1
|
Haraguchi Y, Chiang TK, Yu M. Application of Electrophysiology in Non-Macular Inherited Retinal Dystrophies. J Clin Med 2023; 12:6953. [PMID: 37959417 PMCID: PMC10649281 DOI: 10.3390/jcm12216953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/15/2023] Open
Abstract
Inherited retinal dystrophies encompass a diverse group of disorders affecting the structure and function of the retina, leading to progressive visual impairment and, in severe cases, blindness. Electrophysiology testing has emerged as a valuable tool in assessing and diagnosing those conditions, offering insights into the function of different parts of the visual pathway from retina to visual cortex and aiding in disease classification. This review provides an overview of the application of electrophysiology testing in the non-macular inherited retinal dystrophies focusing on both common and rare variants, including retinitis pigmentosa, progressive cone and cone-rod dystrophy, bradyopsia, Bietti crystalline dystrophy, late-onset retinal degeneration, and fundus albipunctatus. The different applications and limitations of electrophysiology techniques, including multifocal electroretinogram (mfERG), full-field ERG (ffERG), electrooculogram (EOG), pattern electroretinogram (PERG), and visual evoked potential (VEP), in the diagnosis and management of these distinctive phenotypes are discussed. The potential for electrophysiology testing to allow for further understanding of these diseases and the possibility of using these tests for early detection, prognosis prediction, and therapeutic monitoring in the future is reviewed.
Collapse
Affiliation(s)
| | | | - Minzhong Yu
- Department of Ophthalmology, University Hospitals, Case Western Reserve University, Cleveland, OH 44106, USA
| |
Collapse
|
2
|
Jia R, Meng X, Chen S, Zhang F, Du J, Liu X, Yang L. AAV-mediated gene-replacement therapy restores viability of BCD patient iPSC derived RPE cells and vision of Cyp4v3 knockout mice. Hum Mol Genet 2023; 32:122-138. [PMID: 35925866 DOI: 10.1093/hmg/ddac181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/17/2022] [Accepted: 07/31/2022] [Indexed: 01/25/2023] Open
Abstract
Bietti crystalline corneoretinal dystrophy (BCD) is an autosomal recessive retinal degenerative disease characterized by yellow-white crystal deposits in the posterior pole, degeneration of the retinal pigment epithelium (RPE), and sclerosis of the choroid. Mutations in the cytochrome P450 4V2 gene (CYP4V2) cause BCD, which is associated with lipid metabolic disruption. The use of gene-replacement therapy in BCD has been hampered by the lack of disease models. To advance CYP4V2 gene-replacement therapy, we generated BCD patient-specific induced pluripotent stem cell (iPSC)-RPE cells and Cyp4v3 knockout (KO) mice as disease models and AAV2/8-CAG-CYP4V2 as treatment vectors. We demonstrated that after adeno-associated virus (AAV)-mediated CYP4V2 gene-replacement therapy BCD-iPSC-RPE cells presented restored cell survival and reduced lipid droplets accumulation; restoration of vision in Cyp4v3 KO mice was revealed by elevated electroretinogram amplitude and ameliorated RPE degeneration. These results suggest that AAV-mediated gene-replacement therapy in BCD patients is a promising strategy.
