The Experts below are selected from a list of 7062 Experts worldwide ranked by ideXlab platform
Eberhart Zrenner - One of the best experts on this subject based on the ideXlab platform.
-
gucy2d or guca1a related autosomal dominant cone rod dystrophy is there a phenotypic difference
Retina-the Journal of Retinal and Vitreous Diseases, 2014Co-Authors: Ditta Zobor, Bernd Wissinger, Eberhart Zrenner, Susanne Kohl, Herbert JagleAbstract:Purpose To compare the phenotype of patients with heterozygous mutation in GUCY2D or GUCA1A causing autosomal dominant cone or cone-rod dystrophies. Methods Five patients from one family with GUCA1A and nine patients from four families with GUCY2D mutations were included. Psychophysical and electrophysiological examinations were performed to study retinal function. Fundus autofluorescence imaging and spectral domain optical coherence tomography were performed for morphologic characterization. Results Genetic analysis revealed the mutation c.451C>T (p.L151F) in the GUCA1A family. In the GUCY2D group, c.2512C>T (p.R838C) was the most frequent (2 families), c.2512C>G (p.R838G) and c.2513G>A (p.R838H) were found in one family each. Visual acuity was reduced to 0.04 to 0.7 in GUCA1A and to 0.014 to 0.5 in patients with GUCY2D. Dark adaptation showed elevated thresholds in the GUCY2D group. Scotopic Electroretinography revealed a tendency to a more affected rod function in the GUCY2D group. Photopic Electroretinography showed residual or absent responses in both groups. Fundus alterations were confined to the macula in both groups. Conclusion GUCA1A and GUCY2D mutations are both accompanied by similar pattern of generalized cone dysfunction with a tendency to less involvement of the rod photoreceptors and a less severe phenotype in patients with GUCA1A.
-
a novel mutation of the rp1 gene lys778ter associated with autosomal dominant retinitis pigmentosa
British Journal of Ophthalmology, 2002Co-Authors: K Dietrich, Felix K Jacobi, Bernd Wissinger, Eberhart Zrenner, Stefan Tippmann, R. Schmid, Eckart ApfelstedtsyllaAbstract:Background: Besides the three known genes (RHO, RDS/Peripherin, NRL) involved in autosomal dominant retinitis pigmentosa (adRP), a fourth gene, RP1, has been recently identified. Initial reports suggest that mutations in the RP1 gene are the second most frequent cause of adRP. The clinical findings were described in a family with adRP and a novel mutation in the RP1 gene. Method: Index patients from 15 independent families with adRP in which RHO mutations had been excluded in previous examinations were screened for mutations in the RP1 gene by means of direct DNA sequencing. Evaluation of the RP1 phenotype in patients included funduscopy, kinetic perimetry, dark adapted final threshold test, standard Electroretinography and, in one case, multifocal Electroretinography. Results: One novel nonsense mutation (Lys778ter) in one of these 15 patients was detected. Cosegregation of the mutation with the disease phenotype could be established in the index patient9s family. The phenotype comprises variable expression of clinical disease probably including one case of incomplete penetrance, a onset of symptoms beginning in adulthood, and evidence of regionally varying retinal function loss. Conclusion: The Lys778ter mutation localises inside the critical region harbouring all mutations described so far. The ophthalmic findings support previous observations that variation of disease expression appears as a typical feature of the RP1 phenotype.
