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Perrier S, Guerrero K, Tran LT, Michell-Robinson MA, Legault G, Brais B, Sylvain M, Dorman J, Demos M, Köhler W, Pastinen T, Thiffault I, Bernard G. Solving inherited white matter disorder etiologies in the neurology clinic: Challenges and lessons learned using next-generation sequencing. Front Neurol 2023; 14:1148377. [PMID: 37077564 PMCID: PMC10108901 DOI: 10.3389/fneur.2023.1148377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 02/23/2023] [Indexed: 04/05/2023] Open
Abstract
IntroductionRare neurodevelopmental disorders, including inherited white matter disorders or leukodystrophies, often present a diagnostic challenge on a genetic level given the large number of causal genes associated with a range of disease subtypes. This study aims to demonstrate the challenges and lessons learned in the genetic investigations of leukodystrophies through presentation of a series of cases solved using exome or genome sequencing.MethodsEach of the six patients had a leukodystrophy associated with hypomyelination or delayed myelination on MRI, and inconclusive clinical diagnostic genetic testing results. We performed next generation sequencing (case-based exome or genome sequencing) to further investigate the genetic cause of disease.ResultsFollowing different lines of investigation, molecular diagnoses were obtained for each case, with patients harboring pathogenic variants in a range of genes including TMEM106B, GJA1, AGA, POLR3A, and TUBB4A. We describe the lessons learned in reaching the genetic diagnosis, including the importance of (a) utilizing proper multi-gene panels in clinical testing, (b) assessing the reliability of biochemical assays in supporting diagnoses, and (c) understanding the limitations of exome sequencing methods in regard to CNV detection and region coverage in GC-rich areas.DiscussionThis study illustrates the importance of applying a collaborative diagnostic approach by combining detailed phenotyping data and metabolic results from the clinical environment with advanced next generation sequencing analysis techniques from the research environment to increase the diagnostic yield in patients with genetically unresolved leukodystrophies.
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Affiliation(s)
- Stefanie Perrier
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Kether Guerrero
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Luan T. Tran
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Mackenzie A. Michell-Robinson
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Geneviève Legault
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
| | - Bernard Brais
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Michel Sylvain
- Division of Pediatric Neurology, Centre Mère-Enfant Soleil du CHU de Québec - Université Laval, Québec City, QC, Canada
| | - James Dorman
- John H. Stroger Jr. Hospital of Cook County, Chicago, IL, United States
- Department of Neurological Sciences, Rush Medical College, Chicago, IL, United States
| | - Michelle Demos
- Division of Neurology, Department of Pediatrics, University of British Columbia, BC Children's Hospital, Vancouver, BC, Canada
| | - Wolfgang Köhler
- Leukodystrophy Center, University of Leipzig Medical Center, Leipzig, Germany
| | - Tomi Pastinen
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO, United States
- University of Missouri Kansas City School of Medicine, Kansas City, MO, United States
| | - Isabelle Thiffault
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO, United States
- University of Missouri Kansas City School of Medicine, Kansas City, MO, United States
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO, United States
- Isabelle Thiffault
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
- *Correspondence: Geneviève Bernard
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Machado RA, Júnior HM, Ferreira SBP, Leão LL, Coletta RD, Aguiar MJB. Novel mutations in GJA1 in two Brazilian families with oculodentodigital dysplasia. Oral Surg Oral Med Oral Pathol Oral Radiol 2023; 135:96-100. [PMID: 36396593 DOI: 10.1016/j.oooo.2022.09.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 08/10/2022] [Accepted: 09/22/2022] [Indexed: 01/02/2023]
Abstract
Oculodentodigital dysplasia (ODDD; MIM #164200), a rare genetic disorder characterized by abnormal craniofacial, dental, ocular, and digital features, is caused by mutations in GJA1 (gap junction alpha-1) gene and inherited in an autosomal dominant pattern. However, an autosomal recessive pattern is also reported. Here we described 2 families with members affected by ODDD. In the first family, the c.752G>C (p.S251T) and c.848C>T (p.P283L) heterozygous missense mutations and the c.825C>T (p.T275T) silent mutation were identified in the proband, which showed mild ODDD phenotypes, and in his mother, which displayed hemolytic anemia and thrombocytopenia. In the second family, the patients displayed typical features of ODDD, and Sanger sequencing identified a novel homozygous c.604C>T (p.R202C) missense mutation, whereas the parents carried the mutation. Together, these findings suggest that homozygous mutation in GJA1 induces a more severe ODDD phenotype, though interfamilial phenotype variability was observed, whereas compound heterozygous mutations in GJA1 cause a mild phenotype.
