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van Genderen MM, Bijveld MMC, Claassen YB, Florijn RJ, Pearring JN, Meire FM, McCall MA, Riemslag FCC, Gregg RG, Bergen AAB, Kamermans M. Mutations in TRPM1 are a common cause of complete congenital stationary night blindness. Am J Hum Genet 2009; 85:730-6. [PMID: 19896109 DOI: 10.1016/j.ajhg.2009.10.012] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2009] [Revised: 10/16/2009] [Accepted: 10/16/2009] [Indexed: 11/19/2022] Open
Abstract
Congenital stationary night blindness (CSNB) is a clinically and genetically heterogeneous group of retinal disorders characterized by nonprogressive impaired night vision and variable decreased visual acuity. We report here that six out of eight female probands with autosomal-recessive complete CSNB (cCSNB) had mutations in TRPM1, a retinal transient receptor potential (TRP) cation channel gene. These data suggest that TRMP1 mutations are a major cause of autosomal-recessive CSNB in individuals of European ancestry. We localized TRPM1 in human retina to the ON bipolar cell dendrites in the outer plexifom layer. Our results suggest that in humans, TRPM1 is the channel gated by the mGluR6 (GRM6) signaling cascade, which results in the light-evoked response of ON bipolar cells. Finally, we showed that detailed electroretinography is an effective way to discriminate among patients with mutations in either TRPM1 or GRM6, another autosomal-recessive cCSNB disease gene. These results add to the growing importance of the diverse group of TRP channels in human disease and also provide new insights into retinal circuitry.
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Hamilton R, Bees MA, Chaplin CA, McCulloch DL. The luminance-response function of the human photopic electroretinogram: a mathematical model. Vision Res 2007; 47:2968-72. [PMID: 17889925 DOI: 10.1016/j.visres.2007.04.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 04/20/2007] [Accepted: 04/28/2007] [Indexed: 11/17/2022]
Abstract
The luminance-response function of the brief flash full-field photopic electroretinogram (ERG) rises to a peak before falling to a sub-maximal plateau -- the 'photopic hill'. The combination of on- and off-responses inherent in the brief flash photopic ERG suggests that this luminance-response function could be modelled by the sum of a Gaussian function and a logistic growth function. Photopic ERGs to a luminance series of brief flashes against three different background luminances recorded from seven healthy adults showed the characteristic 'photopic hill' function for b-wave amplitudes which were satisfactorily fitted with the sum of a Gaussian curve and a logistic growth curve. As background luminance increased, both components shifted to the right on the luminance axis. The Gaussian component increased in amplitude while the logistic growth function component decreased in amplitude. The luminance-response function of a complete congenital stationary night blindness patient had almost no logistic growth component.
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Affiliation(s)
- R Hamilton
- Department of Clinical Physics, Yorkhill NHS Trust and University of Glasgow, Glasgow, UK.
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Tremblay F, Parkinson J. Gradient of deficit in cone responses in the incomplete form of congenital stationary night blindness revealed by multifocal electroretinography. Doc Ophthalmol 2007; 116:41-7. [PMID: 17721714 DOI: 10.1007/s10633-007-9073-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 05/17/2007] [Accepted: 07/12/2007] [Indexed: 11/30/2022]
Abstract
Multifocal electroretinograms were recorded in one case of incomplete form of congenital stationary night blindness. First order kernel revealed reduced cone macular P1 responses with normal implicit time (22.7 nV, 33.3 ms; normal 43.3 +/- 8.2 nV, 32.7 +/- 0.6 ms) whereas more peripheral responses exhibited low responses of extremely delayed implicit time (5.1 nV, 47.5 ms; normal 7.4 +/- 2.1 nV, 32.3 +/- 0.8 ms). Responses from the first slice of the second kernel were present in the macular area but absent from the more peripheral areas. In comparison, mfERGs in the complete form of CSNB showed normal amplitude but slightly delayed responses at all eccentricities and normal second kernel responses. Results are discussed in terms of the dichotomy in synaptic transmission between macular and peripheral cones.
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Affiliation(s)
- Francois Tremblay
- Department of Ophthalmology & Visual Sciences, IWK Health Center, Dalhousie University, Halifax, NS, Canada.
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Szabo V, Kreienkamp HJ, Rosenberg T, Gal A. p.Gln200Glu, a putative constitutively active mutant of rod alpha-transducin (GNAT1) in autosomal dominant congenital stationary night blindness. Hum Mutat 2007; 28:741-2. [PMID: 17584859 DOI: 10.1002/humu.9499] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Congenital stationary night blindness (CSNB) is a non-progressive Mendelian condition resulting from a functional defect in rod photoreceptors. A small number of unique missense mutations in the genes encoding various members of the rod phototransduction cascade, e.g. rhodopsin (RHO), cGMP phosphodiesterase beta-subunit (PDE6B), and transducin alpha-subunit (GNAT1) have been reported to cause autosomal dominant (ad) CSNB. While the RHO and PDE6B mutations result in constitutively active proteins, the only known adCSNB-associated GNAT1 change (p.Gly38Asp) produces an alpha-transducin that is unable to activate its downstream effector molecule in vitro. In a multigeneration Danish family with adCSNB, we identified a novel heterozygous C to G transversion (c.598C>G) in exon 6 of GNAT1 that should result in a p.Gln200Glu substitution in the evolutionarily highly conserved Switch 2 region of alpha-transducin, a domain that has an important role in binding and hydrolyzing GTP. Computer modeling based on the known crystal structure of transducin suggests that the p.Gln200Glu mutant exhibits impaired GTPase activity, and thereby leads to constitutive activation of phototransduction. This assumption is in line with our results of trypsin protection assays as well as previously published biochemical data on mutants of this glutamine in the GTPase active site of alpha-transducin following in vitro expression, and observations that inappropriately activating mutants of various members of the rod phototransduction cascade represent one of the major molecular causes of adCSNB.
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Affiliation(s)
- Viktoria Szabo
- Institut für Humangenetik, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
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Tsang SH, Woodruff ML, Jun L, Mahajan V, Yamashita CK, Pedersen R, Lin CS, Goff SP, Rosenberg T, Larsen M, Farber DB, Nusinowitz S. Transgenic mice carrying the H258N mutation in the gene encoding the beta-subunit of phosphodiesterase-6 (PDE6B) provide a model for human congenital stationary night blindness. Hum Mutat 2007; 28:243-54. [PMID: 17044014 PMCID: PMC2753261 DOI: 10.1002/humu.20425] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mutations in the beta-subunit of cGMP-phosphodiesterase (PDE6beta) can lead to either progressive retinal disease, such as human retinitis pigmentosa (RP), or stationary disease, such as congenital stationary night blindness (CSNB). Individuals with CSNB in the Rambusch pedigree were found to carry the H258N allele of PDE6B (MIM# 180072); a similar mutation was not found in RP patients. This report describes an individual carrying the H258N allele, who presented with generalized retinal dysfunction affecting the rod system and a locus of dysfunction at the rod-bipolar interface. Also described are preclinical studies in which transgenic mice with the H258N allele were generated to study the pathophysiological mechanisms of CSNB. While Pde6b(rd1)/Pde6b(rd1) mice have severe photoreceptor degeneration, as in human RP, the H258N transgene rescued these cells. The cGMP-PDE6 activity of dark-adapted H258N mice showed an approximate three-fold increase in the rate of retinal cGMP hydrolysis: from 130.1 nmol x min(-1) x nmol(-1) rhodopsin in wild-type controls to 319.2 nmol x min(-1) x nmol(-1) rhodopsin in mutants, consistent with the hypothesis that inhibition of the PDE6beta activity by the regulatory PDE6gamma subunit is blocked by this mutation. In the albino (B6CBA x FVB) F2 hybrid background, electroretinograms (ERG) from H258N mice were similar to those obtained from affected Rambusch family members, as well as humans with the most common form of CSNB (X-linked), demonstrating a selective loss of the b-wave with relatively normal a-waves. When the H258N allele was introduced into the DBA background, there was no evidence of selective reduction in b-wave amplitudes; rather a- and b-wave amplitudes were both reduced. Thus, factors other than the PDE6B mutation itself could contribute to the variance of an electrophysiological response. Therefore, caution is advisable when interpreting physiological phenotypes associated with the same allele on different genetic backgrounds. Nevertheless, such animals should be of considerable value in further studies of the molecular pathology of CSNB.
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Affiliation(s)
- Stephen H Tsang
- Brown Glaucoma Laboratory, Center for Neurobiology and Behavior, Columbia University, New York, New York, USA.