Collapse
Affiliation(s)
- Ruixuan Jia
- Key Laboratory of Vision Loss and Restoration, Department of Ophthalmology, Ministry of Education, Peking University Third Hospital, Beijing, People's Republic of China
| | - Xiang Meng
- Key Laboratory of Vision Loss and Restoration, Department of Ophthalmology, Ministry of Education, Peking University Third Hospital, Beijing, People's Republic of China
| | - Shaohong Chen
- Beijing Chinagene Corporation Ltd, Beijing, People's Republic of China
| | - Fan Zhang
- Beijing Chinagene Corporation Ltd, Beijing, People's Republic of China
| | - Juan Du
- Key Laboratory of Vision Loss and Restoration, Department of Ophthalmology, Ministry of Education, Peking University Third Hospital, Beijing, People's Republic of China.,Department of Anatomy, Histology, and Embryology, Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center, Beijing, People's Republic of China
| | - Xiaozhen Liu
- Key Laboratory of Vision Loss and Restoration, Department of Ophthalmology, Ministry of Education, Peking University Third Hospital, Beijing, People's Republic of China
| | - Liping Yang
- Key Laboratory of Vision Loss and Restoration, Department of Ophthalmology, Ministry of Education, Peking University Third Hospital, Beijing, People's Republic of China
| |
Collapse
|
3
|
Saatci AO, Ataş F, Çetin GO, Kayabaşı M. Diagnostic and Management Strategies of Bietti Crystalline Dystrophy: Current Perspectives. Clin Ophthalmol 2023; 17:953-967. [PMID: 36998515 PMCID: PMC10046287 DOI: 10.2147/opth.s388292] [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: 02/14/2023] [Accepted: 03/15/2023] [Indexed: 04/01/2023] Open
Abstract
Bietti crystalline dystrophy (BCD) is a rare, genetically determined chorioretinal dystrophy presenting with intraretinal crystalline deposits and varying degrees of progressive chorioretinal atrophy commencing at the posterior pole. In some cases, there can be concomitant corneal crystals noted first in the superior or inferior limbus. CYP4V2 gene, a member of the cytochrome P450 family is responsible for the disease and more than 100 mutations have been defined thus far. However, a genotype-phenotype correlation has not been established yet. Visual impairment commonly occurs between the second and third decades of life. By the fifth or sixth decade of life, vision loss can become so severe that the patient may potentially become legally blind. Multitudes of multimodal imaging modalities can be utilized to demonstrate the clinical features, course, and complications of the disease. This present review aims to reiterate the clinical features of BCD, update the clinical perspectives with the help of multimodal imaging techniques, and overview its genetic background with future therapeutic approaches.
Collapse
Affiliation(s)
- Ali Osman Saatci
- Department of Ophthalmology, Dokuz Eylul University, Izmir, Turkey
- Correspondence: Ali Osman Saatci, Department of Ophthalmology, Dokuz Eylul University, Mustafa Kemal Sahil Bulvari, No: 73 A Blok, Daire 9, Narlidere, Izmir, Turkey, Tel +90 5327437071, Email
| | - Ferdane Ataş
- Department of Ophthalmology, Çerkezköy State Hospital, Tekirdağ, Turkey
| | - Gökhan Ozan Çetin
- Department of Medical Genetics, Pamukkale University, Denizli, Turkey
| | - Mustafa Kayabaşı
- Department of Ophthalmology, Dokuz Eylul University, Izmir, Turkey
| |
Collapse
|
4
|
A Bietti Crystalline Dystrophy Mouse Model Shows Increased Sensitivity to Light-Induced Injury. Int J Mol Sci 2022; 23:ijms232113108. [DOI: 10.3390/ijms232113108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 11/16/2022] Open
Abstract
Bietti crystalline corneo-retinal dystrophy (BCD) is an autosomal recessive inherited retinal dystrophy characterized by multiple shimmering yellow-white deposits in the posterior pole of the retina in association with atrophy of the retinal pigment epithelium (RPE), pigment clumps, and choroidal atrophy and sclerosis. Blindness and severe visual damage are common in late-stage BCD patients. We generated a Cyp4v3 knockout mouse model to investigate the pathogenesis of BCD. This model exhibits decreased RPE numbers and signs of inflammation response in the retina. Rod photoreceptors were vulnerable to light-induced injury, showing increased deposits through fundoscopy, a decrease in thickness and a loss of cells in the ONL, and the degeneration of rod photoreceptors. These results suggest that an inflammatory response might be an integral part of the pathophysiology of BCD, suggesting that it might be reasonable for BCD patients to avoid strong light, and the results provide a useful model for evaluating the effects of therapeutic approaches.
