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Bianco L, Arrigo A, Antropoli A, Saladino A, Spiga I, Patricelli MG, Bandello F, Carrera P, Battaglia Parodi M. PRPH2-Associated Retinopathy: Novel Variants and Genotype-Phenotype Correlations. Ophthalmol Retina 2022; 7:450-461. [PMID: 36563963 DOI: 10.1016/j.oret.2022.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/01/2022] [Accepted: 12/13/2022] [Indexed: 12/25/2022]
Abstract
PURPOSE A broad spectrum of autosomal-dominant inherited retinal diseases (IRDs), ranging from mild macular pattern dystrophy to severe cone-rod degeneration, is associated with PRPH2 variants (peripherinopathies). We present detailed clinical and molecular characterization of patients affected by peripherinopathies, aiming to expand the mutational spectrum, and propose novel genotype-phenotype correlations. DESIGN Observational, retrospective case series. PARTICIPANTS Patients with an IRD related to a molecularly proven PRPH2 variant. METHODS Data from ophthalmic examinations and retinal imaging were collected for each follow-up visit. The standard imaging protocol included OCT, blue-light autofluorescence, near-infrared autofluorescence, and ultra-widefield fundus imaging. Genetic analysis was performed with a genomic approach by next-generation sequencing. MAIN OUTCOME MEASURES Results of ophthalmic examination, retinal imaging, and molecular genetic analysis. RESULTS Overall, a total of 19 patients with an IRD and a (likely) pathogenic PRPH2 variant were identified. Their age at presentation had a median of 48 years, whereas the symptomatic disease onset was in their 30s or 40s in 74% of cases. The median follow-up time was 4 years. Clinically, 6 patients were diagnosed with cone-rod dystrophy and 13 with pattern dystrophy. Among the 13 PRPH2 pathogenic variants identified in our cohort, 7 were missense, 3 nonsense, 2 frame shifting, and 1 splice site. Missense variants in the D2 loop were associated with cone-rod dystrophies and poor visual prognosis, whereas predicted loss-of-function alleles with pattern dystrophies and retention of a good visual function into adulthood. Overall, the following 7 variants were novel and never associated to a clinical phenotype: c.68delT, c.290G>A, c.413T>G, c.642C>G, c.702_706dupCAGTT, c.771_772delinsGA, and c.850C>G. CONCLUSIONS Here, we report the findings of a retrospective case series that provided a detailed clinical and molecular characterization of 19 patients harboring 13 different PRPH2 pathogenic variants, 7 of which were previously unreported, expanding the mutational spectrum of the PRPH2 gene. Loss-of-function variants might be preferentially associated with mild-pattern dystrophies, whereas missense dominant-negative variants might be preferentially associated with severely blinding cone-rod degenerations. Further studies are needed to better define the pathogenetic mechanisms and the functional effects of most variants to allow the development of successful gene therapy. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Lorenzo Bianco
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Alessandro Arrigo
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy.
| | - Alessio Antropoli
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Andrea Saladino
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Ivana Spiga
- Laboratory of Clinical Genomics, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | | | - Francesco Bandello
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Paola Carrera
- Laboratory of Clinical Genomics, IRCCS San Raffaele Scientific Institute, Milan, Italy; Unit of Genomics for Human Disease Diagnosis, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maurizio Battaglia Parodi
- Department of Ophthalmology, Vita-Salute San Raffaele University, IRCCS San Raffaele Scientific Institute, Milan, Italy
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Genetic and Phenotypic Landscape of PRPH2-Associated Retinal Dystrophy in Japan. Genes (Basel) 2021; 12:genes12111817. [PMID: 34828423 PMCID: PMC8624169 DOI: 10.3390/genes12111817] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/14/2021] [Accepted: 11/17/2021] [Indexed: 11/29/2022] Open
Abstract
Peripherin-2 (PRPH2) is one of the causative genes of inherited retinal dystrophy. While the gene is relatively common in Caucasians, reports from Asian ethnicities are limited. In the present study, we report 40 Japanese patients from 30 families with PRPH2-associated retinal dystrophy. We identified 17 distinct pathogenic or likely pathogenic variants using next-generation sequencing. Variants p.R142W and p.V200E were relatively common in the cohort. The age of onset was generally in the 40’s; however, some patients had earlier onset (age: 5 years). Visual acuity of the patients ranged from hand motion to 1.5 (Snellen equivalent 20/13). The patients showed variable phenotypes such as retinitis pigmentosa, cone-rod dystrophy, and macular dystrophy. Additionally, intrafamilial phenotypic variability was observed. Choroidal neovascularization was observed in three eyes of two patients with retinitis pigmentosa. The results demonstrate the genotypic and phenotypic variations of the disease in the Asian cohort.
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Nash BM, Wright DC, Grigg JR, Bennetts B, Jamieson RV. Retinal dystrophies, genomic applications in diagnosis and prospects for therapy. Transl Pediatr 2015; 4:139-63. [PMID: 26835369 PMCID: PMC4729094 DOI: 10.3978/j.issn.2224-4336.2015.04.03] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Retinal dystrophies (RDs) are degenerative diseases of the retina which have marked clinical and genetic heterogeneity. Common presentations among these disorders include night or colour blindness, tunnel vision and subsequent progression to complete blindness. The known causative disease genes have a variety of developmental and functional roles with mutations in more than 120 genes shown to be responsible for the phenotypes. In addition, mutations within the same gene have been shown to cause different disease phenotypes, even amongst affected individuals within the same family highlighting further levels of complexity. The known disease genes encode proteins involved in retinal cellular structures, phototransduction, the visual cycle, and photoreceptor structure or gene regulation. This review aims to demonstrate the high degree of genetic complexity in both the causative disease genes and their associated phenotypes, highlighting the more common clinical manifestation of retinitis pigmentosa (RP). The review also provides insight to recent advances in genomic molecular diagnosis and gene and cell-based therapies for the RDs.
