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Autosomal recessive bestrophinopathy (ARB) has been reported as clinically heterogeneous. Eighteen patients (mean age: 22.5 years, 15 unrelated families) underwent ophthalmological examination, fundus photography, fundus autofluorescence, and optical coherence tomography (OCT). Molecular genetic testing of the BEST1 gene was conducted by the chain-terminating dideoxynucleotide Sanger methodology. Onset of symptoms (3 to 50 years of age) and best-corrected visual acuity (0.02&ndash, 1.0) were highly variable. Ophthalmoscopic and retinal imaging defined five phenotypes. Phenotype I presented with single or confluent yellow lesions at the posterior pole and midperiphery, serous retinal detachment, and intraretinal cystoid spaces. In phenotype II fleck-like lesions were smaller and extended to the far periphery. Phenotype III showed a widespread continuous lesion with sharp peripheral demarcation. Single (phenotype IV) or multifocal (phenotype V) vitelliform macular dystrophy-like lesions were observed as well. Phenotypes varied within families and in two eyes of one patient. In addition, OCT detected hyperreflective foci (13/36 eyes) and choroidal excavation (11/36). Biallelic mutations were identified in each patient, six of which have not been reported so far [c.454C&gt, T/p.(Pro152Ser), c.620T&gt, A/p.(Leu207His), c.287_298del/p.(Gln96_Asn99del), c.199_200del/p.(Leu67Valfs*164), c.524del/p.(Ser175Thrfs*19), c.590_615del/p.(Leu197Profs*26)]. BEST1-associated ARB presents with a variable age of onset and clinical findings, that can be categorized in 5 clinical phenotypes. Hyperreflective foci and choroidal excavation frequently develop as secondary manifestations.

PURPOSE In patients with central visual field scotomata, a large part of visual cortex is not adequately stimulated. Patients often use a new eccentric fixation area on intact peripheral retina ("preferred retinal locus"-PRL) that functions as a pseudo-fovea. We used functional magnetic resonance imaging (fMRI) to examine whether stimulating this pseudo-fovea leads to increased activation or altered activation patterns in visual cortex in comparison to stimulating a comparable peripheral area in the opposite hemifield (OppPRL). METHODS Nineteen patients with binocular central scotomata caused by hereditary retinal dystrophies and an age-matched control group were tested. The center of the visual field, PRL, and OppPRL were stimulated with flickering checkerboard stimuli and object pictures during fMRI measurement. RESULTS Results show that stimulation with pictures of everyday objects led to overall larger BOLD (blood oxygen level dependent) responses in visual cortex compared to that evoked by stimulation with flickering checkerboards. Patients showed this enhancement as early as in V1. When the PRL was directly stimulated with object pictures, the central representation area in early visual cortex was coactivated in the patients but not in the controls. In higher visual areas beyond retinotopic cortex, BOLD responses to stimulation of the PRL with object pictures were significantly enhanced in comparison to stimulation of the OppPRL area. Highly stable eccentric fixation with the PRL was associated with a higher BOLD signal in visual cortex in patients, and this effect was most pronounced in the conditions with object picture stimulation. CONCLUSIONS The observed results suggest that naturalistic images are more likely to trigger top-down processes that regulate activation in early visual cortex in patients with central vision loss.

To describe clinical characteristics of Muller cell sheen dystrophy (MCSD) in two unrelated patients followed for 10 years. Best-corrected visual acuity (BCVA), kinetic perimetry, biomicroscopy, ophthalmoscopy, fundus photography, fluorescein angiography, fundus autofluorescence, near-infrared reflectance, optical coherence tomography (OCT), and electroretinography (ERG). Case 1: A 61-year-old woman showed internal limiting membrane (ILM) folds at the posterior pole (OU), and cystoid macular edema (CME) in OD. During follow-up, BCVA decreased from 0.2 to 0.06 (OD) and from 0.7 to hand movements (OS). Fundus presented fluctuant CME and subretinal fluid, and an increase in ILM folds and intraretinal schisis cavities. ERG was negative in OD and initially normal in OS. Case 2: A 60-year-old man was first diagnosed with epiretinal membrane before MCSD with ILM folds was detected. OCT showed schisis cavities in all retinal layers. After vitrectomy with ILM peeling in OD because of visual loss and massive CME, BCVA recovered from 0.05 to 0.4. BCVA in OS remained at 0.6. OD developed negative ERG. MCSD presents with late onset, ILM folds, intraretinal schisis cavities, and negative ERG. Visual loss is accompanied by CME and subretinal fluid. Vitrectomy with ILM peeling led to BCVA increase and anatomic improvement.

To describe a distinctive foveal cavitation as seen by spectral-domain optical coherence tomography in certain cone dysfunction syndromes.Observational case series. Patients were evaluated by dilated fundus examination, fundus photography, fundus autofluorescence, full-field electroretinogram, multifocal electroretinogram, spectral-domain optical coherence tomography, color vision testing, fluorescein angiography, Goldmann visual field testing, and molecular genetic analysis.We present eight patients with foveal cavitation in association with presumed cone dysfunction. This was characterized on spectral-domain optical coherence tomography by a gap in the subfoveal outer segment layer without more diffuse retinal thinning. There were 5 patients of age 10 years to 27 years and 3 patients of age 49 years to 52 years, with a 1.5- to 38-year history of bilateral visual loss. A small foveal oval-shaped area of reduced foveal fundus autofluorescence, surrounded by increased fundus autofluorescence, was seen in the younger patients, and a broad circle of increased fundus autofluorescence in the older patients. The multifocal electroretinogram always showed central amplitude reduction, but there were varying degrees of cone dysfunction on full-field electroretinogram. There were mild abnormalities on desaturated color vision testing. The family history was noncontributory in all cases. None of the cases were congenital. ABCA4 gene mutations were identified in three of five patients tested; CNGB3 testing was negative in these patients.Cone dysfunction syndromes typically show retinal thinning on optical coherence tomography imaging, although several case reports have noted focal outer retinal loss. Our case series shows that a distinctive optical coherence tomography finding, foveal cavitation, may be a clue to cone dysfunction syndromes, but is not specific to any one hereditary disorder or age group.