Collapse
|
5
|
Choi KY, Wong HHY, Chan HHL. Utilizing Advanced Technology to Facilitate Diagnosis of Rare Retinal Disorders: A Case of Bietti Crystalline Dystrophy. Optom Vis Sci 2021; 98:1031-1038. [PMID: 34459467 DOI: 10.1097/opx.0000000000001763] [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: 11/26/2022] Open
Abstract
SIGNIFICANCE Optometrists, as primary eye care providers, encounter patients with rare ocular disease such as Bietti crystalline dystrophy from time to time. Using advanced technologies, which are also useful in managing common ocular conditions, to facilitate a prompt diagnosis is highly recommended. PURPOSE This report describes a patient with clinically diagnosed Bietti crystalline dystrophy with findings on funduscopy, multimodal imaging, and visual electrophysiology. CASE REPORT A 41-year-old Chinese woman who had subjectively progressing dimmed vision (especially in the left eye) for 9 months was referred to our clinic to test for retinitis pigmentosa. Best-corrected visual acuities were 6/6 and 6/7.6 in the right and left eyes, respectively. Funduscopy revealed multiple crystalline deposits on the posterior pole in both eyes. The 30-2 perimetry displayed bi-inferotemporal scotoma (left > right eye). Scotopic flash electroretinogram (ERG) yielded a normal result, whereas photopic ERG was slightly attenuated. Electro-oculogram showed an abnormal adaptation time course of the retinal pigmented epithelium (RPE). Multifocal ERG revealed a decreased central retinal response, but paracentral responses were relatively better preserved. Optical coherence tomography showed multiple patches of RPE atrophy, with disruption of the left ellipsoid zone. Outer retinal tubulations, hyperreflective dots on RPE-Bruch's membrane interface, and intraretinal bright spots were also identified. CONCLUSIONS Rare ocular diseases like Bietti crystalline dystrophy can be encountered by optometrists. This case report shows the ophthalmic findings of a rare chorioretinal dystrophy and provides insight on how to better use advanced equipment in an optometric practice to facilitate prompt diagnoses.
Collapse
Affiliation(s)
- Kai Yip Choi
- Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Horace Ho Yin Wong
- Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | | |
Collapse
|
6
|
Zhang S, Wang L, Liu Z, Sun H, Li Q, Xing C, Xiao Z, Peng X. Observation of the characteristics of the natural course of Bietti crystalline dystrophy by fundus fluorescein angiography. BMC Ophthalmol 2021; 21:239. [PMID: 34049507 PMCID: PMC8161580 DOI: 10.1186/s12886-021-01999-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 05/18/2021] [Indexed: 11/25/2022] Open
Abstract
Background Bietti crystalline dystrophy (BCD) is an autosomal recessive genetic disorder that causes progressive vision loss. Here, 12 patients were followed up for 1–5 years with fundus fluorescein angiography (FFA) to observe BCD disease progression. Methods FFA images were collected for 12 patients with BCD who visited our clinic twice or more over a 5-year period. Peripheral venous blood was collected to identify the pathogenic gene related to the clinical phenotype. Results We observed two types in FFA images of patients with BCD. Type 1 showed retinal pigment epithelium (RPE) atrophy in the macular area, followed by choriocapillaris atrophy and the subsequent appearance of RPE atrophy appeared at the peripheral retina. Type 2 showed RPE atrophy at the posterior pole and peripheral retina, followed by choriocapillaris atrophy around the macula and along the superior and inferior vascular arcades and the nasal side of the optic disc. The posterior and peripheral lesions of both type 1 and type 2 BCD subsequently extended to the mid-periphery; finally, all the RPEs and choriocapillaris atrophied, exposing the choroid great vessels, but type 2 macular RPE atrophy could last longer. Conclusions The characterization of two different types of BCD development provides a better understanding of the phenotype and the progression of the disease for a precise prognosis and prediction of pathogenesis.
Collapse
Affiliation(s)
- Shengjuan Zhang
- Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 17 Hougou Lane, Chongnei Street, 100005, Beijing, People's Republic of China.,Hebei Provincial Key Laboratory of Ophthalmology, Hebei Provincial Eye Institute, Hebei Provincial Eye Hospital, 399 East Quanbei Street, Xingtai, 054001, Hebei, People's Republic of China
| | - Lifei Wang
- Hebei Provincial Key Laboratory of Ophthalmology, Hebei Provincial Eye Institute, Hebei Provincial Eye Hospital, 399 East Quanbei Street, Xingtai, 054001, Hebei, People's Republic of China
| | - Zhiqiang Liu
- Hebei Provincial Key Laboratory of Ophthalmology, Hebei Provincial Eye Institute, Hebei Provincial Eye Hospital, 399 East Quanbei Street, Xingtai, 054001, Hebei, People's Republic of China
| | - Huijing Sun
- Hebei Provincial Key Laboratory of Ophthalmology, Hebei Provincial Eye Institute, Hebei Provincial Eye Hospital, 399 East Quanbei Street, Xingtai, 054001, Hebei, People's Republic of China
| | - Qian Li
- Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 17 Hougou Lane, Chongnei Street, 100005, Beijing, People's Republic of China
| | - Chen Xing
- Hebei Provincial Key Laboratory of Ophthalmology, Hebei Provincial Eye Institute, Hebei Provincial Eye Hospital, 399 East Quanbei Street, Xingtai, 054001, Hebei, People's Republic of China
| | - Zhe Xiao
- Hebei Provincial Key Laboratory of Ophthalmology, Hebei Provincial Eye Institute, Hebei Provincial Eye Hospital, 399 East Quanbei Street, Xingtai, 054001, Hebei, People's Republic of China
| | - Xiaoyan Peng
- Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 17 Hougou Lane, Chongnei Street, 100005, Beijing, People's Republic of China.