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Affiliation(s)
- Benjamin M Nash
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - Dale C Wright
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - John R Grigg
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - Bruce Bennetts
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
| | - Robyn V Jamieson
- 1 Eye Genetics Research Group, Children's Medical Research Institute, University of Sydney, The Children's Hospital at Westmead and Save Sight Institute, Sydney, NSW, Australia ; 2 Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, NSW, Australia ; 3 Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, NSW, Australia
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Manes G, Guillaumie T, Vos WL, Devos A, Audo I, Zeitz C, Marquette V, Zanlonghi X, Defoort-Dhellemmes S, Puech B, Said SM, Sahel JA, Odent S, Dollfus H, Kaplan J, Dufier JL, Le Meur G, Weber M, Faivre L, Cohen FB, Béroud C, Picot MC, Verdier C, Sénéchal A, Baudoin C, Bocquet B, Findlay JB, Meunier I, Dhaenens CM, Hamel CP. High prevalence of PRPH2 in autosomal dominant retinitis pigmentosa in france and characterization of biochemical and clinical features. Am J Ophthalmol 2015; 159:302-14. [PMID: 25447119 DOI: 10.1016/j.ajo.2014.10.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/27/2014] [Accepted: 10/29/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE To assess the prevalence of PRPH2 in autosomal dominant retinitis pigmentosa (adRP), to report 6 novel mutations, to characterize the biochemical features of a recurrent novel mutation, and to study the clinical features of adRP patients. DESIGN Retrospective clinical and molecular genetic study. METHODS Clinical investigations included visual field testing, fundus examination, high-resolution spectral-domain optical coherence tomography (OCT), fundus autofluorescence imaging, and electroretinogram (ERG) recording. PRPH2 was screened by Sanger sequencing in a cohort of 310 French families with adRP. Peripherin-2 protein was produced in yeast and analyzed by Western blot. RESULTS We identified 15 mutations, including 6 novel and 9 previously reported changes in 32 families, accounting for a prevalence of 10.3% in this adRP population. We showed that a new recurrent p.Leu254Gln mutation leads to protein aggregation, suggesting abnormal folding. The clinical severity of the disease in examined patients was moderate with 78% of the eyes having 1-0.5 of visual acuity and 52% of the eyes retaining more than 50% of the visual field. Some patients characteristically showed vitelliform deposits or macular involvement. In some families, pericentral RP or macular dystrophy were found in family members while widespread RP was present in other members of the same families. CONCLUSIONS The mutations in PRPH2 account for 10.3% of adRP in the French population, which is higher than previously reported (0%-8%) This makes PRPH2 the second most frequent adRP gene after RHO in our series. PRPH2 mutations cause highly variable phenotypes and moderate forms of adRP, including mild cases, which could be underdiagnosed.
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Conley SM, Stuck MW, Burnett JL, Chakraborty D, Azadi S, Fliesler SJ, Naash MI. Insights into the mechanisms of macular degeneration associated with the R172W mutation in RDS. Hum Mol Genet 2014; 23:3102-14. [PMID: 24463884 DOI: 10.1093/hmg/ddu014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Mutations in the photoreceptor tetraspanin gene peripherin-2/retinal degeneration slow (PRPH2/RDS) cause both rod- and cone-dominant diseases. While rod-dominant diseases, such as autosomal dominant retinitis pigmentosa, are thought to arise due to haploinsufficiency caused by loss-of-function mutations, the mechanisms underlying PRPH2-associated cone-dominant diseases are unclear. Here we took advantage of a transgenic mouse line expressing an RDS mutant (R172W) known to cause macular degeneration (MD) in humans. To facilitate the study of cones in the heavily rod-dominant mouse retina, R172W mice were bred onto an Nrl(-/-) background (in which developing rods adopt a cone-like fate). In this model the R172W protein and the key RDS-binding partner, rod outer segment (OS) membrane protein 1 (ROM-1), were properly expressed and trafficked to cone OSs. However, the expression of R172W led to dominant defects in cone structure and function with equal effects on S- and M-cones. Furthermore, the expression of R172W in cones induced subtle alterations in RDS/ROM-1 complex assembly, specifically resulting in the formation of abnormal, large molecular weight ROM-1 complexes. Fundus imaging demonstrated that R172W mice developed severe clinical signs of disease nearly identical to those seen in human MD patients, including retinal degeneration, retinal pigment epithlium (RPE) defects and loss of the choriocapillaris. Collectively, these data identify a primary disease-causing molecular defect in cone cells and suggest that RDS-associated disease in patients may be a result of this defect coupled with secondary sequellae involving RPE and choriocapillaris cell loss.
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Affiliation(s)
- Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
| | - Michael W Stuck
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
| | - Justin L Burnett
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
| | - Dibyendu Chakraborty
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
| | - Seifollah Azadi
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
| | - Steven J Fliesler
- Research Service, Veterans Administration Western New York Healthcare System, Buffalo, NY 14215, USA Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, University at Buffalo-S.U.N.Y, Buffalo, NY 14215, USA
| | - Muna I Naash
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
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Novel GUCA1A mutations suggesting possible mechanisms of pathogenesis in cone, cone-rod, and macular dystrophy patients. BIOMED RESEARCH INTERNATIONAL 2013; 2013:517570. [PMID: 24024198 PMCID: PMC3759255 DOI: 10.1155/2013/517570] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 06/19/2013] [Indexed: 01/06/2023]
Abstract
Here, we report two novel GUCA1A (the gene for guanylate cyclase activating protein 1) mutations identified in unrelated Spanish families affected by autosomal dominant retinal degeneration (adRD) with cone and rod involvement. All patients from a three-generation adRD pedigree underwent detailed ophthalmic evaluation. Total genome scan using single-nucleotide polymorphisms and then the linkage analysis were undertaken on the pedigree. Haplotype analysis revealed a 55.37 Mb genomic interval cosegregating with the disease phenotype on chromosome 6p21.31-q15. Mutation screening of positional candidate genes found a heterozygous transition c.250C>T in exon 4 of GUCA1A, corresponding to a novel mutation p.L84F. A second missense mutation, c.320T>C (p.I107T), was detected by screening of the gene in a Spanish patients cohort. Using bioinformatics approach, we predicted that either haploinsufficiency or dominant-negative effect accompanied by creation of a novel function for the mutant protein is a possible mechanism of the disease due to c.250C>T and c.320T>C. Although additional functional studies are required, our data in relation to the c.250C>T mutation open the possibility that transacting factors binding to de novo created recognition site resulting in formation of aberrant splicing variant is a disease model which may be more widespread than previously recognized as a mechanism causing inherited RD.