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Abstract
INTRODUCTION Oguchi disease, originally described in Japanese people, is a rare form of stationary night blindness in patients with normal acuity. OBSERVATION We report the case of an 8-year-old girl who presented with an abnormal terrified behavior in the dark. Thorough questioning revealed hemeralopia. Her clinical examination (visual acuity, Goldmann visual field, and color vision) were normal. The fundus examination showed golden-brown color, grayish, almost greenish yellow discoloration in the peripheral area with no osteoclast. This abnormality disappeared after prolonged dark adaptation. The electroretinogram showed a reduced b wave amplitude under scotopic conditions. Her parents were cousins. CONCLUSION This diagnosis should be suggested when hemeralopia is associated with typical fundus aspect resolving after dark adaptation (so called Mizuo-Nakamura phenomenon). The long-term prognosis in these patients is good in the absence of clinical progression. This is a genetic autosomal recessive disease caused by mutations in the gene coding for arrestin located in 2q37.1.
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Affiliation(s)
- M Boissonnot
- Service d'Ophtalmologie, Centre Hospitalier Universitaire, Poitiers, France.
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Sandmeyer LS, Grahn BH, Breaux CB. Diagnostic ophthalmology. Congenital stationary night blindness (CSNB). Can Vet J 2006; 47:1131, 1133. [PMID: 17147148 PMCID: PMC1624921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Affiliation(s)
- Lynne S Sandmeyer
- Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan
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Zeitz C, Kloeckener-Gruissem B, Forster U, Kohl S, Magyar I, Wissinger B, Mátyás G, Borruat FX, Schorderet DF, Zrenner E, Munier FL, Berger W. Mutations in CABP4, the gene encoding the Ca2+-binding protein 4, cause autosomal recessive night blindness. Am J Hum Genet 2006; 79:657-67. [PMID: 16960802 PMCID: PMC1592568 DOI: 10.1086/508067] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 07/28/2006] [Indexed: 11/03/2022] Open
Abstract
Mutations in genes encoding either components of the phototransduction cascade or proteins presumably involved in signaling from photoreceptors to adjacent second-order neurons have been shown to cause congenital stationary night blindness (CSNB). Sequence alterations in CACNA1F lead to the incomplete type of CSNB (CSNB2), which can be distinguished by standard electroretinography (ERG). CSNB2 is associated with a reduced rod b-wave, a substantially reduced cone a-wave, and a reduced 30-Hz flicker ERG response. CACNA1F encodes the alpha 1-subunit of an L-type Ca2+ channel (Cav1.4 alpha ), which is specific to photoreceptors and is present at high density in the synaptic terminals. Ten of our patients with CSNB2 showed no mutation in CACNA1F. To identify the disease-causing mutations, we used a candidate-gene approach. CABP4, a member of the calcium-binding protein (CABP) family, is located in photoreceptor synaptic terminals and is directly associated with the C-terminal domain of the Cav1.4 alpha . Mice lacking either Cabp4 or Cav1.4 alpha display a CSNB2-like phenotype. Here, we report for the first time that mutations in CABP4 lead to autosomal recessive CSNB. Our studies revealed homozygous and compound heterozygous mutations in two families. We also show that these mutations reduce the transcript levels to 30%-40% of those in controls. This suggests that the reduced amount of CABP4 is the reason for the signaling defect in these patients.
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Affiliation(s)
- Christina Zeitz
- Division of Medical Molecular Genetics and Gene Diagnostics, Institute of Medical Genetics, University of Zurich, Schwerzenbach, Switzerland.
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Kouassi FX, Koffi KV, Safede K, Daccache W, Cochener B. [Fundus albipunctatus incidentally discovered in a black African man]. J Fr Ophtalmol 2006; 29:e12. [PMID: 16885819 DOI: 10.1016/s0181-5512(06)73814-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fundus albipunctatus is a recessive autosomal disease classified as one of the causes of congenital stationary night blindness. It is characterized by early hemeralopia beginning in infancy. We report the incidental discovery of the disease in a 23-year-old black African man with late hemeralopia onset. During the 4 years of follow-up, visual acuity, ERG, and visual field remained normal. We underline the possibility of late hemeralopia onset and discuss the possible progressive features of this disease. Progression may be conditioned by the mutation of the RDH5 gene, which codes for retinol dehydrogenase-5.
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Affiliation(s)
- F X Kouassi
- Service d'Ophtalmologie, CHU de Cocody, Abidjan, Côte-d'Ivoire.
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Xiao X, Jia X, Guo X, Li S, Yang Z, Zhang Q. CSNB1 in Chinese families associated with novel mutations in NYX. J Hum Genet 2006; 51:634-40. [PMID: 16670814 DOI: 10.1007/s10038-006-0406-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Accepted: 03/20/2006] [Indexed: 10/24/2022]
Abstract
X-linked congenital stationary night blindness (CSNB) and NYX mutation have not been reported in Chinese. Here, two Chinese families with the complete form of CSNB (CSNB1) are presented. Linkage analysis of one family mapped the disease to Xp11-Xq13 where NYX is located. Sequence analysis of NYX identified two novel mutations, c.281G>C and c.302T>C, which would result in missense changes of p.Arg94Pro and p.Ile101Thr in the encoded protein. These two mutations were not found in 96 controls. The c.281G>C mutation cosegregated with nyctalopia and myopia. Our results expand the mutation spectrum of NYX and enrich the clinical information related to NYX mutation. The importance of associated myopia with NYX mutations is discussed.
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Affiliation(s)
- Xueshan Xiao
- Key Laboratory of Ophthalmology of the Ministry of Education and Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, PR China
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Sui RF, Zhao JL. [Congenital stationary night blindness]. Zhonghua Yan Ke Za Zhi 2006; 42:472-5. [PMID: 16762251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Congenital stationary night blindness (CSNB) is a group of genetically heterogeneous retinopathy with characterized clinical and visual electrophysiological abnormality. Five candidate genes associated with the disease have been identified. Clinical, electrophysiological and molecular genetics about CSNB are reviewed in this paper.
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Affiliation(s)
- Rui-fang Sui
- Department of Ophthalmology, Peking Union Medical College, Eye Reserch Center of Chinese Academy of Medical Sciences, Beijing 100730, China.
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Abstract
This report documents congenital stationary night blindness (CSNB) in two non-Appaloosa horse breeds (Thoroughbred and Paso Fino). History of vision impairment since birth, normal ocular structures on ophthalmic examination, and electroretinographic findings were consistent with CSNB. In one horse (Thoroughbred), a 9-year follow-up was carried out. In the Paso Fino, severe vision impairment from birth to approximately 1 year of age in both dim and bright light situations led to humane euthanasia and histopathologic confirmation of the disorder.
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Affiliation(s)
- Catherine Nunnery
- Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0442, USA
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Ung T, Allen LE, Moore AT, Trump D, Zito I, Hardcastle AJ, Yates J, Bradshaw K. Is Optic Nerve Fibre Mis-Routing a Feature of Congenital Stationary Night Blindness? Doc Ophthalmol 2006; 111:169-78. [PMID: 16523234 DOI: 10.1007/s10633-005-5503-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2005] [Indexed: 10/24/2022]
Abstract
PURPOSE To determine whether patients with congenital stationary night blindness (CSNB) have electrophysiological evidence of optic nerve fibre mis-routing similar to that found in patients with ocular albinism (OA). METHOD We recorded the Pattern Onset VEP using a protocol optimised to detect mis-routing of optic nerve fibres in older children and adults. We tested 20 patients (age 15-69 yrs) with X-linked or autosomal recessive CSNB, 14 patients (age 9-56 yrs) with OA and 13 normally pigmented volunteers (age 21-66 yrs). We measured the amplitude and latency of the CI component at the occipital midline and over left and right occipital hemispheres. We also assessed the computed inter-hemispheric "difference" signal. Subjects with CSNB were classified as having the "complete" or "incomplete" phenotype on the basis of their ERG characteristics. Members of X-linked CSNB pedigrees underwent mutation screening of the NYX and CACNA1F genes. RESULTS CI was significantly smaller over the ipsilateral hemisphere and more prominent over the contralateral hemisphere in OA patients compared with both controls and CSNB patients. In CSNB patients CI response amplitudes were not significantly different from controls but peak latency was prolonged at all three electrodes compared with controls. The inter-hemispheric "difference" signal was abnormal for the OA group but not for the CSNB group. Contralateral dominance of CI could be identified in the majority of OA patients and the "difference" signal was opposite in polarity for left compared with right eye stimulation in every patient in this group. Only 3 of 20 patients with CSNB showed significant inter-hemispheric asymmetry similar to that seen in the OA patients. All 3 CSNB patients with evidence for optic nerve fibre mis-routing had X-linked pedigrees: 2 had an identified mutation in the NYX gene but no mutation in either the NYX or CACNA1F genes was identified in the third. VEP evidence of optic nerve fibre mis-routing was present in 3 of the 11 subjects with "complete" phenotype and none of the 9 patients with "incomplete" phenotype CSNB. CONCLUSION Mis-routing of optic nerve fibres does occur in CSNB but we found evidence of it in only 15% of our patients.