We report the clinical and genetic data obtained at a 17-year follow-up examination of a patient with gyrate atrophy, without an arginine-restricted diet. Patient examinations included visual acuity (VA), perimetry, biomicroscopy, funduscopy, fundus photography, fundus autofluorescence (FAF), spectral-domain optical coherence tomography (OCT), and standard full-field electroretinography (ERG). Blood samples were taken for measurement of serum ornithine level and molecular genetic analysis of the OAT gene. The female was 22 years of age when gyrate atrophy was diagnosed based on peripheral chorioretinal atrophy and an increased ornithine level. Reexamination after 17 years revealed a reduced VA (0.25 OU), dense cataract, extensive peripheral chorioretinal atrophy, a further increased ornithine level, but only slow progression of visual field constriction, and still detectable ERG amplitudes. FAF was absent in the atrophic periphery and almost homogeneous at the posterior pole except parafoveally. OCT showed interruption of the foveal inner/outer segment junction and parafoveal microcystoid spaces. After cataract surgery, VA increased to the same values as those found at the age of 22 years (0.5 OD, 0.6 OS). Molecular analysis revealed a new deletion c.532_536delTGGGG (p.Trp178X) and a known mutation c.897C>G (p.Tyr299X) in the OAT gene. Although the patient had refused to diet during her first 39 years of life, the gyrate atrophy showed a very slow progression. FAF allows evaluating the integrity of the retinal pigment epithelium and may help to delimit gyrate atrophy from choroideremia. Interruption of foveal inner/outer segment junction and cystoid macula edema appears in gyrate atrophy.

In patients with central visual field scotomata a large part of visual cortex is not adequately stimulated. We investigated evidence for possible upregulation in cortical responses in 22 patients (8 females, 14 males; mean age 41.5 years, range 12-65 years) with central visual field loss due to hereditary retinal dystrophies (Stargardt's disease, other forms of hereditary macular dystrophies and cone-rod dystrophy) and compared their results to those of 22 age-matched controls (11 females, 11 males; mean age, 42.4 years, range, 13-70 years). Using functional magnetic resonance imaging (fMRI) we recorded differences in behavioral and BOLD signal distribution in retinotopic mapping and visual search tasks. Patients with an established preferred retinal locus (PRL) exhibited signifi- cantly higher activation in early visual cortex during the visual search task, especially on trials when the target stimuli fell in the vicinity of the PRL. Compared with those with less stable fixation, patients with stable eccentric fixation at the PRL exhibited greater performance levels and more brain activa- tion. Hum Brain Mapp 00:000-000, 2012. V C 2012 Wiley Periodicals, Inc.

Audo, Isabelle, et al., Congenital stationary night blindness (CSNB) is a heterogeneous retinal disorder characterized by visual impairment under low light conditions. This disorder is due to a signal transmission defect from rod photoreceptors to adjacent bipolar cells in the retina. Two forms can be distinguished clinically, complete CSNB (cCSNB) or incomplete CSNB; the two forms are distinguished on the basis of the affected signaling pathway. Mutations in NYX, GRM6, and TRPM1, expressed in the outer plexiform layer (OPL) lead to disruption of the ON-bipolar cell response and have been seen in patients with cCSNB. Whole-exome sequencing in cCSNB patients lacking mutations in the known genes led to the identification of a homozygous missense mutation (c.1807C>T [p.His603Tyr]) in one consanguineous autosomal-recessive cCSNB family and a homozygous frameshift mutation in GPR179 (c.278delC [p.Pro93Glnfs57]) in a simplex male cCSNB patient. Additional screening with Sanger sequencing of 40 patients identified three other cCSNB patients harboring additional allelic mutations in GPR179. Although, immunhistological studies revealed Gpr179 in the OPL in wild-type mouse retina, Gpr179 did not colocalize with specific ON-bipolar markers. Interestingly, Gpr179 was highly concentrated in horizontal cells and Müller cell endfeet. The involvement of these cells in cCSNB and the specific function of GPR179 remain to be elucidated., The project was supported by GIS-maladies rares (C.Z.), Retina France ([part of the 100-Exome Project] I.A., C.P.H., J.-A.S., H.D. and C.Z.), Foundation Voir et Entendre (C.Z.), Agence National de la Recherche (S.S.B), Foundation Fighting Blindness (FFB) grant CD-CL-0808-0466-CHNO (I.A. and the CIC503, recognized as an FFB center), FFB grant C-CMM-0907-0428-INSERM04, Ville de Paris and Région Ille de France, the French Association against Myopathy (AFM) grant KBM-14390 (O.P.), and National Institutes of Health grant 1R01EY020902-01A1 (K.B.).