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Chakraborty D, Rodgers KK, Conley SM, Naash MI. Structural characterization of the second intra-discal loop of the photoreceptor tetraspanin RDS. FEBS J 2012; 280:127-38. [PMID: 23121719 DOI: 10.1111/febs.12055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/20/2012] [Accepted: 10/26/2012] [Indexed: 11/26/2022]
Abstract
Vertebrate photoreceptors contain a unique tetraspanin protein known as 'retinal degeneration slow' (RDS). Mutations in the RDS gene have been identified in a variety of human retinal degenerative diseases, and more than 70% of these mutations are located in the second intra-discal (D2) loop, highlighting the importance of this region. Here we examined the conformational and thermal stability properties of the D2 loop of RDS, as well as interactions with ROM-1, a non-glycosylated homolog of RDS. The RDS D2 loop was expressed in Escherichia coli as a fusion protein with maltose binding protein (MBP). The fusion protein, referred to as MBP-D2, was purified to homogeneity. Circular dichroism spectroscopy showed that the wild-type (WT) D2 loop consists of approximately 21% α-helix, approximately 20% β-sheet and approximately 59% random coil. D2 loop fusion proteins carrying disease-causing mutations in RDS (e.g. R172W, C214S, N244H/K) were also examined, and conformational changes were observed (compared to wild-type D2). In particular, the C150S, C214S and N244H proteins showed significant reductions in α-helicity. However, the thermal stability of the mutants was unchanged compared to wild-type, and all the mutants were capable of interacting with ROM-1, indicating that this functional aspect of the isolated D2 loop remained intact in the mutants despite the observed conformational changes. An I-TASSER model of the RDS D2 loop predicted a structure consistent with the circular dichroism experiments and the structure of the conserved region of the D2 loop of other tetraspanin family members. These results provide significant insight into the mechanism of RDS complex formation and the disease process underlying RDS-associated retinal degeneration.
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Affiliation(s)
- Dibyendu Chakraborty
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73126-0901, USA
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Berger W, Kloeckener-Gruissem B, Neidhardt J. The molecular basis of human retinal and vitreoretinal diseases. Prog Retin Eye Res 2010; 29:335-75. [PMID: 20362068 DOI: 10.1016/j.preteyeres.2010.03.004] [Citation(s) in RCA: 392] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
During the last two to three decades, a large body of work has revealed the molecular basis of many human disorders, including retinal and vitreoretinal degenerations and dysfunctions. Although belonging to the group of orphan diseases, they affect probably more than two million people worldwide. Most excitingly, treatment of a particular form of congenital retinal degeneration is now possible. A major advantage for treatment is the unique structure and accessibility of the eye and its different components, including the vitreous and retina. Knowledge of the many different eye diseases affecting retinal structure and function (night and colour blindness, retinitis pigmentosa, cone and cone rod dystrophies, photoreceptor dysfunctions, as well as vitreoretinal traits) is critical for future therapeutic development. We have attempted to present a comprehensive picture of these disorders, including biological, clinical, genetic and molecular information. The structural organization of the review leads the reader through non-syndromic and syndromic forms of (i) rod dominated diseases, (ii) cone dominated diseases, (iii) generalized retinal degenerations and (iv) vitreoretinal disorders, caused by mutations in more than 165 genes. Clinical variability and genetic heterogeneity have an important impact on genetic testing and counselling of affected families. As phenotypes do not always correlate with the respective genotypes, it is of utmost importance that clinicians, geneticists, counsellors, diagnostic laboratories and basic researchers understand the relationships between phenotypic manifestations and specific genes, as well as mutations and pathophysiologic mechanisms. We discuss future perspectives.
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Affiliation(s)
- Wolfgang Berger
- Division of Medical Molecular Genetics and Gene Diagnostics, Institute of Medical Genetics, University of Zurich, Schorenstrasse 16, CH-8603 Schwerzenbach, Switzerland.
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Conley SM, Stricker HM, Naash MI. Biochemical analysis of phenotypic diversity associated with mutations in codon 244 of the retinal degeneration slow gene. Biochemistry 2010; 49:905-11. [PMID: 20055437 DOI: 10.1021/bi901622w] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mutations in the protein product of the retinal degeneration slow (RDS) gene cause both rod-dominant retinitis pigmentosa and different forms of cone-dominant macular dystrophies. In particular, mutations in codon 244 can cause either of these types of disease. In this study, we examine the biochemical effects of N244H and N244K in an effort to understand the mechanism underlying rod- and cone-dominant defects, respectively. COS-1 cells were cotransfected with either wild-type (WT) RDS or RDS containing an N244H or N244K mutation along with its binding partner, ROM-1 (rod outer segment membrane protein 1). Cell extracts were analyzed for mutant protein stability by Western blot, and localization was examined by immunocytochemistry. Interactions between transfected proteins were assessed by reciprocal co-immunoprecipitation, and nonreducing velocity sedimentation was used to identify the pattern of RDS complex assembly. Interactions were confirmed using GST fusion constructs of WT and mutant RDS in GST pull-down assays from WT mouse retinal extract. In COS-1 cells, recombinant N244H RDS had a weakened ability to assemble into higher-order complexes but retained the ability to co-immunoprecipitate with ROM-1 as well as localize properly throughout the cells. In contrast, recombinant N244K protein did not associate with ROM-1, showed signs of protein aggregation, and colocalized with an ER marker. These experiments support the hypothesis that RDS mutations that interrupt higher-order oligomer formation but still interact with ROM-1 and fold properly in membranes may cause dominant, gain-of-function disease phenotypes while mutations that cause RDS misfolding (and thus incorrect trafficking and assembly) may be associated with a loss-of-function haploinsufficiency phenotype.
