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Nenninger A, Ben-Shlomo G, Allbaugh R, Valentine B, Snella E, Jens J, Ellinwood NM, Smith J. Clinical and pathological characterization of ophthalmic disease in a canine model of mucopolysaccharidosis type I. J Inherit Metab Dis 2023; 46:348-357. [PMID: 36601751 DOI: 10.1002/jimd.12587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/29/2022] [Accepted: 01/03/2023] [Indexed: 01/06/2023]
Abstract
Mucopolysaccharidosis type I (MPS I) is a rare lysosomal storage disease caused by α-L-iduronidase enzyme deficiency, resulting in glycosaminoglycan (GAG) accumulation in various cell types, including ocular tissues. Ocular manifestations in humans are common with significant pathological changes including corneal opacification, retinopathy, optic nerve swelling and atrophy, and glaucoma. Available treatments for MPS I are suboptimal and there is limited to no effect in treating the ocular disease. The goal of this study was to characterize the clinical and pathological features of ocular disease in a line of MPS I affected dogs, including changes not previously reported. A total of 22 dogs were studied; 12 MPS I were affected and 10 were unaffected. A subset of each underwent complete ophthalmic examination including slit lamp biomicroscopy, indirect ophthalmoscopy, rebound tonometry, and ultrasonic pachymetry. Globes were evaluated microscopically for morphological changes and GAG accumulation. Clinical corneal abnormalities in affected dogs included edema, neovascularization, fibrosis, and marked stromal thickening. Intraocular pressures were within reference interval for affected and unaffected dogs. Microscopically, vacuolated cells containing alcian blue positive inclusions were detected within the corneal stroma, iris, ciliary body, sclera, and optic nerve meninges of affected dogs. Ganglioside accumulation was identified by luxol fast blue staining in rare retinal ganglion cells. Increased lysosomal integral membrane protein-2 expression was demonstrated within the retina of affected animals when compared to unaffected controls. Results of this study further characterize ocular pathology in the canine model of MPS I and provide foundational data for future therapeutic efficacy studies.
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Affiliation(s)
- Ariel Nenninger
- Department of Veterinary Pathology, Iowa State University, Ames, Iowa, USA
| | - Gil Ben-Shlomo
- Department of Veterinary Clinical Sciences, Iowa State University, Ames, Iowa, USA
| | - Rachel Allbaugh
- Department of Veterinary Clinical Sciences, Iowa State University, Ames, Iowa, USA
| | - Bethann Valentine
- Department of Animal Science, Iowa State University, Ames, Iowa, USA
| | - Elizabeth Snella
- Department of Animal Science, Iowa State University, Ames, Iowa, USA
| | - Jackie Jens
- Department of Animal Science, Iowa State University, Ames, Iowa, USA
| | | | - Jodi Smith
- Department of Veterinary Pathology, Iowa State University, Ames, Iowa, USA
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Intartaglia D, Giamundo G, Conte I. Autophagy in the retinal pigment epithelium: a new vision and future challenges. FEBS J 2022; 289:7199-7212. [PMID: 33993621 PMCID: PMC9786786 DOI: 10.1111/febs.16018] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/07/2021] [Accepted: 05/12/2021] [Indexed: 01/13/2023]
Abstract
The retinal pigment epithelium (RPE) is a highly specialized monolayer of polarized, pigmented epithelial cells that resides between the vessels of the choriocapillaris and the neural retina. The RPE is essential for the maintenance and survival of overlying light-sensitive photoreceptors, as it participates in the formation of the outer blood-retinal barrier, phagocytosis, degradation of photoreceptor outer segment (POS) tips, maintenance of the retinoid cycle, and protection against light and oxidative stress. Autophagy is an evolutionarily conserved 'self-eating' process, designed to maintain cellular homeostasis. The daily autophagy demands in the RPE require precise gene regulation for the digestion and recycling of intracellular and POS components in lysosomes in response to light and stress conditions. In this review, we discuss selective autophagy and focus on the recent advances in our understanding of the mechanism of cell clearance in the RPE for visual function. Understanding how this catabolic process is regulated by both transcriptional and post-transcriptional mechanisms in the RPE will promote the recognition of pathological pathways in genetic disease and shed light on potential therapeutic strategies to treat visual impairments in patients with retinal disorders associated with lysosomal dysfunction.