Interferon (IFN) beta is commonly used in the treatment of multiple sclerosis. Thromboembolic complications may be associated with this therapy. We describe a case of branch arterial occlusions combined with central vein occlusion in a female patient who had undergone IFN beta therapy for 10 years. Thromboembolic and cardiovascular risk factors responsible for this event were excluded. The appearance of retinal vein and artery occlusions in our patient indicates an association with the long-term use of IFN beta.

Hornhauterkrankungen stellen einen wichtigen Bereich in der Kinderophthalmologie dar. Die Pathogenese der Keratoconjunctivitis sicca und der neurotrophen Keratopathie ist auch im Kindesalter komplex: Beide Entitaten konnen sowohl isoliert als auch im Rahmen von systemischen Erkrankungen auftreten. Die Diagnosestellung erfolgt bei Kindern aufgrund der teilweise erschwerten Untersuchbarkeit haufig verzogert. Bei nicht rechtzeitiger Behandlung kann es zu bleibenden Schaden und Amblyopie kommen. Literaturubersicht uber die Pathogenese der Keratoconjunctivitis sicca und neurotrophen Keratopathie im Kindesalter sowie klinische Beispiele aus der kinderophthalmologischen Sprechstunde und Ubersicht zur Therapie. Keratoconjunctivitis sicca und neurotrophe Keratopathie sind bei Kindern seltener als bei Erwachsen, zeigen aber ein sehr breites atiopathologisches Spektrum. Die Kenntnis der Differenzialdiagnosen und die Anwendung kindgerechter Untersuchungstechniken sowie in einigen Fallen eine interdisziplinare Zusammenarbeit sind wichtig fur die fruhzeitige Diagnosestellung und die Vermeidung von Komplikationen. Keratoconjunctivitis sicca und neurotrophe Keratopathie konnen bei Kindern leicht ubersehen werden, da ihr Vorkommen im Kindesalter teilweise unterschatzt wird und die Untersuchbarkeit bei Kindern haufig reduziert ist.

BACKGROUND: Hereditary retinal dystrophies comprise a heterogeneous group of inherited retinal disorders with variable clinical presentation and multiple associated genes. Clinical diagnosis and differential diagnosis are difficult. The purpose of the current paper is to provide guidelines for an effective diagnostic approach. METHODS: A literature search was carried out and our own data on clinical (n = 3200) and molecular genetic (n = 4050) diagnosis of patients with retinal dystrophies were evaluated. RESULTS: For an early diagnosis it is of importance to include inherited retinal dystrophies in the differential diagnosis of unexplained visual disturbances. The most important clinical test is the full-field electroretinogram (ERG), which allows detection or exclusion of generalised retinal dystrophies. If the full-field ERG is normal, a multifocal ERG will distinguish macular dystrophies. Fundus autofluorescence, near-infrared autofluorescence and high resolution optical coherence tomography improve the early diagnosis because morphological alterations can be detected prior to their ophthalmoscopic visibility. In addition, these non-invasive imaging techniques reveal new phenomena which are important for the differential diagnosis and follow-up of retinal dystrophies as well as for an improved understanding of their pathogenesis. Routine molecular genetic diagnosis is available for an increasing number of retinal dystrophies. A succinct clinical diagnosis is a prerequisite to allow selection of the gene(s) to be analysed. If genetic testing is indicated, a human geneticist should be involved for counselling of the patient and possibly further family members and initiation of the necessary steps for DNA testing. CONCLUSION: The combination of electrophysiological testing, retinal imaging and molecular genetic analysis allows a differentiated diagnosis of inherited retinal dystrophies and an individual counselling of patients. If inherited retinal dystrophies are suspected, a detailed examination in a retinal centre specialised on inherited retinal dystrophies is recommended.

The retinal pigment epithelium (RPE) serves a variety of different functions and impairment of these functions can lead to a multitude of different diseases of the posterior segment of the eye. The RPE plays an important role as an ion and fluid pump for the reabsorption of subretinal fluid in retinal detachment. On the other hand, defects in this pump function and in the outer blood-retinal barrier formed by the RPE, lead to fluid retention in inflammatory diseases. Metaplasia of RPE cells to myofibroblasts can lead to proliferative vitreoretinopathy and tractive retinal detachment. Early age-related maculopathy is caused by disturbances of phagocytosis and metabolism of the RPE. Imbalance of the physiological equilibrium between vasoproliferative and vasoinhibitory factors secreted by the RPE is probably involved in the development of atrophic or neovascular forms of advanced age-related macular degeneration. Mutations in the different steps involved in regeneration of the visual pigment (visual cycle) may lead to retinal dystrophy. Finally, immunoregulatory properties of the RPE are responsible for the phenomenon of immunological privilege, which may facilitate clinical interventions such as gene therapy and RPE transplantation.

