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Damagatla M, Verma A, Pochaboina V, Bhate M, Senthil S. GAPO syndrome: a novel variant in ANTXR1 gene. Ophthalmic Genet 2024; 45:395-400. [PMID: 38691016 DOI: 10.1080/13816810.2024.2345879] [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: 11/04/2023] [Revised: 03/11/2024] [Accepted: 04/16/2024] [Indexed: 05/03/2024]
Abstract
BACKGROUND GAPO syndrome is a rare autosomal recessive disorder characterized by the acronym of growth retardation, alopecia, pseudo-anodontia and progressive optic atrophy. While the genetic alteration of the ANTXR1 gene has been known for its cause, the full range of its clinical and genetic manifestations is not well explored due to the syndrome's extreme rarity. MATERIALS/METHODS We report two children born to a non-consanguineous parent in India with classical features of GAPO syndrome. The whole exome sequencing analysis (WES) was performed in both siblings, and the parent's genetic and clinical status was determined. The identified variation was characterized in silico using homology-based protein modelling. RESULTS In WES analysis, a homozygous ANTXR1 gene indel variant c. 151_152 + 2delAAGT (p.Lys51fs) was identified in both siblings. The parents were identified as the carriers of the ANTXR1 variant. Additionally, they also displayed mild GAPO-related facial and glaucomatous features. In silico analysis and homology-based ANTXR1 protein structure illustrate a frameshift and the subsequent premature truncation of the protein. CONCLUSIONS Our reports contribute to the comprehension of GAPO syndrome within the Indian context describing an ANTXR1 novel variant causing premature protein truncation. WES-based genetic testing can significantly aid in expertly diagnosing GAPO syndrome. In the present case scenario, a variable penetrance of ANTXR1 variation was acknowledged as the carrier parents also had a mild degree of GAPO-related features. Future reports that include parental clinical diagnosis can offer further insights in this context.
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Affiliation(s)
| | - Anshuman Verma
- Institute of Rare Eye Diseases and Ocular Genetics, LV Prasad Eye Institute, Hyderabad, India
| | - Venkatesh Pochaboina
- Institute of Rare Eye Diseases and Ocular Genetics, LV Prasad Eye Institute, Hyderabad, India
| | - Manju Bhate
- Strabismus, Paediatric and Neuro-Ophthalmology Services (MB), Jasti V Ramanamma Children's Eye Care Center, LV Prasad Eye Institute, Hyderabad, India
| | - Sirisha Senthil
- VST Centre for Glaucoma Services, LV Prasad Eye Institute, Hyderabad, India
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Chung DD, Chen AC, Choo CH, Zhang W, Williams D, Griffis CG, Bonezzi P, Jatavallabhula K, Sampath AP, Aldave AJ. Investigation of the functional impact of CHED- and FECD4-associated SLC4A11 mutations in human corneal endothelial cells. PLoS One 2024; 19:e0296928. [PMID: 38252645 PMCID: PMC10802951 DOI: 10.1371/journal.pone.0296928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 12/22/2023] [Indexed: 01/24/2024] Open
Abstract
Mutations in the solute linked carrier family 4 member 11 (SLC4A11) gene are associated with congenital hereditary endothelial dystrophy (CHED) and Fuchs corneal endothelial dystrophy type 4 (FECD4), both characterized by corneal endothelial cell (CEnC) dysfunction and/or cell loss leading to corneal edema and visual impairment. In this study, we characterize the impact of CHED-/FECD4-associated SLC4A11 mutations on CEnC function and SLC4A11 protein localization by generating and comparing human CEnC (hCEnC) lines expressing wild type SLC4A11 (SLC4A11WT) or mutant SLC4A11 harboring CHED-/FECD4-associated SLC4A11 mutations (SLC4A11MU). SLC4A11WT and SLC4A11MU hCEnC lines were generated to express either SLC4A11 variant 2 (V2WT and V2MU) or variant 3 (V3WT and V3MU), the two major variants expressed in ex vivo hCEnC. Functional assays were performed to assess cell barrier, proliferation, viability, migration, and NH3-induced membrane conductance. We demonstrate SLC4A11-/- and SLC4A11MU hCEnC lines exhibited increased migration rates, altered proliferation and decreased cell viability compared to SLC4A11WT hCEnC. Additionally, SLC4A11-/- hCEnC demonstrated decreased cell-substrate adhesion and membrane capacitances compared to SLC4A11WT hCEnC. Induction with 10mM NH4Cl led SLC4A11WT hCEnC to depolarize; conversely, SLC4A11-/- hCEnC hyperpolarized and the majority of SLC4A11MU hCEnC either hyperpolarized or had minimal membrane potential changes following NH4Cl induction. Immunostaining of primary hCEnC and SLC4A11WT hCEnC lines for SLC4A11 demonstrated predominately plasma membrane staining with poor or partial colocalization with mitochondrial marker COX4 within a subset of punctate subcellular structures. Overall, our findings suggest CHED-associated SLC4A11 mutations likely lead to hCEnC dysfunction, and ultimately CHED, by interfering with cell migration, proliferation, viability, membrane conductance, barrier function, and/or cell surface localization of the SLC4A11 protein in hCEnC. Additionally, based on their similar subcellular localization and exhibiting similar cell functional profiles, protein isoforms encoded by SLC4A11 variant 2 and variant 3 likely have highly overlapping functional roles in hCEnC.