| |
Collapse
|
7
|
Wang W, Chen W, Bai X, Chen L. Multimodal imaging features and genetic findings in Bietti crystalline dystrophy. BMC Ophthalmol 2020; 20:331. [PMID: 32799831 PMCID: PMC7429681 DOI: 10.1186/s12886-020-01545-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/03/2020] [Indexed: 11/10/2022] Open
Abstract
Background Bietti crystalline dystrophy (BCD) is a distinct entity of retinitis pigmentosa with a wide range of genotypic and phenotypic variabilities. The goal of the present study was to investigate the morphological, functional and genetic features of BCD. Methods A full series of multimodal imaging was performed in four Chinese patients with BCD, including fundus photography, fundus autofluorescence, fundus fluorescein angiography (FFA), indocyanine green (ICG) angiography, optical coherence tomography (OCT) and microperimetry. Electrophysiological tests including full-field electroretinography (ERG) and multifocal ERG were employed. CYP4V2 gene sequencing was performed. Results Intraretinal crystalline deposits were observed in fundus photographs in all patients. The crystals were better appreciated in infrared images. Autofluorescence imaging demonstrated multifocal patchy hypofluorescence, suggesting massive RPE atrophy. FFA and ICG angiography further confirmed atrophy of the RPE and the underlying choroidal vessels. OCT revealed disruption of the photoreceptors, RPE and the choroid. Outer retinal tubulations (ORTs) confining to the outer nuclear layer were detected in three out of four patients. Full-field ERG showed markedly diminished responses. Multifocal ERG displayed reduced central and peripheral responses in a patient with normal vision. Gene sequencing identified two deletion mutations in CYP4V2, c.802_807del and c.810delT. BCD complicated by choroidal neovascularization (CNV) was diagnosed in one patient, and intravitreal anti-vascular endothelial growth factor (VEGF) injection was given with favorable response. Conclusions Multimodal imaging features and electrophysiological findings of BCD patients were comprehensively discussed. A novel deletion mutation, c.802_807del, in the CYP4V2 gene was reported. ORTs are important changes in the outer retina of BCD patients, further investigation of this structure may provide insights into pathology of BCD. Intravitreal anti-VEGF therapy was effective for treatment of BCD complicated by CNV.
Collapse
Affiliation(s)
- Wei Wang
- Department of Ophthalmology and Vision Science, the Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China.,Key Laboratory of Myopia of State Health Ministry (Fudan University) and Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China.,Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Wei Chen
- Department of Ophthalmology and Vision Science, the Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China.,Key Laboratory of Myopia of State Health Ministry (Fudan University) and Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China
| | - Xinyue Bai
- Department of Ophthalmology and Vision Science, the Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China.,Key Laboratory of Myopia of State Health Ministry (Fudan University) and Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China
| | - Ling Chen
- Department of Ophthalmology and Vision Science, the Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China. .,Key Laboratory of Myopia of State Health Ministry (Fudan University) and Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China.
| |
Collapse
|
8
|
Meng XH, He Y, Zhao TT, Li SY, Liu Y, Yin ZQ. Novel mutations in CYP4V2 in Bietti corneoretinal crystalline dystrophy: Next-generation sequencing technology and genotype-phenotype correlations. Mol Vis 2019; 25:654-662. [PMID: 31741654 PMCID: PMC6828992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 10/29/2019] [Indexed: 11/11/2022] Open
Abstract
Purpose To identify any novel mutations in CYP4V2 in 85 Chinese families with Bietti corneoretinal crystalline dystrophy (BCD) by using next-generation sequencing, and to summarize the mutation spectrum in this population, along with any genotype-phenotype correlations. Methods A total of 90 patients with BCD from 85 unrelated Chinese families were recruited. All probands were analyzed by using gene chip-based next-generation sequencing, to capture and sequence all the exons of 57 known hereditary retinal degeneration-associated genes. The candidate variants were validated with PCR and Sanger sequencing. Results Twenty-eight mutations were detected in all patients, including thirteen novel mutations (five missense, six deletions, one splicing and one frame-shift mutations) and 15 previously reported mutations. Mutations in 64 patients were inherited from their parents, while three patients had de novo mutations. c.802-8_810del17insGC was the most common mutation, accounting for 78% of the mutations. Although 16 patients were homozygous at this site, the clinical features of all 16 patients were highly heterogeneous. Conclusions These results expand the spectrum of mutations in CYP4V2, and suggest that mutations in CYP4V2 may be common in the Chinese population. The phenotype of patients with the homozygous mutation (hom.c.802-8_810del17insGC) is highly heterogeneous.