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Affiliation(s)
- Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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Van Ghelue M, Eriksen HL, Ponjavic V, Fagerheim T, Andréasson S, Forsman-Semb K, Sandgren O, Holmgren G, Tranebjærg L. Autosomal dominant cone-rod dystrophy due to a missense mutation (R838C) in the guanylate cyclase 2D gene (GUCY2D) with preserved rod function in one branch of the family. Ophthalmic Genet 2009. [DOI: 10.1076/1381-6810(200012)2141-hft197] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Abd El-Aziz MM, El-Ashry MF, Barragan I, Marcos I, Borrego S, Antiñolo G, Bhattacharya SS. Molecular Genetic Analysis of Two Functional Candidate Genes in the Autosomal Recessive Retinitis Pigmentosa, RP25, Locus. Curr Eye Res 2009; 30:1081-7. [PMID: 16354621 DOI: 10.1080/02713680500351039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To identify the disease gene in five Spanish families with autosomal recessive retinitis pigmentosa (arRP) linked to the RP25 locus. Two candidate genes, EEF1A1 and IMPG1, were selected from the region between D6S280 and D6S1644 markers where the families are linked. The genes were selected as good candidates on the basis of their function, tissue expression pattern, and/or genetic data. METHODS A molecular genetic study was performed on DNA extracted from one parent and one affected member of each studied family. The coding exons, splice sites, and the 5' UTR of the genes were amplified by polymerase chain reaction (PCR). For mutation detection, direct sequence analysis was performed using the ABI 3100 automated sequencer. Segregation of an IMPG1 single nucleotide polymorphism (SNP) in all the families studied was analyzed by restriction enzyme digest of the amplified gene fragments. RESULTS In total, 15 SNPs were identified of which 7 were novel. Of the identified SNPs, one was insertion, two were deletions, five were intronic, six were missense, and one was located in the 5' UTR. These changes, however, were also identified in unaffected members of the families and/or 50 control Caucasians. The examined known IMPG1 SNP was not segregating with the disease phenotype but was correlating with the genetic data in all families studied. CONCLUSIONS Our results indicate that neither EEF1A1 nor IMPG1 could be responsible for RP25 in the studied families due to absence of any pathogenic variants. However, it is important to notice that the methodology used in this study cannot detect larger deletions that lie outside the screened regions or primer site mutations that exist in the heterozygous state. A role of both genes in other inherited forms of RP and/or retinal degenerations needs to be elucidated.
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Affiliation(s)
- Mai M Abd El-Aziz
- Department of Ophthalmology, Tanta University Hospital, Tanta, Egypt.
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Renner AB, Fiebig BS, Weber BHF, Wissinger B, Andreasson S, Gal A, Cropp E, Kohl S, Kellner U. Phenotypic variability and long-term follow-up of patients with known and novel PRPH2/RDS gene mutations. Am J Ophthalmol 2009; 147:518-530.e1. [PMID: 19038374 DOI: 10.1016/j.ajo.2008.09.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 08/30/2008] [Accepted: 09/02/2008] [Indexed: 11/17/2022]
Abstract
PURPOSE To describe the phenotypic variability in 22 patients with PRPH2 gene mutations and to report six novel mutations. DESIGN Retrospective study. METHODS Clinical examinations included color vision testing, perimetry, fundus autofluorescence (FAF), fluorescein angiography, optical coherence tomography (OCT), and full-field and multifocal electroretinography (International Society for Clinical Electrophysiology of Vision standards). Blood samples were taken for deoxyribonucleic acid (DNA) extraction and mutation screening was performed by direct sequencing of polymerase chain reaction amplicons. RESULTS Eleven unrelated patients and four unrelated families each with two affected members as well as one family with three affected members were examined. Diagnoses included central areolar choroidal dystrophy (CACD; n = 9), autosomal dominant retinitis pigmentosa (adRP; n = 7), adult vitelliform macular dystrophy (n = 3), and cone-rod dystrophy (CRD; n = 3). FAF was abnormal in all patients and showed various retinal pigment epithelial alterations, in CACD with a speckled FAF pattern. OCT revealed reduced retinal thickness, mostly in CACD, subretinal lesions, macula edema, or was normal. Follow-up (n = 12; range, 1.3 to 26 years) showed a slow progression of the retinal dystrophies. DNA testing revealed previously reported PRPH2 mutations in two families and eight individuals of whom two carried the same mutation but had different phenotypes. Novel PRPH2 mutations were detected in two families with adRP, in identical twins with CACD, and in each of an individual with CACD, CRD, and adRP. CONCLUSIONS This series describes the broad spectrum of phenotypes associated with PRPH2 mutations. FAF and OCT are helpful tools for diagnosis and evaluation of disease progression. We report novel PRPH2 mutations in patients with CACD, CRD, and adRP.
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Affiliation(s)
- Agnes B Renner
- Augenklinik, Charité-Universitätsmedizin Berlin, Germany.
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Abstract
Peripherin/rds is an integral membrane glycoprotein, mainly located in the rod and cone outer segments. The relevance of this protein to photoreceptor outer segment morphology was first demonstrated in retinal degeneration slow (rds) mice. Thus far, over 90 human peripherin/RDS gene mutations have been identified. These mutations have been associated with a variety of retinal dystrophies, in which there is a remarkable inter- and intrafamilial variation of the retinal phenotype. In this paper, we discuss the characteristics of the peripherin/RDS gene and its protein product. An overview is presented of the broad spectrum of clinical phenotypes caused by human peripherin/RDS gene mutations, ranging from various macular dystrophies to widespread forms of retinal dystrophy such as retinitis pigmentosa. Finally, we review the proposed genotype-phenotype correlation and the pathophysiologic mechanisms underlying this group of retinal dystrophies.
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Conley S, Nour M, Fliesler SJ, Naash MI. Late-onset cone photoreceptor degeneration induced by R172W mutation in Rds and partial rescue by gene supplementation. Invest Ophthalmol Vis Sci 2007; 48:5397-407. [PMID: 18055786 PMCID: PMC2263142 DOI: 10.1167/iovs.07-0663] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE R172W is a common mutation in the human retinal degeneration slow (RDS) gene, associated with a late-onset dominant macular dystrophy. In this study, the authors characterized a mouse model that closely mimics the human phenotype and tested the feasibility of gene supplementation as a disease treatment strategy. METHODS Transgenic mouse lines carrying the R172W mutation were generated. The retinal phenotype associated with this mutation in a low-expresser line (L-R172W) was examined, both structurally (histology with correlative immunohistochemistry) and functionally (electroretinography). By examining animals over time and with various rds genetic backgrounds, the authors evaluated the dominance of the defect. To assess the efficacy of gene transfer therapy as a treatment for this defect, a previously characterized transgenic line expressing the normal mouse peripherin/Rds (NMP) was crossed with a higher-expresser Rds line harboring the R172W mutation (H-R172W). Functional, structural, and biochemical analyses were used to assess rescue of the retinal disease phenotype. RESULTS In the wild-type (WT) background, L-R172W mice exhibited late-onset (12-month) dominant cone degeneration without any apparent effect on rods. The degeneration was slightly accelerated (9 months) in the rds(+/-) background. L-R172W retinas did not form outer segments in the absence of endogenous Rds. With use of the H-R172W line on an rds(+/-) background for proof-of-principle genetic supplementation studies, the NMP transgene product rescued rod and cone functional defects and supported outer segment integrity up to 3 months of age, but the rescue effect did not persist in older (11-month) animals. CONCLUSIONS The R172W mutation leads to dominant cone degeneration in the mouse model, regardless of the expression level of the transgene. In contrast, effects of the mutation on rods are dose dependent, underscoring the usefulness of the L-R172W line as a faithful model of the human phenotype. This model may prove helpful in future studies on the mechanisms of cone degeneration and for elucidating the different roles of Rds in rods and cones. This study provides evidence that Rds genetic supplementation can be used to partially rescue visual function. Although this strategy is capable of rescuing haploinsufficiency, it does not rescue the long-term degeneration associated with a gain-of-function mutation.