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Affiliation(s)
- Doug D. Chung
- Department of Ophthalmology, Stein Eye Institute at UCLA, Los Angeles, California, United States of America
| | - Angela C. Chen
- Department of Ophthalmology, Stein Eye Institute at UCLA, Los Angeles, California, United States of America
| | - Charlene H. Choo
- Department of Ophthalmology, Stein Eye Institute at UCLA, Los Angeles, California, United States of America
| | - Wenlin Zhang
- Department of Ophthalmology, Stein Eye Institute at UCLA, Los Angeles, California, United States of America
| | - Dominic Williams
- Department of Ophthalmology, Stein Eye Institute at UCLA, Los Angeles, California, United States of America
| | - Christopher G. Griffis
- Department of Ophthalmology, Stein Eye Institute at UCLA, Los Angeles, California, United States of America
| | - Paul Bonezzi
- Department of Ophthalmology, Stein Eye Institute at UCLA, Los Angeles, California, United States of America
| | - Kavya Jatavallabhula
- Department of Ophthalmology, Stein Eye Institute at UCLA, Los Angeles, California, United States of America
| | - Alapakkam P. Sampath
- Department of Ophthalmology, Stein Eye Institute at UCLA, Los Angeles, California, United States of America
| | - Anthony J. Aldave
- Department of Ophthalmology, Stein Eye Institute at UCLA, Los Angeles, California, United States of America
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Oie Y, Yamaguchi T, Nishida N, Okumura N, Maeno S, Kawasaki R, Jhanji V, Shimazaki J, Nishida K. Systematic Review of the Diagnostic Criteria and Severity Classification for Fuchs Endothelial Corneal Dystrophy. Cornea 2023; 42:1590-1600. [PMID: 37603692 DOI: 10.1097/ico.0000000000003343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 05/28/2023] [Indexed: 08/23/2023]
Abstract
PURPOSE There are no defined diagnostic criteria and severity classification for Fuchs endothelial corneal dystrophy (FECD), which are required for objective standardized assessments. Therefore, we performed a systematic literature review of the current diagnosis and severity classification of FECD. METHODS We searched the Ovid MEDLINE and Web of Science databases for studies published until January 13, 2021. We excluded review articles, conference abstracts, editorials, case reports with <5 patients, and letters. RESULTS Among 468 articles identified, we excluded 173 and 165 articles in the first and second screenings, respectively. Among the 130 included articles, 61 (47%) and 99 (76%) mentioned the diagnostic criteria for FECD and described its severity classification, respectively. Regarding diagnosis, slitlamp microscope alone was the most frequently used device in 31 (51%) of 61 articles. Regarding diagnostic findings, corneal guttae alone was the most common parameter [adopted in 23 articles (38%)]. Regarding severity classification, slitlamp microscopes were used in 88 articles (89%). The original or modified Krachmer grading scale was used in 77 articles (78%), followed by Adami's classification in six (6%). Specular microscopes or Scheimpflug tomography were used in four articles (4%) and anterior segment optical coherence tomography in one (1%). CONCLUSIONS FECD is globally diagnosed by the corneal guttae using slitlamp examination, and its severity is predominantly determined by the original or modified Krachmer grading scale. Objective severity grading using Scheimpflug or anterior segment optical coherence tomography can be applied in the future innovative therapies such as cell injection therapy or novel small molecules.
