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Purpose: To investigate whether long-term protection from light exposure affects the rate of disease progression in patients with autosomal recessive Stargardt disease (STGD1), measured using fundus autofluorescence imaging., Design: Longitudinal, retrospective, interventional case series., Methods: Five patients with Stargardt disease protected 1 eye from light exposure by applying a black contact lens during waking hours for ≥12 months. Disease progression was followed by performing autofluorescence imaging at semi-regular intervals. Longitudinal changes in autofluorescence were studied by evaluating areas of decreased autofluorescence and areas of increased autofluorescence as a measure of retinal pigment epithelium damage and lipofuscin accumulation, respectively., Results: We observed less progression of decreased autofluorescence in 4 out of 5 light-protected eyes relative to their respective nonprotected eyes. The progression of increased autofluorescence, on the other hand, was highly variable and did not respond consistently to treatment., Conclusions: Areas of decreased autofluorescence may serve as a useful biomarker for measuring the progression of Stargardt disease. The reduced progression of decreased autofluorescence in the light-protected eyes suggests that light deprivation might be beneficial in patients with Stargardt disease., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: To determine the efficacy of multiple versions of a commercially available arrayed primer extension (APEX) microarray chip for autosomal recessive retinitis pigmentosa (arRP)., Methods: We included 250 probands suspected of arRP who were genetically analyzed with the APEX microarray between January 2008 and November 2013. The mode of inheritance had to be autosomal recessive according to the pedigree (including isolated cases). If the microarray identified a heterozygous mutation, we performed Sanger sequencing of exons and exon-intron boundaries of that specific gene. The efficacy of this microarray chip with the additional Sanger sequencing approach was determined by the percentage of patients that received a molecular diagnosis. We also collected data from genetic tests other than the APEX analysis for arRP to provide a detailed description of the molecular diagnoses in our study cohort., Results: The APEX microarray chip for arRP identified the molecular diagnosis in 21 (8.5%) of the patients in our cohort. Additional Sanger sequencing yielded a second mutation in 17 patients (6.8%), thereby establishing the molecular diagnosis. In total, 38 patients (15.2%) received a molecular diagnosis after analysis using the microarray and additional Sanger sequencing approach. Further genetic analyses after a negative result of the arRP microarray (n = 107) resulted in a molecular diagnosis of arRP (n = 23), autosomal dominant RP (n = 5), X-linked RP (n = 2), and choroideremia (n = 1)., Conclusions: The efficacy of the commercially available APEX microarray chips for arRP appears to be low, most likely caused by the limitations of this technique and the genetic and allelic heterogeneity of RP. Diagnostic yields up to 40% have been reported for next-generation sequencing (NGS) techniques that, as expected, thereby outperform targeted APEX analysis.

Objective: Currently, six genes are known to be associated with Usher syndrome type I, and mutations in most of these genes can also cause nonsyndromic hearing loss. The one exception is USH1G, which is currently only known to be involved in Usher syndrome type I and atypical Usher syndrome., Design: A Dutch family with autosomal recessively inherited hearing loss was examined. Audiometric, ophthalmic, and vestibular evaluations were performed besides the genetic analysis., Results: The hearing loss had an early onset with a downsloping audiogram configuration. Slight progression of the hearing loss was seen in both affected individuals. Compound heterozygous mutations in USH1G were found to segregate with the hearing loss in this family, a missense (c.310A>G, p.Met104Val) and a frameshift mutation (c.780insGCAC, p.Tyr261Alafs*96). Extensive ophthalmic and vestibular examinations demonstrated no abnormalities that are usually associated with Usher syndrome type I., Conclusions: This is the first family presented with nonsyndromic hearing loss caused by mutations in USH1G. Our findings expand the phenotypic spectrum of mutations in USH1G.