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Affiliation(s)
- Shannon Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - May Nour
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Steven J. Fliesler
- Department of Ophthalmology, St. Louis University School of Medicine, St. Louis, Missouri
- Department of Pharmacological & Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri
| | - Muna I. Naash
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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Ismail M, Abid A, Anwar K, Qasim Mehdi S, Khaliq S. Refinement of the locus for autosomal recessive cone-rod dystrophy (CORD8) linked to chromosome 1q23-q24 in a Pakistani family and exclusion of candidate genes. J Hum Genet 2006; 51:827-831. [PMID: 16897189 DOI: 10.1007/s10038-006-0028-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Accepted: 06/05/2006] [Indexed: 11/29/2022]
Abstract
Cone-rod retinal dystrophy (CORD) characteristically leads to early impairment of vision due to the simultaneous involvement of both cone and rod photoreceptor cells. Several loci/genes have been identified for CORD, including the cone-rod dystrophy (CORD8) locus [OMIM#605549] identified for a Pakistani family. All members of this family underwent detailed clinical re-examination to determine the nature of the dystrophy. All affected individuals suffered from bilateral CORD8 with an autosomal recessive mode of inheritance. The CORD8 locus, mapped on chromosome 1q12-q24, consisted of a very large critical disease region of 21 cM. Analysis with more recently available microsatellite markers within the reported region showed heterozygosity with some of the new markers, and the crossovers lead to a refinement of the disease region from 21 to 11.53 cM. Mutation screening has excluded some of the candidate genes in the region. The disease phenotype of this family could be due to a mutation in a novel gene located within the refined CORD8 locus.
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Affiliation(s)
- Muhammad Ismail
- Biomedical and Genetic Engineering Division, Dr. A. Q. Khan Research Laboratories, GPO Box 2891, 25 Mauve Area, Islamabad, 44000, Pakistan
| | - Aiysha Abid
- Biomedical and Genetic Engineering Division, Dr. A. Q. Khan Research Laboratories, GPO Box 2891, 25 Mauve Area, Islamabad, 44000, Pakistan
| | - Khalid Anwar
- Biomedical and Genetic Engineering Division, Dr. A. Q. Khan Research Laboratories, GPO Box 2891, 25 Mauve Area, Islamabad, 44000, Pakistan
| | - S Qasim Mehdi
- Biomedical and Genetic Engineering Division, Dr. A. Q. Khan Research Laboratories, GPO Box 2891, 25 Mauve Area, Islamabad, 44000, Pakistan.
| | - Shagufta Khaliq
- Biomedical and Genetic Engineering Division, Dr. A. Q. Khan Research Laboratories, GPO Box 2891, 25 Mauve Area, Islamabad, 44000, Pakistan
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17
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Michaelides M, Hardcastle AJ, Hunt DM, Moore AT. Progressive cone and cone-rod dystrophies: phenotypes and underlying molecular genetic basis. Surv Ophthalmol 2006; 51:232-58. [PMID: 16644365 DOI: 10.1016/j.survophthal.2006.02.007] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The cone and cone-rod dystrophies form part of a heterogeneous group of retinal disorders that are an important cause of visual impairment in children and adults. There have been considerable advances made in recent years in our understanding of the pathogenesis of these retinal dystrophies, with many of the chromosomal loci and causative genes having now been identified. Mutations in 12 genes, including GUCA1A, peripherin/RDS, ABCA4 and RPGR, have been described to date; and in many cases detailed functional assessment of the effects of the encoded mutant proteins has been undertaken. This improved knowledge of disease mechanisms has raised the possibility of future treatments for these disorders, for which there are no specific therapies available at the present time.
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18
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Weleber RG, Gregory-Evans K. Retinitis Pigmentosa and Allied Disorders. Retina 2006. [DOI: 10.1016/b978-0-323-02598-0.50023-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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19
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Newbold RJ, Deery EC, Payne AM, Wilkie SE, Hunt DM, Warren MJ. Guanylate cyclase activating proteins, guanylate cyclase and disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 514:411-38. [PMID: 12596936 DOI: 10.1007/978-1-4615-0121-3_25] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
A range of cone and cone-rod dystrophies (CORD) have been observed in man, caused by mutations in retinal guanylate cyclase 1 (RetGC1) and guanylate cyclase activating protein 1 (GCAP 1). The CORD causing mutations in RetGC1 are located at a mutation "hot spot" within the dimerisation domain, where R838 is the key residue. Three disease causing mutations have been found in human GCAP1, resulting in cone or cone-rod degeneration. All three mutations are dominant in their effect although the mechanism by which the P50L mutation exerts its influence remains unclear although it might act due to a haplo-insufficiency, arising from increased susceptibility to protease activity and increased thermal instability. In contrast, loss of Ca2+ sensitivity appears to be the main cause of the diseased state for the Y99C and E155G mutations. The cone and cone-rod dystrophies that are caused by mutations in RetGC1 or GCAP1 arise from a perturbation of the delicate balance of Ca2+ and cGMP within the photoreceptor cells and it is this disruption that is believed to cause cell death. The diseases caused by mutations in RetGC1 and GCAP1 prominently affect cones, consistent with the higher concentrations of these proteins in cone cells.