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Affiliation(s)
- Yoshinori Oie
- Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Takefumi Yamaguchi
- Department of Ophthalmology, Tokyo Dental College Ichikawa General Hospital, Ichikawa, Japan
| | - Nozomi Nishida
- Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Naoki Okumura
- Department of Biomedical Engineering, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan; and
| | - Sayo Maeno
- Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Ryo Kawasaki
- Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Vishal Jhanji
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Jun Shimazaki
- Department of Ophthalmology, Tokyo Dental College Ichikawa General Hospital, Ichikawa, Japan
| | - Kohji Nishida
- Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Japan
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Mehta N, Verma A, Achanta DS, Kannabiran C, Roy S, Mishra DK, Chaurasia S, Edward DP, Ramappa M. Updates on congenital hereditary endothelial dystrophy. Taiwan J Ophthalmol 2023; 13:405-416. [PMID: 38249503 PMCID: PMC10798399 DOI: 10.4103/tjo.tjo-d-23-00135] [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: 09/11/2023] [Revised: 10/08/2023] [Accepted: 10/09/2023] [Indexed: 01/23/2024] Open
Abstract
Congenital hereditary endothelial dystrophy (CHED) is a rare genetic corneal disorder causing progressive cornea clouding and significant visual impairment. CHED remains a leading indication for pediatric corneal transplantation despite its infrequency, particularly in regions with high consanguinity rates like Southeast Asia. Identifying the Solute Carrier Family 4 Member 11 (SLC4A11) gene as the genetic basis of CHED has led to the discovery of it's various genetic variations. However, a comprehensive understanding of its clinical-genetic correlation, pathophysiology, and optimal management is ongoing. This review aims to consolidate current knowledge about CHED, covering its genetic origins, pathophysiological mechanisms, clinical presentation, and management strategies. Surgical intervention, such as penetrating keratoplasty (PK), Descemet stripping automated endothelial keratoplasty (DSAEK), and Descemet membrane endothelial keratoplasty (DMEK), remains the primary treatment. DSAEK and DMEK offer advantages over PK, including quicker visual recovery, reduced complications, and longer graft survival, especially in the pediatric age group. The timing of surgical interventions depends on disease severity, age at presentation, comorbidities, and visual potential. Elevated oxidative stress in CHED corneal tissue suggests potential benefits from anti-inflammatory drugs to rescue mutated endothelial cells. Considering the limitations of corneal graft surgeries, exploring novel gene-based molecular therapies are essential for future management. Early diagnosis, appropriate surgical interventions, amblyopia control, and genetic counseling for predictive analysis are pivotal for optimizing CHED management. A multidisciplinary approach involving ophthalmologists, researchers, and genetic counselors is essential for precise diagnosis and optimal care for CHED patients.
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Affiliation(s)
- Neet Mehta
- Academy of Eye Care Education, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Anshuman Verma
- Centre for Rare Eye Diseases and Ophthalmic Genetics, L V Prasad Eye Institute, Hyderabad, Telangana, India
- Prof. Brien Holden Eye Research Center, LV Prasad Eye Institute, Hyderabad, Telangana, India
| | - Divya Sree Achanta
- Centre for Rare Eye Diseases and Ophthalmic Genetics, L V Prasad Eye Institute, Hyderabad, Telangana, India
- The Cornea Institute, L V Prasad Eye Institute, Hyderabad, Telangana, India
- Jasti V Ramanamma Children’s Eye Care Center, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Chitra Kannabiran
- Prof. Brien Holden Eye Research Center, LV Prasad Eye Institute, Hyderabad, Telangana, India
| | - Sanhita Roy
- Prof. Brien Holden Eye Research Center, LV Prasad Eye Institute, Hyderabad, Telangana, India
| | - Dilip Kumar Mishra
- Ophthalmic Pathology Services, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Sunita Chaurasia
- The Cornea Institute, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Deepak Paul Edward
- Department of Ophthalmology and Visual Sciences and Pathology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Muralidhar Ramappa
- Centre for Rare Eye Diseases and Ophthalmic Genetics, L V Prasad Eye Institute, Hyderabad, Telangana, India
- The Cornea Institute, L V Prasad Eye Institute, Hyderabad, Telangana, India
- Jasti V Ramanamma Children’s Eye Care Center, L V Prasad Eye Institute, Hyderabad, Telangana, India
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Tsedilina TR, Sharova E, Iakovets V, Skorodumova LO. Systematic review of SLC4A11, ZEB1, LOXHD1, and AGBL1 variants in the development of Fuchs' endothelial corneal dystrophy. Front Med (Lausanne) 2023; 10:1153122. [PMID: 37441688 PMCID: PMC10333596 DOI: 10.3389/fmed.2023.1153122] [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: 01/28/2023] [Accepted: 03/30/2023] [Indexed: 07/15/2023] Open
Abstract
Introduction The pathogenic role of variants in TCF4 and COL8A2 in causing Fuchs' endothelial corneal dystrophy (FECD) is not controversial and has been confirmed by numerous studies. The causal role of other genes, SLC4A11, ZEB1, LOXHD1, and AGBL1, which have been reported to be associated with FECD, is more complicated and less obvious. We performed a systematic review of the variants in the above-mentioned genes in FECD cases, taking into account the currently available population frequency information, transcriptomic data, and the results of functional studies to assess their pathogenicity. Methods Search for articles published in 2005-2022 was performed manually between July 2022 and February 2023. We searched for original research articles in peer-reviewed journals, written in English. Variants in the genes of interest identified in patients with FECD were extracted for the analysis. We classified each presented variant by pathogenicity status according to the ACMG criteria implemented in the Varsome tool. Diagnosis, segregation data, presence of affected relatives, functional analysis results, and gene expression in the corneal endothelium were taken into account. Data on the expression of genes of interest in the corneal endothelium were extracted from articles in which transcriptome analysis was performed. The identification of at least one variant in a gene classified as pathogenic or significantly associated with FECD was required to confirm the causal role of the gene in FECD. Results The analysis included 34 articles with 102 unique ZEB1 variants, 20 articles with 64 SLC4A11 variants, six articles with 26 LOXHD1 variants, and five articles with four AGBL1 variants. Pathogenic status was confirmed for seven SLC4A11 variants found in FECD. No variants in ZEB1, LOXHD1, and AGBL1 genes were classified as pathogenic for FECD. According to the transcriptome data, AGBL1 and LOXHD1 were not expressed in the corneal endothelium. Functional evidence for the association of LOXHD1, and AGBL1 with FECD was conflicting. Conclusion Our analysis confirmed the causal role of SLC4A11 variants in the development of FECD. The causal role of ZEB1, LOXHD1, and AGBL1 variants in FECD has not been confirmed. Further evidence from familial cases and functional analysis is needed to confirm their causal roles in FECD.
