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Ong Tone S, Kocaba V, Böhm M, Wylegala A, White TL, Jurkunas UV. Fuchs endothelial corneal dystrophy: The vicious cycle of Fuchs pathogenesis. Prog Retin Eye Res 2021; 80:100863. [PMID: 32438095 PMCID: PMC7648733 DOI: 10.1016/j.preteyeres.2020.100863] [Citation(s) in RCA: 93] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 04/05/2020] [Accepted: 04/10/2020] [Indexed: 12/13/2022]
Abstract
Fuchs endothelial corneal dystrophy (FECD) is the most common primary corneal endothelial dystrophy and the leading indication for corneal transplantation worldwide. FECD is characterized by the progressive decline of corneal endothelial cells (CECs) and the formation of extracellular matrix (ECM) excrescences in Descemet's membrane (DM), called guttae, that lead to corneal edema and loss of vision. FECD typically manifests in the fifth decades of life and has a greater incidence in women. FECD is a complex and heterogeneous genetic disease where interaction between genetic and environmental factors results in cellular apoptosis and aberrant ECM deposition. In this review, we will discuss a complex interplay of genetic, epigenetic, and exogenous factors in inciting oxidative stress, auto(mito)phagy, unfolded protein response, and mitochondrial dysfunction during CEC degeneration. Specifically, we explore the factors that influence cellular fate to undergo apoptosis, senescence, and endothelial-to-mesenchymal transition. These findings will highlight the importance of abnormal CEC-DM interactions in triggering the vicious cycle of FECD pathogenesis. We will also review clinical characteristics, diagnostic tools, and current medical and surgical management options for FECD patients. These new paradigms in FECD pathogenesis present an opportunity to develop novel therapeutics for the treatment of FECD.
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Affiliation(s)
- Stephan Ong Tone
- Cornea Center of Excellence, Schepens Eye Research Institute, Harvard Medical School, Boston, MA, United States; Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States; Department of Ophthalmology, Harvard Medical School, Boston, MA, United States
| | - Viridiana Kocaba
- Cornea Center of Excellence, Schepens Eye Research Institute, Harvard Medical School, Boston, MA, United States; Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States; Department of Ophthalmology, Harvard Medical School, Boston, MA, United States
| | - Myriam Böhm
- Cornea Center of Excellence, Schepens Eye Research Institute, Harvard Medical School, Boston, MA, United States; Department of Ophthalmology, Harvard Medical School, Boston, MA, United States
| | - Adam Wylegala
- Cornea Center of Excellence, Schepens Eye Research Institute, Harvard Medical School, Boston, MA, United States; Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States; Department of Ophthalmology, Harvard Medical School, Boston, MA, United States
| | - Tomas L White
- Cornea Center of Excellence, Schepens Eye Research Institute, Harvard Medical School, Boston, MA, United States; Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States; Department of Ophthalmology, Harvard Medical School, Boston, MA, United States
| | - Ula V Jurkunas
- Cornea Center of Excellence, Schepens Eye Research Institute, Harvard Medical School, Boston, MA, United States; Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States; Department of Ophthalmology, Harvard Medical School, Boston, MA, United States.
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Abstract
Fuchs' endothelial corneal dystrophy (FECD) is a common disease resulting from corneal endothelial cell dysfunction. It is inherited in an autosomal dominant fashion with incomplete penetrance, and with a female bias. Approximately half of cases occur sporadically, and the remainder are familial. Early and late-onset forms of the disease exist. A review of the literature has revealed more than 15 genes harbouring mutations and/or single nucleotide polymorphisms associated with FECD. The proteins encoded by these genes cover a wide range of endothelial function, including transcription regulation, DNA repair, mitochondrial DNA mutations, targeting of proteins to the cell membrane, deglutamylation of proteins, extracellular matrix secretion, formation of cell-cell and cell-extracellular matrix junctions, water pump, and apoptosis. These genetic variations will form the platform for the further understanding of the pathological basis of the disease, and the development of targeted treatments. This review aims to summarise known genetic variations associated with FECD, discuss any known molecular effects of the variations, how these provide opportunities for targeted therapies, and what therapies are currently in development.