Tamoxifen wird in der adjuvanten Therapie bei der Behandlung des Mammakarzinoms eingesetzt. In seltenen Fallen konnen Sehstorungen unter Tamoxifen-Therapie beobachtet werden. Retrospektive Auswertung von klinischen und funktionellen (Visus, Gesichtsfeld, Farbensehen) Befunden bei einer Fallserie von 8 Patientinnen unter Tamoxifen-Therapie mit Einschluss einer elektrophysiologischen Untersuchung. Sieben der 8 Patientinnen gaben Sehstorungen an. Bei einer Patientin zeigten sich kristalline Ablagerungen in der Hornhaut und Makula. Drei Patientinnen wiesen Veranderungen im Ganzfeld- und multifokalen Elektroretinogramm auf, 2 Patientinnen zeigten lediglich ein pathologisches multifokales Elektroretinogramm. In 6 Fallen wurde ein desaturierter Panel-D-15-Farbsehtest durchgefuhrt, der bei 5 Patientinnen masige Verwechselungen offenbarte. Die Mehrzahl der sehbeeintrachtigten Tamoxifen-Patientinnen zeigte elektrophysiologische Veranderungen, insbesondere im multifokalen Elektroretinogramm, wobei sich ein morphologisches Korrelat haufig nicht sicher nachweisen lies. Bei unklaren Sehstorungen unter Tamoxifen-Einnahme empfiehlt sich daher eine elektrophysiologische Abklarung.

The purpose of this retrospective study was to determine the relevance of both visual-evoked potentials (VEP) and multifocal electroretinography (mfERG) to evaluate unexplained visual loss. Seventy-two consecutive patients (1996-2002) with visual disturbances of unknown origin underwent both VEP and mfERG (ISCEV standard). The mean age was 42.4 years (11.8-74.5) and median visual acuity 0.5 (no light perception - 1.0). Symptoms reported included visual acuity loss (n=69), visual field defects (n=11), disturbances of colour vision, light or dark adaptation (n=10). VEP and mfERG were normal in 43% (n=31). Both VEP and mfERG were pathological in 24% (n=17). In a further 18% (n=13) only the mfERG was pathological and in 15% (n=11) only the VEP was pathological. Macular dysfunction as detected with mfERG was present in 73% of 41 patients with at least one pathological test. Neuroimaging (MRI, CCT) and/or neurological examination was performed in 27/72 patients (38%), to account for unexplained visual loss, prior to the electrophysiological tests; these were normal in all patients. Electrophysiological tests revealed disturbances of the post-retinal visual pathway in only 3/27 patients. In 12/27 patients, mfERG revealed a macular disorder; in a further 12/27 patients VEP and mfERG were normal. The combined evaluation of VEP and mfERG is useful both to establish the area of dysfunction and the normality of the visual system. Electrophysiological testing prior to neuroimaging is recommended for patients where clear clinical signs of cerebral disorders are not evident. This reduces the frequency of unnecessary neuroimaging and associated radiation exposure.

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 generally accepted classification for inherited retinochoroidal dystrophies does not exist. The names given to certain disorders are either based on ophthalmoscopic findings, or on histologic, electrophysiologic and genetic findings. Future research on the molecular genetic background will result in better definition of clinical entities. The purpose of this project is to outline a practical approach to inherited retinochoroidal dystrophies. For this reason, disorders with similar clinical symptoms are grouped together. Generalized retinochoroidal dystrophies affecting all retinal areas can be distinguished from regional dystrophies. Generalized dystrophies can be subdivided into those with peripheral onset, usually associated with initial rod function loss (night blindness, peripheral field loss: e.g. retinitis pigmentosa, choroideremia) and those with central onset associated with cone function loss (visual acuity loss, central scotoma, color vision deficits: e.g. cone or cone-rod dystrophies). Regionally limited dystrophies include the multitude of macular dystrophies and the autosomal dominant vitreoretinochoroidopathy, which remains limited to the periphery. It is important for a differential diagnosis to exclude involvement of other organ systems in syndromic disorders. Stationary inherited retinal dysfunction (e.g. monochromatism, congenital stationary night blindness) and other inherited or acquired diseases have to be excluded as well. Guidelines for differential diagnosis are presented.

Purpose. Age-related macular degeneration (AMD) is a heterogeneous condition of high prevalence and complex etiology involving genetic as well as environmental factors. By fundus autofluorescence (FAF) imaging, AMD can be classified into several distinct phenotypes, with one subgroup characterized by fine granular pattern with peripheral punctate spots (GPS[+]). Some features of GPS[+] overlap with Stargardt disease (STGD1), a recessive macular dystrophy caused by biallelic sequence variants in the ATP-binding cassette transporter 4 (ABCA4) gene. The aim of this study was to investigate the role of ABCA4 in GPS[+]. Methods. The ABCA4 gene was sequenced in 25 patients with the GPS[+] phenotype and 29 with geographic atrophy (GA)-AMD but no signs of GPS (GPS[-]). In addition, frequencies of risk-increasing alleles at three known AMD susceptibility loci, including complement factor H (CFH), age-related maculopathy susceptibility 2 (ARMS2), and complement component 3 (C3), were evaluated. Results. We demonstrate that GPS[+] is associated significantly with monoallelic ABCA4 sequence variants. Moreover, frequencies of AMD risk-increasing alleles at CFH, ARMS2, and C3 are similar in GPS[+] and STGD1 patients, with risk allele frequencies in both subcategories comparable to population-based control individuals estimated from 3,510 individuals from the NHLBI Exome Sequencing Project. Conclusions. Our data suggest that the GPS[+] phenotype is accounted for by monoallelic variants in ABCA4 and unlikely by the well-established AMD risk-increasing alleles at CFH, ARMS2, and C3. These findings provide support for a complex role of ABCA4 in the etiology of a minor proportion of patients with AMD.