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Affiliation(s)
- Tatiana Romanovna Tsedilina
- Laboratory of Human Molecular Genetics, Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Elena Sharova
- Laboratory of Human Molecular Genetics, Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Valeriia Iakovets
- Laboratory of Human Molecular Genetics, Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
- I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Liubov Olegovna Skorodumova
- Laboratory of Human Molecular Genetics, Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
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Iulmetova LN, Kulemin NA, Sharova EI. The approach to patient clustering based on the microchip data confined to distinct loci using the combinations of variants. BULLETIN OF RUSSIAN STATE MEDICAL UNIVERSITY 2023. [DOI: 10.24075/brsmu.2023.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Fuchs' endothelial corneal dystrophy is a socially significant hereditary disease. More than a half of cases in the European population are caused by the increased number of trinucleotude repeats in the TCF4 gene. The study was aimed to develop and test the approach of dividing patients into groups based on the chip-based genotyping and genome-wide association study (GWAS) results. The analysis was conducted using FECD Genetics Multi-center Study and AREDs project datasets containing the data of 1721 clinical cases and 2408 control patients. When analyzing the GWAS results, the patients and the control group were divided into two groups by means of hierarchical clustering suggesting that patients with the increased number of repeats in the TCF4 gene are carriers of specific combinations of genomic variants (haplotypes). It was shown that individual variants cannot be used for the molecular genetic stratification of patients with the increased number of repeats in TCF4 due to inconsistent results obtained for the variants. Furthermore, the haplotype-based approach outperformed the SNPs in terms of odds ratio. The paper proposes a method that enables further search for the biologically relevant combinations of genomic variants.
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Affiliation(s)
- LN Iulmetova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of the Federal Medical Biological Agency, Moscow, Russia
| | - NA Kulemin
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of the Federal Medical Biological Agency, Moscow, Russia
| | - EI Sharova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of the Federal Medical Biological Agency, Moscow, Russia
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Vanathi M, Raj N, Kusumesh R, Aron N, Gupta N, Tandon R. Update on Pediatric Corneal Diseases and Keratoplasty. Surv Ophthalmol 2022; 67:1647-1684. [PMID: 35918016 DOI: 10.1016/j.survophthal.2022.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/24/2022] [Accepted: 07/25/2022] [Indexed: 10/31/2022]
Abstract
Managing pediatric corneal disorders is challenging as the prognosis of pediatric keratoplasty depends on several factors. Advancements in the genetic basis of congenital corneal diseases and investigations in congenital corneal conditions provide a better understanding of pediatric corneal conditions. Surgeons performing keratoplasty in children now have a choice of various techniques. Evolving surgical techniques of anterior lamellar and endothelial keratoplasties has expanded the management interventions in these pediatric corneal morbidity conditions; however, considerable concerns still exist in association with corneal transplantation in infants and children. Outcomes in pediatric keratoplasty depend upon the preoperative indications, the timing of surgical intervention, intraoperative and postoperative factors including the patient/care givers' compliance. Factors such as low scleral rigidity, higher rate of graft failure, need for frequent examinations under anesthesia, and difficulty in optimal visual acuity assessment still remain a considerable challenge in pediatric scenarios. In children, deprivation amblyopia as a result of the corneal opacification can adversely affect visual development, causing dense amblyopia. Outcomes to surgical interventions for management of corneal opacification in children is further compromised by the pre-existing amblyopia apart from the concerns of refractive outcome of the graft. Graft rejection, graft infection, amblyopia, and glaucoma continue to be serious concerns. In recent years both anterior and posterior lamellar keratoplasty techniques are being increasingly performed in pediatric eyes, which offer advantages in the form of lower risk of graft rejection. The timing of surgery, careful case selection, cautious intraoperative approach, and optimal postoperative management can improve the anatomical and functional outcome in difficult cases.