Collapse
Affiliation(s)
- Xiao Hong Meng
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, China
| | - Yan He
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, China
| | - Tong Tao Zhao
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, China
| | - Shi Ying Li
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, China
| | - Yong Liu
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, China
| | - Zheng Qin Yin
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China,Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, China
| |
Collapse
|
9
|
García-García GP, Martínez-Rubio M, Moya-Moya MA, Pérez-Santonja JJ, Escribano J. Identification of novel CYP4V2 genotypes associated with Bietti crystalline dystrophy and atypical anterior segment phenotypes in Spanish patients. Acta Ophthalmol 2018; 96:e865-e873. [PMID: 29691984 DOI: 10.1111/aos.13768] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/01/2018] [Indexed: 11/29/2022]
Abstract
PURPOSE To identify the spectrum of disease-causing CYP4V2 variants in Spanish patients with clinically diagnosed Bietti crystalline dystrophy (BCD) over an 8-year period and to analyse the phenotype-genotype correlation of the identified variants. METHODS Four unrelated Spanish probands with a clinical diagnosis of BCD were recruited. Ophthalmological examination included visual acuity (VA), slit lamp examination, in vivo corneal confocal microscopy, funduscopy and fluoresceinic angiography. Genomic DNA was obtained from blood samples, and the exons and flanking intron sequences of the CYP4V2 gene were screened by Sanger sequencing. Family members of the patients with mutations in CYP4V2 gene were subsequently studied. RESULTS Clinical examination revealed retinal and corneal patterns compatible with BCD in all the participants. We identified a total of six CYP4V2 variants among the four carriers. As far as we know, the variant p.(Trp244Cysfs*33) has not previously been reported. This variant along with p.(Ala204Thr) and p.(Arg443Trp) were combined in three novel pathogenic phenotypes that share the presence of bilateral limbic glistening deposits, severe retinal damage and visual impairment and a fast rate of progression of the disease. CONCLUSION To the best of our knowledge, this study represents the largest effort to determine the genetic alterations underlying BCD in Spain to date. Our results show that analysis of CYP4V2 variants is required for a reliable diagnosis of BCD. We report a high prevalence of anterior segment changes in this Spanish BCD cohort, which we consider representative of the Spanish patients.
Collapse
Affiliation(s)
| | | | | | | | - Julio Escribano
- Laboratory of Human Molecular Genetics; School of Medicine/Research Institute of Neurological Disabilities (IDINE); University of Castilla La-Mancha; Albacete Spain
- Cooperative Research Network on Visual and Life Quality; Instituto de Salud Carlos III; Madrid Spain
| |
Collapse
|
10
|
Abstract
Bietti crystalline dystrophy (BCD) is an inherited retinal degenerative disease characterized by crystalline deposits in the retina, followed by progressive atrophy of the retinal pigment epithelium (RPE), choriocapillaris, and photoreceptors. CYP4V2 has been identified as the causative gene for BCD. The CYP4V2 gene belongs to the cytochrome P450 superfamily and encodes for fatty acid ω-hydroxylase of both saturated and unsaturated fatty acids. The CYP4V2 protein is localized most abundantly within the endoplasmic reticulum in the RPE and is postulated to play a role in the physiological lipid recycling system between the RPE and photoreceptors to maintain visual function. Electroretinographic assessments have revealed progressive dysfunction of rod and cone photoreceptors in patients with BCD. Several genotypes have been associated with more severe phenotypes based on clinical and electrophysiological findings. With the advent of multimodal imaging with spectral domain optical coherence tomography, fundus autofluorescence, and adaptive optics scanning laser ophthalmoscopy, more precise delineation of BCD severity and progression is now possible, allowing for the potential future development of targets for gene therapy.