In patients with central visual field scotomata a large part of visual cortex is not adequately stimulated. Over time this lack of input could lead to a reduction of gray matter in the affected cortical areas. We used Voxel Based Morphometry to investigate structural brain changes in patients with central scotomata due to hereditary retinal dystrophies and compared their results to those of normal sighted subjects. Additionally we correlated clinical and demographic characteristics like duration of disease, scotoma size, visual acuity, fixation stability and reading speed to the amount of gray matter in whole brain analyses within the patient group. We found a decrease in gray matter around the lesion projection zone in visual cortex of patients in comparison to controls. Gray matter loss along the posterior and middle portions of the calcarine sulcus is also correlated with scotoma size, indicating that indeed the lack of functional input provokes the gray matter alterations. In whole brain regression analyses within the patient group we found an additional cluster in the right superior and middle frontal gyri, slightly anterior to the frontal eye fields, where gray matter correlated positively with fixation stability. This could be regarded as a consequence of oculomotor learning.

Retinitis pigmentosa (RP) is a degenerative disease of the retina leading to progressive loss of vision and, in many instances, to legal blindness at the end stage. The RP28 locus was assigned in 1999 to the short arm of chromosome 2 by homozygosity mapping in a large Indian family segregating autosomal-recessive RP (arRP). Following a combined approach of chromatin immunoprecipitation and parallel sequencing of genomic DNA, we identified a gene, FAM161A, which was shown to carry a homozygous nonsense mutation (p.Arg229X) in patients from the original RP28 pedigree. Another homozygous FAM161A stop mutation (p.Arg437X) was detected in three subjects from a cohort of 118 apparently unrelated German RP patients. Age at disease onset in these patients was in the second to third decade, with severe visual handicap in the fifth decade and legal blindness in the sixth to seventh decades. FAM161A is a phylogenetically conserved gene, expressed in the retina at relatively high levels and encoding a putative 76 kDa protein of unknown function. In the mouse retina, Fam161a mRNA is developmentally regulated and controlled by the transcription factor Crx, as demonstrated by chromatin immunoprecipitation and organotypic reporter assays on explanted retinas. Fam161a protein localizes to photoreceptor cells during development, and in adult animals it is present in the inner segment as well as the outer plexiform layer of the retina, the synaptic interface between photoreceptors and their efferent neurons. Taken together, our data indicate that null mutations in FAM161A are responsible for the RP28-associated arRP.

International audience; Night vision requires signaling from rod photoreceptors to adjacent bipolar cells in the retina. Mutations in the genes NYX and GRM6, expressed in ON bipolar cells, lead to a disruption of the ON bipolar cell response. This dysfunction is present in patients with complete X-linked and autosomal-recessive congenital stationary night blindness (CSNB) and can be assessed by standard full-field electroretinography (ERG), showing severely reduced rod b-wave amplitude and slightly altered cone responses. Although many cases of complete CSNB (cCSNB) are caused by mutations in NYX and GRM6, in~60% of the patients the gene defect remains unknown. Animal models of human diseases are a good source for candidate genes, and we noted that a cCSNB phenotype present in homozygous Appaloosa horses is associated with downregulation of TRPM1. TRPM1, belonging to the family of transient receptor potential channels, is expressed in ON bipolar cells and therefore qualifies as an excellent candidate. Indeed, mutation analysis of 38 patients with CSNB identified ten unrelated cCSNB patients with 14 different mutations in this gene. The mutation spectrum comprises missense, splice-site, deletion, and nonsense mutations. We propose that the cCSNB phenotype in these patients is due to the absence of functional TRPM1 in retinal ON bipolar cells.

PURPOSE. Heterozygous mutations in the GUCY2D gene, which encodes the membrane-bound retinal guanylyl cyclase-1 protein (RetGC-1), have been shown to cause autosomal dominant inherited cone degeneration and cone–rod degeneration (adCD, adCRD). The present study was a comprehensive screening of the GUCY2D gene in 27 adCD and adCRD unrelated families of these rare disorders. METHODS. Mutation analysis was performed by direct sequencing as well as PCR and subsequent restriction length polymorphism analysis (PCR/RFLP). Haplotype analysis was performed in selected patients by using microsatellite markers. RESULTS. GUCY2D gene mutations were identified in 11 (40%) of 27 patients, and all mutations clustered to codon 838, including two known and one novel missense mutation: p.R838C, p.R838H, and p.R838G. Haplotype analysis showed that among the studied patients only two of the six analyzed p.R838C mutation carriers shared a common haplotype and that none of the p.R838H mutation carriers did. CONCLUSIONS. GUCY2D is a major gene responsible for progressive autosomal dominant cone degeneration. All identified mutations localize to codon 838. Haplotype analysis indicates that in most cases these mutations arise independently. Thus, codon 838 is likely to be a mutation hotspot in the GUCY2D gene. (Invest Ophthalmol Vis Sci. 2008;49:5015–5023) DOI: 10.1167/iovs.08-1901

The ATP-binding cassette (ABC) transporters constitute a family of large membrane proteins, which transport a variety of substrates across membranes. The ABCA4 protein is expressed in photoreceptors and possibly functions as a transporter for N-retinylidene-phosphatidylethanolamine (N-retinylidene-PE), the Schiff base adduct of all-trans-retinal with PE. Mutations in the ABCA4 gene have been initially associated with autosomal recessive Stargardt disease. Subsequent studies have shown that mutations in ABCA4 can also cause a variety of other retinal dystrophies including cone rod dystrophy and retinitis pigmentosa. To determine the prevalence and mutation spectrum of ABCA4 gene mutations in non-Stargardt phenotypes, we have screened 64 unrelated patients with autosomal recessive cone (arCD) and cone rod dystrophy (arCRD) applying the Asper Ophthalmics ABCR400 microarray followed by DNA sequencing of all coding exons of the ABCA4 gene in subjects with single heterozygous mutations. Disease-associated ABCA4 alleles were identified in 20 of 64 patients with arCD or arCRD. In four of 64 patients (6%) only one mutant ABCA4 allele was detected and in 16 patients (25%), mutations on both ABCA4 alleles were identified. Based on these data we estimate a prevalence of 31% for ABCA4 mutations in arCD and arCRD, supporting the concept that the ABCA4 gene is a major locus for various types of degenerative retinal diseases with abnormalities in cone or both cone and rod function.