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New Insights Into Corneal Endothelial Regeneration. CURRENT OPHTHALMOLOGY REPORTS 2019. [DOI: 10.1007/s40135-019-00197-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Uittenbogaard M, Brantner CA, Fang Z, Wong LJ, Gropman A, Chiaramello A. The m.11778 A > G variant associated with the coexistence of Leber's hereditary optic neuropathy and multiple sclerosis-like illness dysregulates the metabolic interplay between mitochondrial oxidative phosphorylation and glycolysis. Mitochondrion 2018; 46:187-194. [PMID: 29890302 DOI: 10.1016/j.mito.2018.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/18/2018] [Accepted: 06/07/2018] [Indexed: 01/07/2023]
Abstract
Little is known about the molecular mechanism of the rare coexistence of Leber's Hereditary Optic Neuropathy (LHON) and multiple sclerosis (MS), also known as the Harding's syndrome. In this study, we provide novel evidence that the m.11778A > G variant causes a defective metabolic interplay between mitochondrial oxidative phosphorylation and glycolysis. We used dermal fibroblasts derived from a female proband exhibiting clinical symptoms compatible with LHON-MS due to the presence of the pathogenic m.11778A > G variant at near homoplasmic levels. Our mitochondrial morphometric analysis reveals abnormal cristae architecture. Live-cell respiratory studies show stunted metabolic potential and spare respiratory capacity, vital for cell survival upon a sudden energy demand. The m.11778 A > G variant also alters glycolytic activities with a diminished compensatory glycolysis, thereby preventing an efficient metabolic reprogramming during a mitochondrial ATP crisis. Our collective results provide evidence of limited bioenergetic flexibility in the presence of the m.11778 A > G variant. Our study sheds light on the potential pathophysiologic mechanism of the m.11778 A > G variant leading to energy crisis in this patient with the LHON-MS disease.
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Affiliation(s)
- Martine Uittenbogaard
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Christine A Brantner
- GW Nanofabrication and Imaging Center, Office of the Vice President for Research, George Washington University, Washington, DC 20052, USA
| | - ZiShui Fang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Andrea Gropman
- Children's National Medical Center, Division of Neurogenetics and Developmental Pediatrics, Washington, DC 20010, USA
| | - Anne Chiaramello
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA.
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Mitochondrial A3243G mutation results in corneal endothelial polymegathism. Graefes Arch Clin Exp Ophthalmol 2018; 256:583-588. [PMID: 29376197 DOI: 10.1007/s00417-018-3914-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/07/2018] [Accepted: 01/17/2018] [Indexed: 12/17/2022] Open
Abstract
PURPOSE The mitochondrial DNA point mutation A3243G leads to a spectrum of syndromes ranging from MIDD to MELAS. Ocular manifestations include pattern macular dystrophy and concentric perifoveal atrophy. Given the high metabolic demand of corneal endothelial cells, we performed specular biomicroscopy analysis in patients harboring the mitochondrial DNA point mutation A3243G to assess for the associated presence of corneal endothelial abnormalities. METHODS We present a case series with participants from two institutions. Patients diagnosed with macular dystrophy associated with MIDD or MELAS, and the mitochondrial DNA point mutation A3243G were recruited. Exclusion criteria included a prior diagnosis, or a positive family history, of endothelial corneal dystrophy. Slit-lamp corneal examination and specular biomicroscopy were performed. Corneal endothelial cell count, cell size and polymegathism, and central corneal thickness were assessed. Patients diagnosed with MIDD or MELAS based on clinical history and examination were genetically tested for the mitochondrial DNA point mutation A3243G using pyrosequencing. RESULTS Five patients (two male and three female participants) from five different families, and with different ethnic backgrounds, met the inclusion criteria. Their ages ranged from 41 to 60 years. Corneal endothelial changes observed using slit-lamp examination were primarily mild to rare guttata. Specular biomicroscopy displayed mainly polymegathism associated with guttata. The average endothelial cell count was 2358 ± 456 cells per mm2, the average endothelial cell size was 442 ± 103 μm2 and the average central corneal thickness (CCT) was 551 ± 33 μm. These values were similar to that of the average population. The average coefficient of variation (COV), an index of heterogeneity in cell size, was 42.0 ± 4.1%. When compared to the average population, the average COV was significantly higher than predicted for the patients' age. None of the patients had signs of corneal edema. One patient had a pre-Descemet's opacity. CONCLUSIONS In patients with the mitochondrial DNA point mutation A3243G, corneal endothelial polymegathism is present. This is mainly associated with mild guttata. The findings of corneal endothelial cell polymegathism may be a biomarker of mitochondrial disease, specifically in patients with the mitochondrial DNA A3243G mutation.