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Affiliation(s)
- Renato Assis Machado
- Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo (HRAC/USP), Bauru, São Paulo, Brazil; Department of Oral Diagnosis, School of Dentistry, University of Campinas, Piracicaba, São Paulo, Brazil
| | - Hercílio Martelli Júnior
- Oral Diagnosis, Dental School, State University of Montes Claros, Unimontes, Montes Claros, Minas Gerais, Brazil; Center for Rehabilitation of Craniofacial Anomalies, Dental School, University of Alfenas, Minas Gerais, Brazil
| | | | - Letícia Lima Leão
- Special Medical Genetics Service, Clinical Hospital, Federal University of Minas Gerais, UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Ricardo D Coletta
- Department of Oral Diagnosis, School of Dentistry, University of Campinas, Piracicaba, São Paulo, Brazil; Graduate Program in Oral Biology, School of Dentistry, University of Campinas, Piracicaba, São Paulo, Brazil
| | - Marcos José Burle Aguiar
- Special Medical Genetics Service, Clinical Hospital, Federal University of Minas Gerais, UFMG, Belo Horizonte, Minas Gerais, Brazil
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Hsu CC, Chuang HK, Hsiao YJ, Teng YC, Chiang PH, Wang YJ, Lin TY, Tsai PH, Weng CC, Lin TC, Hwang DK, Hsieh AR. Polygenic Risk Score Improves Cataract Prediction in East Asian Population. Biomedicines 2022; 10:biomedicines10081920. [PMID: 36009466 PMCID: PMC9406175 DOI: 10.3390/biomedicines10081920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 06/30/2022] [Accepted: 08/04/2022] [Indexed: 11/16/2022] Open
Abstract
Cataracts, characterized by crystalline lens opacities in human eyes, is the leading cause of blindness globally. Due to its multifactorial complexity, the molecular mechanisms remain poorly understood. Larger cohorts of genome-wide association studies (GWAS) are needed to investigate cataracts’ genetic basis. In this study, a GWAS was performed on the largest Han population to date, analyzing a total of 7079 patients and 13,256 controls from the Taiwan Biobank (TWB) 2.0 cohort. Two cataract-associated SNPs with an adjustment of p < 1 × 10−7 in the older groups and nine SNPs with an adjustment of p < 1 × 10−6 in the younger group were identified. Except for the reported AGMO in animal models, most variations, including rs74774546 in GJA1 and rs237885 in OXTR, were not identified before this study. Furthermore, a polygenic risk score (PRS) was created for the young and old populations to identify high-risk cataract individuals, with areas under the receiver operating curve (AUROCs) of 0.829 and 0.785, respectively, after covariate adjustments. Younger individuals had 17.45 times the risk while older people had 10.97 times the risk when comparing individuals in the highest and lowest PRS quantiles. Validation analysis on an independent TWB1.0 cohort revealed AUROCs of 0.744 and 0.659.
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Affiliation(s)
- Chih-Chien Hsu
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112027, Taiwan
| | - Hao-Kai Chuang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 112027, Taiwan
- Correspondence: (H.-K.C.); (D.-K.H.); (A.-R.H.); Tel.: +886-02-28757325 (D.-K.H.)
| | - Yu-Jer Hsiao
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 112027, Taiwan
| | - Yuan-Chi Teng
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 112027, Taiwan
| | - Pin-Hsuan Chiang
- Department of Statistics, Tamkang University, New Taipei 251301, Taiwan
| | - Yu-Jun Wang
- Department of Statistics, Tamkang University, New Taipei 251301, Taiwan
| | - Ting-Yi Lin
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 112027, Taiwan
| | - Ping-Hsing Tsai
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 112027, Taiwan
| | - Chang-Chi Weng
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112027, Taiwan
| | - Tai-Chi Lin
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112027, Taiwan
| | - De-Kuang Hwang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112027, Taiwan
- Correspondence: (H.-K.C.); (D.-K.H.); (A.-R.H.); Tel.: +886-02-28757325 (D.-K.H.)
| | - Ai-Ru Hsieh
- Department of Statistics, Tamkang University, New Taipei 251301, Taiwan
- Correspondence: (H.-K.C.); (D.-K.H.); (A.-R.H.); Tel.: +886-02-28757325 (D.-K.H.)
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Shinya A, Takahashi M, Sato N, Nishida Y, Inaba A, Inaji M, Yokota T, Orimo S. Oculo-dento-digital Dysplasia Presenting as Spastic Paraparesis Which Was Successfully Treated by Intrathecal Baclofen Therapy. Intern Med 2021; 60:2301-2305. [PMID: 33612672 PMCID: PMC8355389 DOI: 10.2169/internalmedicine.6145-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A 42-year-old man with a history of migraine and bilateral syndactyly presented with numbness of the extremities and shaking legs, which thus prevented him from working as a carpenter. A neurological examination revealed spastic paraparesis with pathological reflexes on all four extremities. Oculo-dento-digital dysplasia (ODDD) was suspected based on his medical history and characteristic facial appearance including small eye slits, thin mouth, and pinched nose with anteverted nostrils. Genetic tests revealed a gap junction alpha 1 (GJA1) gene mutation and confirmed the diagnosis of ODDD. His spastic paraparesis was resistant to oral antispastic medication, however, his symptoms successfully improved after the initiation of intrathecal baclofen therapy, which thus allowed him to return to work.