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Affiliation(s)
- T Ung
- Ophthalmology Department, Addenbrooke's Hospital, Cambridge, CB2 2QQ, UK
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Leifert D, Todorova MG, Prünte C, Palmowski-Wolfe AM. LED-generated Multifocal ERG On- and Off-responses in Complete Congenital Stationary Night Blindness – A Case Report. Doc Ophthalmol 2006; 111:1-6. [PMID: 16502301 DOI: 10.1007/s10633-005-2303-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2005] [Indexed: 10/25/2022]
Abstract
We report on the application of a light emitting diode (LED) screen to elicit multifocal ERG on- and off-responses in a patient presenting with the complete type of congenital stationary night blindness (cCSNB): A 63-years old woman was diagnosed with cCSNB by means of standard ERG procedures and dark adaptometry. To confirm this diagnosis and to investigate topographical differences of on- and off-responses a multifocal approach employing long-duration stimuli was added. Results of mfERG-testing were averaged in three groups (a central area of 7.5 degrees , a ring area of 7.5-21.9 degrees and a peripheral ring of 21.9-31.1 degrees ). When compared to normal controls (n = 4) on-responses (P1-amplitudes) were severely reduced symmetrically at all eccentricities, while off-responses showed no reduction resulting in an increased off/on-ratio. Furthermore on-latencies of P1 were delayed symmetrically at all eccentricities, whereas off-latencies were normal. To our knowledge this is the first report of multifocal on- and off-responses in a CSNB-patient. Stimulus-generation with a LED-screen provides the advantage of a stable luminance during the long-duration on-phase.
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Affiliation(s)
- Dorothee Leifert
- Department of Ophthamlology, University Hospital Basel, Mittlere Strasse 91, CH-4056, Basel, Switzerland.
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Hoda JC, Zaghetto F, Singh A, Koschak A, Striessnig J. Effects of congenital stationary night blindness type 2 mutations R508Q and L1364H on Cav1.4 L-type Ca2+ channel function and expression. J Neurochem 2006; 96:1648-58. [PMID: 16476079 DOI: 10.1111/j.1471-4159.2006.03678.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
At least 48 mutations in the CACNA1F gene encoding retinal Ca(v)1.4 L-type Ca(2+) channels have been linked to X-linked recessive congenital stationary night blindness type 2 (CSNB2). A large number of these are missense mutations encoding full-length alpha1-subunits that can potentially form functional channels. We have previously shown that such missense mutations can confer their phenotype by different pathological mechanisms, such as complete lack of alpha1 subunit protein expression or dramatic changes in channel gating. Here we investigated the functional consequences of CSNB2 missense mutations R508Q and L1364H. We found no (R508Q) or only minor (L1364H) changes in the gating properties of both mutants after heterologous expression in Xenopus laevis oocytes (at 20 degrees C). However, both mutants resulted in altered expression density of Ca(v)1.4 currents. When expressed in the mammalian cell line tsA-201, the current amplitude of L1364H channels was reduced when cells were grown at 30 degrees C and both mutations affected total alpha1 protein expression. This effect was temperature dependent. Our data provide evidence that, in contrast to previously characterized CSNB2 missense mutations, the clinical phenotype of R508Q and L1364H is unlikely to be explained by changes in channel gating. Instead, these mutations affect the protein expression of Ca(v)1.4 Ca(2+) channels.
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Affiliation(s)
- Jean-Charles Hoda
- Abteilung Pharmakologie und Toxikologie, Institut für Pharmazie, Universität Innsbruck, Innsbruck, Austria
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Zeitz C, van Genderen M, Neidhardt J, Luhmann UFO, Hoeben F, Forster U, Wycisk K, Mátyás G, Hoyng CB, Riemslag F, Meire F, Cremers FPM, Berger W. Mutations in GRM6 cause autosomal recessive congenital stationary night blindness with a distinctive scotopic 15-Hz flicker electroretinogram. Invest Ophthalmol Vis Sci 2005; 46:4328-35. [PMID: 16249515 DOI: 10.1167/iovs.05-0526] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Congenital stationary night blindness (CSNB) is a group of nonprogressive retinal disorders characterized by impaired night vision that occurs in autosomal dominant, autosomal recessive, or X-linked forms. Autosomal recessive (ar)CSNB seems to be very rare. Mice lacking the metabotropic glutamate receptor 6 (Grm6) have a defect in signal transmission from the photoreceptors to ON-bipolar cells. In the current study, the human orthologue (GRM6) was screened as a likely candidate for arCSNB. METHODS arCSNB individuals of five families were screened for mutations in GRM6. Subsequently, they were examined with standard and 15-Hz flicker electroretinography (ERG). These recordings were compared with those of patients with X-linked CSNB1. RESULTS Affected individuals in three of five families carried either compound heterozygous or homozygous mutations in GRM6. Strikingly, all of them displayed a distinctive abnormality of the rod pathway signals on scotopic 15-Hz flicker ERG. CONCLUSIONS The novel profile identified in this study suggests the existence of more than two rod pathways. The distinctive ERG feature was not observed in patients with X-linked CSNB1 and additional affected individuals with unknown molecular defect. These observations will help to discriminate autosomal recessive from X-linked recessive cases by ERG and molecular genetic analysis.
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Affiliation(s)
- Christina Zeitz
- Division of Medical Molecular Genetics and Gene Diagnostics, Institute of Medical Genetics, University of Zurich, Schwerzenbach, Switzerland.
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Imaizumi M, Tatewaki SY, Kimoto KI, Takaki Y, Nakatsuka K, Furushima M, Matsumoto CS, Choshi T. DISAPPEARANCE OF PUNCTA AFTER UVEITIS IN AN EYE WITH FUNDUS ALBIPUNCTATUS. Retina 2005; 25:1096-8. [PMID: 16340543 DOI: 10.1097/00006982-200512000-00021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Masamoto Imaizumi
- Department of Ophthalmology, Oita Prefectural Hospital, Oita University Faculty of Medicine, Hasama-machi, Oita, Japan.
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Zhuang SL, Zou JW, Peng CL, Liu XL, Chen SH, Huang FL, Hu SN, Yu QS. [Exclusion of the association of five known mutations with congenital stationary nyctalopia in a large Chinese family]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2005; 34:255-9. [PMID: 15940795 DOI: 10.3785/j.issn.1008-9292.2005.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
OBJECTIVE To detect gene mutations associated with autosomal dominant congenital stationary night blindness(ADCSNB) in a large Chinese family. METHODS Genomic DNAs were extracted from peripheral blood samples of 16 affected and 14 unaffected family members. According to 5 missense mutations in 3 genes reported previously, 4 pairs of primers were designed and corresponding exons containing the five mutation sites were amplified by polymerase chain reaction. Amplified products were purified and sequenced by MegaBACE1000 capillary array electrophoresis DNA sequencer. Full field electroretinogram (ERG, ISCEV) of patients was recorded and analyzed by Roland Consult System. RESULTS Dark-adapted ERG showed a-wave was normal, but b-wave of the patients was markedly decreased. None of the five missense mutations were detected in 16 affected and 14 unaffected family members. CONCLUSION The molecular pathogenesis of ADCSNB in this family does not involve point mutations or deletions of these five sites, which indicates the heterogeneity of ADCSNB.
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Affiliation(s)
- Shu-lin Zhuang
- Chemistry Department, Zhejiang University, Hangzhou 310027, China
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Liu X, Zhuang S, Hu S, Zhang F, Lin B, Li X, Xu D, Chen SH. A dominant form of congenital stationary night blindness (adCSNB) in a large Chinese family. Ann Hum Genet 2005; 69:315-21. [PMID: 15845035 DOI: 10.1046/j.1529-8817.2005.00159.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Summary A pedigree of congenital stationary night blindness (CSNB) is described in a large Chinese family. The clinical description, pedigree, dark adaptation and elctroretinogram (ERG) studies indicate that the patients have an autosomal dominant form (ad) of CSNB. The disorder has been transmitted through at least 12 generations with over 40 affected individuals identified. The ERG data reveal that affected persons have severely diminished b-wave responses to dim light, but normal a-wave and subnormal b-wave responses to maximum light stimuli. The dark adaptation curves of three patients show a monophase curve, typical for night blindness. We have excluded the five previously known mutations in the three genes (RHO, PDE6B and GNAT1) associated with adCSNB, and linkage studies have excluded tight linkage between the disease locus and markers associated with these three genes. Thus, this family has adCSNB caused by a different gene from the previously identified RHO, PDE6B, and GNAT1.