-
Clinical applications of multifocal Electroretinography
Documenta Ophthalmologica, 2000Co-Authors: Ulf Kretschmann, Markus Bock, Roland Gockeln, Eberhart ZrennerAbstract:The multifocal ERG using the m-sequence stimulation technique allows the derivation of 61 – 241 local ERG signals in a central visual field of about 60 degree diameter in a short time between 4 and 16 min. A recording in a light adapted state offers local information comparable to cone responses in the full-field ERG. Retinal functional losses due to regional disorders in outer retinal layers can be described in detail with this technique. In maculopathies decreased or absent central ERGs are found surrounded by normal ERG. The extent of the central lesion can be estimated. In diseases of the outer retina the pattern of distribution of multifocal ERG activity is similar to the the pattern of the visual field defect. In addition to decreased ERG amplitudes a delay of implicit time may be an important sign of pathology, i.e. the pronounced delay of implicit times in the periphery in retinitis pigmentosa and the implicit time delays in regions associated with retinal edema like CRVO and cystoid macula edema in intermediate uveitis. No simple correlation of the first order kernel multifocal ERG and field defects could be found in disorders of the ganglion cell layer. The multifocal ERG is therefore useful in the differential diagnosis of retinal and optic nerve diseases.
-
Multifocal Electroretinography in retinitis pigmentosa.
American Journal of Ophthalmology, 1998Co-Authors: Mathias W Seeliger, Ulf Kretschmann, Eckart Apfelstedt-sylla, Klaus Rüther, Eberhart ZrennerAbstract:Purpose To investigate the diagnostic potential of multifocal Electroretinography for the evaluation of retinal affection by retinitis pigmentosa in a clinical setting. Methods For this prospective study, multifocal electroretinograms were obtained from 38 patients who matched the inclusion criteria of either a detectable photopic Ganzfeld response or visual fields of 10 degrees or more, and from 30 normal volunteers. Recordings were performed with the visual evoked response imaging system, using a resolution of 61 hexagonal elements within a 30-degree visual field. The results of the left eye of each patient and control subject were used for statistical evaluation by the Mann-Whitney U test. Results The 38 eligible patients included those with Usher syndrome types I and II (one patient and six patients, respectively) and those with autosomal-recessive (18), X-recessive (two), and autosomal-dominant (11) forms of retinitis pigmentosa. In 27 (71%) of these 38 patients, at least a central response of the multifocal electroretinogram was detectable. Loss of multifocal electroretinogram response density in patients with retinitis pigmentosa was significant ( P P P Conclusions Because the multifocal electroretinogram differentiates between affected and nonaffected retinal areas, eccentricity-dependent changes in both amplitude and implicit time were found. It can therefore add to the diagnostic information of many patients with retinitis pigmentosa.
-
standard for clinical Electroretinography 1999 update
Documenta Ophthalmologica, 1998Co-Authors: Michael F Marmor, Eberhart ZrennerAbstract:(for the International Society for Clinical Electrophysiology of Vision) (for the International Society for Clinical Electrophysiology of Vision)
Bernd Wissinger - One of the best experts on this subject based on the ideXlab platform.
-
CLINICAL SCIENCE A novel mutation of the RP1 gene (Lys778ter) associated with autosomal dominant retinitis pigmentosa