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Affiliation(s)
- Richard J Newbold
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK
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20
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Sohocki MM, Daiger SP, Bowne SJ, Rodriquez JA, Northrup H, Heckenlively JR, Birch DG, Mintz-Hittner H, Ruiz RS, Lewis RA, Saperstein DA, Sullivan LS. Prevalence of mutations causing retinitis pigmentosa and other inherited retinopathies. Hum Mutat 2001; 17:42-51. [PMID: 11139241 PMCID: PMC2585107 DOI: 10.1002/1098-1004(2001)17:1<42::aid-humu5>3.0.co;2-k] [Citation(s) in RCA: 240] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Inherited retinopathies are a genetically and phenotypically heterogeneous group of diseases affecting approximately one in 2000 individuals worldwide. For the past 10 years, the Laboratory for Molecular Diagnosis of Inherited Eye Diseases (LMDIED) at the University of Texas-Houston Health Science Center has screened subjects ascertained in the United States and Canada for mutations in genes causing dominant and recessive autosomal retinopathies. A combination of single strand conformational analysis (SSCA) and direct sequencing of five genes (rhodopsin, peripherin/RDS, RP1, CRX, and AIPL1) identified the disease-causing mutation in approximately one-third of subjects with autosomal dominant retinitis pigmentosa (adRP) or with autosomal dominant cone-rod dystrophy (adCORD). In addition, the causative mutation was identified in 15% of subjects with Leber congenital amaurosis (LCA). Overall, we report identification of the causative mutation in 105 of 506 (21%) of unrelated subjects (probands) tested; we report five previously unreported mutations in rhodopsin, two in peripherin/RDS, and one previously unreported mutation in the cone-rod homeobox gene, CRX. Based on this large survey, the prevalence of disease-causing mutations in each of these genes within specific disease categories is estimated. These data are useful in estimating the frequency of specific mutations and in selecting individuals and families for mutation-specific studies.
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Affiliation(s)
- Melanie M. Sohocki
- Human Genetics Center, School of Public Health, University of Texas-Houston Health Science Center, Houston, Texas
| | - Stephen P. Daiger
- Human Genetics Center, School of Public Health, University of Texas-Houston Health Science Center, Houston, Texas
- Department of Ophthalmology and Visual Science, Medical School, University of Texas-Houston Health Science Center, Houston, Texas
| | - Sara J. Bowne
- Human Genetics Center, School of Public Health, University of Texas-Houston Health Science Center, Houston, Texas
| | - Joseph A. Rodriquez
- Department of Pediatrics, Medical School, University of Texas-Houston Health Science Center, Houston, Texas
| | - Hope Northrup
- Department of Pediatrics, Medical School, University of Texas-Houston Health Science Center, Houston, Texas
| | | | | | - Helen Mintz-Hittner
- Department of Ophthalmology and Visual Science, Medical School, University of Texas-Houston Health Science Center, Houston, Texas
| | - Richard S. Ruiz
- Department of Ophthalmology and Visual Science, Medical School, University of Texas-Houston Health Science Center, Houston, Texas
| | - Richard A. Lewis
- Departments of Ophthalmology and Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas
| | | | - Lori S. Sullivan
- Human Genetics Center, School of Public Health, University of Texas-Houston Health Science Center, Houston, Texas
- Department of Ophthalmology and Visual Science, Medical School, University of Texas-Houston Health Science Center, Houston, Texas
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21
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Felbor U, Schilling H, Weber BH. Adult vitelliform macular dystrophy is frequently associated with mutations in the peripherin/RDS gene. Hum Mutat 2000; 10:301-9. [PMID: 9338584 DOI: 10.1002/(sici)1098-1004(1997)10:4<301::aid-humu6>3.0.co;2-j] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mutations in the peripherin/RDS gene, which encodes a photoreceptor-specific membrane glycoprotein, have been identified in a variety of retinal phenotypes. However, the mechanisms by which specific mutations in this gene can cause typical features of retinal dystrophies clinically as distinct as retinitis pigmentosa or macular degeneration are still unknown. Recently, a single case of adult vitelliform macular dystrophy (AVMD) has been associated with a Y258Stop mutation. To assess the frequency of peripherin/RDS mutations in the clinically heterogeneous group of AVMD, we analyzed the entire coding region of the gene in 28 unrelated patients. We identified five novel mutations including two presumed null allele mutations. Thus, our results demonstrate that a significant portion of AVMD patients (18%) carry point mutations in peripherin/RDS, suggesting that this gene is frequently involved in the pathogenesis of this macular disorder. In addition, this study shows that the variable phenotypes in AVMD are due, at least in part, to genetic heterogeneity and are likely to be caused by mutations in disease genes thus far unknown.
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Affiliation(s)
- U Felbor
- Institut für Humangenetik, Universität Würzburg, Germany
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22
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Sohocki MM, Sullivan LS, Mintz-Hittner HA, Birch D, Heckenlively JR, Freund CL, McInnes RR, Daiger SP. A range of clinical phenotypes associated with mutations in CRX, a photoreceptor transcription-factor gene. Am J Hum Genet 1998; 63:1307-15. [PMID: 9792858 PMCID: PMC1377541 DOI: 10.1086/302101] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Mutations in the retinal-expressed gene CRX (cone-rod homeobox gene) have been associated with dominant cone-rod dystrophy and with de novo Leber congenital amaurosis. However, CRX is a transcription factor for several retinal genes, including the opsins and the gene for interphotoreceptor retinoid binding protein. Because loss of CRX function could alter the expression of a number of other retinal proteins, we screened for mutations in the CRX gene in probands with a range of degenerative retinal diseases. Of the 294 unrelated individuals screened, we identified four CRX mutations in families with clinical diagnoses of autosomal dominant cone-rod dystrophy, late-onset dominant retinitis pigmentosa, or dominant congenital Leber amaurosis (early-onset retinitis pigmentosa), and we identified four additional benign sequence variants. These findings imply that CRX mutations may be associated with a wide range of clinical phenotypes, including congenital retinal dystrophy (Leber) and progressive diseases such as cone-rod dystrophy or retinitis pigmentosa, with a wide range of onset.