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Affiliation(s)
- X Liu
- Eye Hospital, School of Optometry and Ophthalmology, Wenzhou Medical College, Wenzhou, Zhejiang 325003, PR China
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Liláková D, Svĕrák J, Hejcmanová D. [Congenital stationary night blindness (CSNB)--a case report]. Cesk Slov Oftalmol 2005; 61:218-23. [PMID: 15981496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
PURPOSE To document occurrence of the congenital stationary night blindness type Schubert-Bornschein in some members of one family, to put together the family tree, and to evaluate the examination methods. Among others the electroretinogram (ERG) is substantial in the diagnosis of the disease and to distinguish different types of CSNB. In the affected family, only in men the disease is expressed, females are transmitters. This corresponds to the X-linked inheritance. Simultaneously with CSNB, in this family, high myopia occurs not only in men, but also in women. CONCLUSION CSNB is an inherited disease, mostly with X-linked inheritance. Affected are predominantly males, females are transmitters. This disease is not possible to treat. Despite this, to determine proper diagnosis is important and use of ERG is mandatory.
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Zeitz C, Minotti R, Feil S, Mátyás G, Cremers FPM, Hoyng CB, Berger W. Novel mutations in CACNA1F and NYX in Dutch families with X-linked congenital stationary night blindness. Mol Vis 2005; 11:179-83. [PMID: 15761389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
PURPOSE To describe the clinical features and genetic analysis of eight X-linked congenital stationary night blindness (XLCSNB) Dutch patients. METHODS Electroretinogram (ERG) measurements were assessed in Dutch patients. Molecular genetic testing by denaturing high performance liquid chromatography (DHPLC), single stranded conformation polymorphism (SSCP) analysis, and direct sequencing of the CACNA1F and NYX genes were performed in the patients possessing a negative Schubert Bornschein ERG. RESULTS Molecular genetic testing of CACNA1F and NYX revealed three novel and two known CACNA1F sequence variants as well as two novel sequence alterations in the NYX gene. While one of the CACNA1F sequence variants (5756G>A, R1919H) has been previously described as a common polymorphism in Japanese families, we did not found this transition in 100 European control alleles. CONCLUSIONS In a pool of eight diagnosed XLCSNB patients, five showed a sequence variation in the CACNA1F and two in the NYX gene. In only one of the eight patients no sequence alteration could be detected. This might be explained by a mutation in other, as yet unidentified coding or regulatory sequences of NYX or CACNA1F or additional genes.
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Affiliation(s)
- Christina Zeitz
- Division of Medical Molecular Genetics and Gene Diagnostics, Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
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Abstract
Congenital stationary night blindness (CSNB) is a group of rare, non-progressive conditions of the retina characterized by abnormal rod function causing impaired night vision. Among them, the Schubert-Bornschein subgroup, itself divided into a complete and an incomplete form, is characterized by a specific electrophysiological pattern. Complete, Schubert-Bornschein CSNB is usually transmitted as a monogenic trait, and most familial cases result from mutations of the NYX gene located on the X chromosome. We report a very rare family with consanguineous, first-cousin parents, where a son and a daughter are affected with this condition, indicating autosomal recessive inheritance. As the family was too small for genome-wide linkage, we considered several candidate loci, including the sidekick SDK1 and SDK2 genes. The latter determine lamina-specific connectivity in the retina, a histological substrate of the ON pathway implicated in complete, Schubert-Bornschein CSNB. Although linkage was excluded in our family, observations like the present one may lead to the identification of a new molecular cause for this condition.
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Affiliation(s)
- Marc J Abramowicz
- Service de Génétique Médicale, Hôpital Erasme and Laboratoire de Génétique Médicale-ULB, Brussels, Belgium.
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Schuster A, Pusch CM, Gamer D, Apfelstedt-Sylla E, Zrenner E, Kurtenbach A. Multifocal oscillatory potentials in CSNB1 and CSNB2 type congenital stationary night blindness. Int J Mol Med 2005; 15:159-67. [PMID: 15583843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023] Open
Abstract
We evaluated the function of the inner retina in patients with congenital stationary night blindness of the complete (CSNB1) and the incomplete type (CSNB2) by recording multifocal oscillatory potentials (mf-OPs). The VERIS system was used to record mf-OPs from 61 areas of the central retina from 5 CSNB1 patients (4 with NYX gene mutation), 6 CSNB2 patients (2 with CACNA1F mutation) and 11 control subjects. For each subject group, the first- and second-order kernel responses for one eye were analysed and the amplitudes and implicit times of their major components compared to 5 concentric rings centred on the fovea. In CSNB1 patients, the mf-OP peak amplitudes of the first-order kernel responses showed a significant reduction of the first peak without significant reduction of the second, whereas in CSNB2 both peak amplitudes were barely discernable from noise for all eccentricities. In the second-order kernel, the third peak was reduced in CSNB1 patients, and again not discernable from noise in CSNB2 patients. The difference in amplitude between the control and CSNB1 groups was significant for the late components of the first- and the second-order kernel. Implicit times were not significantly altered. The difference in mf-OP amplitude between CSNB1 and CSNB2 patients reflects the different molecular mechanisms underlying the two types of disease, which differentially affect the postreceptoral pathways of cone signal processing. The well-preserved peak 2 amplitudes of first-order mf-OPs and peak 3 amplitudes of second-order mf-OPs in CSNB1 patients point to a major impact of OFF-pathway components on these responses which are not present in CSNB2 patients. In conclusion, our results show that CSNB1 and CSNB2 are two different types of disease, not only on a genetic but also on a pathophysiological level.
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Affiliation(s)
- Andreas Schuster
- Department of Pathophysiology of Vision and Neuroophthalmology, University Eye Hospital, Tübingen, Germany
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Nakamura M, Miyake Y. [Molecular genetic study of congenital stationary night blindness]. Nippon Ganka Gakkai Zasshi 2004; 108:665-73. [PMID: 15584351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
PURPOSE Molecular genetic study was conducted on patients with fundus albipunctatus, incomplete and complete types of congenital stationary night blindness(CSNB), and Oguchi disease. RESULTS Mutations in the RDH5 gene were identified in all 10 patients with typical clinical features of fundus albipunctatus. Mutations in the gene were also detected in patients with fundus albipunctatus associated with cone dystrophy, and it was supposed that mutations of the gene cause progressive retinal dystrophy as well as fundus albipunctatus. Mutations in the CACNA1F gene were identified in all 15 patients with typical clinical features of incomplete CSNB. We found that some cases with incomplete CSNB were associated with retinal degeneration or optic atrophy with progressive impairment of vision. We detected mutations in the NYX gene in about half of the cases with complete CSNB. Molecular examination was useful to determine the exact hereditary pattern. We examined the arrestin gene and the rhodopsin kinase gene in 5 unrelated patients with Oguchi disease, and found arrestin gene mutations in 4 of them and a rhodopsin kinase gene mutation in the fifth patient. CONCLUSIONS We confirmed that fundus albipunctatus, incomplete CSNB, complete CSNB, and Oguchi disease were associated with mutations in the RDH5, CACNA1F, NYX, arrestin or rhodopsin kinase genes, respectively, in Japanese patients. Molecular analysis made it possible to diagnose patients with atypical phenotype and to obtain novel information about phenotypic variation.
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Affiliation(s)
- Makoto Nakamura
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Japan
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Kabanarou SA, Holder GE, Fitzke FW, Bird AC, Webster AR. Congenital stationary night blindness and a "Schubert-Bornschein" type electrophysiology in a family with dominant inheritance. Br J Ophthalmol 2004; 88:1018-22. [PMID: 15258017 PMCID: PMC1772254 DOI: 10.1136/bjo.2003.033555] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS To present the clinical, psychophysical, and electrophysiological characteristics of a family with dominantly inherited congenital stationary night blindness (CSNB). METHODS Five affected family members from three generations were ascertained. Four affected individuals underwent ophthalmic examination and electrodiagnostic investigations. Three affected individuals also underwent scanning laser ophthalmoscopy and psychophysical testing. RESULTS Affected individuals reported night blindness from an early age. Visual acuities were normal. Fundal appearances were normal apart from one older patient showing areas of peripheral chorioretinal atrophy. Autofluorescence images showed no gross abnormality. International Society for Clinical Electrophysiology of Vision (ISCEV) standard electroretinography (ERG) showed undetectable rod specific responses and electronegative maximal responses, but normal ISCEV cone responses. Additional S-cone specific ERG recordings were of reduced amplitude in all patients studied. There was no apparent rod component to the dark adaptation curve. Central 30 degrees thresholds were normal under photopic conditions but showed increased thresholds under scotopic conditions for both red and blue stimuli. CONCLUSION Results from investigation of this family are consistent with an impairment of rod photoreceptor signalling. The ERG findings suggest an abnormality occurring after phototransduction with rod and S-cone pathway involvement. These findings differ from those rare families reported previously with dominant CSNB.