Collapse
Affiliation(s)
- Danny S C Ng
- From the *Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong; and †2010 Retina and Macula Centre, Kowloon, Hong Kong
| | | | | | | |
Collapse
|
11
|
Şahin M, Yıldırım A, Türkcü FM, Yüksel H, Şahin A. Bietti Crystalline Retinal Dystrophy: A Case Report. JOURNAL OF CLINICAL AND EXPERIMENTAL INVESTIGATIONS 2016. [DOI: 10.5799/jcei.328695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
12
|
Lockhart CM, Nakano M, Rettie AE, Kelly EJ. Generation and characterization of a murine model of Bietti crystalline dystrophy. Invest Ophthalmol Vis Sci 2014; 55:5572-81. [PMID: 25118264 DOI: 10.1167/iovs.13-13717] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Bietti crystalline dystrophy (BCD) is a rare, autosomal recessive, progressive, degenerative eye disease caused by mutations in the CYP4V2 gene, for which no treatments are currently available. Cyp4v3 is the murine ortholog to CYP4V2, and to better understand the molecular pathogenesis of this disease we have established a Cyp4v3-null mouse line. METHODS Cyp4v3(-/-) mice were generated by homologous recombination in embryonic stem cells. Ocular morphologic characteristics were evaluated via fundus imaging, plasma lipid profiling, and histologic analysis via Oil Red O reactivity, hematoxylin and eosin staining, and transmission electron microscopy. RESULTS The Cyp4v3(-/-) mouse recapitulates the characteristic features of corneoretinal crystal accumulation and systemic dyslipidemia seen in BCD. The Cyp4v3(-/-) mice behave normally and are viable and fertile when maintained under specific pathogen-free (SPF) housing conditions. CONCLUSIONS Cyp4v3(-/-) mice represent a promising preclinical model that may be used to better understand the disease etiology and to evaluate pharmacotherapies for this devastating condition.
Collapse
Affiliation(s)
- Catherine M Lockhart
- Department of Pharmaceutics, University of Washington, Seattle, Washington, United States
| | - Mariko Nakano
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, United States
| | - Allan E Rettie
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, United States
| | - Edward J Kelly
- Department of Pharmaceutics, University of Washington, Seattle, Washington, United States
| |
Collapse
|
13
|
Nakano M, Lockhart CM, Kelly EJ, Rettie AE. Ocular cytochrome P450s and transporters: roles in disease and endobiotic and xenobiotic disposition. Drug Metab Rev 2014; 46:247-60. [PMID: 24856391 PMCID: PMC4676416 DOI: 10.3109/03602532.2014.921190] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Drug metabolism and transport processes in the liver, intestine and kidney that affect the pharmacokinetics and pharmacodynamics of therapeutic agents have been studied extensively. In contrast, comparatively little research has been conducted on these topics as they pertain to the eye. Recently, however, catalytic functions of ocular cytochrome P450 enzymes have gained increasing attention, in large part due to the roles of CYP1B1 and CYP4V2 variants in primary congenital glaucoma and Bietti's corneoretinal crystalline dystrophy, respectively. In this review, we discuss challenges to ophthalmic drug delivery, including Phase I drug metabolism and transport in the eye, and the role of three specific P450s, CYP4B1, CYP1B1 and CYP4V2 in ocular inflammation and genetically determined ocular disease.
Collapse
Affiliation(s)
- Mariko Nakano
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, USA
| | - Catherine M. Lockhart
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA, USA
| | - Edward J. Kelly
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA, USA
| | - Allan E. Rettie
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, USA
| |
Collapse
|
14
|
Halford S, Liew G, Mackay DS, Sergouniotis PI, Holt R, Broadgate S, Volpi EV, Ocaka L, Robson AG, Holder GE, Moore AT, Michaelides M, Webster AR. Detailed Phenotypic and Genotypic Characterization of Bietti Crystalline Dystrophy. Ophthalmology 2014; 121:1174-84. [DOI: 10.1016/j.ophtha.2013.11.042] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 11/27/2013] [Accepted: 11/27/2013] [Indexed: 10/25/2022] Open
|
15
|
Molecular analysis and phenotypic study in 14 Chinese families with Bietti crystalline dystrophy. PLoS One 2014; 9:e94960. [PMID: 24739949 PMCID: PMC3989252 DOI: 10.1371/journal.pone.0094960] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 03/21/2014] [Indexed: 11/19/2022] Open
Abstract
Purpose To investigate the clinical features and cytochrome P450 family 4 subfamily V polypeptide 2 (CYP4V2) gene mutations in 14 Chinese families with Bietti crystalline dystrophy (BCD). Methods Seventeen patients from 14 unrelated Chinese families with BCD were recruited for complete clinical ophthalmic examination and genetic study. The 11 exons of CYP4V2 were amplified from genomic DNA of all patients and their family members by polymerase chain reaction (PCR) and then sequenced. Exons of TIMP3 were also sequenced in BCD patient associated with choroidal neovascularization (CNV). One hundred and seventy unrelated healthy Chinese subjects were screened for mutations in CYP4V2. Results All 17 patients with BCD had mutations in CYP4V2; one of these mutations was novel (c.219T>A, p.F73L) and four other mutations had been reported. The p.F73L mutation was a commonly detected mutation in our study (seven out of 34 alleles), either in the homozygous state or in the heterozygous state. Among the patients, considerable phenotypic variability was detected, both within and between families. Screening of TIMP3 did not find any mutation in the BCD patient associated with CNV. Conclusion The novel CYP4V2 c.219T>A (p.F73L) mutation may be another recurrent mutation in Chinese patients with BCD. Our study expands the mutation spectrum of CYP4V2 and characterizes novel genotype–phenotype associations in Chinese patients with BCD.