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Affiliation(s)
- Murugesan Vanathi
- Cornea, Lens & Refractive Services, Dr. R P Centre for Ophthalmic Sciences - ALL INDIA INSTITUTE OF MEDICAL SCIENCES, New Delhi 110029, India.
| | - Nimmy Raj
- Cornea, Lens & Refractive Services, Dr. R P Centre for Ophthalmic Sciences - ALL INDIA INSTITUTE OF MEDICAL SCIENCES, New Delhi 110029, India
| | - Rakhi Kusumesh
- Cornea & Ocular Surface Services, Indira Gandhi Institute of Medical Sciences, Patna, Bihar, India
| | - Neelima Aron
- Cornea, Lens & Refractive Services, Dr. R P Centre for Ophthalmic Sciences - ALL INDIA INSTITUTE OF MEDICAL SCIENCES, New Delhi 110029, India
| | - Noopur Gupta
- Cornea, Lens & Refractive Services, Dr. R P Centre for Ophthalmic Sciences - ALL INDIA INSTITUTE OF MEDICAL SCIENCES, New Delhi 110029, India
| | - Radhika Tandon
- Cornea, Lens & Refractive Services, Dr. R P Centre for Ophthalmic Sciences - ALL INDIA INSTITUTE OF MEDICAL SCIENCES, New Delhi 110029, India
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Salman M, Verma A, Singh VK, Jaffet J, Chaurasia S, Sahel DK, Ramappa M, Singh V. New Frontier in the Management of Corneal Dystrophies: Basics, Development, and Challenges in Corneal Gene Therapy and Gene Editing. Asia Pac J Ophthalmol (Phila) 2022; 11:346-359. [PMID: 36041149 DOI: 10.1097/apo.0000000000000443] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/26/2021] [Indexed: 12/13/2022] Open
Abstract
ABSTRACT Corneal dystrophies represent a group of heterogeneous hereditary disorders causing progressive corneal opacification and blindness. Current corneal transplant management for corneal dystrophies faces the challenges of repeated treatments, complex surgical procedures, shortage of appropriate donor cornea, and, more importantly, graft rejection. Genetic medicine could be an alternative treatment regime to overcome such challenges. Cornea carries promising scope for a gene-based therapy involving gene supplementation, gene silencing, and gene editing in both ex vivo and in vivo platforms. In the cornea, ex vivo gene therapeutic strategies were attempted for corneal graft survival, and in vivo gene augmentation therapies aimed to prevent herpes stromal keratitis, neovascularization, corneal clouding, and wound healing. However, none of these studies followed a clinical trial-based successful outcome. CRISPR/Cas system offers a broad scope of gene editing and engineering to correct underlying genetic causes in corneal dystrophies. Corneal tissue--specific gene correction in vitro with minimal off-target effects and optimal gene correction efficiency followed by their successful surgical implantation, or in vivo CRISPR administration targeting pathogenic genes finds a way to explore therapeutic intervention for corneal dystrophies. However, there are many limitations associated with such CRISPR-based corneal treatment management. This review will look into the development of corneal gene therapy and CRISPR-based study in corneal dystrophies, associated challenges, potential approaches, and future directions.