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Affiliation(s)
- Akiko Shinya
- Department of Neurology, Kanto Central Hospital, Japan
- Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Japan
| | | | - Nozomu Sato
- Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Japan
| | - Yoichiro Nishida
- Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Japan
| | - Akira Inaba
- Department of Neurology, Kanto Central Hospital, Japan
| | - Motoki Inaji
- Department of Neurosurgery, Tokyo Medical and Dental University, Japan
| | | | - Satoshi Orimo
- Department of Neurology, Kanto Central Hospital, Japan
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Li X, Xiao X, Li S, Ouyang J, Sun W, Liu X, Zhang Q. Heterozygous GJA1 variants with ocular phenotype: Missense in domain but truncation out of domain. Mol Vis 2021; 27:309-322. [PMID: 34035645 PMCID: PMC8131177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 05/11/2021] [Indexed: 11/10/2022] Open
Abstract
Purpose Oculodentodigital dysplasia (ODDD) is a group disorder caused by GJA1 variants, of which glaucoma leading to blindness is a frequent complication of the ocular phenotype. In this study, the correlation of the GJA1 genotype with the ocular phenotype was analyzed systematically. Methods GJA1 variants were collected from in-house whole-exome sequencing data of 5,307 individuals. Potentially pathogenic variants (PPVs) were defined based on prediction of multiple in silico tools, related phenotypes, and previously established evidence. The characteristics of GJA1 PPVs were evaluated based on our data, gnomAD, and HGMD. Results In total, 21 rare variants in GJA1 were detected in 32 subjects from the study cohort. Four of the 21 variants were classified as PPVs, including two frameshift, one missense, and one in-frame deletion. The four PPVs were detected in four probands with microcornea or high hyperopia; two developed glaucoma. A systematic review of GJA1 variants in literature suggested that most heterozygous missense PPVs are located inside the connexin domain. All truncations downstream of the connexin domain are associated with autosomal dominant disease, while most truncations within the domain are associated with autosomal recessive ODDD. Ocular signs were present in 80.0% (116/145) of patients with GJA1 PPVs. Of the 116 patients, glaucoma was observed in 26.7% (31/116), among whom 77.4% (24/31) of cases occurred in patients ≥10 years old. Conclusions Eye abnormalities are the most common signs associated with GJA1 PPVs, and they carry a high risk of developing glaucoma. The identification of GJA1 PPVs needs further attention and clarification.
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Okuda S, Takata N, Hasegawa Y, Kawada M, Inoue Y, Adachi T, Sasai Y, Eiraku M. Strain-triggered mechanical feedback in self-organizing optic-cup morphogenesis. SCIENCE ADVANCES 2018; 4:eaau1354. [PMID: 30474058 PMCID: PMC6248953 DOI: 10.1126/sciadv.aau1354] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 10/19/2018] [Indexed: 05/27/2023]
Abstract
Organogenesis is a self-organizing process of multiple cells in three-dimensional (3D) space, where macroscopic tissue deformations are robustly regulated by multicellular autonomy. It is clear that this robust regulation requires cells to sense and modulate 3D tissue formation across different scales, but its underlying mechanisms are still unclear. To address this question, we developed a versatile computational model of 3D multicellular dynamics at single-cell resolution and combined it with the 3D culture system of pluripotent stem cell-derived optic-cup organoid. The complementary approach enabled quantitative prediction of morphogenesis and its corresponding verification and elucidated that the macroscopic 3D tissue deformation is fed back to individual cellular force generations via mechanosensing. We hereby conclude that mechanical force plays a key role as a feedback regulator to establish the robustness of organogenesis.
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Affiliation(s)
- S. Okuda
- RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - N. Takata
- RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Y. Hasegawa
- RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - M. Kawada
- RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Y. Inoue
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - T. Adachi
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Y. Sasai
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - M. Eiraku
- RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
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Orosz O, Fodor M, Balogh I, Losonczy G. Relative anterior microphthalmos in oculodentodigital dysplasia. Indian J Ophthalmol 2018; 66:334-336. [PMID: 29380799 PMCID: PMC5819136 DOI: 10.4103/ijo.ijo_756_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Here, we report a patient with oculodentodigital dysplasia (ODDD) caused by the c. 413G>A, p.Gly138Asp mutation in the gap junction protein alpha-1 gene. The patient suffered from characteristic dysmorphic features of ODDD. Ophthalmological investigation disclosed microcornea and a shallow anterior chamber, as expected. Surprisingly, the patient had a normal axial length and moderate myopia on both eyes. To the best of our knowledge, this is the first report on ODDD associated with relative anterior microphthalmos and myopia.