2016Co-Authors: K Dietrich, Felix K Jacobi, Bernd Wissinger, R. Schmid, E Zrenner, Br J OphthalmolAbstract:Background: Besides the three known genes (RHO, RDS/Peripherin, NRL) involved in autosomal dominant retinitis pigmentosa (adRP), a fourth gene, RP1, has been recently identified. Initial reports suggest that mutations in the RP1 gene are the second most frequent cause of adRP. The clinical find-ings were described in a family with adRP and a novel mutation in the RP1 gene. Method: Index patients from 15 independent families with adRP in which RHO mutations had been excluded in previous examinations were screened for mutations in the RP1 gene by means of direct DNA sequencing. Evaluation of the RP1 phenotype in patients included funduscopy, kinetic perimetry, dark adapted final threshold test, standard Electroretinography and, in one case, multifocal Electroretinography. Results: One novel nonsense mutation (Lys778ter) in one of these 15 patients was detected. Cosegre-gation of the mutation with the disease phenotype could be established in the index patient’s family. The phenotype comprises variable expression of clinical disease probably including one case of incomplete penetrance, a onset of symptoms beginning in adulthood, and evidence of regionally vary-ing retinal function loss. Conclusion: The Lys778ter mutation localises inside the critical region harbouring all mutation
-
gucy2d or guca1a related autosomal dominant cone rod dystrophy is there a phenotypic difference
Retina-the Journal of Retinal and Vitreous Diseases, 2014Co-Authors: Ditta Zobor, Bernd Wissinger, Eberhart Zrenner, Susanne Kohl, Herbert JagleAbstract:Purpose To compare the phenotype of patients with heterozygous mutation in GUCY2D or GUCA1A causing autosomal dominant cone or cone-rod dystrophies. Methods Five patients from one family with GUCA1A and nine patients from four families with GUCY2D mutations were included. Psychophysical and electrophysiological examinations were performed to study retinal function. Fundus autofluorescence imaging and spectral domain optical coherence tomography were performed for morphologic characterization. Results Genetic analysis revealed the mutation c.451C>T (p.L151F) in the GUCA1A family. In the GUCY2D group, c.2512C>T (p.R838C) was the most frequent (2 families), c.2512C>G (p.R838G) and c.2513G>A (p.R838H) were found in one family each. Visual acuity was reduced to 0.04 to 0.7 in GUCA1A and to 0.014 to 0.5 in patients with GUCY2D. Dark adaptation showed elevated thresholds in the GUCY2D group. Scotopic Electroretinography revealed a tendency to a more affected rod function in the GUCY2D group. Photopic Electroretinography showed residual or absent responses in both groups. Fundus alterations were confined to the macula in both groups. Conclusion GUCA1A and GUCY2D mutations are both accompanied by similar pattern of generalized cone dysfunction with a tendency to less involvement of the rod photoreceptors and a less severe phenotype in patients with GUCA1A.
-
morphology and functional characteristics in adult vitelliform macular dystrophy
Retina-the Journal of Retinal and Vitreous Diseases, 2004Co-Authors: Agnes B Renner, Bernd Wissinger, Ulrich Kellner, H Tillack, Hannelore Kraus, Susanne Kohl, Nicole Mohr, Bernhard H F Weber, M H FoersterAbstract:Purpose: Detailed morphologic and functional evaluation of adult vitelliform macular dystrophy (AVMD). Methods: The records of 61 consecutive AVMD patients (inclusion criterion: vitelliform lesion smaller than one disk diameter at least in one eye) were evaluated retrospectively regarding visual acuity, color vision, perimetry, retinal pigment epithelium (RPE) autofluorescence, fluorescein angiography, electro-oculography, full-field and multifocal Electroretinography, and molecular genetic evaluation of the VMD2 and RDS/peripherin genes. Results: The mean age of subjects was 54.6 years. Visual loss was variable (median, 0.6; range, 1.25–0.05). Color vision and visual field were normal in about half of the patients but presented defects with high variability in the remaining patients. Autofluorescence findings showed increased fluorescence within the foveal yellow lesion in 76%. In the majority of eyes, the amplitude of the 30 Hz flicker response of the full-field electroretinogram (72%) and the central P1 amplitude of the multifocal electroretinogram (63%) were reduced. Mutational analyses revealed a potentially disease-associated mutation in the RDS/peripherin gene in one patient. Conclusion: AVMD is characterized by late onset, slow progression, good prognosis, and high variability of morphologic and functional abnormalities resulting frequently in misdiagnosis. Autofluorescence findings indicate lipofuscin accumulation in the yellow lesion. Electroretinography revealed a generalized cone system dysfunction with increasing severity toward the fovea.