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Affiliation(s)
- Mohd Salman
- Prof. Brien Holden Eye Research Center, Champalimaud Translational Centre for Eye Research L.V. Prasad Eye Institute, Hyderabad, India
- Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Anshuman Verma
- Prof. Brien Holden Eye Research Center, Champalimaud Translational Centre for Eye Research L.V. Prasad Eye Institute, Hyderabad, India
- MNR Foundation for Research and Innovations, MNR Medical College, MNR Nagar, Sangareddy, Telangana, India
| | - Vijay Kumar Singh
- Prof. Brien Holden Eye Research Center, Champalimaud Translational Centre for Eye Research L.V. Prasad Eye Institute, Hyderabad, India
| | - Jilu Jaffet
- Prof. Brien Holden Eye Research Center, Champalimaud Translational Centre for Eye Research L.V. Prasad Eye Institute, Hyderabad, India
| | - Sunita Chaurasia
- The Centre of Excellence for Rare Eye Diseases, L. V. Prasad Eye Institute, Hyderabad, India
| | - Deepak Kumar Sahel
- Department of Pharmacy, Birla Institute of Technology and Science - Pilani Campus. Vidya Vihar, Pilani, Rajasthan, India and
| | - Muralidhar Ramappa
- Cornea and Anterior Segment Services, L.V. Prasad Eye Institute, Kallam Anji Reddy Campus, L.V. Prasad Marg, Hyderabad, Telangana, India
| | - Vivek Singh
- Prof. Brien Holden Eye Research Center, Champalimaud Translational Centre for Eye Research L.V. Prasad Eye Institute, Hyderabad, India
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Kannabiran C, Chaurasia S, Ramappa M, Mootha VV. Update on the genetics of corneal endothelial dystrophies. Indian J Ophthalmol 2022; 70:2239-2248. [PMID: 35791103 PMCID: PMC9426112 DOI: 10.4103/ijo.ijo_992_22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Corneal endothelial dystrophies are a heterogeneous group of diseases with different modes of inheritance and genetic basis for each dystrophy. The genes associated with these diseases encode transcription factors, structural components of the stroma and Descemet membrane, cell transport proteins, and others. Congenital hereditary endothelial dystrophy (CHED) is associated with mutations in two genes, OVOL2 and SLC4A11, for dominant and recessive forms of CHED, respectively. Mutations in three genes are known to cause posterior polymorphous corneal dystrophy (PPCD). They are OVOL2 (PPCD1), ZEB1 (PPCD3), and GRHL1 (PPCD4). The PPCD2 locus involving the collagen gene COL8A2 on chromosome 1 is disputed due to insufficient evidence. Mutations in the COL8A2 gene are associated with early-onset Fuchs’ endothelial corneal dystrophy (FECD). Several genes have been associated with the more common, late-onset FECD. Alterations in each of these genes occur in a fraction of patients, and the most prevalent genetic alteration in FECD patients across the world is a triplet repeat expansion in the TCF4 gene. Knowledge of the genetics of corneal endothelial dystrophies has considerably advanced within the last decade and has contributed to better diagnosis of these dystrophies as well as opened up the possibility of novel therapeutic approaches based on the molecular mechanisms involved. The functions of genes identified to date provide insights into the pathogenic mechanisms involved in each disorder.
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Affiliation(s)
- Chitra Kannabiran
- Kallam Anji Reddy Molecular Genetics Laboratory, Prof Brien Holden Eye Research Centre, L.V. Prasad Eye Institute, Hyderabad, Telangana, India
| | - Sunita Chaurasia
- Centre for Rare Eye Diseases and Ocular Genetics; The Cornea Institute; Jasti V Ramanamma Children's Eye Care Center, L.V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, India
| | - Muralidhar Ramappa
- Centre for Rare Eye Diseases and Ocular Genetics; The Cornea Institute; Jasti V Ramanamma Children's Eye Care Center, L.V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, India
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Bonanno JA, Shyam R, Choi M, Ogando DG. The H + Transporter SLC4A11: Roles in Metabolism, Oxidative Stress and Mitochondrial Uncoupling. Cells 2022; 11:197. [PMID: 35053313 PMCID: PMC8773465 DOI: 10.3390/cells11020197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/03/2022] [Accepted: 01/05/2022] [Indexed: 12/23/2022] Open
Abstract
Solute-linked cotransporter, SLC4A11, a member of the bicarbonate transporter family, is an electrogenic H+ transporter activated by NH3 and alkaline pH. Although SLC4A11 does not transport bicarbonate, it shares many properties with other members of the SLC4 family. SLC4A11 mutations can lead to corneal endothelial dystrophy and hearing deficits that are recapitulated in SLC4A11 knock-out mice. SLC4A11, at the inner mitochondrial membrane, facilitates glutamine catabolism and suppresses the production of mitochondrial superoxide by providing ammonia-sensitive H+ uncoupling that reduces glutamine-driven mitochondrial membrane potential hyperpolarization. Mitochondrial oxidative stress in SLC4A11 KO also triggers dysfunctional autophagy and lysosomes, as well as ER stress. SLC4A11 expression is induced by oxidative stress through the transcription factor NRF2, the master regulator of antioxidant genes. Outside of the corneal endothelium, SLC4A11's function has been demonstrated in cochlear fibrocytes, salivary glands, and kidneys, but is largely unexplored overall. Increased SLC4A11 expression is a component of some "glutamine-addicted" cancers, and is possibly linked to cells and tissues that rely on glutamine catabolism.
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Affiliation(s)
- Joseph A. Bonanno
- Vision Science Program, School of Optometry, Indiana University, Bloomington, IN 47405, USA; (R.S.); (M.C.).; (D.G.O.)