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Affiliation(s)
- Orsolya Orosz
- Department of Ophthalmology, University of Debrecen, Debrecen, Hungary, The Netherlands
| | - Mariann Fodor
- Department of Ophthalmology, University of Debrecen, Debrecen, Hungary, The Netherlands
| | - István Balogh
- Department of Laboratory Medicine, Division of Clinical Genetics, University of Debrecen, Debrecen, Hungary, The Netherlands
| | - Gergely Losonczy
- Department of Ophthalmology, University of Debrecen; Department of Ophthalmology, Zuyderland Hospital, Eyescan BV, Sittard, The Netherlands
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Abstract
PURPOSE OF REVIEW To discuss current knowledge on the role of connexins and pannexins in the musculoskeletal system. RECENT FINDINGS Connexins and pannexins are crucial for the development and maintenance of both bone and skeletal muscle. In bone, the presence of connexin and more recently of pannexin channels in osteoblasts, osteoclasts, and osteocytes has been described and shown to be essential for normal skeletal development and bone adaptation. In skeletal muscles, connexins and pannexins play important roles during development and regeneration through coordinated regulation of metabolic functions via cell-to-cell communication. Further, under pathological conditions, altered expression of these proteins can promote muscle atrophy and degeneration by stimulating inflammasome activity. In this review, we highlight the important roles of connexins and pannexins in the development, maintenance, and regeneration of musculoskeletal tissues, with emphasis on the mechanisms by which these molecules mediate chemical (e.g., ATP and prostaglandin E2) and physical (e.g., mechanical stimulation) stimuli that target the musculoskeletal system and their involvement in the pathophysiological changes in both genetic and acquired diseases.
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Affiliation(s)
- Lilian I Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS5045, Indianapolis, IN, 46202, USA.
- Roudebush Veterans Administration Medical Center, Indianapolis, Indiana, USA.
- Indiana Center for Musculoskeletal Health, Indianapolis, Indiana, USA.
| | - Hannah M Davis
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS5045, Indianapolis, IN, 46202, USA
| | - Bruno A Cisterna
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Alameda 340, Santiago, Chile
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Alameda 340, Santiago, Chile.
- Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile.
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Porntaveetus T, Srichomthong C, Ohazama A, Suphapeetiporn K, Shotelersuk V. A novel GJA1 mutation in oculodentodigital dysplasia with extensive loss of enamel. Oral Dis 2017; 23:795-800. [PMID: 28258662 DOI: 10.1111/odi.12663] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 02/11/2017] [Accepted: 02/23/2017] [Indexed: 01/18/2023]
Abstract
OBJECTIVE To characterize clinical features and identify genetic causes of a patient with oculodentodigital dysplasia (ODDD). SUBJECTS AND METHODS Clinical, dental, radiological features were obtained. DNA was collected from an affected Thai family. Whole-exome sequencing was employed to identify the disease-causing mutation causing ODDD. The presence of the identified variant was confirmed by Sanger sequencing. RESULTS The proband suffered with extensive enamel hypoplasia, polysyndactyly and clinodactyly of the 3rd-5th fingers, microphthalmia, and unique facial characteristics of ODDD. Mutation analysis revealed a novel missense mutation, c. 31C>A, p.L11I, in the GJA1 gene which encodes gap junction channel protein connexin 43. Bioinformatics and structural modeling suggested the mutation to be pathogenic. The parents did not harbor the mutation. CONCLUSIONS This study identified a novel de novo mutation in the GJA1 gene associated with severe tooth defects. These results expand the mutation spectrum and understanding of pathologic dental phenotypes related to ODDD.
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Affiliation(s)
- T Porntaveetus
- Department of Physiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.,STAR on Craniofacial and Skeletal Disorders, Chulalongkorn University, Bangkok, Thailand
| | - C Srichomthong
- Department of Pediatrics, Center of Excellence for Medical Genetics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Excellence Center for Medical Genetics, King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - A Ohazama
- Division of Oral Anatomy, Niigata University, Niigata, Japan
| | - K Suphapeetiporn
- Department of Pediatrics, Center of Excellence for Medical Genetics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Excellence Center for Medical Genetics, King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - V Shotelersuk
- Department of Pediatrics, Center of Excellence for Medical Genetics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Excellence Center for Medical Genetics, King Chulalongkorn Memorial Hospital, Bangkok, Thailand
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Dang FT, Yang FY, Yang YQ, Ge XL, Chen D, Zhang L, Yu XP, Gu F, Zhu YH. A novel mutation of p.F32I in GJA8 in human dominant congenital cataracts. Int J Ophthalmol 2016; 9:1561-1567. [PMID: 27990357 DOI: 10.18240/ijo.2016.11.05] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 06/16/2016] [Indexed: 11/23/2022] Open
Abstract
AIM To identify a causative mutation in a three-generation family with autosomal dominant congenital total cataract and dissect the molecular consequence of the identified mutation. METHODS Clinical and ophthalmological examinations were performed on the affected and unaffected family members. Mutation were screened in recruited family members by polymerase chain reaction (PCR) of the two reported genes (CRYAA and GJA8) which were linked to human total cataracts and direct sequencing of the PCR product. The molecular consequences of the identified mutation was dissected. The plasmids carrying wild-type and mutant mouse ORF of Gja8, coding for connexin 50 (Cx50), were generated and ectopic expressed in 293 cells. Recombinant protein expression and cellular localization of recombinated Cx50 were assessed by confocal microscopy. RESULTS Clinical and ophthalmological examinations were performed on the affected and unaffected family members. Mutation were screened in recruited family members by PCR of the two reported genes (CRYAA and GJA8) which were linked to human total cataracts and direct sequencing of the PCR product. The molecular consequences of the identified mutation was dissected. The plasmids carrying wild-type and mutant mouse ORF of Gja8, coding for Cx50, were generated and ectopic expressed in 293 cells. Recombinant protein expression and cellular localization of recombinated Cx50 were assessed by confocal microscopy. CONCLUSION This study has identified a novel cataract mutation in GJA8, which adds a novel mutation to the existing spectrum of Cx50 mutations with cataract. The molecular consequences of p.F32I mutation in GJA8 exclude instability and the mislocalization of mutant Cx50 protein.