Purpose: Defects in MAK, encoding a protein localized to the photoreceptor connecting cilium, have recently been associated with autosomal recessive retinitis pigmentosa (RP). The aim of this study is to describe our detailed clinical observations in patients with MAK-associated RP, including an assessment of syndromic symptoms frequently observed in ciliopathies., Methods: In this international collaborative study, 11 patients carrying nonsense or missense mutations in MAK were clinically evaluated, including extensive assessment of the medical history, slit-lamp biomicroscopy, ophthalmoscopy, kinetic perimetry, electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), autofluorescence imaging and fundus photography. Additionally, we used a questionnaire to evaluate the presence of syndromic features and tested the olfactory function., Results: MAK-associated RP is not associated with syndromic features, not even with subclinical dysfunction of the olfactory apparatus. All patients experienced typical RP symptoms of night blindness followed by visual field constriction. Symptoms initiated between childhood and the age of 43 (mean: 23 years). Although some patients experienced vision loss, the visual acuity remained normal in most patients. ERG and ophthalmoscopy revealed classic RP characteristics, and SD-OCT demonstrated thinning of the overall retina, outer nuclear layer and photoreceptor-pigment epithelium complex., Conclusion: Nonsense and missense mutations in MAK give rise to a non-syndromic recessive RP phenotype without apparent extra-ocular features. When compared to other retinal ciliopathies, MAK-associated RP appears to be relatively mild and shows remarkable resemblance to RP1-associated RP, which could be explained by the close functional relation of these proteins., (© 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Objective: To describe the phenotype and genotype of patients with early-onset Stargardt disease., Design: Retrospective cohort study., Participants: Fifty-one Stargardt patients with age at onset ≤10 years., Methods: We reviewed patient medical records for age at onset, medical history, initial symptoms, best-corrected visual acuity (BCVA), ophthalmoscopy, fundus photography, fundus autofluorescence (FAF), fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), and full-field electroretinography (ffERG). The ABCA4 gene was screened for mutations., Main Outcome Measures: Age at onset, BCVA, fundus appearance, FAF, FA, SD-OCT, ffERG, and presence of ABCA4 mutations., Results: The mean age at onset was 7.2 years (range, 1-10). The median times to develop BCVA of 20/32, 20/80, 20/200, and 20/500 were 3, 5, 12, and 23 years, respectively. Initial ophthalmoscopy in 41 patients revealed either no abnormalities or foveal retinal pigment epithelium (RPE) changes in 10 and 9 patients, respectively; the other 22 patients had foveal atrophy, atrophic RPE lesions, and/or irregular yellow-white fundus flecks. On FA, there was a "dark choroid" in 21 out of 29 patients. In 14 out of 50 patients, foveal atrophy occurred before flecks developed. On FAF, there was centrifugal expansion of disseminated atrophic spots, which progressed to the eventual profound chorioretinal atrophy. Spectral-domain OCT revealed early photoreceptor damage followed by atrophy of the outer retina, RPE, and choroid. On ffERG in 26 patients, 15 had normal amplitudes, and 11 had reduced photopic and/or scotopic amplitudes at their first visit. We found no correlation between ffERG abnormalities and the rate of vision loss. Thirteen out of 25 patients had progressive ffERG abnormalities. Finally, genetic screening of 44 patients revealed ≥2 ABCA4 mutations in 37 patients and single heterozygous mutations in 7., Conclusions: In early-onset Stargardt, initial ophthalmoscopy can reveal no abnormalities or minor retinal abnormalities. Yellow-white flecks can be preceded by foveal atrophy and may be visible only on FAF. Although ffERG is insufficient for predicting the rate of vision loss, abnormalities can develop. Over time, visual acuity declines rapidly in parallel with progressive retinal degeneration, resulting in profound chorioretinal atrophy. Thus, early-onset Stargardt lies at the severe end of the spectrum of ABCA4-associated retinal phenotypes., (Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To describe the clinical characteristics and long-term follow-up in patients with autosomal dominant cystoid macular dystrophy (DCMD)., Design: Retrospective case series., Participants: Ninety-seven patients with DCMD., Methods: Extensive ophthalmic examination, including visual acuity (VA), fundus photography, fluorescein angiography (FA), fundus autofluorescence (FAF) imaging, optical coherence tomography (OCT), color vision testing, dark adaptation testing, full-field electroretinography (ERG), and electro-oculography (EOG). Blood samples were obtained for DNA extraction and subsequent haplotype analysis., Main Outcome Measures: Age at onset, VA, fundus appearance, and characteristics on FA, FAF, OCT, ERG, and EOG., Results: Cystoid fluid collections (CFCs) were the first retinal abnormalities detectable in DCMD, developing during childhood. At long-term follow-up, the CFCs decreased in size and number, and eventually disappeared with concurrent development of progressive chorioretinal atrophy and hyperpigmented deposits in the posterior pole. Dominant cystoid macular dystrophy could be classified into 3 stages, based on characteristics on ophthalmoscopy, FAF, FA, and OCT, as well as on results of electrophysiologic analysis. The staging system correlated with age and VA. In stage 1 DCMD (20 patients; 22%), patients generally were younger than 20 years and had CFCs with fine folding of the internal limiting membrane and mild pigment changes. In stage 2 DCMD (48 patients; 52%), the CFCs tended to decrease in size, and moderate macular chorioretinal atrophy developed. Patients with stage 3 DCMD (24 patients; 26%) generally were older than 50 years and showed profound chorioretinal atrophy, as well as coarse hyperpigmented deposits in the posterior pole. Most patients were (highly) hyperopic (72 patients; 92%). All DCMD patients shared the disease haplotype at the DCMD locus at 7p15.3., Conclusions: Dominant cystoid macular dystrophy is a progressive retinal dystrophy, characterized primarily by early-onset cystoid fluid collections in the neuroretina, which distinguishes this disorder from other retinal dystrophies. The phenotypic range of DCMD can be classified into 3 stages. The genetic locus for this retinal dystrophy has been mapped to 7p15.3, but the involved gene is currently unknown., (Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Inherited retinal diseases (IRDs) represent a clinical and genetic heterogeneous group of chorioretinal disorders. The frequency of persons affected by an IRD due to mutations in the same gene varies from 1 in 10,000 to less than 1 in a million. To perform meaningful genotype-phenotype analyses for rare genetic conditions, it is necessary to collect data from sizable populations. Although several standardized functional tests are used widely, ophthalmologic data usually are stored in local databases and not in multicenter databases that are linked with other centers. To be able to register ophthalmologic data of all Dutch patients with IRDs into one database, we developed the RD5000 database (RD5000db), which can harbor all ophthalmologic and selected genetic data. Authorization rights for the management, data entry, and data sharing have been set up, rendering this database into a user-friendly, secure, and widely used repository that will facilitate future studies into molecular genetics and therapies for IRDs. The RD5000db database has the potential to grow into a European standard for the registration of data from IRDs., (Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.)