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11
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Regenerative capacity of the corneal transition zone for endothelial cell therapy. Stem Cell Res Ther 2020; 11:523. [PMID: 33276809 PMCID: PMC7716425 DOI: 10.1186/s13287-020-02046-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022] Open
Abstract
The corneal endothelium located on the posterior corneal surface is responsible for regulating stromal hydration. This is contributed by a monolayer of corneal endothelial cells (CECs), which are metabolically active in a continuous fluid-coupled efflux of ions from the corneal stroma into the aqueous humor, preventing stromal over-hydration and preserving the orderly arrangement of stromal collagen fibrils, which is essential for corneal transparency. Mature CECs do not have regenerative capacity and cell loss due to aging and diseases results in irreversible stromal edema and a loss of corneal clarity. The current gold standard of treatment for this worldwide blindness caused by corneal endothelial failure is the corneal transplantation using cadaveric donor corneas. The top indication is Fuchs corneal endothelial dystrophy/degeneration, which represents 39% of all corneal transplants performed. However, the global shortage of transplantable donor corneas has restricted the treatment outcomes, hence instigating a need to research for alternative therapies. One such avenue is the CEC regeneration from endothelial progenitors, which have been identified in the peripheral endothelium and the adjacent transition zone. This review examines the evidence supporting the existence of endothelial progenitors in the posterior limbus and summarizes the existing knowledge on the microanatomy of the transitional zone. We give an overview of the isolation and ex vivo propagation of human endothelial progenitors in the transition zone, and their growth and differentiation capacity to the corneal endothelium. Transplanting these bioengineered constructs into in vivo models of corneal endothelial degeneration will prove the efficacy and viability, and the long-term maintenance of functional endothelium. This will develop a novel regenerative therapy for the management of corneal endothelial diseases.
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12
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Determination of Oxidative Stress Markers in the Aqueous Humor and Corneal Tissues of Patients With Congenital Hereditary Endothelial Dystrophy. Cornea 2020; 40:491-496. [PMID: 33177409 DOI: 10.1097/ico.0000000000002568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim of this study is to determine the presence of oxidative stress markers in the aqueous humor (AH) and corneal tissues of patients with congenital hereditary endothelial dystrophy (CHED). METHODS Interventional prospective study was undertaken to quantify levels of ascorbic acid and glutathione in the AH of patients with CHED. AH was collected from patients undergoing keratoplasty and levels of ascorbic acid and glutathione were determined using biochemical assays and measured spectrophotometrically. AH collected from pediatric patients with cataract were used as control. Corneal sections of patients who underwent penetrating keratoplasty were obtained, and presence of glutathione peroxidase 1, catalase, and superoxide dismutase was determined by immunohistochemistry. Tissue sections obtained from cadaveric corneas unsuitable for clinical transplant were used as control. RESULTS Significantly increased ascorbic acid levels were determined in patients with CHED (605.6 ± 158.9 μM) compared with those in controls (190.5 ± 74.72 μM). However, a trend toward reduced level of glutathione was detected in patients with CHED compared with that in the controls. Increased glutathione peroxidase 1 staining and reduced expression of catalase was detected in corneal tissues of patients with CHED compared with those in control corneal tissues. There was no apparent changes observed in the expression of superoxide dismutase in the corneal sections obtained from patients with CHED. CONCLUSIONS To the best of our knowledge, this is the first study to determine the levels of ascorbic acid and glutathione in AH of patients with CHED. Our data suggest the presence of oxidative stress in CHED that might be responsible for the pathological changes in patients with CHED.
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13
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Tananuvat N, Tananuvat R, Chartapisak W, Mahanupab P, Hokierti C, Srikummool M, Kampuansai J, Intachai W, Olsen B, Ketudat Cairns JR, Kantaputra P. Harboyan syndrome: novel SLC4A11 mutation, clinical manifestations, and outcome of corneal transplantation. J Hum Genet 2020; 66:193-203. [PMID: 32884076 DOI: 10.1038/s10038-020-00834-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/20/2020] [Accepted: 08/27/2020] [Indexed: 11/10/2022]
Abstract
Harboyan syndrome or corneal dystrophy and progressive deafness (MIM #217400) is characterized by congenital hereditary endothelial dystrophy (CHED) and progressive, sensorineural hearing loss. Mutations in SLC4A11 are responsible for this rare genetic syndrome. Eight patients from seven unrelated families affected with Harboyan Syndrome with mean follow-up of 12.0 ± 0.9 years were thoroughly investigated for the ocular, hearing, and kidney function abnormalities and the outcome of penetrating keratoplasty (PK). Mutation analysis of SLC4A11 was performed. All patients presented with bilateral cloudy corneas since birth. Sensorineural hearing loss was detected in all patients. Seven patients (11 eyes) underwent PK with the median age at surgery of 10.1 years (7.1-22.9). The overall corneal graft survival rate after primary PK was 72.7% (8/11 eyes). The mean graft survival time was 94.6 months (95% CI 83.1-126.0). All patients had unremarkable kidney function. The c.2264G>A (p.Arg755Gln) mutation in SCL4A11 was detected in most patients (87.5%). All unrelated Karen tribe patients had p.Arg755Gln mutation, suggestive of founder effect. We found the allele frequency of this variant in the Karen population to be 0.01. The c.2263C>T (p.Arg755Trp) mutation was found in one patient with mild phenotype and the novel truncating protein mutation c.2127delG (p.Gly710fsx*25) in SCL4A11 was identified in two Thai sisters. Visual outcome and graft survival after PK were satisfactory. Our study shows that all studied patients with SLC4A11 mutations had CHED and sensorineural hearing loss, and SLC4A11 mutations were not related to the onset and severity of hearing loss or outcome of keratoplasty.