Collapse
|
16
|
Song Y, Mo G, Yin G. A novel mutation in the CYP4V2 gene in a Chinese patient with Bietti's crystalline dystrophy. Int Ophthalmol 2012; 33:269-76. [PMID: 23242590 DOI: 10.1007/s10792-012-9686-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 11/24/2012] [Indexed: 11/25/2022]
Abstract
Bietti crystalline corneoretinal dystrophy (BCD, MIM 210370) is a type of hereditary retinal disorder which commonly occurs in China. It is known that mutations in the CYP4V2 gene result in BCD. The purpose of this study was to investigate the case of a Chinese family and characterize the polymorphisms of the CYP4V2 gene. A 29-year-old male (the son of a Chinese family) with typical clinical symptoms of BCD and his family were recruited into this study. Ophthalmologic examination, including best-corrected visual acuity, slit-lamp, and fundus examination with dilated pupils, was conducted to determine the clinical characteristics of the whole family. The entire coding region and adjacent intronic sequences of 11 coding regions of the CYP4V2 gene of the whole family were then amplified by polymerase chain reaction and sequenced. Our results show that the son had typical clinical features of BCD. His bilateral decimal visual acuity was 0.06 (left eye) and 0.01 (right eye). Bilateral crystal-like deposits were found in the posterior pole of his fundus, and differing extent of atrophy of the retinal pigment epithelium, and carpet-like retinal degeneration along with numerous tiny glittering crystals were also clearly observed. However, such characteristics were not found on the fundus of his parents' eyes. Five mutations within the CYP4V2 gene (c.64C>G, c.775C>A, c.810T>G, c.1091-2A>G, and c.1399T>C) were identified in the son. Among the five mutations, four had previously been reported and the c.1399T>C was discovered for the first time. This novel mutation causes an amino acid substitution (C467R) in the CYP4V2 protein, but it was not detected in the parents. As there is no apparent relationship in genotype-phenotype correlation between the CYP4V2 gene and the occurrence of BCD, this novel mutation may be a possible cause that could induce the clinical phenotype of BCD.
Collapse
Affiliation(s)
- Yanping Song
- Department of Ophthalmology, Wuhan General Hospital of Guangzhou Military Command, Wuhan, 430070, China
| | | | | |
Collapse
|
17
|
Rossi S, Testa F, Li A, Yaylacioğlu F, Gesualdo C, Hejtmancik JF, Simonelli F. Clinical and genetic features in Italian Bietti crystalline dystrophy patients. Br J Ophthalmol 2012; 97:174-9. [PMID: 23221965 PMCID: PMC3582089 DOI: 10.1136/bjophthalmol-2012-302469] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Aim The aim of the study was to describe the clinical and genetic features of 15 Italian patients with Bietti crystalline dystrophy (BCD). Methods All study participants underwent a complete ophthalmological examination, including standard electroretinogram (ERG), optical coherence tomography, microperimetry, autofluorescence and multifocal electroretinogram. The 11 exons of the CYP4V2 gene were sequenced. The effect of mutations on protein function was estimated by a combination of web based programs. Results 15 patients (eight women, 7 men, aged 29–60 years) with BCD were recruited into this study. Sequencing of CYP4V2 revealed nine sequence variants in four unrelated families and six isolated individuals with BCD. Seven of these variants were novel. Among the patients, even with the same genotype, considerable variability in phenotypic expression with different degrees of accumulation of the typical intraretinal crystalline deposits was detected. Moreover, we found that more than 50% of patients had recordable standard ERG responses and in two patients the responses were within normal limits after 20 years of symptom onset. Conclusions In conclusion, we have reported seven new mutations and illustrated the large range of genotypic and phenotypic variability in BCD, highlighting the lack of a clear genotype–phenotype correlation and underlining the existence of less severe clinical manifestations, probably linked to relatively mild mutations.