Unlabelled: Age-related macular degeneration (AMD) is the leading cause of blindness in the Western world. AMD is a multifactorial disorder but complement-mediated inflammation at the level of the retina plays a pivotal role. Oral zinc supplementation can reduce the progression of AMD but the precise mechanism of this protective effect is as yet unclear. We investigated whether zinc supplementation directly affects the degree of complement activation in AMD and whether there is a relation between serum complement catabolism during zinc administration and the complement factor H (CFH) gene or the Age-Related Maculopathy susceptibility 2 (ARMS2) genotype. In this open-label clinical study, 72 randomly selected AMD patients in various stages of AMD received a daily supplement of 50 mg zinc sulphate and 1 mg cupric sulphate for three months. Serum complement catabolism-defined as the C3d/C3 ratio-was measured at baseline, throughout the three months of supplementation and after discontinuation of zinc administration. Additionally, downstream inhibition of complement catabolism was evaluated by measurement of anaphylatoxin C5a. Furthermore, we investigated the effect of zinc on complement activation in vitro. AMD patients with high levels of complement catabolism at baseline exhibited a steeper decline in serum complement activation (p<0.001) during the three month zinc supplementation period compared to patients with low complement levels. There was no significant association of change in complement catabolism and CFH and ARMS2 genotype. In vitro zinc sulphate directly inhibits complement catabolism in hemolytic assays and membrane attack complex (MAC) deposition on RPE cells. This study provides evidence that daily administration of 50 mg zinc sulphate can inhibit complement catabolism in AMD patients with increased complement activation. This could explain part of the mechanism by which zinc slows AMD progression., Trial Registration: The Netherlands National Trial Register NTR2605.

Purpose: To provide a clinical and genetic description of a patient cohort with Stargardt disease (STGD1) with identifiable foveal sparing., Methods: Patients with retinal atrophy (defined as an absence of autofluorescence) that surrounded the fovea by at least 180° and did not include the fovea were defined as having foveal sparing; eyes with visual acuity (VA) worse than 20/200 were excluded. We reviewed the medical files and extracted data regarding medical history, VA, ophthalmoscopy, static perimetry, fundus photography, spectral-domain optical coherence tomography (SD-OCT), fluorescein angiography (FA), fundus autofluorescence (FAF), and electroretinography (ERG). We screened each patient's ABCA4 gene for mutations., Results: Seventeen eyes with foveal sparing were identified in 13 unrelated patients. In 4 eyes, the fovea gradually became atrophic after the initial foveal sparing. The mean age at onset was 51 years (range, 32-67 years). Visual acuity was 20/40 or better in all foveal sparing eyes and was 20/25 or better in 41%. Fundus autofluorescence imaging revealed hyperautofluorescent flecks and parafoveal retinal atrophy; SD-OCT revealed sharply delineated atrophy; and perimetry revealed parafoveal scotomas with intact foveal sensitivity. Finally, genetic screening identified mutations in 19 of the 26 ABCA4 gene alleles., Conclusions: Foveal sparing occurs mainly in patients with late-onset STGD1 and represents the milder end of the clinical spectrum in STGD1. The anatomy, metabolism, and biochemistry of the retina, as well as genetic variations in genes other than ABCA4, can influence the etiology of foveal sparing. Identifying these fovea-protecting factors will facilitate the future development of strategies designed to treat STGD1., (Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.)