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Affiliation(s)
- Napaporn Tananuvat
- Department of Ophthalmology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Rak Tananuvat
- Department of Otolaryngology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Wattana Chartapisak
- Department of Pediatrics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Pongsak Mahanupab
- Department of Pathology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | | | - Metawee Srikummool
- Department of Biochemistry, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Jatupol Kampuansai
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Worrachet Intachai
- Center of Excellence in Medical Genetics Research, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Bjorn Olsen
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA
| | - James R Ketudat Cairns
- School of Chemistry, Institute of Science, and Center for Biomolecular Structure, Function and Application, Suranaree University of Technology, Nakhon Ratchasima, Thailand.,Laboratory of Biochemistry, Chulabhorn Research Institute, Bangkok, Thailand
| | - Piranit Kantaputra
- Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.
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14
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Bansal M, Tandon R, Saxena R, Sharma A, Sen S, Kishore A, Venkatesh P, Maiti S, Chakraborty D. Ophthalmic genetics practice and research in India: Vision in 2020. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:718-727. [PMID: 32865332 DOI: 10.1002/ajmg.c.31827] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/19/2020] [Accepted: 07/28/2020] [Indexed: 12/13/2022]
Abstract
Ophthalmic genetics is a much needed and growing area in India. Ethnic diversity, with a high degree of consanguinity, has led to a high prevalence of genetic disorders in the country. As the second most populous country in the world, this naturally results in a significant number of affected people overall. Practice involves coherent association between ophthalmologists, genetic counselor and pediatricians. Eye genetics in India in recent times has witnessed advanced research using cutting edge diagnostics, next generation sequencing (NGS) approaches, stem cell therapies, gene therapy and genomic editing. This article will highlight the studies reporting genetic variations in the country, challenges in practice, and the latest advances in ophthalmic genetic research in India.
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Affiliation(s)
- Mayank Bansal
- Council for Scientific and Industrial Research (CSIR), Institute of Genomics and Integrative Biology (IGIB), New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), Delhi, India.,Department of Ophthalmology, Fortis Memorial Research Institute, Gurugram, India
| | - Radhika Tandon
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Rohit Saxena
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Arundhati Sharma
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Sagnik Sen
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Alisha Kishore
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Pradeep Venkatesh
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Souvik Maiti
- Council for Scientific and Industrial Research (CSIR), Institute of Genomics and Integrative Biology (IGIB), New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), Delhi, India
| | - Debojyoti Chakraborty
- Council for Scientific and Industrial Research (CSIR), Institute of Genomics and Integrative Biology (IGIB), New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), Delhi, India
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15
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Malhotra D, Casey JR. Molecular Mechanisms of Fuchs and Congenital Hereditary Endothelial Corneal Dystrophies. Rev Physiol Biochem Pharmacol 2020; 178:41-81. [PMID: 32789790 DOI: 10.1007/112_2020_39] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The cornea, the eye's outermost layer, protects the eye from the environment. The cornea's innermost layer is an endothelium separating the stromal layer from the aqueous humor. A central role of the endothelium is to maintain stromal hydration state. Defects in maintaining this hydration can impair corneal clarity and thus visual acuity. Two endothelial corneal dystrophies, Fuchs Endothelial Corneal Dystrophy (FECD) and Congenital Hereditary Endothelial Dystrophy (CHED), are blinding corneal diseases with varied clinical presentation in patients across different age demographics. Recessive CHED with an early onset (typically age: 0-3 years) and dominantly inherited FECD with a late onset (age: 40-50 years) have similar phenotypes, although caused by defects in several different genes. A range of molecular mechanisms have been proposed to explain FECD and CHED pathology given the involvement of multiple causative genes. This critical review provides insight into the proposed molecular mechanisms underlying FECD and CHED pathology along with common pathways that may explain the link between the defective gene products and provide a new perspective to view these genetic blinding diseases.
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Affiliation(s)
- Darpan Malhotra
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
- Membrane Protein Disease Research Group, University of Alberta, Edmonton, AB, Canada
| | - Joseph R Casey
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.
- Membrane Protein Disease Research Group, University of Alberta, Edmonton, AB, Canada.
- Department of Physiology, University of Alberta, Edmonton, AB, Canada.
- Department of Ophthalmology and Visual Science, University of Alberta, Edmonton, AB, Canada.
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