with recurrent skin rashes and sensorineural hearing loss harboured a heterozygous point mutation in GJB2 (c.424T > C; p.F142L). To characterize the impact of CX26F142L on cellular events. Plasmids CX26WT, CX26F142L, CX26G12R (KID) or CX26D66H (Vohwinkel) were transfected into HeLa cells expressing Cx26 or Cx43 or into HaCaT cells, a model keratinocyte cell line. Confocal microscopy determined protein localization. MTT assays assessed cell viability in the presence or absence of carbenoxolone, a connexin-channel blocker. Co-immunoprecipitation/Western blot analysis determined Cx43:Cx26 interactions. Quantitative real-time polymerase chain reaction assessed changes in gene expression of ER stress markers. Dye uptake assays determined Connexin-channel functionality. F142L and G12R were restricted to perinuclear areas. Collapse of the microtubule network, rescued by co-treatment with paclitaxel, occurred. ER stress was not involved. Cell viability was reduced in cells expressing F142L and G12R but not D66H. Unlike G12R that forms "leaky" hemichannels, F142L had restricted permeability. Cell viability of F142L and G12R transfected cells was greater in HeLa cells expressing Cx43 than in native Cx-free HeLa cells. Co-immunoprecipitation suggested a possible interaction between Cx43 and the three mutations. Expression of CX26F142L and G12R results in microtubule collapse, rescued by interaction with Cx43. The GJB2 mutations interacted with Cx43 suggesting that unique Cx43:Cx26 channels are central to the diverse phenotype of CX26 skin-related channelopathies.
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Affiliation(s)
- Ahmad Albuloushi
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK
| | - Marie-Louise Lovgren
- Department of Dermatology, University Hospital Crosshouse, Kilmarnock, UK.,Department of Dermatology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Ainsley Steel
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK
| | - Yeelon Yeoh
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK
| | - Alex Waters
- Department of Dermatology, University Hospital Crosshouse, Kilmarnock, UK
| | - Mozheh Zamiri
- Department of Dermatology, University Hospital Crosshouse, Kilmarnock, UK.,Department of Dermatology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Patricia E Martin
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK
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