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Kubová Z, Kremlácek J, Kuba M, Chlubnová J, Sverák J. Photopic and scotopic VEPs in patients with congenital stationary night-blindness. Doc Ophthalmol 2004; 109:9-15. [PMID: 15675196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Extended set of visual evoked potentials (VEPs) using pattern-reversal (PREPs), linear motion-onset and radial (expansion) motion-onset stimuli (M-VEPs) (detailed specification at http://www.lfhk.cuni.cz/elf) was used to verify congenital stationary night-blindness (CSNB) characteristics in 7 patients (compared to 7 age matched controls) in photopic conditions (luminance of 17 cd/m2). No differences were found in any of the M-VEPs, whilst PREPs displayed prolonged latencies in 3 of 7 CSNB patients. Additionally, the PREPs and M-VEPs were tested in 3 normal and 3 CSNB subjects (the only available ones from the original group) over large range of scotopic, mesopic and photopic luminances (from 0.0001 to 65.4 cd/m2). Both types of low luminance VEPs had distinctly increased luminance threshold needed for reliable VEPs eliciting in CSNB patients (0.06 cd/m2) when compared with controls (0.003 cd/m2); the VEP appearance threshold was almost identical with the perceptual threshold in both groups. Thus, our pilot study proved that CSNB can be objectively detected also via scotopic VEP examination. Since the prolonged PREP latencies at 17 cd/m2 normalised with luminance increase, it indicates that the lower luminance stimuli (compared to the standard recommended by ISCEV) can be more sensitive for some visual disorders detection.
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Affiliation(s)
- Zuzana Kubová
- Faculty of Medicine, Charles University, Czech Republic.
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Rigaudière F, Roux C, Lachapelle P, Rosolen SG, Bitoun P, Gay-Duval A, Le Gargasson JF. ERGs in female carriers of incomplete congenital stationary night blindness (I-CSNB). A family report. Doc Ophthalmol 2004; 107:203-12. [PMID: 14661912 DOI: 10.1023/a:1026212318245] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
ERG findings in five sisters are reported. By pedigree analysis, four of the five must be obligate carriers for I-CSNB since their sons were affected (impaired night vision, reduced visual acuity, variable ametropia, congenital nystagmus and ERG with both scotopic and photopic b-wave reduced amplitude). The fifth was childless at the time of examination and her ERG analysis was normal. Three of the four obligate carriers showed significant reduction in the sum of the OPs amplitude as previously reported as being an electrophysiological signs in female carriers: two without alteration in other ERG components and the third with association with a flicker ERG amplitude significantly increased. The fourth female carrier showed a normal sum of the OPs amplitude whereas the other b-wave ERG or flicker amplitudes were significantly decreased. These last two ERG results suggest a possible modifications of synaptic transmission at a post-receptoral site (outer plexiform layer or involvement of the bipolar pathways) in these two carriers.
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Affiliation(s)
- Florence Rigaudière
- Université Paris 7, UFR Lariboisière-Saint-Louis, Unité INSERM U-483, Service de Biophysique, Département Vision, Paris, France.
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Kocyła-Karczmarewicz B, Grałek M, Juszko J, Trzebicka A, Sarti G. [Congenital stationary night blindness]. Klin Oczna 2004; 106:509-11. [PMID: 15636252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Authors present diagnostic procedures and dinical features of the congenital stationary night blindness (CSNB) in 19 patients. Effective therapy of the concomitant ophthalmological pathologies usually improves patient's vision ability.
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Bradshaw K, Newman D, Allen L, Moore A. Abnormalities of the scotopic threshold response correlated with gene mutation in X-linked retinoschisis and congenital stationary night blindness. Doc Ophthalmol 2003; 107:155-64. [PMID: 14661905 DOI: 10.1023/a:1026245931580] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
STRs and dark-adapted ERGs were recorded in nine normal subjects, nine patients with XLRS, 11 patients with CSNB1 and one patient with CSNB2. In XLRS STR amplitude was significantly lower than normal at every intensity, but the response could be recorded in every patient and the maximum amplitude response was outside the 95% confidence limits in only four of the nine patients. STRs were significantly poorer in patients with CSNB and a responses was not measurable at any intensity in nine of the 11 patients with CSNB1. In both CSNB and XLRS the STR could only be recorded at higher stimulus intensities, suggesting reduced sensitivity of the STR. In XLRS onset and peak latencies were also significantly prolonged and the slope of the intensity-response functions for amplitude and onset latency differed significantly from normal. Maximum STR amplitude did not correlate with the maximum dark-adapted ERG response. The finding of abnormal STRs and dark adapted ERGs in all three dystrophies indicates that the different causative genes must have similar effects on the rod On-bipolar cell pathway. But there were also differences between the three clinical groups, particularly in the greater severity of the abnormality in CSNB1, which suggests that there may be multiple sites of abnormality.
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Affiliation(s)
- Keith Bradshaw
- Ophthalmology Department, Addenbrooke's Hospital, Hills Road, Cambridge, UK.
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Kiratli H, Oztürkmen C. Coats-like lesions in Usher syndrome type II. Graefes Arch Clin Exp Ophthalmol 2003; 242:265-7. [PMID: 14652768 DOI: 10.1007/s00417-003-0818-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2003] [Revised: 11/06/2003] [Accepted: 11/07/2003] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND An unusual case of Usher syndrome type II associated with bilateral Coats-like exudative retinopathy is described. METHODS A 14-year-old boy with congenital sensorineural deafness and normal vestibular functions presented with a recent history of night blindness. He was followed for 3 years with fundus photography, intravenous fluorescein angiography, electroretinography and audiometric testings. His parents refused any form of treatment. RESULTS Fundoscopy showed bilateral retinitis pigmentosa and a single focus of subretinal exudation and overlying telangiectatic retinal vessels inferotemporal to the vascular arcade in the right eye. He had bilateral mild macular edema. A year later, a similar lesion developed inferotemporally in the left fundus. Electroretinography responses, particularly the rod-mediated signals, were significantly reduced. Audiometric studies documented hearing loss in high frequencies. His visual acuity declined from 20/40 to 20/80 RE and from 20/80 to 20/100 LE during follow-up. No new lesions developed. CONCLUSIONS Coats-type exudative lesions may develop in patients with Usher syndrome type II. Although left untreated, only a minimal increase in exudation occurred over 3 years.
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Affiliation(s)
- Hayyam Kiratli
- Department of Ophthalmology, Hacettepe University School of Medicine, Ankara, Turkey.
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Del Valle LJ, Ramon E, Bosch L, Manyosa J, Garriga P. Specific isomerization of rhodopsin-bound 11-cis-retinal to all-trans-retinal under thermal denaturation. Cell Mol Life Sci 2003; 60:2532-7. [PMID: 14625696 DOI: 10.1007/s00018-003-3113-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The natural ligand of the retinal photoreceptor rhodopsin, 11-cis-retinal, is isomerized to its all-trans configuration as a consequence of light absorption in the first step of the visual phototransduction process. Here we show, by means of difference spectroscopy and high-performance liquid chromatography analysis, that thermal denaturation of rhodopsin induces the same type of isomerization. This effect is likely due to thermally induced conformational rearrangements of amino acid residues in the retinal-binding pocket--possibly implying helical movements--and highlights the tight coupling between 11-cis-retinal and opsin. This effect could have implications in the instability and functional changes seen for certain mutations in rhodopsin associated with retinal disease, and in the stability of the different conformers induced by mutations in other G protein-coupled receptors.
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Affiliation(s)
- L J Del Valle
- Centre de Biotecnologia Molecular, Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, Colom 1, 08222 Terrassa, Catalonia, Spain
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Zeitz C, Scherthan H, Freier S, Feil S, Suckow V, Schweiger S, Berger W. NYX (nyctalopin on chromosome X), the gene mutated in congenital stationary night blindness, encodes a cell surface protein. Invest Ophthalmol Vis Sci 2003; 44:4184-91. [PMID: 14507859 DOI: 10.1167/iovs.03-0251] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The complete type of X-linked congenital stationary night blindness (CSNB1) in human and mouse is caused by mutations in the NYX gene. The human NYX protein has been predicted to contain an N-terminal endoplasmic reticulum (ER) signaling sequence and a C-terminal glycosylphosphatidylinositol (GPI) anchor. In the current study, these computer predictions were verified experimentally by expression of domain-specific cDNA constructs in COS-7 and HeLa cells. Moreover, computer-based analysis of the orthologue mouse amino acid sequence did not reveal a GPI anchor, which may result in a different protein localization compared with human NYX. Therefore, the cellular localization for the mouse Nyx protein was also examined. METHODS A new method was established that differentially visualizes both the protein at the surface of the living cell and subsequently in intracellular compartments. The localization of the human and mouse V5-tagged wild-type and mutant NYX protein were studied. RESULTS Human and mouse V5-NYX proteins were dispersed in the form of speckles over the entire cell surface. Subsequent staining of the same cells after detergent extraction revealed that V5-NYX located to the ER and Golgi apparatus. Deletion of the GPI anchor domain of NYX resulted in a time-dependent loss of V5-NYX from the surface of living cells and accumulation of this truncated protein in the ER and Golgi apparatus. Deletion of the ER signal sequence in Nyx delocalized the intracellular V5-Nyx protein and caused its dispersion in the cytosol. Furthermore, mutations introduced in the leucine-rich repeat (LRR)-region, which has been described as a pathogenic variant of NYX, had no effect on subcellular localization of the protein. CONCLUSIONS These data provide evidence that human and mouse nyctalopin are membrane-bound extracellular proteins and are functionally conserved.