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Affiliation(s)
| | | | - Ivan Conte
- Telethon Institute of Genetics and MedicinePozzuoli (Naples)Italy,Department of BiologyUniversity of Naples Federico IINaplesItaly
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Yılmaz Çebi A, Hepokur M. OCT imaging of macular cysts and treatment response with nepafenac in mucopolysaccharidosis type 1. Ophthalmic Genet 2022; 44:273-275. [PMID: 35876331 DOI: 10.1080/13816810.2022.2103836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
PURPOSE Mucopolysaccharidosis Type I (MPS I) is an autosomal recessive lysosomal storage disorder characterized by a defect in the enzyme alpha-L-iduronidase. Glycosaminoglycan accumulation causes ocular involvement such as corneal clouding or pigmentary retinopathy. Here we report bilateral macular cysts in mucopolysaccharidosis type I (MPS I) that responds to nepafenac treatment. METHODS Retrospective case report. RESULTS A 27-year-old woman with MPS I (Scheie phenotype) was complaining of slightly blurred vision. She had been on alpha-L-iduronidase enzyme replacement therapy for ten years. Best-corrected visual acuity was 20/25 in both eyes. Biomicroscopy was normal. Dilated fundus examination revealed pigmentary retinopathy. Optical coherence tomography (OCT) detected macular cysts in inner and outer nuclear layers, with preservation of ellipsoid zone and IS/OS line. There was no dye leakage on fluorescein angiography. Macular cysts regressed partially after one month with topical nepafenac 0.1% four times a day. BCVA improved to 20/20 in both eyes. CONCLUSIONS This is the first report of bilateral macular cysts that was demonstrated with OCT and treated with topical nepafenac in a patient with MPS I. Because the symptoms of our patient were mild, large-scaled cohort studies are required to ascertain the real prevalence of macular cysts in MPS I. It may also be beneficial to do more research on the possible benefits of nepafenac on the retinal manifestations of MPS.
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Affiliation(s)
- Aslıhan Yılmaz Çebi
- Ophthalmology Department, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Mustafa Hepokur
- Ophthalmology Department, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
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Macular Changes in a Mucopolysaccharidosis Type I Patient with Earlier Systemic Therapies. Case Rep Ophthalmol Med 2021; 2021:8866837. [PMID: 34306784 PMCID: PMC8267582 DOI: 10.1155/2021/8866837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 03/21/2021] [Accepted: 04/05/2021] [Indexed: 11/17/2022] Open
Abstract
Purpose To describe retinal findings in a patient with mucopolysaccharidosis type I (MPS I) that underwent an early treatment with hematopoietic stem cell transplantation (HSCT) and enzyme replacement therapy (ERT). Case Report. We describe a case of a 12-year-old female with a biochemical and genetic diagnosis of MPS I. She underwent HSCT and ERT on the first year of life. The visual acuity was 5/10 in both eyes and she had bilateral grade 2 corneal haze. Spectral domain optical coherence tomography (SD-OCT) revealed thickening of the external limiting membrane (ELM) at the fovea. In the parafoveal and perifoveal regions, SD-OCT displayed a loss of the interdigitation, ellipsoid, and myoid zones and of the ELM accompanied by progressive thinning of the outer nuclear layer. Fundus infrared imaging revealed a hyperreflective ring centred on the fovea and hyporeflective areas in temporal parafoveal regions in both eyes. En face OCT imaging revealed two hyperreflective rings on the outer retinal level. Conclusion This patient developed macular changes with foveal deposition of hyperreflective material and parafoveal thinning, despite early systemic treatment. Systemic therapies can provide an increase in life expectancy and stabilize visual acuity and corneal clouding, although their effect on retinal degeneration is unknown.
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Arora V, Setia N, Dalal A, Vanaja MC, Gupta D, Razdan T, Phadke SR, Saxena R, Rohtagi A, Verma IC, Puri RD. Sialidosis type II: Expansion of phenotypic spectrum and identification of a common mutation in seven patients. Mol Genet Metab Rep 2020; 22:100561. [PMID: 31956508 PMCID: PMC6957780 DOI: 10.1016/j.ymgmr.2019.100561] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 12/25/2019] [Accepted: 12/25/2019] [Indexed: 12/18/2022] Open
Abstract
Sialidosis, an autosomal recessive disorder, is characterized by progressive lysosomal storage of sialylated glycopeptides and oligosaccharides. It occurs as a result of biallelic mutations in the NEU1 gene. Sialidosis is traditionally classified as a milder, late-onset type I and a severe early-onset type II disease. The presence of a cherry-red spot is a well-established ophthalmological clue to the disorder. We present a clinical-radiological report of seven unrelated patients with molecularly confirmed sialidosis type II. To the best of our knowledge, This is the largest reported series of patients with Sialidosis type II. A novel, previously unreported ophthalmic phenotype of bulls-eye maculopathy, is described. All seven phenotypically heterogeneous patients had the same pathogenic variant (c.679G > A; p.Gly227Arg) at a homozygous level in the NEU1 gene. We propose that this is a common mutation in north Indians for this rare disorder. We also observed an overlap of symptoms and a continuum of phenotypes in type I and II Sialidosis.