Collapse
Affiliation(s)
- Settimio Rossi
- Department of Ophthalmology, Seconda Università degli Studi di Napoli, Via S Panini, 5, Naples 80131, Italy
| | | | | | | | | | | | | |
Collapse
|
18
|
Haddad NMN, Waked N, Bejjani R, Khoueir Z, Chouery E, Corbani S, Mégarbané A. Clinical and molecular findings in three Lebanese families with Bietti crystalline dystrophy: report on a novel mutation. Mol Vis 2012; 18:1182-8. [PMID: 22605929 PMCID: PMC3351416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 05/02/2012] [Indexed: 11/12/2022] Open
Abstract
PURPOSE Bietti crystalline dystrophy (BCD) is a rare autosomal recessive disorder caused by mutation of the cytochrome P450, family 4, subfamily V, polypeptide 2 (CYP4V2) gene and characterized by retinal pigmentary abnormalities and scattered deposits of crystals in the retina and the marginal cornea. The aim of this study was to investigate the spectrum of mutations in CYP4V2 in Lebanese families, and to characterize the phenotype of patients affected with BCD. METHODS Nine patients from three unrelated Lebanese families were clinically and molecularly investigated. Detailed characterization of the patients' phenotype was performed with comprehensive ophthalmic examination, color vision study, fundus photography, visual field testing, retinal fluorescein angiography, electroretinography, and electrooculography. One family was followed for 12 years. The 11 exons of the CYP4V2 gene were sequenced. RESULTS Symptoms consisting of night blindness, loss of paracentral visual field, and disturbed color vision were apparent during the third decade of life. Ophthalmoscopy revealed posterior pole crystalline deposits and areas of retinal pigment epithelium atrophy. Fluorescein angiography disclosed geographic areas of the pigment epithelium layer and choriocapillaris atrophy in the posterior pole and fundus periphery. The most striking findings were those of normal electroretinographic responses in some patients and clinical heterogeneity. Two mutations in CYP4V2 were found: p.I111T (c.332T>C) in exon 3 in two families and the novel p.V458M (c.1372G>A) mutation in exon 9 in one family. CONCLUSIONS These patients are affected with Bietti crystalline dystrophy without corneal involvement. Variation in disease severity and electroretinographic responses suggests that environmental or additional genetic factors influence the course of the retinal disease. The CYP4V2 p.I111T (c.332T>C) mutant allele may be especially prevalent among patients with BCD in Lebanon, resulting from a single founder.
Collapse
Affiliation(s)
- Nour Maya N. Haddad
- Service d’Ophtalmologie, Hôtel-Dieu de France Hospital, Beirut, Lebanon,Fondation ophtalmologique Adolphe de Rothschild, Paris, France
| | - Naji Waked
- Service d’Ophtalmologie, Hôtel-Dieu de France Hospital, Beirut, Lebanon
| | - Riad Bejjani
- Service d’Ophtalmologie, Hôtel-Dieu de France Hospital, Beirut, Lebanon
| | - Ziad Khoueir
- Service d’Ophtalmologie, Hôtel-Dieu de France Hospital, Beirut, Lebanon
| | - Eliane Chouery
- Unité de Génétique Médicale. Faculté de Médecine, Université Saint-Joseph, Beirut, Lebanon
| | - Sandra Corbani
- Unité de Génétique Médicale. Faculté de Médecine, Université Saint-Joseph, Beirut, Lebanon
| | - André Mégarbané
- Unité de Génétique Médicale. Faculté de Médecine, Université Saint-Joseph, Beirut, Lebanon
| |
Collapse
|
19
|
Xiao X, Mai G, Li S, Guo X, Zhang Q. Identification of CYP4V2 mutation in 21 families and overview of mutation spectrum in Bietti crystalline corneoretinal dystrophy. Biochem Biophys Res Commun 2011; 409:181-6. [DOI: 10.1016/j.bbrc.2011.04.112] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 04/23/2011] [Indexed: 10/18/2022]
|