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Affiliation(s)
- Christina Zeitz
- Institute of Medical Genetics, University of Zurich, Schwerzenbach, Switzerland.
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Abstract
Three different mutations of rhodopsin are known to cause autosomal dominant congenital night blindness in humans. Although the mutations have been studied for 10 years, the molecular mechanism of the disease is still a subject of controversy. We show here, using a transgenic Xenopus laevis model, that the photoreceptor cell desensitization that is a hallmark of the disease results from persistent signaling by constitutively active mutant opsins.
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Affiliation(s)
- Shengnan Jin
- Department of Biochemistry and Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454, USA
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Abstract
PURPOSE To report a Japanese family with fundus albipunctatus and macular dystrophy associated with a mutation in the 11-cis retinol dehydrogenase (RDH5) gene. DESIGN Observational case report. METHOD Ophthalmic examinations and DNA analysis were performed. RESULTS The fundi of a 56-year-old man and his 51-year-old sister showed numerous yellow-white punctata. He also had bull's-eye maculopathy and prepappillary arterial loops, whereas she did not, and his best-corrected visual acuity was impaired, whereas hers was normal. Their kinetic visual fields did, however, show central or paracentral scotoma, and both had tritanomalous color vision. Their scotopic electroretinograms were typical of fundus albipunctatus, and photopic electroretinograms were significantly reduced. A homozygous Gly107Arg mutation in the RDH5 gene was detected in both siblings. CONCLUSIONS We suggest that the macular dystrophy is caused by the RDH5 gene mutation as a phenotype variation in fundus albipunctatus.
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Affiliation(s)
- Kazuki Hotta
- Department of Ophthalmology, Kameda Medical Center, Kamogowa, Japan.
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Jacobi FK, Hamel CP, Arnaud B, Blin N, Broghammer M, Jacobi PC, Apfelstedt-Sylla E, Pusch CM. A novel CACNA1F mutation in a french family with the incomplete type of X-linked congenital stationary night blindness. Am J Ophthalmol 2003; 135:733-6. [PMID: 12719097 DOI: 10.1016/s0002-9394(02)02109-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE To describe a French family with the incomplete type of X-linked congenital stationary night blindness (CSNB2) associated with a novel mutation in the retina-specific calcium channel alpha(1) subunit gene (CACNA1F). DESIGN Interventional case report. METHODS Two family members with a history of nonprogressive night blindness and subnormal visual acuity were clinically examined and the genotype determined by molecular genetic analysis. RESULT Both patients had clinical manifestations characteristic of CSNB2. Electrophysiologically, we found a predominant reduction of the ERG B-wave in the maximal response. Both rod and cone function were subnormal, with the latter tending to be more attenuated. We identified a C deletion at nucleotide position 4548, resulting in a frameshift with a predicted premature termination at codon 1524. CONCLUSIONS The clinical and genetic study of a novel mutation in the CACNA1F gene adds further support to the contention that CSNB2 represents a genetically distinct retinal disorder of a calcium channel.
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Pesch K, Zeitz C, Fries JE, Münscher S, Pusch CM, Kohler K, Berger W, Wissinger B. Isolation of the mouse nyctalopin gene nyx and expression studies in mouse and rat retina. Invest Ophthalmol Vis Sci 2003; 44:2260-6. [PMID: 12714669 DOI: 10.1167/iovs.02-0115] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE It has been shown recently that mutations in NYX (nyctalopin on chromosome X), encoding a novel protein associated with the leucine-rich repeat (LRR) protein superfamily, are responsible for the complete form of X-linked congenital stationary night blindness (CSNB1). This study describes the isolation and molecular characterization of the mouse orthologue Nyx and its expression pattern in the retina. METHODS Nyx was isolated by conventional DNA library screening and polymerase chain reaction (PCR)-based approaches. Gene expression in different mouse tissues was studied by RT-PCR. Subsequently, the expression pattern of Nyx and its gene product in mouse and rat retinas was investigated by RNA in situ hybridization and immunohistochemistry with Nyx-specific antibodies. RESULTS The Nyx gene encodes a protein of 476 amino acids that contain 11 consecutive LRR motifs flanked by amino- and carboxyl-terminal cysteine-rich LRRs. At the amino acid level, Nyx is highly homologous to its human orthologue (86% identity). The gene is expressed in the eye but also, at lower levels, in brain, lung, spleen, and testis. Nyx expression was found during all stages of postnatal retinal development and was confined to cells of the inner nuclear layer and the ganglion cell layer in adult mouse and rat retinas. CONCLUSIONS These data suggest an important function of the Nyx protein in the inner retina and provide evidence that CSNB1 is based on a defect in the inner retinal circuitry.
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Affiliation(s)
- Katrin Pesch
- Molekulargenetisches Labor, Universitäts-Augenklinik Tübingen, Germany
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38
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Abstract
The Thr94 --> Ile mutation in the second transmembrane segment of rhodopsin has been reported to be associated with a congenital night blindness phenotype in a large Irish pedigree. Previously, two other known rhodopsin mutants that cause congenital night blindness, A292E and G90D, have been shown in vitro to constitutively activate the G protein transducin in the absence of a chromophore. The proposed mechanism of constitutive activation of these two mutants is an electrostatic disruption of the active site salt bridge between Glu113 and Lys296 that contributes to stabilization of the protein in the inactive state. Here, the T94I rhodopsin mutant is characterized and compared to the two other known rhodopsin night blindness mutants. The T94I mutant opsin is shown also to constitutively activate transducin. The T94I mutant pigment (with a bound 11-cis-retinal chromophore), like the other known rhodopsin night blindness mutants, is not active in the dark and has wild-type activity upon exposure to light. Similar to the Gly90 --> Asp substitution, position 94 is close enough to the Schiff base nitrogen that an Asp at this position can functionally substitute for the Glu113 counterion. However, in contrast to the other night blindness mutants, the T94I MII intermediate decays with a half-life that is approximately 8-fold slower than in the wild-type MII intermediate. Thus, the one phenotype shared by all congenital night blindness mutants that is different from the wild-type protein is constitutive activation of the apoprotein.
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Affiliation(s)
- Alecia K Gross
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454, USA
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39
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Ramon E, del Valle LJ, Garriga P. Unusual thermal and conformational properties of the rhodopsin congenital night blindness mutant Thr-94 --> Ile. J Biol Chem 2003; 278:6427-32. [PMID: 12466267 DOI: 10.1074/jbc.m210929200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Naturally occurring point mutations in the opsin gene cause the retinal diseases retinitis pigmentosa and congenital night blindness. Although these diseases involve similar mutations in very close locations in rhodopsin, their progression is very different, with retinitis pigmentosa being severe and causing retinal degeneration. We report on the expression and characterization of the recently found T94I mutation associated with congenital night blindness, in the second transmembrane helix or rhodopsin, and mutations at the same site. T94I mutant rhodopsin folded properly and was able to bind 11-cis-retinal to form chromophore, but it showed a blue-shifted visible band at 478 nm and reduced molar extinction coefficient. Furthermore, T94I showed dramatically reduced thermal stability, extremely long lived metarhodopsin II intermediate, and highly increased reactivity toward hydroxylamine in the dark, when compared with wild type rhodopsin. The results are consistent with the location of Thr-94 in close proximity to Glu-113 counterion in the vicinity of the Schiff base linkage and suggest a role for this residue in maintaining the correct dark inactive conformation of the receptor. The reported results, together with previously published data on the other two known congenital night blindness mutants, suggest that the molecular mechanism underlying this disease may not be structural misfolding, as proposed for retinitis pigmentosa mutants, but abnormal functioning of the receptor by decreased thermal stability and/or constitutive activity.