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Affiliation(s)
- Feng-Tao Dang
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Fa-Yu Yang
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Ye-Qin Yang
- School of Nursing, Wenzhou Medical University, Wenzhou 325000, Zhejiang Province, China
| | - Xiang-Lian Ge
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Ding Chen
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Liu Zhang
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Xin-Ping Yu
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Feng Gu
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Yi-Hua Zhu
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
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A novel GJA1 mutation identified by whole exome sequencing in a Chinese family with autosomal dominant syndactyly. Clin Chim Acta 2016; 459:73-78. [PMID: 27241686 DOI: 10.1016/j.cca.2016.05.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/23/2016] [Accepted: 05/26/2016] [Indexed: 12/22/2022]
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12
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Plotkin LI, Laird DW, Amedee J. Role of connexins and pannexins during ontogeny, regeneration, and pathologies of bone. BMC Cell Biol 2016; 17 Suppl 1:19. [PMID: 27230612 PMCID: PMC4896274 DOI: 10.1186/s12860-016-0088-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Electron micrographs revealed the presence of gap junctions in osteoblastic cells over 40 years ago. These intercellular channels formed from connexins are present in bone forming osteoblasts, bone resorbing osteoclasts, and osteocytes (mature osteoblasts embedded in the mineralized bone matrix). More recently, genetic and pharmacologic studies revealed the role of connexins, and in particular Cx43, in the differentiation and function of all bone types. Furthermore, mutations in the gene encoding Cx43 were found to be causally linked to oculodentodigital dysplasia, a condition that results in an abnormal skeleton. Pannexins, molecules with similar structure and single-membrane channel forming potential as connexins when organized as hemichannels, are also expressed in osteoblastic cells. The function of pannexins in bone and cartilage is beginning to be uncovered, but more research is needed to determine the role of pannexins in bone development, adult bone mass and skeletal homeostasis. We describe here the current knowledge on the role of connexins and pannexins on skeletal health and disease.
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Affiliation(s)
- Lilian I Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA. .,Roudebush Veterans Administration Medical Center Indiana, Indianapolis, IN, 46202, USA.
| | - Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, N6A-5C1, Canada
| | - Joelle Amedee
- INSERM U1026, Tissue Bioengineering, Université Bordeaux, Bordeaux, F-33076, France
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Manipulating Cx43 expression triggers gene reprogramming events in dermal fibroblasts from oculodentodigital dysplasia patients. Biochem J 2015; 472:55-69. [PMID: 26349540 DOI: 10.1042/bj20150652] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 09/08/2015] [Indexed: 02/06/2023]
Abstract
Oculodentodigital dysplasia (ODDD) is primarily an autosomal dominant disorder linked to over 70 GJA1 gene [connexin43 (Cx43)] mutations. For nearly a decade, our laboratory has been investigating the relationship between Cx43 and ODDD by expressing disease-linked mutants in reference cells, tissue-relevant cell lines, 3D organ cultures and by using genetically modified mouse models of human disease. Although salient features of Cx43 mutants have been revealed, these models do not necessarily reflect the complexity of the human context. To further overcome these limitations, we have acquired dermal fibroblasts from two ODDD-affected individuals harbouring D3N and V216L mutations in Cx43, along with familial controls. Using these ODDD patient dermal fibroblasts, which naturally produce less GJA1 gene product, along with RNAi and RNA activation (RNAa) approaches, we show that manipulating Cx43 expression triggers cellular gene reprogramming. Quantitative RT-PCR, Western blot and immunofluorescent analysis of ODDD patient fibroblasts show unusually high levels of extracellular matrix (ECM)-interacting proteins, including integrin α5β1, matrix metalloproteinases as well as secreted ECM proteins collagen-I and laminin. Cx43 knockdown in familial control cells produces similar effects on ECM expression, whereas Cx43 transcriptional up-regulation using RNAa decreases production of collagen-I. Interestingly, the enhanced levels of ECM-associated proteins in ODDD V216L fibroblasts is not only a consequence of increased ECM gene expression, but also due to an apparent deficit in collagen-I secretion which may further contribute to impaired collagen gel contraction in ODDD fibroblasts. These findings further illuminate the altered function of Cx43 in ODDD-affected individuals and highlight the impact of manipulating Cx43 expression in human cells.