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Balasubramani PP, Chakravarthy VS, Ali M, Ravindran B, Moustafa AA. Identifying the Basal Ganglia network model markers for medication-induced impulsivity in Parkinson's disease patients. PLoS One 2015; 10:e0127542. [PMID: 26042675 PMCID: PMC4456385 DOI: 10.1371/journal.pone.0127542] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 04/16/2015] [Indexed: 01/23/2023] Open
Abstract
Impulsivity, i.e. irresistibility in the execution of actions, may be prominent in Parkinson's disease (PD) patients who are treated with dopamine precursors or dopamine receptor agonists. In this study, we combine clinical investigations with computational modeling to explore whether impulsivity in PD patients on medication may arise as a result of abnormalities in risk, reward and punishment learning. In order to empirically assess learning outcomes involving risk, reward and punishment, four subject groups were examined: healthy controls, ON medication PD patients with impulse control disorder (PD-ON ICD) or without ICD (PD-ON non-ICD), and OFF medication PD patients (PD-OFF). A neural network model of the Basal Ganglia (BG) that has the capacity to predict the dysfunction of both the dopaminergic (DA) and the serotonergic (5HT) neuromodulator systems was developed and used to facilitate the interpretation of experimental results. In the model, the BG action selection dynamics were mimicked using a utility function based decision making framework, with DA controlling reward prediction and 5HT controlling punishment and risk predictions. The striatal model included three pools of Medium Spiny Neurons (MSNs), with D1 receptor (R) alone, D2R alone and co-expressing D1R-D2R. Empirical studies showed that reward optimality was increased in PD-ON ICD patients while punishment optimality was increased in PD-OFF patients. Empirical studies also revealed that PD-ON ICD subjects had lower reaction times (RT) compared to that of the PD-ON non-ICD patients. Computational modeling suggested that PD-OFF patients have higher punishment sensitivity, while healthy controls showed comparatively higher risk sensitivity. A significant decrease in sensitivity to punishment and risk was crucial for explaining behavioral changes observed in PD-ON ICD patients. Our results highlight the power of computational modelling for identifying neuronal circuitry implicated in learning, and its impairment in PD. The results presented here not only show that computational modelling can be used as a valuable tool for understanding and interpreting clinical data, but they also show that computational modeling has the potential to become an invaluable tool to predict the onset of behavioral changes during disease progression.
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Affiliation(s)
| | | | - Manal Ali
- School of Medicine, Ain Shams University, Cairo, Egypt
| | - Balaraman Ravindran
- Department of Computer Science and Engineering, Indian Institute of Technology, Madras, Chennai, India
| | - Ahmed A. Moustafa
- Marcs Institute for Brain and Behaviour & School of Social Sciences and Psychology, University of Western Sydney, Penrith, Australia
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Li YJ, Minear MA, Qin X, Rimmler J, Hauser MA, Allingham RR, Igo RP, Lass JH, Iyengar SK, Klintworth GK, Afshari NA, Gregory SG. Mitochondrial polymorphism A10398G and Haplogroup I are associated with Fuchs' endothelial corneal dystrophy. Invest Ophthalmol Vis Sci 2014; 55:4577-84. [PMID: 24917144 DOI: 10.1167/iovs.13-13517] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
PURPOSE We investigated whether mitochondrial DNA (mtDNA) variants affect the susceptibility of Fuchs endothelial corneal dystrophy (FECD). METHODS Ten mtDNA variants defining European haplogroups were genotyped in a discovery dataset consisting of 530 cases and 498 controls of European descent from the Duke FECD cohort. Association tests for mtDNA markers and haplogroups were performed using logistic regression models with adjustment of age and sex. Subset analyses included controlling for additional effects of either the TCF4 SNP rs613872 or cigarette smoking. Our replication dataset was derived from the genome-wide association study (GWAS) of the FECD Genetics Consortium, where genotypes for three of 10 mtDNA markers were available. Replication analyses were performed to compare non-Duke cases to all GWAS controls (GWAS1, N = 3200), and to non-Duke controls (GWAS2, N = 3043). RESULTS The variant A10398G was significantly associated with FECD (odds ratio [OR] = 0.72; 95% confidence interval [CI] = [0.53, 0.98]; P = 0.034), and remains significant after adjusting for smoking status (min P = 0.012). This variant was replicated in GWAS1 (P = 0.019) and GWAS2 (P = 0.036). Haplogroup I was significantly associated with FECD (OR = 0.46; 95% CI = [0.22, 0.97]; P = 0.041) and remains significant after adjusting for the effect of smoking (min P = 0.008) or rs613872 (P = 0.034). CONCLUSIONS The 10398G allele and Haplogroup I appear to confer significant protective effects for FECD. The effect of A10398G and Haplogroup I to FECD is likely independent of the known TCF4 variant. More data are needed to decipher the interaction between smoking and mtDNA haplogroups.