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Affiliation(s)
- Eva Ramon
- Centre de Biotecnologia Molecular (CEBIM), Departament d'Enginyeria Quimica, Universitat Politècnica de Catalunya, Colom 1, 08222 Terrassa, Catalonia, Spain
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40
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Zito I, Allen LE, Patel RJ, Meindl A, Bradshaw K, Yates JR, Bird AC, Erskine L, Cheetham ME, Webster AR, Poopalasundaram S, Moore AT, Trump D, Hardcastle AJ. Mutations in the CACNA1F and NYX genes in British CSNBX families. Hum Mutat 2003; 21:169. [PMID: 12552565 DOI: 10.1002/humu.9106] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
X-linked congenital stationary night blindness (CSNBX) is a genetically and phenotypically heterogeneous non-progressive disorder, characterised by impaired night vision but grossly normal retinal appearance. Other more variable features include reduction in visual acuity, myopia, nystagmus and strabismus. Genetic mapping studies by other groups, and our own studies of British patients, identified key recombination events indicating the presence of at least 2 disease genes on Xp11. Two causative genes (CACNA1F and NYX) for CSNBX have now been identified through positional cloning strategies. In this report, we present the results of comprehensive mutation screening in 14 CSNBX families, three with mutations in the CACNA1F gene and 10 with mutations in the NYX gene. In one family we failed to identify the mutation after testing RP2, RPGR, NYX and CACNA1F. NYX gene mutations are a more frequent cause of CSNBX, although there is evidence for founder mutations. Our report of patient population mutation screening for both CSNBX genes, and our exclusion of RP2 and RGPR, indicates that mutations in CACNA1F and NYX are likely to account for all CSNBX.
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Affiliation(s)
- Ilaria Zito
- Division of Molecular Genetics, Institute of Ophthalmology, UCL, London, UK
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41
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Miyake Y. [Establishment of the concept of new clinical entities--complete and incomplete form of congenital stationary night blindness]. Nippon Ganka Gakkai Zasshi 2002; 106:737-55; discussion 756. [PMID: 12610835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
I summarized our long-term study to prove that the complete and incomplete types of congenital stationary night blindness (CSNB) are different clinical entities and that the latter is a newly identified disease which has never been reported in the past. CSNB with normal fundi and negative electroretinogram (ERG) showing selective reduction of the b-wave was previously known as the "Schubert-Bornschein type". For the sake of convenience, we classified the disease into two types according to the absence or the presence of rod function: complete CSNB and incomplete CSNB. The hereditary mode of the former is X-linked recessive and autosomal recessive, while that of the latter is X-linked recessive. They are never found together in a single family. We found several additional differences between the two types, including ERG oscillatory potentials, cone mediated ERG, and refractive errors, all leading us to hypothesize that the two types are not variants of a single disease but are the sum of two different clinical entities. Our hypothesis has recently been proven true by molecular genetical analysis. Namely, the mutated gene in X-linked recessive complete CSNB was found in the nyctalopin (NYX) gene, while that in incomplete CSNB was found in the calcium channel (CANCA1F) gene which encodes the retina-specific calcium channel alpha 1-subunit. These results proved that complete and incomplete CSNB are different clinical entities and that the latter is the first disease of the eye which discloses mutation of this region. We classified 90 patients to include 49 complete and 41 incomplete types. Fifteen incomplete CSNB patients underwent gene analysis and they all showed mutation of the CACNA1F gene. We also examined for gene mutation in several patients who had progressive retinal disease and negative ERG and found two siblings with CANA1F gene mutation. This finding indicates that the mutation of the CACNA1F gene can also cause progressive retinal disease in addition to incomplete CSNB. Gene analysis of 11 patients with complete CSNB was performed and 6 revealed mutation of the NYX gene. The remaining 5 patients showed neither NYX nor CACNA1F gene mutation, suggesting they are of autosomal recessive complete CSNB where gene mutation has not been identified. The comparison of our phenotype and genotype diagnosis indicated that a precise ERG analysis can provide correct differentiation between complete and incomplete types. Other clinical findings include moderately low visual acuity in both types, high or moderate myopia in complete CSNB, and wide distribution from myopia to hyperopia in incomplete CSNB. Pathophysiology studies using clinical patients and animal models suggested that complete CSNB has a complete defect of the ON-bipolar cells or their synapses in the rod and cone visual pathways, leaving the OFF pathway intact (OFF-retina). On the other hand, the incomplete CSNB has an incomplete defect of the ON and OFF bipolar cells or their synapses in the rod and cone visual pathways. The macular function is relatively well preserved in both types, which was shown by focal macular ERG. The incomplete CSNB patients seldom complain of night blindness, which causes us to overlook this disease because we then tend not to perform ERG testing. This disease is not so rare and clinicians should be more aware of its existence. The incomplete CSNB is a new hereditary retinal disease detected by Japanese investigators just like the Oguchi disease, and it has much unknown pathophysiology which needs to be identified in the future. Since the namings of complete and incomplete CSNB may be misunderstood as indicating functional classification of one disease, it has been proposed internationally to change the name "complete type" to CSNB1 and that of "incomplete type" to CSNB2.
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Affiliation(s)
- Yozo Miyake
- Department of Ophthalmology, Nagoya University School of Medicine, 65 Tsuruma-cho, Showa-ku, Nagoya 466-8550, Japan
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42
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Abstract
Rhodopsin is the membrane receptor responsible for photoreception in the vertebrate retina. Its characteristic seven-transmembrane helical structural motif is today widely recognised as a paradigm in signal transduction. Rhodopsin and the phototransduction system are frequently used as structural and mechanistic models for the G-protein coupled receptor superfamily. Recent advances in the activation mechanism (as derived from the structural available data) and the implications for normal and pathological - in retinal disorders - visual function will be reviewed.
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Affiliation(s)
- Pere Garriga
- Secció de Terrassa, Departament d'Enginyeria Qui;mica, Universitat Politècnica de Catalunya, Colom 1, 08222 Terrassa, Catalonia, Spain.
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43
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Abstract
PURPOSE To describe a Japanese patient with incomplete congenital stationary night blindness (iCSNB) with atypical retinal atrophy and kinetic visual field defects. METHODS An ophthalmologic examination was performed, and the CACNA1F gene was analyzed by direct genomic sequencing. RESULTS The patient had a hemizygous Arg913stop mutation in CACNA1F and had electroretinographic changes that were typical of iCSNB. The fundus had atrophic retinal lesions around the inferior vascular arcades OU, and Goldmann kinetic perimetry showed relative scotomas in the corresponding areas. CONCLUSIONS Although most patients with iCSNB show essentially normal fundi without visual field defects, this case demonstrated retinal atrophy associated with visual field defects indicating a phenotypic heterogeneity induced by the CACNA1F mutation.
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Affiliation(s)
- Makoto Nakamura
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Japan.
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44
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Langrová H, Gamer D, Friedburg C, Besch D, Zrenner E, Apfelstedt-Sylla E. Abnormalities of the long flash ERG in congenital stationary night blindness of the Schubert-Bornschein type. Vision Res 2002; 42:1475-83. [PMID: 12044753 DOI: 10.1016/s0042-6989(02)00068-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated abnormalities of the retinal cone ON- and OFF-pathways in 24 males with Schubert-Bornschein congenital stationary night blindness (CSNB). Substantial differences were found between both CSNB types. In incomplete type, a-, b- and d-waves were reduced and delayed, whereas in complete type only the b-wave showed significant changes. Oscillatory potentials (OPs) were not discernible from noise in incomplete CSNB and showed significant peak alterations of the ON-OPs only in complete CSNB. In the complete CSNB type, the ON pathway appeared to be mainly affected. In the incomplete CSNB form marked involvement of both the ON and the OFF pathways was noted.
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Affiliation(s)
- Hana Langrová
- Department of Pathophysiology of Vision and Neuroophthalmology, University Eye Hospital, 72075 Tübingen, Germany.
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45
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Ball SL, Powers PA, Shin HS, Morgans CW, Peachey NS, Gregg RG. Role of the beta(2) subunit of voltage-dependent calcium channels in the retinal outer plexiform layer. Invest Ophthalmol Vis Sci 2002; 43:1595-603. [PMID: 11980879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
PURPOSE Mutations in the alpha(1F) subunit of voltage-dependent calcium channels (VDCCs) have been shown to cause incomplete congenital stationary night blindness (CSNB2). The purpose of this study was to dentify which of the four beta subunits of VDCCs participates in the formation of this channel at the photoreceptor synapse and to determine how its absence affects visual processing. METHODS Mice without each of the four known beta subunits of VDCCs were generated by gene targeting and transgenic rescue (CNS-beta(1), -beta(2)) or by gene targeting alone (beta(3)) or were obtained from a commercial provider (beta(4)). Retinal function and visual sensitivity were examined by electroretinography and an active avoidance behavioral test, respectively. The structure of the retina and expression of the alpha(1F) subunit were examined at the light microscopic level and by immunohistochemistry. RESULTS Under dark-adapted conditions, CNS-beta(2)-null mice had a normal ERG a-wave, but did not have a normal b-wave. In addition, these mice showed decreased sensitivity to light. Both the a- and b-waves appear normal in the CNS-beta(1)-, beta(3)-, and beta(4)-null mice. Histologic analyses of all four mouse lines indicated that only the CNS-beta(2)-null mice had altered retinal morphology. Eyes of these mice had a thinner outer plexiform layer (OPL) than eyes of control animals. In addition, the labeling pattern of the alpha(1F) subunit in the OPL was altered in CNS-beta(2)-null mice. CONCLUSIONS The normal distribution of the alpha(1F) subunit of the VDCCs in the OPL is dependent on the expression of the beta(2) subunit. The expression of both of these subunits is required for normal maintenance and/or formation of the OPL and synaptic transmission.