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A novel truncation mutation in GJA1 associated with open angle glaucoma and microcornea in a large Chinese family. Eye (Lond) 2015; 29:972-7. [PMID: 25976645 DOI: 10.1038/eye.2015.74] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 03/17/2015] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To identify genetic defects in a large family with open angle glaucoma (OAG) and microcornea. METHODS Genomic DNA was prepared from leukocytes of 15 individuals from three generations of a Chinese family, including seven individuals with OAG and microcornea, one with microcornea alone, and seven healthy individuals. Whole exome sequencing was performed on genomic DNA of the proband. Candidate variants were obtained through multiple steps of bioinformatics analysis and validated by Sanger sequencing and segregation analysis. RESULTS Exome sequencing detected a candidate variant in GJA1, a novel truncation mutation (c.791_792delAA, p.K264Ifs*43). This mutation was present in all seven individuals with OAG and microcornea and the individual with microcornea alone, but not in the seven unaffected relatives in the family. It was not present in 1394 alleles from 505 unrelated controls without glaucoma and 192 normal controls. Extraocular signs were not observed in seven out of the eight individuals; only one was affected with dental enamel hypoplasia and syndactyly. CONCLUSIONS A novel truncation mutation in GJA1 is associated with OAG and microcornea in a Chinese family. This suggests that GJA1 should be included as a candidate gene for glaucoma.
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Syndromic and non-syndromic disease-linked Cx43 mutations. FEBS Lett 2014; 588:1339-48. [PMID: 24434540 DOI: 10.1016/j.febslet.2013.12.022] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 12/30/2013] [Indexed: 01/05/2023]
Abstract
There are now at least 14 distinct diseases linked to germ line mutations in the 21 genes that encode the connexin (Cx) family of gap junction proteins. This review focuses on the links between germ-line mutations in the gene encoding Cx43 (GJA1) and the human disease termed oculodentodigital dysplasia (ODDD). This disease is clinically characterized by soft tissue fusion of the digits, abnormal craniofacial bone development, small eyes and loss of tooth enamel. However, the disease is considerably more complex and somewhat degenerative as patients often suffer from other syndromic effects that include incontinence, glaucoma, skin diseases and neuropathies that become more pronounced during aging. The challenge continues to be understanding how distinct Cx43 gene mutations cause such a diverse range of tissue phenotypes and pathophysiological changes while other Cx43-rich organs are relatively unaffected. This review will provide an overview of many of these studies and distill some themes and outstanding questions that need to be addressed in the coming years.
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De Bock M, Kerrebrouck M, Wang N, Leybaert L. Neurological manifestations of oculodentodigital dysplasia: a Cx43 channelopathy of the central nervous system? Front Pharmacol 2013; 4:120. [PMID: 24133447 PMCID: PMC3783840 DOI: 10.3389/fphar.2013.00120] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 09/02/2013] [Indexed: 12/30/2022] Open
Abstract
The coordination of tissue function is mediated by gap junctions (GJs) that enable direct cell–cell transfer of metabolic and electric signals. GJs are formed by connexins of which Cx43 is most widespread in the human body. In the brain, Cx43 GJs are mostly found in astroglia where they coordinate the propagation of Ca2+ waves, spatial K+ buffering, and distribution of glucose. Beyond its role in direct intercellular communication, Cx43 also forms unapposed, non-junctional hemichannels in the plasma membrane of glial cells. These allow the passage of several neuro- and gliotransmitters that may, combined with downstream paracrine signaling, complement direct GJ communication among glial cells and sustain glial-neuronal signaling. Mutations in the GJA1 gene encoding Cx43 have been identified in a rare, mostly autosomal dominant syndrome called oculodentodigital dysplasia (ODDD). ODDD patients display a pleiotropic phenotype reflected by eye, hand, teeth, and foot abnormalities, as well as craniofacial and bone malformations. Remarkably, neurological symptoms such as dysarthria, neurogenic bladder (manifested as urinary incontinence), spasticity or muscle weakness, ataxia, and epilepsy are other prominent features observed in ODDD patients. Over 10 mutations detected in patients diagnosed with neurological disorders are associated with altered functionality of Cx43 GJs/hemichannels, but the link between ODDD-related abnormal channel activities and neurologic phenotype is still elusive. Here, we present an overview on the nature of the mutants conveying structural and functional changes of Cx43 channels and discuss available evidence for aberrant Cx43 GJ and hemichannel function. In a final step, we examine the possibilities of how channel dysfunction may lead to some of the neurological manifestations of ODDD.