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Affiliation(s)
- Yi-Ju Li
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina, United States Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States
| | - Mollie A Minear
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States
| | - Xuejun Qin
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States
| | - Jacqueline Rimmler
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States
| | - Michael A Hauser
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States
| | - R Rand Allingham
- Duke Eye Center, Duke University Medical Center, Durham, North Carolina, United States
| | - Robert P Igo
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio, United States
| | - Jonathan H Lass
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio, United States
| | - Sudha K Iyengar
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio, United States
| | - Gordon K Klintworth
- Duke Eye Center, Duke University Medical Center, Durham, North Carolina, United States Department of Pathology, Duke University Medical Center, Durham, North Carolina, United States
| | - Natalie A Afshari
- Duke Eye Center, Duke University Medical Center, Durham, North Carolina, United States Shiley Eye Center, University of California San Diego, La Jolla, California, United States
| | - Simon G Gregory
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States
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Abstract
Fuchs' corneal dystrophy (FCD) is a common late-onset genetic disorder of the corneal endothelium. It causes loss of endothelial cell density and excrescences in the Descemet membrane, eventually progressing to corneal edema, necessitating corneal transplantation. The genetic basis of FCD is complex and heterogeneous, demonstrating variable expressivity and incomplete penetrance. To date, three causal genes, ZEB1, SLC4A11 and LOXHD1, have been identified, representing a small proportion of the total genetic load of FCD. An additional four loci have been localized, including a region on chromosome 18 that is potentially responsible for a large proportion of all FCD cases. The elucidation of the causal genes underlying these loci will begin to clarify the pathogenesis of FCD and pave the way for the emergence of nonsurgical treatments.
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Affiliation(s)
- Benjamin W Iliff
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Kasbekar SA, Gonzalez-Martin JA, Shafiq AE, Chandna A, Willoughby CE. Corneal endothelial dysfunction in Pearson syndrome. Ophthalmic Genet 2011; 34:55-7. [PMID: 21936618 DOI: 10.3109/13816810.2011.610862] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mitochondrial disorders are associated with well recognized ocular manifestations. Pearson syndrome is an often fatal, multisystem, mitochondrial disorder that causes variable bone marrow, hepatic, renal and pancreatic exocrine dysfunction. Phenotypic progression of ocular disease in a 12-year-old male with Pearson syndrome is described. This case illustrates phenotypic drift from Pearson syndrome to Kearns-Sayre syndrome given the patient's longevity. Persistent corneal endothelial failure was noted in addition to ptosis, chronic external ophthalmoplegia and mid-peripheral pigmentary retinopathy. We propose that corneal edema resulting from corneal endothelial metabolic pump failure occurs within a spectrum of mitochondrial disorders.
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Affiliation(s)
- Shivani A Kasbekar
- Department of Ophthalmology, Southport and Ormskirk Hospital NHS Trust, Southport, UK
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Abstract
Fuchs' corneal dystrophy (FCD) is a progressive, hereditary disease of the cornea first described a century ago by the Austrian ophthalmologist Ernst Fuchs. Patients often present in the fifth to sixth decade of life with blurry morning vision that increases in duration as the disease progresses. Primarily a condition of the posterior cornea, characteristic features include the formation of focal excrescences of Descemet membrane termed 'guttae', loss of endothelial cell density and end-stage disease manifested by corneal edema and the formation of epithelial bullae. Recent advances in our understanding of the genetic and pathophysiological mechanisms of the disease, as well as the application of new imaging modalities and less invasive surgical procedures, present new opportunities for improved outcomes among patients with FCD.