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Affiliation(s)
- M M Sohocki
- Human Genetics Center, School of Public Health, The University of Texas Health Science Center, Houston, TX 77225-0334, USA
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23
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Perrault I, Rozet JM, Gerber S, Kelsell RE, Souied E, Cabot A, Hunt DM, Munnich A, Kaplan J. A retGC-1 mutation in autosomal dominant cone-rod dystrophy. Am J Hum Genet 1998; 63:651-4. [PMID: 9683616 PMCID: PMC1377325 DOI: 10.1086/301985] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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24
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Kelsell RE, Gregory-Evans K, Payne AM, Perrault I, Kaplan J, Yang RB, Garbers DL, Bird AC, Moore AT, Hunt DM. Mutations in the retinal guanylate cyclase (RETGC-1) gene in dominant cone-rod dystrophy. Hum Mol Genet 1998; 7:1179-84. [PMID: 9618177 DOI: 10.1093/hmg/7.7.1179] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dominant cone-rod dystrophy gene CORD6 has previously been mapped to within an 8 cM interval on chromosome 17p12-p13. The retinal-specific guanylate cyclase gene (RETGC-1), which maps to within this genetic interval and previously was implicated in Leber's congenital amaurosis, was screened for mutations within this family and in a panel of small families and individuals with various cone and cone- rod dystrophy phenotypes. A missense mutation (E837D) was identified in affected members of the CORD6 family, as well as a second missense mutation (R838C) in three other families with dominant cone-rod dystrophy. RETGC-1 is only the fourth gene to be implicated in cone-rod dystrophy and this is the first report of dominant mutations in this gene.
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Affiliation(s)
- R E Kelsell
- Department of Molecular Genetics, Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, UK
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25
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Kelsell RE, Gregory-Evans K, Gregory-Evans CY, Holder GE, Jay MR, Weber BH, Moore AT, Bird AC, Hunt DM. Localization of a gene (CORD7) for a dominant cone-rod dystrophy to chromosome 6q. Am J Hum Genet 1998; 63:274-9. [PMID: 9634506 PMCID: PMC1377229 DOI: 10.1086/301905] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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26
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Klaver CC, Kliffen M, van Duijn CM, Hofman A, Cruts M, Grobbee DE, van Broeckhoven C, de Jong PT. Genetic association of apolipoprotein E with age-related macular degeneration. Am J Hum Genet 1998; 63:200-6. [PMID: 9634502 PMCID: PMC1377225 DOI: 10.1086/301901] [Citation(s) in RCA: 299] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most common geriatric eye disorder leading to blindness and is characterized by degeneration of the neuroepithelium in the macular area of the eye. Apolipoprotein E (apoE), the major apolipoprotein of the CNS and an important regulator of cholesterol and lipid transport, appears to be associated with neurodegeneration. The apoE gene (APOE) polymorphism is a strong risk factor for various neurodegenerative diseases, and the apoE protein has been demonstrated in disease-associated lesions of these disorders. Hypothesizing that variants of APOE act as a potential risk factor for AMD, we performed a genetic-association study among 88 AMD cases and 901 controls derived from the population-based Rotterdam Study in the Netherlands. The APOE polymorphism showed a significant association with the risk for AMD; the APOE epsilon4 allele was associated with a decreased risk (odds ratio 0.43 [95% confidence interval 0.21-0. 88]), and the epsilon2 allele was associated with a slightly increased risk of AMD (odds ratio 1.5 [95% confidence interval 0.8-2. 82]). To investigate whether apoE is directly involved in the pathogenesis of AMD, we studied apoE immunoreactivity in 15 AMD and 10 control maculae and found that apoE staining was consistently present in the disease-associated deposits in AMD-maculae-that is, drusen and basal laminar deposit. Our results suggest that APOE is a susceptibility gene for AMD.
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Affiliation(s)
- C C Klaver
- Department of Epidemiology, Erasmus University Medical School, Rotterdam, The Netherlands
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27
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Bareil C, Hamel C, Arnaud B, Demaille J, Claustres M. A complex allele (1064delTC and IVS2 + 22ins7) in the peripherin/RDS gene in retinitis pigmentosa with macular dystrophy. Ophthalmic Genet 1997; 18:129-38. [PMID: 9361310 DOI: 10.3109/13816819709057126] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Because mutations in the peripherin/RDS gene have been found in retinal dystrophies involving the macula, we examined various types of macular dystrophies from southern France to characterize sequence variations that may be associated with these conditions. DNA sequence analysis of the full coding and flanking regions of the peripherin/RDS gene was performed in fifteen unrelated patients with different types of macular dystrophy, including nine with retinitis pigmentosa (RP). Of the 15 probands with macular disease, two (13.3%) were found to carry a mutation in the peripherin/RDS gene. The recurrent mutation P216S was identified in a pedigree with autosomal dominant RP. A previously unreported complex allele (1064delTC associated with IVS2 + 22ins7) that is predicted to result in the premature termination of peripherin/RDS synthesis was identified in a sporadic case of macular atrophy with RP. We also report eight novel neutral sequence variations in the peripherin/RDS gene, most of them found in the 3' untranslated part of the gene.
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Affiliation(s)
- C Bareil
- Laboratoire de Biochimie Génétique, University and Hospital of Montpellier, France
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28
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Kohl S, Christ-Adler M, Apfelstedt-Sylla E, Kellner U, Eckstein A, Zrenner E, Wissinger B. RDS/peripherin gene mutations are frequent causes of central retinal dystrophies. J Med Genet 1997; 34:620-6. [PMID: 9279751 PMCID: PMC1051021 DOI: 10.1136/jmg.34.8.620] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Patients from 76 independent families with various forms of mostly central retinal dystrophies were screened for mutations in the RDS/peripherin gene by means of SSCP analysis and direct DNA sequencing. Two nonsense mutations (Gln239ter, Tyr285ter), five missense mutations (Arg172Trp, Lys197Glu, Gly208Asp, Trp246Arg, Ser289Leu), and one single base insertion (Gly208insG), heterozygous in all cases, were detected. Only one of these mutations, Arg172Trp, has been reported previously. Cosegregation of the mutation with the disease phenotype could be established in selected families. Other missense mutations were excluded from a panel of 55-75 control subjects. The patients showed remarkable variation in phenotype and disease expression not only between cases with different mutations but also between affected members of the same family. This study indicates that RDS/peripherin mutations are a frequent cause of various types of central retinal dystrophies and that the RDS/peripherin gene exhibits a broad spectrum of allelic mutations. Comparative analysis of known mutations allowed us to hypothesise that the deleterious effect of RDS/peripherin gene mutations is the result of different molecular mechanisms.