X-linked congenital retinoschisis (RS) is a relatively frequent retinal dystrophy associated with RS1 gene mutations. A negative electroretinogram (ERG), i.e., a b/a wave ratio1.0 in the standard combined response, is considered a key diagnostic feature of RS. Only a few cases without a negative ERG have been reported.This study includes 24 RS patients with RS1 mutations. ERGs (according to ISCEV standards, n = 23), ON-OFF-responses (n = 9), fundus autofluorescence (FAF, n = 8), and optical coherence tomography (OCT, n = 6) were performed.The mean age at examination was 22.6 years (0.5-53.2 years), and median visual acuity was 0.3 (no light perception to 0.6). A negative ERG was found in 13 of 23 patients (56.5%), of whom one patient presented a negative ERG at the 2-year follow-up, with an initial b/a wave ratio1.0. Another patient had a b/a wave ratio of 0.96 in one eye and 1.02 in the fellow eye. In 10 of 23 patients, the b/a wave ratio ranged from 1.03 to 1.34. Single-flash cone and 30 Hz flicker responses were always reduced. FAF and OCT were pathologic in all patients tested. FAF was increased in the fovea. OCT revealed foveal schisis to various degrees and thinning of the retina in an older patient.Although ERG abnormalities were detected in all patients tested, more than 40% of patients with RS1 mutations did not have a negative ERG. In clinically suspected RS a combination of ERG, FAF, OCT, and molecular-genetic testing is advised to verify the diagnosis.

Only limited data exist on the incidence of negative electroretinograms (ERG) in clinical practice. The purpose of this study is therefore to determine the incidence and clinical causes of a negative ERG in a tertiary care centre focused on inherited and acquired retinal degenerations. All ERGs recorded (in accordance with ISCEV standards) in our electrophysiological laboratory from 1992 to 2004 were retrospectively reviewed. The negative ERGs (criterion: ERG with b:a wave ratio≤1 in the scotopic standard combined response in at least one eye) were analysed in the context of further clinical results. The photopic ON- and OFF-responses were recorded with long duration (200 ms) stimuli. A total of 1999 ERGs from 1644 patients were performed during the study period. 47/1644 patients (2.9%) presented with a negative ERG and were included in the study. Clinical diagnoses included inherited retinal dystrophies [X-linked congenital retinoschisis (XRS) (n=17), congenital stationary night blindness (CSNB) (n=6), retinitis pigmentosa (RP) (n=6), cone (-rod) dystrophy (n=5), choroideremia (n=1), Muller cell sheen dystrophy (MCSD) (n=1)] and acquired retinopathies (melanoma-associated retinopathy (MAR) (n=1), vigabatrin retinotoxicity (n=1)). In nine patients a definitive diagnosis could not be established. Unilateral negative ERGs were seen in 10/37 patients where ERG was bilaterally recorded. The fellow eye presented with a b:a wave ratio >1 (8 eyes) or ERG responses were not detectable (2 eyes). Photopic ON- and OFF-responses were recorded in 38 eyes of 29 patients and 32/38 eyes presented with a negative ERG. The ON-response was reduced in 25/32 eyes, whereas the OFF-response was reduced in only 11/32 eyes. The incidence of a negative ERG can differ between the laboratories depending on the causes for ERG recording and was in our laboratory 2.9% in a consecutive series of patients with inherited or acquired retinal degenerations. A disorder characteristically associated with negative ERG (e.g. XRS, CSNB, MAR) was diagnosed in 53% of these patients, whereas in 47% the negative ERG indicated an unexpected post-receptoral dysfunction, e.g. in cone (-rod) dystrophy or RP. The ON-bipolar pathway was affected in most cases.