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Affiliation(s)
- Allen O Eghrari
- Cataract, Cornea and External Disease Service, Wilmer Eye Institute, 600 North Wolfe Street, 317 Maumenee Building, Baltimore, MD 21287, USA
| | - John D Gottsch
- Cataract, Cornea and External Disease Service, Wilmer Eye Institute, 600 North Wolfe Street, 317 Maumenee Building, Baltimore, MD 21287, USA, Tel.: +1 410 955 7929, Fax: +1 410 614 2816
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Tourbah A, Sedel F, Miléa D, Bellefqih S, Lyon-Caen O. [Isolated ptosis in a 58-year-old woman]. Rev Neurol (Paris) 2005; 161:596-8. [PMID: 16106815 DOI: 10.1016/s0035-3787(05)85098-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
A 60-year-old woman who had experienced isolated ptosis for two years was seen when it had been fixed for one year. She had a personal and familial history of stromal corneal dystrophy. The diagnosis of mitochondrial cytopathy was made on the basis of clinical, electrophysiological, biological and histological findings. Surgical repair of the ptosis allowed visual recovery. The relationship between ptosis, corneal dystrophy and mitochondrial cytopathy is discussed.
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Affiliation(s)
- A Tourbah
- Fédération de Neurologie, Hôpital de la Pitié-Salpêtrière, Paris.
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Yuen HKL, Rassier CE, Jardeleza MSR, Green WR, de la Cruz Z, Stark WJ, Gottsch JD. A Morphologic Study of Fuchs Dystrophy and Bullous Keratopathy. Cornea 2005; 24:319-27. [PMID: 15778606 DOI: 10.1097/01.ico.0000148288.53323.b2] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To describe the morphologic features of Fuchs corneal dystrophy and compare them with those of bullous keratopathy. METHODS This was an observational case series. The study group consisted of 32 corneal buttons with a diagnosis of Fuchs dystrophy and the comparison group consisted of 22 corneal buttons with bullous keratopathy. Morphologic analysis was performed of corneal buttons from patients with the clinical diagnosis of Fuchs dystrophy or bullous keratopathy by light and electron microscopy. RESULTS The main outcome measure was identification of degenerated keratocytes, granular material in and around keratocytes, and lipid keratopathy. The overall morphologic features of Fuchs dystrophy and bullous keratopathy are similar to those described in previous literature. A high proportion of keratocytes exhibited degenerative changes (78.9% in Fuchs dystrophy versus 50.5% in bullous keratopathy). Granular material was identified in and around variably degenerated keratocytes in all cases of Fuchs dystrophy and in 14 of 22 (64%) of the corneas with bullous keratopathy. The percentage of keratocytes with granular deposits was higher in Fuchs dystrophy corneas as compared with corneas with bullous keratopathy (51.7% versus 14.1%, P < 0.0005). Lipid keratopathy was a common occurrence in both Fuchs dystrophy and bullous keratopathy (23/32 [72%] versus 12/22 [55%]). CONCLUSIONS Histopathologic changes in the corneal stroma and keratocytes occur in Fuchs dystrophy. Secondary lipid keratopathy ensues and may contribute to corneal haze. A higher proportion of keratocytes in Fuchs dystrophy have granular deposit than in bullous keratopathy. That a high proportion of keratocytes had degenerative changes in both Fuchs dystrophy and bullous keratopathy suggests that keratocytes may degenerate secondary to altered stromal microenvironment because of endothelial cell loss.
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Affiliation(s)
- Hunter K L Yuen
- Eye Pathology Laboratory, Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD 21287-9248, USA
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Shimizu S, Krafchak C, Fuse N, Epstein MP, Schteingart MT, Sugar A, Eibschitz-Tsimhoni M, Downs CA, Rozsa F, Trager EH, Reed DM, Boehnke M, Moroi SE, Richards JE. A locus for posterior polymorphous corneal dystrophy (PPCD3) maps to chromosome 10. Am J Med Genet A 2005; 130A:372-7. [PMID: 15384081 PMCID: PMC1249494 DOI: 10.1002/ajmg.a.30267] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Posterior polymorphous corneal dystrophy (PPCD) is an autosomal dominant disorder characterized by corneal endothelial abnormalities, which can lead to blindness due to loss of corneal transparency and sometimes glaucoma. We mapped a new locus responsible for PPCD in a family in which we excluded the previously reported PPCD locus on 20q11, and the region containing COL8A2 on chromosome 1. Results of a 317-marker genome scan provided significant evidence of linkage of PPCD to markers on chromosome 10, with single-point LOD scores of 2.63, 1.63, and 3.19 for markers D10S208 (at (circumflex)theta = 0.03), D10S1780 (at (circumflex)theta = 0.00), and D10S578 (at (circumflex)theta = 0.06). A maximum multi-point LOD score of 4.35 was found at marker D10S1780. Affected family members shared a haplotype in an 8.55 cM critical interval that was bounded by markers D10S213 and D10S578. Our finding of another PPCD locus, PPCD3, on chromosome 10 indicates that PPCD is genetically heterogeneous. Guttae, a common corneal finding sometimes observed along with PPCD, were found among both affected and unaffected members of the proband's sib ship, but were absent in the younger generations of the family. Evaluation of phenotypic differences between family members sharing the same affected haplotype raises questions about whether differences in disease severity, including differences in response to surgical interventions, could be due to genetic background or other factors independent of the PPCD3 locus.