-
a novel mutation of the rp1 gene lys778ter associated with autosomal dominant retinitis pigmentosa
British Journal of Ophthalmology, 2002Co-Authors: K Dietrich, Felix K Jacobi, Bernd Wissinger, Eberhart Zrenner, Stefan Tippmann, R. Schmid, Eckart ApfelstedtsyllaAbstract:Background: Besides the three known genes (RHO, RDS/Peripherin, NRL) involved in autosomal dominant retinitis pigmentosa (adRP), a fourth gene, RP1, has been recently identified. Initial reports suggest that mutations in the RP1 gene are the second most frequent cause of adRP. The clinical findings were described in a family with adRP and a novel mutation in the RP1 gene. Method: Index patients from 15 independent families with adRP in which RHO mutations had been excluded in previous examinations were screened for mutations in the RP1 gene by means of direct DNA sequencing. Evaluation of the RP1 phenotype in patients included funduscopy, kinetic perimetry, dark adapted final threshold test, standard Electroretinography and, in one case, multifocal Electroretinography. Results: One novel nonsense mutation (Lys778ter) in one of these 15 patients was detected. Cosegregation of the mutation with the disease phenotype could be established in the index patient9s family. The phenotype comprises variable expression of clinical disease probably including one case of incomplete penetrance, a onset of symptoms beginning in adulthood, and evidence of regionally varying retinal function loss. Conclusion: The Lys778ter mutation localises inside the critical region harbouring all mutations described so far. The ophthalmic findings support previous observations that variation of disease expression appears as a typical feature of the RP1 phenotype.
Mathias W Seeliger - One of the best experts on this subject based on the ideXlab platform.
-
visual function in cav1 4 deficient mice
Biophysical Journal, 2012Co-Authors: Lior Shaltiel, Mathias W Seeliger, Martin Biel, Stylianos Michalakis, Vithiyanjali Sothilingam, Marina Garcia Garrido, Susanne Koch, Naoyuki Tanimoto, Christian WahlschottAbstract:CACNA1F encodes the alpha1 subunit of retina-specific Cav1.4 voltage-gated L type calcium channels. Mutations in this gene cause congenital stationary night blindness type 2A (CSNB2), Aland Island eye disease (AIED) and cone-rod dystrophy type 3 (CORDX3). The clinical phenotypes of these eye diseases vary substantially regarding the ratio of rod to cone functional impairment. The reasons for this variability are not known. To gain more insights into the pathophysiology caused by loss of Cav1.4 function we analyzed the visual phenotype of Cav1.4-deficient mice. To this end, we combined immunohistochemistry, Electroretinography (ERG) and vision-dependent behavioral testing. Immunohistochemical analysis using synaptic and postsynaptic markers revealed severe synaptic defects in Cav1.4-deficient mice. Heterozygous Cav1.4 mice showed mosaic synaptic defects most probably caused by random X-chromosomal inactivation of the healthy allele. Electroretinography revealed a loss of scotopic and photopic photoreceptor function. This loss of retinal network function resulted in impaired perfomance of Cav1.4 knockout mice in a water maze-based behavioral test of rod and cone function. In conclusion, loss of Cav1.4 channels strongly impairs rod and cone retinal function and vision in mice.
-
vision tests in the mouse functional phenotyping with Electroretinography
Frontiers in Bioscience, 2009Co-Authors: Naoyuki Tanimoto, Martin Biel, Regine Muehlfriedel, M D Fischer, E Fahl, Peter Humphries, Mathias W SeeligerAbstract:: Electroretinography (ERG) is an established diagnostic technique in clinical ophthalmology and provides objective information about retinal function. This technique is also applied in basic research, where animal models of hereditary retinopathies have significantly contributed to our understanding of the composition of ERG responses in general and how retinal degenerative pathologies alter retinal function specifically. Indeed, electrophysiologic assessment of transgenic mice, which are genetically engineered to mimic human mutations that lead to retinal diseases, can be well compared with clinical data. Furthermore, limitations on examinations (e.g. length of measurement, range of light intensity) are much less of a concern when assessing mice compared to human patients. In order to measure and analyze retinal responses properly, several important aspects have to be considered. This paper focuses on these aspects, and shows exemplary ERG data which were obtained from normal wild-type mice and from transgenic mice with specific functional properties, namely Rho-/- (rod opsin knockout, cone function only), and Cnga3-/- (cone CNG channel deficient, rod function only) to illustrate rod and cone system contributions to ERG responses.