Purpose To analyze the variability of clinical and electrophysiological characteristics in X-linked choroideremia and provide the first report of a negative electroretinogram in choroideremia. Design Retrospective study. Participants The records of 18 male patients with choroideremia and 8 female carriers were evaluated. Methods The data were reviewed regarding visual acuity (VA), color vision, perimetry, fundus autofluorescence, and full-field electroretinography (according to standards of the International Society for Clinical Electrophysiology of Vision). Main Outcome Measures Morphological and functional phenotype characteristics, fundus autofluorescence, electroretinography, and Rab escort protein 1 ( REP-1 ) mutations. Results Four unrelated families with choroideremia (9 affected males, 7 carriers) and 10 unrelated individuals (9 affected males, 1 carrier) were included. Mutational analysis, performed in 2 families and 3 individual males, revealed REP-1 mutations in all except 1 male. The age of the males ranged from 5.9 to 63.0 years (mean, 33.9), and VA ranged from hand movements to 1.0 (median, 0.7). Fundus autofluorescence (n = 7) showed defects in the retinal pigment epithelium in all males. Electroretinography (n = 13) was almost undetectable in 6 males and reduced in 6, indicating a rod–cone dystrophy. A further male showed a negative electroretinogram, with a b:a wave ratio of 0.5. Visual acuity of the 8 carriers (age, 4.8–56.8 years [mean, 24.0]) ranged from light perception to 1.2 (median, 1.0). Light perception was present in 1 carrier manifesting choroideremia with distinct chorioretinal atrophy. Pigmentary stippling, seen in the other carriers, was seen in fundus autofluorescence (n = 1) with a distinct speckled pattern. Electroretinograms were normal in 6 of 7 and reduced in the manifesting carrier. Defects in color vision and visual field were found in affected males and in the female carriers. Conclusions The phenotype of choroideremia presents with high variability. In addition to the previously reported findings, we observed a negative electroretinogram, indicating a postreceptoral retinal dysfunction, in 1 affected male; severe course of choroideremia with early blindness in 1 manifesting carrier; color vision deficits in the majority of affected males and carriers; and characteristic alterations in fundus autofluorescence.

Photopigment optical density (OD) of middle-(M) and long-(L) wavelength-sensitive cones was determined to evaluate the hypothesis that reductions in the amount of photopigment are responsible for age-dependent sensitivity losses of the human cone pathways. Flicker thresholds were measured at the peak and tail of the photoreceptor's absorption spectrum as a function of the intensity of a bleaching background. Photopigment OD was measured at 0 (fovea), 2, 4, and 8 deg in the temporal retina by use of a 0.3-deg-diameter test spot. Seventy-two genetically characterized dichromats were studied so that the L- and M-cones could be analyzed separately. Subjects included 28 protanopes with M- but no L-cones and 44 deuteranopes with L- but no M-cones (all male, age range 12-29 and 55-83 years). Previous methods have not provided estimates of photopigment OD for separate cone classes in the foveola. In this study, it was found that foveolar cones are remarkably efficient, absorbing 78% of the available photons (OD = 0.65). Photopigment OD decreased exponentially with retinal eccentricity independently of age and cone type. Paradoxically, the OD of perifoveal cones increased significantly with age. Over the 70-year age range of our participants, the perifoveal M- and L-cones showed a 14% increase in capacity to absorb photons despite a 30% decrease in visual sensitivity over the same period. Copyright © 2004 Cambridge University Press.

The hypothesis that dichromatic behavior on a clinical anomaloscope can be explained by the complement and arrangement of the long- (L) and middle-wavelength (M) pigment genes was tested. It was predicted that dichromacy is associated with an X-chromosome pigment gene array capable of producing only a single functional pigment type. The simplest case of this is when deletion has left only a single X-chromosome pigment gene. The production of a single L or M pigment type can also result from rearrangements in which multiple genes remain. Often, only the two genes at the 5′ end of the array are expressed; thus, dichromacy is also predicted to occur if one of these is defective or encodes a defective pigment, or if both of them encode pigments with identical spectral sensitivities. Subjects were 128 males who accepted the full range of admixtures of the two primary lights as matching the comparison light on a Neitz or Nagel anomaloscope. Strikingly, examination of the L and M pigment genes revealed a potential cause for a color-vision defect in all 128 dichromats. This indicates that the major component of color-vision deficiency could be attributed to alterations of the pigment genes or their regulatory regions in all cases, and the variety of gene arrangements associated with dichromacy is cataloged here. However, a fraction of the dichromats (17 out of 128; 13%) had genes predicted to encode pigments that would result in two populations of cones with different spectral sensitivities. Nine of the 17 were predicted to have two pigments with slightly different spectral peaks (usually ≤ 2.5 nm) and eight had genes which specified pigments identical in peak absorption, but different in amino acid positions previously associated with optical density differences. In other subjects, reported previously, the same small spectral differences were associated with anomalous trichromacy rather than dichromacy. It appears that when the spectral difference specified by the genes is very small, the amount of residual red–green color vision measured varies; some individuals test as dichromats, others test as anomalous trichromats. The discrepancy is probably partly attributable to testing method differences and partly to a difference in performance not perception, but it seems there must also be cases in which other factors, for example, cone ratio, contribute to a person's ability to extract a color signal from a small spectral difference.

Objectives To report clinical and functional findings in 2 female carriers of choroideremia who were followed up for 11 and 17 years and who showed progression of fundus alterations; and to report a novel CHM mutation. Methods We performed follow-ups in 2 female carriers of choroideremia, including repeated clinical and electrophysiologic examinations and fundus autofluorescence. Molecular analysis of the CHM gene was done by direct sequencing of the coding exons. Results Follow-up of female carrier 327 took place during 17 years. A second female carrier (subject 869) with a novel gene mutation in CHM was followed up for 11 years. The 2 carriers showed marked pigmentary alterations in the periphery of the retina. At the initial visit, carrier 869 had multiple small, yellowish flecks in the macula. Both carriers developed subnormal 30-Hz flicker responses on full-field electroretinography during follow-up, whereas electrooculography responses were normal. In both carriers, progression of fundus alterations was noted. Fundus autofluorescence images showed multiple small flecks with reduced autofluorescence. Conclusions Over time, fundus alterations in female carriers of choroideremia are visible, and mild cone dysfunction might develop. Multiple yellowish flecks can exist in the macula. The typical mottled irregularity in fundus autofluorescence is a valuable diagnostic criterion that facilitates specific genetic testing. Clinical Relevance Fundus alterations in female carriers of choroideremia can progress over time and a mild generalized cone dysfunction can develop. Characteristic irregularities are seen in fundus autofluorescence imaging, which is helpful in identifying female carriers of choroideremia.