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Affiliation(s)
- Marijke De Bock
- Physiology Group, Department of Basic Medical Sciences, Ghent University Ghent, Belgium
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Nishat S, Mansoor Q, Javaid A, Ismail M. Oculodentodigital Syndrome with Syndactyly Type III in a Pakistani consanguineous family. J Dermatol Case Rep 2012; 6:43-8. [PMID: 22826718 DOI: 10.3315/jdcr.2012.1094] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 04/05/2012] [Indexed: 11/11/2022]
Abstract
BACKGROUND Oculodentodigital syndrome (ODD; OMIM #164200) is a rare autosomal dominant disorder with pleiotropic effects. It is caused by mutation in gap junction protein α 1 (GJA1) gene which encodes connexion 43. ODD is characterised by symptoms i.e. craniofacial, neurologic, limb, ocular abnormalities, syndactyly type III of the hands, phalangeal abnormalities, diffuse skeletal dysplasia, enamel dysplasia, and hypotrichosis. OBJECTIVES To study the Molecular Genetics of Oculodentodigital syndrome. PATIENTS/MATERIALS AND METHODS Our current study includes a Pakistani family affected with ODD. Clinical evaluation revealed that this family shows typical form of ODD with Syndactyly type III. Mutations in GJA1 have been reported in ODD and also in syndactyly type III. In this study we sequenced the coding exons of GJA1 gene in affected and normal individuals of the family for mutation detection. RESULTS Direct sequencing of the affected individuals showed a mutation at the nucleotide position 389 T>C. This mutation changed the codon 130 from Isoleucine to Threonine. Normal family members did not show this mutation. CONCLUSION Our study showed no gross neurological upset with I130T mutation in GJA1 gene. This may present novel phenotypic outcome with the I130T. The study will help in better understanding of pathophysiology of oculodentodigital syndrome and type III syndactyly.
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Affiliation(s)
- Sumaira Nishat
- Institute of Biomedical and Genetic Engineering (IBGE), 24 Mauve Area, Sector G-9/1, Islamabad
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18
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Abrams CK, Scherer SS. Gap junctions in inherited human disorders of the central nervous system. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1818:2030-47. [PMID: 21871435 PMCID: PMC3771870 DOI: 10.1016/j.bbamem.2011.08.015] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 08/04/2011] [Accepted: 08/10/2011] [Indexed: 12/15/2022]
Abstract
CNS glia and neurons express connexins, the proteins that form gap junctions in vertebrates. We review the connexins expressed by oligodendrocytes and astrocytes, and discuss their proposed physiologic roles. Of the 21 members of the human connexin family, mutations in three are associated with significant central nervous system manifestations. For each, we review the phenotype and discuss possible mechanisms of disease. Mutations in GJB1, the gene for connexin 32 (Cx32) cause the second most common form of Charcot-Marie-Tooth disease (CMT1X). Though the only consistent phenotype in CMT1X patients is a peripheral demyelinating neuropathy, CNS signs and symptoms have been found in some patients. Recessive mutations in GJC2, the gene for Cx47, are one cause of Pelizaeus-Merzbacher-like disease (PMLD), which is characterized by nystagmus within the first 6 months of life, cerebellar ataxia by 4 years, and spasticity by 6 years of age. MRI imaging shows abnormal myelination. A different recessive GJC2 mutation causes a form of hereditary spastic paraparesis, which is a milder phenotype than PMLD. Dominant mutations in GJA1, the gene for Cx43, cause oculodentodigital dysplasia (ODDD), a pleitropic disorder characterized by oculo-facial abnormalities including micropthalmia, microcornia and hypoplastic nares, syndactyly of the fourth to fifth fingers and dental abnormalities. Neurologic manifestations, including spasticity and gait difficulties, are often but not universally seen. Recessive GJA1 mutations cause Hallermann-Streiff syndrome, a disorder showing substantial overlap with ODDD. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and functions.
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Affiliation(s)
- Charles K. Abrams
- Department of Neurology and Physiology & Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, 1-718-270-1270 Phone, 1-718-270-8944 Fax,
| | - Steven S. Scherer
- Department of Neurology, The University of Pennsylvania School of Medicine, Room 450 Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA 19104-6077, 215-573-3198,
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Xu Q, Kopp RF, Chen Y, Yang JJ, Roe MW, Veenstra RD. Gating of connexin 43 gap junctions by a cytoplasmic loop calmodulin binding domain. Am J Physiol Cell Physiol 2012; 302:C1548-56. [PMID: 22422398 PMCID: PMC3361999 DOI: 10.1152/ajpcell.00319.2011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 03/13/2012] [Indexed: 11/22/2022]
Abstract
Calmodulin (CaM) binding sites were recently identified on the cytoplasmic loop (CL) of at least three α-subfamily connexins (Cx43, Cx44, Cx50), while Cx40 does not have this putative CaM binding domain. The purpose of this study was to examine the functional relevance of the putative Cx43 CaM binding site on the Ca(2+)-dependent regulation of gap junction proteins formed by Cx43 and Cx40. Dual whole cell patch-clamp experiments were performed on stable murine Neuro-2a cells expressing Cx43 or Cx40. Addition of ionomycin to increase external Ca(2+) influx reduced Cx43 gap junction conductance (G(j)) by 95%, while increasing cytosolic Ca(2+) concentration threefold. By contrast, Cx40 G(j) declined by <20%. The Ca(2+)-induced decline in Cx43 G(j) was prevented by pretreatment with calmidazolium or reversed by the addition of 10 mM EGTA to Ca(2+)-free extracellular solution, if Ca(2+) chelation was commenced before complete uncoupling, after which g(j) was only 60% recoverable. The Cx43 CL(136-158) mimetic peptide, but not the scrambled control peptide, or Ca(2+)/CaM-dependent kinase II 290-309 inhibitory peptide also prevented the Ca(2+)/CaM-dependent decline of Cx43 G(j). Cx43 gap junction channel open probability decreased to zero without reductions in the current amplitudes during external Ca(2+)/ionomycin perfusion. We conclude that Cx43 gap junctions are gated closed by a Ca(2+)/CaM-dependent mechanism involving the carboxyl-terminal quarter of the connexin CL domain. This study provides the first evidence of intrinsic differences in the Ca(2+) regulatory properties of Cx43 and Cx40.