-
standard for clinical Electroretinography 2004 update
Documenta Ophthalmologica, 2004Co-Authors: Michael F Marmor, Mathias W Seeliger, Graham E. Holder, Shuichi YamamotoAbstract:Michael F. Marmor1, Graham E. Holder2, Mathias W. Seeliger3 & Shuichi Yamamoto4∗∗, For the International Society for Clinical Electrophysiology of Vision 1Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA; 2Department of Electrophysiology, Moorfields Eye Hospital, London, England; 3Retinal Electrodiagnostics Research Group, University Eye Hospital, Dept. II, Tubingen, Germany; 4Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan
-
guidelines for basic multifocal Electroretinography mferg
Documenta Ophthalmologica, 2003Co-Authors: Michael F Marmor, David Keating, Mathias W Seeliger, Donald C. Hood, Mitsuhiro Kondo, Yozo MiyakeAbstract:Michael F. Marmor1, Donald C. Hood2, David Keating3, Mitsuhiro Kondo4, Mathias W. Seeliger5 & Yozo Miyake4 (for the International Society for Clinical Electrophysiology of Vision) 1Department of Ophthalmology, Stanford University School of Medicine, Stanford, California, USA; 2Department of Psychology, Columbia University, New York, New York, USA; 3Department of Ophthalmology, Gartnavel General Hospital, Glasgow, UK; 4Department of Ophthalmology, Nagoya University School of Medicine, Nagoya, Japan; 5Department II, University Eye Hospital, Tubingen, Germany
-
Multifocal Electroretinography in retinitis pigmentosa.
American Journal of Ophthalmology, 1998Co-Authors: Mathias W Seeliger, Ulf Kretschmann, Eckart Apfelstedt-sylla, Klaus Rüther, Eberhart ZrennerAbstract:Purpose To investigate the diagnostic potential of multifocal Electroretinography for the evaluation of retinal affection by retinitis pigmentosa in a clinical setting. Methods For this prospective study, multifocal electroretinograms were obtained from 38 patients who matched the inclusion criteria of either a detectable photopic Ganzfeld response or visual fields of 10 degrees or more, and from 30 normal volunteers. Recordings were performed with the visual evoked response imaging system, using a resolution of 61 hexagonal elements within a 30-degree visual field. The results of the left eye of each patient and control subject were used for statistical evaluation by the Mann-Whitney U test. Results The 38 eligible patients included those with Usher syndrome types I and II (one patient and six patients, respectively) and those with autosomal-recessive (18), X-recessive (two), and autosomal-dominant (11) forms of retinitis pigmentosa. In 27 (71%) of these 38 patients, at least a central response of the multifocal electroretinogram was detectable. Loss of multifocal electroretinogram response density in patients with retinitis pigmentosa was significant ( P P P Conclusions Because the multifocal electroretinogram differentiates between affected and nonaffected retinal areas, eccentricity-dependent changes in both amplitude and implicit time were found. It can therefore add to the diagnostic information of many patients with retinitis pigmentosa.
Maurice Ptito - One of the best experts on this subject based on the ideXlab platform.
-
Standardized full-field Electroretinography in the Green Monkey (Chlorocebus sabaeus).