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Affiliation(s)
- Sherry L Ball
- Research Service, Cleveland VA Medical Center, Cleveland, Ohio, USA
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46
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Abstract
PURPOSE To characterize a distinctive form of congenital stationary night blindness (CSNB). DESIGN Observational case report. PARTICIPANTS A 30-year-old male with a history of night blindness, several members of his family, a patient with "complete" congenital stationary night blindness (CSNB1), and groups of age-similar control subjects. METHODS Rod-system function was evaluated by measuring psychophysical dark-adapted thresholds, by recording dark-adapted electroretinograms (ERGs), and by fundus reflectometry. Cone-system function was evaluated by recording light-adapted ERGs, including those to sawtooth flicker, and by recording light-adapted visually evoked potentials (VEPs) to luminance increments and decrements. MAIN OUTCOME MEASURES Dark-adapted thresholds, ERGs, rhodopsin double densities, Goldmann visual fields, and VEPs. RESULTS The patient's visual acuity, visual fields, and color vision were normal. His peripheral dark-adapted thresholds were rod-mediated but elevated by approximately 3 log units above normal. Rhodopsin double density and bleaching recovery were normal. His dark-adapted maximal-flash ERG showed a "negative" waveform, in which the b-wave was more reduced in amplitude than the a-wave, although the a-wave amplitude was also reduced. The rod photoreceptors contributed to the patient's dark-adapted ERGs, as illustrated by the unequal responses to cone-matched stimuli. The patient's cone-mediated thresholds for long-wavelength stimuli were within the normal range. However, his light-adapted brief-flash b-wave was abnormal in amplitude and implicit time. Selective abnormalities of the ON responses of the cone system were apparent in the patient's reduced b-wave amplitude to rapid-on flicker with a normal response to rapid-off flicker, and his prolonged VEP latencies to increments but not to decrements. CONCLUSIONS The overall pattern of findings distinguishes this patient from previously described forms of CSNB. The results suggest that two factors likely contribute to the patient's night blindness: (1) a rod phototransduction defect and (2) a postreceptoral defect. The results also indicate dysfunction within the cone ON pathway.
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Affiliation(s)
- Claire S Barnes
- Department of Ophthalmology and Visual Science, University of Illinois at Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA
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47
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Abstract
PURPOSE To report a 9-year-old boy with fundus albipunctatus and macular dystrophy. DESIGN Observational case report. METHODS A complete ophthalmic examination was performed. The 11-cis retinol dehydrogenase gene (RDH5) was examined by direct genomic sequencing. RESULTS The fundi of the 9-year-old boy showed numerous yellow-white punctata as well as foveal atrophic lesions in both eyes. His corrected visual acuity was RE: 0.5 and LE: 0.3. Scotopic full-field electroretinograms were not present after 20 minutes of dark-adaptation but were normal after 3 hours of dark-adaptation. Full-field cone and 30-Hz flicker electroretinograms were normal; however, focal macular cone electroretinograms were significantly reduced. A compound heterozygous mutation of Tyr281His and Leu310GluVal in RDH5 was detected. CONCLUSION We suggest that the macular dystrophy is caused by the RDH5 mutation as a phenotype variation in fundus albipunctatus.
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Affiliation(s)
- Makoto Nakamura
- Department of Ophthalmology, Nagoya University School of Medicine, 65-Tsuruma-cho, Showa-ku, Nagoya 466-8550, Japan.
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48
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Saitoh S. [Night blindness, congenital]. Ryoikibetsu Shokogun Shirizu 2002:318-9. [PMID: 11528760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Affiliation(s)
- S Saitoh
- Department of Pediatrics, Hokkaido University School of Medicine
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49
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Morgans CW, Gaughwin P, Maleszka R. Expression of the alpha1F calcium channel subunit by photoreceptors in the rat retina. Mol Vis 2001; 7:202-9. [PMID: 11526344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
PURPOSE The CACNA1F gene encodes a voltage-gated calcium channel alpha1 subunit, alpha1F, which is expressed in the human retina. Mutations in this gene cause incomplete X-linked congenital stationary night blindness (CSNB2). The aim of this study was to obtain the sequence of the rat alpha1F cDNA and localize the encoded polypeptide in the rat retina. METHODS The full-length rat alpha1F sequence was compiled from sequencing of overlapping alpha1F PCR fragments amplified from rat retinal cDNA. Antiserum was raised against a human alpha1F peptide. It was found that the human alpha1F peptide used to generate the antiserum was conserved at only 11 out of 19 residues in the cloned rat sequence. Therefore, antibodies were affinity purified against either the human alpha1F peptide or the equivalent rat peptide and used for immunofluorescent staining of rat retina sections. RESULTS The rat alpha1F amino acid sequence was found to be 91% and 95% identical to the human and mouse alpha1F sequences, respectively. Antibodies affinity purified against the human alpha1F peptide stained both the outer nuclear layer (ONL) and outer plexiform layer of rat retina sections. In contrast, staining with antibodies affinity purified against the corresponding rat alpha1F peptide was restricted to the ONL. CONCLUSIONS The rat alpha1F amino acid sequence is highly homologous to the human and mouse sequences. The immunohistochemical results indicate the existence of distinct alpha1F isoforms or alpha1F-like channels, which are differentially distributed in the cell bodies and synaptic terminals of photoreceptors in the rat retina.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies/immunology
- Antibodies/isolation & purification
- Base Sequence
- Blotting, Western
- Calcium/metabolism
- Calcium Channels/genetics
- Calcium Channels/immunology
- Calcium Channels/metabolism
- Calcium Channels, L-Type
- Chromatography, Affinity
- DNA Primers/chemistry
- DNA, Complementary/analysis
- Eye Proteins/genetics
- Eye Proteins/immunology
- Eye Proteins/metabolism
- Fluorescent Antibody Technique, Indirect
- Gene Expression
- Humans
- Mice
- Molecular Sequence Data
- Night Blindness/congenital
- Peptide Fragments/immunology
- Photoreceptor Cells, Vertebrate/cytology
- Photoreceptor Cells, Vertebrate/metabolism
- Polymerase Chain Reaction
- Presynaptic Terminals/metabolism
- RNA, Messenger/biosynthesis
- Rats
- Rats, Inbred WKY
- Sequence Homology, Amino Acid
- Sheep
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Affiliation(s)
- C W Morgans
- John Curtin School of Medical Research, Australian National University, Canberra, Australia.
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50
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Pesch K, Tomiuk J, Broghammer M, Zrenner E, Apfelstedt-Sylla E, Jacobi FK, Wissinger B, Pusch CM. Case populations must match the respective disease model: Genotype diversity causes linkage disequilibrium mapping failure in monogenic disorders. Int J Mol Med 2001; 8:53-8. [PMID: 11408949 DOI: 10.3892/ijmm.8.1.53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Traditional linkage analysis in large families is the most promising approach for mapping disease genes of monogenic heritable disorders when the number of informative meioses is sufficient. With rare diseases, however, the low availability of informative pedigrees poses a significant limitation. As an adjunct to family linkage methods, association studies based on the investigation of individual haplotypes from a number of unrelated patients (i.e. linkage disequilibrium analysis) have recently been employed in mapping hereditary disease loci. However, such haplotype analysis is hampered by a number of effects that influence statistical evaluation, e.g. i) population history and size, ii) allele and haplotype frequencies in the respective population(s), iii) heterogeneous mutation and natural selection processes, and iv) small sample sizes of patient groups. The purpose of the present study was to determine the utility and limitations of haplotype-based genetic mapping in estimating the location of the NYX gene, which has recently been identified as the causative gene for a rare inherited retinal disorder known as the complete type of X-linked congenital stationary night blindness (CSNB1). For this purpose we recapitulated haplotypes and tested for linkage disequilibrium in 20 unrelated male CSNB1 patients from three European populations and 44 healthy individuals. All subjects were genotyped for 17 polymorphic microsatellite loci covering the Xp11.4 region with an average marker density of approximately 0.29 cM. We found that a precise model to describe mutations at loci that erroneously break up linkage is highly required, and that the case population must match the respective disease model.
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Affiliation(s)
- K Pesch
- Molekulargenetisches Labor, Universitäts-Augenklinik Tübingen, 72076 Tübingen, Germany
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