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Affiliation(s)
- Qin Xu
- Department of Pharmacology, SUNY Upstate Medical University, 750 East Adams St., Syracuse, NY 13210, USA
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Jordan D, Hindocha S, Dhital M, Saleh M, Khan W. The epidemiology, genetics and future management of syndactyly. Open Orthop J 2012; 6:14-27. [PMID: 22448207 PMCID: PMC3308320 DOI: 10.2174/1874325001206010014] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/26/2011] [Accepted: 10/29/2011] [Indexed: 12/18/2022] Open
Abstract
Syndactyly is a condition well documented in current literature due to it being the most common congenital hand defect, with a large aesthetic and functional significance.There are currently nine types of phenotypically diverse non-syndromic syndactyly, an increase since the original classification by Temtamy and McKusick(1978). Non-syndromic syndactyly is inherited as an autosomal dominant trait, although the more severe presenting types and sub types appear to have autosomal recessive and in some cases X-linked hereditary.Gene research has found that these phenotypes appear to not only be one gene specific, although having individual localised loci, but dependant on a wide range of genes and subsequent signalling pathways involved in limb formation. The principal genes so far defined to be involved in congenital syndactyly concern mainly the Zone of Polarizing Activity and Shh pathway.Research into the individual phenotypes appears to complicate classification as new genes are found both linked, and not linked, to each malformation. Consequently anatomical, phenotypical and genotypical classifications can be used, but are variable in significance, depending on the audience.Currently, management is surgical, with a technique unchanged for several decades, although future development will hopefully bring alternatives in both earlier diagnosis and gene manipulation for therapy.
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Affiliation(s)
- D Jordan
- Department of Plastic Surgery, Countess of Chester Hospital, Liverpool Road Chester, CH21UL, UK
| | - S Hindocha
- Department of Plastic Surgery, Countess of Chester Hospital, Liverpool Road Chester, CH21UL, UK
- Department of Plastic Surgery, Whiston Hospital, Warrington Road, L35 5DR, Liverpool, UK
| | - M Dhital
- University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - M Saleh
- Ain Shams University, Khalifa El-Maamon St, Abbasiya Sq, Cairo. 11566, Egypt
| | - W Khan
- University College London Institute of Orthopaedics and Musculoskeletal Sciences, Royal National Orthopaedic Hospital, Stanmore, Middlesex, HA7 4LP, UK
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A dominant connexin43 mutant does not have dominant effects on gap junction coupling in astrocytes. ACTA ACUST UNITED AC 2011; 6:213-23. [PMID: 21375791 DOI: 10.1017/s1740925x11000019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Dominant mutations in GJA1, the gene encoding the gap junction protein connexin43 (Cx43), cause oculodentodigital dysplasia (ODDD), a syndrome affecting multiple tissues, including the central nervous system (CNS). We investigated the effects of the G60S mutant, which causes a similar, dominant phenotype in mice (Gja1(Jrt/+)). Astrocytes in acute brain slices from Gja1(Jrt/+) mice transfer sulforhodamine-B comparably to that in their wild-type (WT) littermates. Further, astrocytes and cardiomyocytes cultured from Gja1(Jrt/+) mice showed a comparable transfer of lucifer yellow to those from WT mice. In transfected cells, the G60S mutant formed gap junction (GJ) plaques but not functional channels. In co-transfected cells, the G60S mutant co-immunoprecipitated with WT Cx43, but did not diminish GJ coupling as measured by dual patch clamp. Thus, whereas G60S has dominant effects, it did not appreciably reduce GJ coupling.
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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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A novel GJA1 missense mutation in a Polish child with oculodentodigital dysplasia. J Appl Genet 2009; 50:297-9. [PMID: 19638688 DOI: 10.1007/bf03195687] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Oculodentodigital dysplasia (ODDD) (OMIM #164200) is a rare congenital, autosomal dominant disorder comprising craniofacial, ocular, dental, and digital anomalies. The syndrome is caused by GJA1 mutations. The clinical phenotype of ODDD involves a characteristic dysmorphic facies, ocular findings (microphthalmia, microcornea, glaucoma), syndactyly type III of the hands, phalangeal abnormalities, diffuse skeletal dysplasia, enamel dysplasia, and hypotrichosis. In a Polish child with the clinical symptoms typical of ODDD, we demonstrated a novel missense mutation c.C31A resulting in p.L11F substitution. Our report provides evidence on the importance of this highly conserved amino acid residue for the proper functioning of GJA1 protein.
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