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Affiliation(s)
- Veronica Arora
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi 110060, India
| | - Nitika Setia
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi 110060, India
| | - Ashwin Dalal
- Diagnostics Division, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | | | - Deepti Gupta
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi 110060, India
| | - Tinku Razdan
- Department of Ophthalmology, Sir Ganga Ram Hospital, New Delhi 110060, India
| | - Shubha R Phadke
- Department of Medical Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India
| | - Renu Saxena
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi 110060, India
| | - Anshu Rohtagi
- Department of Neurology, Sir Ganga Ram Hospital, New Delhi 110060, India
| | - Ishwar C Verma
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi 110060, India
| | - Ratna Dua Puri
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi 110060, India
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Yamanishi R, Nakamura N, Tsunoda K. Recovery of Vision following Enzyme Replacement Therapy in a Patient with Mucopolysaccharidosis Type II, Hunter Syndrome. Case Rep Ophthalmol 2019; 10:186-194. [PMID: 31692592 PMCID: PMC6760358 DOI: 10.1159/000500804] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 05/07/2019] [Indexed: 12/05/2022] Open
Abstract
We analyzed the effects of enzyme replacement therapy (ERT) on the visual acuity and visual fields of a patient with mucopolysaccharidosis type II, Hunter syndrome, with degeneration of the retina and abnormalities of the optic nerve. After the ERT, there was an improvement of the visual acuity and visual fields and an improvement of the activities of daily living. Despite the late onset of Hunter syndrome in this patient, ERT was still able to improve the visual function. We conclude that ERT should be considered regardless of the age of the manifestations of the signs and symptoms of Hunter syndrome.
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Affiliation(s)
- Ryutaro Yamanishi
- Department of Ophthalmology, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, Keio University, Tokyo, Japan
| | - Natsuko Nakamura
- Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, The University of Tokyo, Tokyo, Japan
| | - Kazushige Tsunoda
- Department of Ophthalmology, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
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Abstract
Mucopolysaccharidoses (MPS) are a group of rare lysosomal storage disorders characterized by the accumulation of glycosaminoglycans (GAGs) in different parts of the eye. Ocular problems are very common in MPS children, and the cornea, sclera, trabecular meshwork, retina, and optic nerve may all be involved. Early diagnosis is very important to preserve the visual function, and the diagnosis requires experience and different evaluations. Follow-up is mandatory to allow a correct pathway to consequent therapy. This article aims to provide a review of ocular alterations and treatment options in MPS. The ophthalmologist is sometimes the first physician who can suspect a metabolic disease and can help to make the correct diagnosis. It is important to stimulate awareness of MPS among ophthalmologists.
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Affiliation(s)
- Alessandra Del Longo
- Pediatric Department, ASST Grande Ospedale Metropolitano Niguarda, Piazza Ospedale Maggiore 3, 20162, Milan, Italy.
| | - Elena Piozzi
- Pediatric Department, ASST Grande Ospedale Metropolitano Niguarda, Piazza Ospedale Maggiore 3, 20162, Milan, Italy
| | - Fiammetta Schweizer
- Department of Ophthalmology, Ospedale San Gerardo, Via G. B. Pergolesi 33, 20052, Monza, MB, Italy
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Mack HG, Symons RCA, de Jong G. Bull's eye maculopathy and subfoveal deposition in two mucopolysaccharidosis type I patients on long-term enzyme replacement therapy. Am J Ophthalmol Case Rep 2017; 9:1-6. [PMID: 29468207 PMCID: PMC5786832 DOI: 10.1016/j.ajoc.2017.10.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 08/01/2017] [Accepted: 10/02/2017] [Indexed: 11/28/2022] Open
Abstract
Purpose To report retinal findings in two patients with mucopolysaccharidosis type I (MPS I) receiving human recombinant alpha-l-iduronidase (Laronidase) as enzyme replacement therapy. Observations Patient 1 had visual acuity 20/20 right eye, 20/25 left eye and unremarkable anterior segment and retinal examination. Optical coherence tomography (OCT) scanning demonstrated parafoveal thinning and subfoveal hyperreflectant material. Patient 2 had visual acuity 20/20 both eyes, with dense nuclear cataract both eyes. Retinal examination demonstrated bull's eye maculopathy both eyes. OCT scanning confirmed parafoveal atrophy and demonstrated similar appearing subfoveal hyperreflectant material, more prominent than in case 1. Conclusions and importance These two patients with MPS I receiving Laronidase treatment have developed bull's eye maculopathy changes and subfoveal deposition of hyperreflectant material despite excellent compliance and good tolerance of the standard dose of enzyme therapy for this disorder. Further studies are required to determine the nature of the material, the incidence and the effect of enzyme replacement therapy on these findings in patients with MPS I.
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Affiliation(s)
- Heather G Mack
- Department of Surgery (Ophthalmology), University of Melbourne, Grattan St, Parkville, Victoria 3052, Australia.,Melbourne Health, 300 Grattan St, Parkville, Victoria 3052, Australia.,Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - R C Andrew Symons
- Department of Surgery (Ophthalmology), University of Melbourne, Grattan St, Parkville, Victoria 3052, Australia.,Melbourne Health, 300 Grattan St, Parkville, Victoria 3052, Australia
| | - Gerard de Jong
- Melbourne Health, 300 Grattan St, Parkville, Victoria 3052, Australia.,Department of Medicine, University of Melbourne, Grattan St, Parkville, Victoria 3052, Australia
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