PLoS ONE, 2014Co-Authors: Joseph Bouskila, Roberta M. Palmour, Jeanfrancois Bouchard, Pasha Javadi, Maurice PtitoAbstract:Full-field Electroretinography is an objective measure of retinal function, serving as an important diagnostic clinical tool in ophthalmology for evaluating the integrity of the retina. Given the similarity between the anatomy and physiology of the human and Green Monkey eyes, this species has increasingly become a favorable non-human primate model for assessing ocular defects in humans. To test this model, we obtained full-field electroretinographic recordings (ERG) and normal values for standard responses required by the International Society for Clinical Electrophysiology of Vision (ISCEV). Photopic and scotopic ERG recordings were obtained by full-field stimulation over a range of 6 log units of intensity in dark-adapted or light-adapted eyes of adult Green Monkeys (Chlorocebus sabaeus). Intensity, duration, and interval of light stimuli were varied separately. Reproducible values of amplitude and latency were obtained for the a- and b-waves, under well-controlled adaptation and stimulus conditions; the i-wave was also easily identifiable and separated from the a-b-wave complex in the photopic ERG. The recordings obtained in the healthy Green Monkey matched very well with those in humans and other non-human primate species (Macaca mulatta and Macaca fascicularis). These results validate the Green Monkey as an excellent non-human primate model, with potential to serve for testing retinal function following various manipulations such as visual deprivation or drug evaluation.
-
Standardized Full-Field Electroretinography in the Green Monkey (Chlorocebus sabaeus)
2014Co-Authors: Joseph Bouskila, Roberta M. Palmour, Pasha Javadi, Maurice PtitoAbstract:Full-field Electroretinography is an objective measure of retinal function, serving as an important diagnostic clinical tool in ophthalmology for evaluating the integrity of the retina. Given the similarity between the anatomy and physiology of the human and Green Monkey eyes, this species has increasingly become a favorable non-human primate model for assessing ocular defects in humans. To test this model, we obtained full-field electroretinographic recordings (ERG) and normal values for standard responses required by the International Society for Clinical Electrophysiology of Vision (ISCEV). Photopic and scotopic ERG recordings were obtained by full-field stimulation over a range of 6 log units of intensity in dark-adapted or light-adapted eyes of adult Green Monkeys (Chlorocebus sabaeus). Intensity, duration, and interval of light stimuli were varied separately. Reproducible values of amplitude and latency were obtained for the a- and b-waves, under well-controlled adaptation and stimulus conditions; the i-wave was also easily identifiable and separated from the a-b-wave complex in the photopic ERG. The recordings obtained in the healthy Green Monkey matched very well with those in humans and other non-human primate species (Macaca mulatta and Macaca fascicularis). These results validate the Green Monkey as an excellent non-human primate model, with potential to serve for testing retinal function following variou
Eckart Apfelstedtsylla - One of the best experts on this subject based on the ideXlab platform.
-
a novel mutation of the rp1 gene lys778ter associated with autosomal dominant retinitis pigmentosa
British Journal of Ophthalmology, 2002Co-Authors: K Dietrich, Felix K Jacobi, Bernd Wissinger, Eberhart Zrenner, Stefan Tippmann, R. Schmid, Eckart ApfelstedtsyllaAbstract:Background: Besides the three known genes (RHO, RDS/Peripherin, NRL) involved in autosomal dominant retinitis pigmentosa (adRP), a fourth gene, RP1, has been recently identified. Initial reports suggest that mutations in the RP1 gene are the second most frequent cause of adRP. The clinical findings were described in a family with adRP and a novel mutation in the RP1 gene. Method: Index patients from 15 independent families with adRP in which RHO mutations had been excluded in previous examinations were screened for mutations in the RP1 gene by means of direct DNA sequencing. Evaluation of the RP1 phenotype in patients included funduscopy, kinetic perimetry, dark adapted final threshold test, standard Electroretinography and, in one case, multifocal Electroretinography. Results: One novel nonsense mutation (Lys778ter) in one of these 15 patients was detected. Cosegregation of the mutation with the disease phenotype could be established in the index patient9s family. The phenotype comprises variable expression of clinical disease probably including one case of incomplete penetrance, a onset of symptoms beginning in adulthood, and evidence of regionally varying retinal function loss. Conclusion: The Lys778ter mutation localises inside the critical region harbouring all mutations described so far. The ophthalmic findings support previous observations that variation of disease expression appears as a typical feature of the RP1 phenotype.