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Affiliation(s)
- Satoko Shimizu
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
- Currently at Department of Ophthalmology, Teikyo University, Tokyo, Japan
| | - Charles Krafchak
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan
| | - Nobuo Fuse
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
- Currently at Department of Ophthalmology, Tohoku University, Sendai, Japan
| | - Michael P. Epstein
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan
- Department of Human Genetics, Emory University, Atlanta, Georgia
| | | | - Alan Sugar
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
| | - Maya Eibschitz-Tsimhoni
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
| | - Catherine A. Downs
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
| | - Frank Rozsa
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
| | - Edward H. Trager
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
| | - David M. Reed
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
| | - Michael Boehnke
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan
| | - Sayoko E. Moroi
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
| | - Julia E. Richards
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan
- *Correspondence to: Julia E. Richards, PhD, Department of Ophthalmology & Visual Sciences, University of Michigan, 1000 Wall Street, Ann Arbor, MI 48105. E-mail:
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Abstract
PURPOSE To indicate important changes in our understanding of the corneal dystrophies. METHODS A review of the literature of the last quarter of a century. RESULTS The earliest clinical classifications of the corneal dystrophies were based on the application of clinical, biological, histochemical, and ultrastructural methods. Since then, the first great impetus to our understanding has come from the application of techniques to map disorders to specific chromosome loci, using polymorphic markers. More recently, using candidate gene and related approaches, it has been possible to identify genes causing several of the corneal dystrophies and the mutations responsible for their phenotypic variation. A notable success has been to show that several important "stromal" dystrophies result from mutations in the gene beta ig-h3, which encodes for the protein keratoepithelin (beta ig-h3). CONCLUSIONS For the corneal dystrophies, as with other inherited disorders, there is room for two sorts of classification system, one based mainly on clinical presentation and the other on an up-to-date understanding of the genetic mechanisms. They are not mutually exclusive. Some developmental corneal disorders are also discussed.
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Affiliation(s)
- A J Bron
- Nuffield Laboratory of Ophthalmology, University of Oxford, UK
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Gupta SK, Hodge WG. A new clinical perspective of corneal dystrophies through molecular genetics. Curr Opin Ophthalmol 1999; 10:234-41. [PMID: 10621529 DOI: 10.1097/00055735-199908000-00003] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In the past 2 years, significant advances have been made in the genetics of corneal dystrophies. Genetic heterogeneity (one disease condition caused by single mutations in any one of multiple genes) and phenotypic diversity (many disease conditions caused by mutations in a single gene) are common emerging themes. Genetic heterogeneity in Meesmann corneal dystrophy was established with the identification of two causative genes, keratins 3 and 12, that encode cytoskeletal proteins. Conversely, mutations in a single gene, keratoepithelin, were found to cause several distinct corneal dystrophies affecting the Bowman layer and the stroma. We present a novel preliminary classification of corneal dystrophies based on molecular etiology. This classification may be useful in understanding the pathogenesis of corneal dystrophies and in developing new strategies to treat these dystrophies.
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Affiliation(s)
- S K Gupta
- University of Ottawa Eye Institute, Ontario, Canada
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Chinnery PF, Turnbull DM, Howell N, Andrews RM. Mitochondrial DNA mutations and pathogenicity. J Med Genet 1998; 35:701-2. [PMID: 9719386 PMCID: PMC1051408 DOI: 10.1136/jmg.35.8.701-a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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