Purpose To describe the phenotypic variability in 22 patients with PRPH2 gene mutations and to report six novel mutations. Design Retrospective study. Methods Clinical examinations included color vision testing, perimetry, fundus autofluorescence (FAF), fluorescein angiography, optical coherence tomography (OCT), and full-field and multifocal electroretinography (International Society for Clinical Electrophysiology of Vision standards). Blood samples were taken for deoxyribonucleic acid (DNA) extraction and mutation screening was performed by direct sequencing of polymerase chain reaction amplicons. Results Eleven unrelated patients and four unrelated families each with two affected members as well as one family with three affected members were examined. Diagnoses included central areolar choroidal dystrophy (CACD; n = 9), autosomal dominant retinitis pigmentosa (adRP; n = 7), adult vitelliform macular dystrophy (n = 3), and cone-rod dystrophy (CRD; n = 3). FAF was abnormal in all patients and showed various retinal pigment epithelial alterations, in CACD with a speckled FAF pattern. OCT revealed reduced retinal thickness, mostly in CACD, subretinal lesions, macula edema, or was normal. Follow-up (n = 12; range, 1.3 to 26 years) showed a slow progression of the retinal dystrophies. DNA testing revealed previously reported PRPH2 mutations in two families and eight individuals of whom two carried the same mutation but had different phenotypes. Novel PRPH2 mutations were detected in two families with adRP, in identical twins with CACD, and in each of an individual with CACD, CRD, and adRP. Conclusions This series describes the broad spectrum of phenotypes associated with PRPH2 mutations. FAF and OCT are helpful tools for diagnosis and evaluation of disease progression. We report novel PRPH2 mutations in patients with CACD, CRD, and adRP.

Purpose To evaluate and compare the value of fundus autofluorescence (FAF) imaging and multifocal electroretinography (mfERG) in early detection of retinal alterations in patients using chloroquine/hydroxychloroquine (CQ/HCQ). Methods FAF imaging was performed in a consecutive series of 25 patients with long-term CQ or HCQ treatment (duration, >1 year), with or without visual disturbances. In addition, mfERG was performed in accordance with ISCEV (International Society for Clinical Electrophysiology of Vision) guidelines in 23/25 patients. Results In 10/25 patients alterations of FAF were observed. Mild changes were limited to a pericentral ring of increased FAF. More advanced stages presented as pericentral mottled loss of FAF with increased FAF in the adjacent retina and later on a complete loss of pericentral FAF. In one case, a pericentral ring was observed when ophthalmoscopy and fluorescein angiography were normal. Marked progression of FAF abnormalities was observed during a 3-year follow-up in two of three patients. With the mfERG, pericentral, central, or generalized amplitude reductions were detected in all patients with FAF abnormalities and in an additional four patients with normal FAF. Conclusions FAF imaging can be reliably used to detect early retinal pigment epithelial alterations in CQ/HCQ retinopathy. Ophthalmoscopy and fluorescein angiography appear to be less sensitive. With the mfERG, more retinal abnormalities were detected compared with FAF imaging.

Purpose To perform a detailed morphologic and functional evaluation of Best macular dystrophy (BMD) associated with mutations in the VMD2 gene. Design Retrospective study. Participants The records of 16 patients with BMD and heterozygous VMD2 mutations (group 1) and 5 patients with Best-like lesions with no detectable disease-associated alterations in the VMD2 gene (group 2) were evaluated retrospectively. Methods The data were reviewed regarding visual acuity (VA), color vision, perimetry, autofluorescence of the retinal pigment epithelium (RPE), fluorescein angiography, electro-oculography (EOG), and full-field electroretinography (ERG) and multifocal ERG (mfERG). Main Outcome Measures VMD2 mutations, age at onset of BMD, RPE autofluorescence, EOG, ERG, and mfERG. Results The mean age of the patients in group 1 was 47.1 years (range, 16.7–86.5), and age at onset varied between 5 and 58 years (median, 42.0). Visual acuity ranged between 20/16 and 20/400 (median, 20/40). No association existed between the specific nature of the VMD2 mutation and disease onset or expressivity. Retinal pigment epithelium autofluorescence was increased corresponding to ophthalmoscopically visible yellow material, whereas it was decreased in the atrophic stage of BMD. Electro-oculography light rise was reduced in 18 of 19 eyes. Electroretinography amplitudes were normal in 3 patients and reduced in 6 patients. Multifocal ERG revealed in 10 of 20 eyes a central amplitude reduction and in 7 eyes a generalized one. There were no marked differences in clinical and functional findings between the patients in groups 1 and 2, except that the mean age of the patients in group 2 was higher (64.0 years [range, 45.7–80.6]) and the median VA lower (20/50 [range, 20/32–20/320]). Conclusions The onset of BMD is highly variable and occurred in the majority of patients after the second decade of life. Best-like lesions may develop in older patients without associated VMD2 mutations. Those manifestations may be related to a specific form of age-related macular degeneration. This article contains additional online-only material available at http://www.ophsource.org/periodicals/ophtha.