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Affiliation(s)
- S Kohl
- Universitäts-Augenklinik Tübingen, Germany
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29
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Cheng T, al Ubaidi MR, Naash MI. Structural and developmental analysis of the mouse peripherin/rds gene. SOMATIC CELL AND MOLECULAR GENETICS 1997; 23:165-83. [PMID: 9330629 DOI: 10.1007/bf02721369] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mutations in the peripherin/rds gene have been reported to be associated with different forms of human autosomal dominant retinitis pigmentosa (ADRP) and macular degeneration (MD). To better understand the disruptive role of these mutations, knowledge of the structure-function relationship of the peripherin/rds gene is needed. To facilitate that, genomic clones encoding the mouse gene were isolated using bovine cDNA sequences as probes. Sequence analysis of clone lambda 6-1-1, that contained the entire coding sequence for the mouse peripherin/rds, yielded the exon-intron organization of the gene. The gene is composed of three exons (581, 247, and 213 bp) and two introns with the first and second introns 8.6 kb and 3.7 kb in size, respectively. Two major (1.6 and 2.7 kb) and three minor (4.0, 5.5, 6.5 kb) transcripts were detected on RNA blots. The major transcripts first appeared in the brain at embryonic day 13 and in the retina at postnatal day 1. Transcripts were missing in brain and eye of mice at embryonic day 15. Several transcription start sites were mapped within 26 nucleotides approximately 200 bp upstream from the translation initiation site. However, transcripts varied in the lengths of their 3' untranslated portion as a result of the utilization of different polyadenylation signals.
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Affiliation(s)
- T Cheng
- Department of Genetics, University of Illinois at Chicago, USA
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30
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Fishman GA, Stone EM, Alexander KR, Gilbert LD, Derlacki DJ, Butler NS. Serine-27-phenylalanine mutation within the peripherin/RDS gene in a family with cone dystrophy. Ophthalmology 1997; 104:299-306. [PMID: 9052636 DOI: 10.1016/s0161-6420(97)30320-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
PURPOSE To evaluate the clinical and electrophysiologic findings in a family with two heterozygous sequence changes in the peripherin-retinal degeneration slow (RDS) gene. METHODS A family study was done of a pedigree obtained by screening for rhodopsin, peripherin/RDS, or rom-1 gene mutations in probands from families with hereditary retinal diseases. The patients consisted of three affected and four unaffected members from a family with cone dystrophy. Ophthalmoscopy, visual field testing, electroretinography, and DNA analysis were performed. RESULTS Denaturing gradient gel electrophoresis showed the presence of two different sequence changes in the RDS genes of this family. In three members with a retinal disease, the authors observed the substitution of phenylalanine for serine in codon 27 (serine-27-phenylalanine). The clinical and functional findings in these three patients were most consistent with autosomal-dominant cone dystrophy. Three other family members, unaffected with retinal disease, were found to show a substitution of serine for cysteine in codon 72 of the peripherin protein. CONCLUSION A peripherin/RDS sequence change may produce a cone dystrophy with minimal ophthalmoscopic changes in the macula and limited peripheral degenerative changes. Caution is warranted to avoid ascribing nondisease-causing sequence polymorphisms in candidate genes as responsible for determining the development of a retinal disease phenotype.
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Affiliation(s)
- G A Fishman
- Department of Ophthalmology and Visual Sciences, University of Illinois, Chicago College of Medicine 60612, USA
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31
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Moore AT, Evans K. Molecular genetics of central retinal dystrophies. AUSTRALIAN AND NEW ZEALAND JOURNAL OF OPHTHALMOLOGY 1996; 24:189-98. [PMID: 8913120 DOI: 10.1111/j.1442-9071.1996.tb01580.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A range of chorioretinal dystrophies that principally affect the central retina have recently been associated with either specific genetic mutations or mapped to refined genomic loci. Mutations of two genes, peripherin/RDS (chromosome 6p) and TIMP3 (chromosome 22q) have been shown to be of particular importance to this group of disorders. Other conditions such as Stargardt's disease, Best's disease, pattern dystrophy, cone dystrophy and cone-rod dystrophy have been mapped to different regions of the genome, however the underlying genetic mutations await identification. Molecular genetic diagnostic techniques are now available for a number of central choroidoretinal dystrophies allowing for earlier, accurate diagnosis and laying the groundwork for future studies of potential therapeutic protocols.
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Affiliation(s)
- A T Moore
- Ophthalmology Department, Addenbrookes Hospital, Cambridge, United Kingdom
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32
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Keen TJ, Inglehearn CF. Mutations and polymorphisms in the human peripherin-RDS gene and their involvement in inherited retinal degeneration. Hum Mutat 1996; 8:297-303. [PMID: 8956033 DOI: 10.1002/(sici)1098-1004(1996)8:4<297::aid-humu1>3.0.co;2-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The RDS gene codes for the protein peripherin-RDS, which is an integral membrane glycoprotein found in the outer segment of both rod and cone photoreceptor cells. It is thought to function as a structural protein involved in the maintenance of the flattened form of the disc lamellae. The RDS gene has been implicated in the mouse phenotype retinal degeneration slow, and mutations in the human homologue are now known to be associated with both central and peripheral retinal degenerations. In all, 43 sequence variants have been described in the human gene, including 30 missense mutations, two single base substitutions producing termination codons, 7 small in-frame deletions, and 4 insertion/ deletion events, which break the reading frame. Of these, 39 are associated with retinal phenotypes, which can be grouped into four broad categories: dominant retinitis pigmentosa, progressive macular degeneration, digenic RP, and pattern dystrophies. The mutations underlying dominant RP and severe macular degeneration are largely missense or small in-frame deletions in a large intradiscal loop between the third and fourth transmembrane domains. In contrast, those associated with the milder pattern phenotypes or with digenic RP are scattered more evenly through the gene and are often nonsense mutations. This observation correlates with the hypothesis that the large loop is an important site of interaction between RDS molecules and other protein components in the disc.
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Affiliation(s)
- T J Keen
- Department of Molecular Genetics, University College London, UK
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