Objective: To identify the genetic causes underlying autosomal recessive retinitis pigmentosa (arRP) and to describe the associated phenotype., Design: Case series., Participants: Three hundred forty-seven unrelated families affected by arRP and 33 unrelated families affected by retinitis pigmentosa (RP) plus noncongenital and progressive hearing loss, ataxia, or both, respectively., Methods: A whole exome sequencing (WES) analysis was performed in 2 families segregating arRP. A mutational screening was performed in 378 additional unrelated families for the exon-intron boundaries of the ABHD12 gene. To establish a genotype-phenotype correlation, individuals who were homozygous or compound heterozygotes of mutations in ABHD12 underwent exhaustive clinical examinations by ophthalmologists, neurologists, and otologists., Main Outcome Measures: DNA sequence variants, best-corrected visual acuity, visual field assessments, electroretinogram responses, magnetic resonance imaging, and audiography., Results: After a WES analysis, we identified 4 new mutations (p.Arg107Glufs*8, p.Trp159*, p.Arg186Pro, and p.Thr202Ile) in ABHD12 in 2 families (RP-1292 and W08-1833) previously diagnosed with nonsyndromic arRP, which cosegregated with the disease among the family members. Another homozygous mutation (p.His372Gln) was detected in 1 affected individual (RP-1487) from a cohort of 378 unrelated arRP and syndromic RP patients. After exhaustive clinical examinations by neurologists and otologists, the 4 affected members of the RP-1292 had no polyneuropathy or ataxia, and the sensorineural hearing loss and cataract were attributed to age or the normal course of the RP, whereas the affected members of the families W08-1833 and RP-1487 showed clearly symptoms associated with polyneuropathy, hearing loss, cerebellar ataxia, RP, and early-onset cataract (PHARC) syndrome., Conclusions: Null mutations in the ABHD12 gene lead to PHARC syndrome, a neurodegenerative disease including polyneuropathy, hearing loss, cerebellar ataxia, RP, and early-onset cataract. Our study allowed us to report 5 new mutations in ABHD12. This is the first time missense mutations have been described for this gene. Furthermore, these findings are expanding the spectrum of phenotypes associated with ABHD12 mutations ranging from PHARC syndrome to a nonsyndromic form of retinal degeneration., (Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: The gene encoding nicotinamide nucleotide adenylyltransferase 1 (NMNAT1) was recently found to be mutated in a subset of patients with Leber congenital amaurosis (LCA) with macular atrophy. The aim of this study was to determine the occurrence and frequency of NMNAT1 mutations and associated phenotypes in different types of inherited retinal dystrophies., Methods: DNA samples of 161 patients with LCA without genetic diagnosis were analyzed for variants in NMNAT1 using Sanger sequencing. Variants in exon 5 of NMNAT1, which harbors the majority of the previously identified mutations, were screened in 532 additional patients with retinal dystrophies. This cohort encompassed 108 persons with isolated or autosomal recessive cone-rod dystrophy (CRD), 271 with isolated or autosomal recessive retinitis pigmentosa (RP), and 49 with autosomal dominant RP, as well as 104 persons with LCA in whom the causative mutation was previously identified., Results: Compound heterozygous alterations were found in six patients with LCA and in one person with early-onset RP. All except one carried the common p.E257K variant on one allele. Macular atrophy was absent in one patient, who carried this variant in combination with a truncating mutation on the other allele. The p.E257K alteration was also found in a heterozygous state in five individuals with LCA and one with RP while no mutation was detected on the other allele. Two individuals with LCA carried other NMNAT1 variants in a heterozygous state, whereas no NMNAT1 variants in exon 5 were identified in individuals with CRD. The p.E257K variant was found to be enriched in a heterozygous state in individuals with LCA (0.94%) compared to Caucasian controls (0.18%), although the difference was statistically insignificant (p=0.12)., Conclusions: Although macular atrophy can occur in LCA and CRD, no NMNAT1 mutations were found in the latter cohort. NMNAT1 variants were also not found in a large group of patients with sporadic or autosomal recessive RP. The enrichment of p.E257K in a heterozygous state in patients with LCA versus controls suggests that this allele could act as a modifier in other genetic subtypes of LCA.

Purpose: To provide the first detailed clinical description in patients with RP caused by recessive mutations in IMPG2., Methods: This international collaborative study includes 17 RP patients with inherited retinal disease caused by mutations in IMPG2. The patients were clinically (re-)examined, including extensive medical history taking, slit-lamp biomicroscopy, ophthalmoscopy, perimetry, ERG, optical coherence tomography (OCT), fundus autofluorescence (FAF) imaging, fundus photography, and color vision tests. The main outcome measures included mean age at onset, initial symptom, best-corrected visual acuity, fundus appearance, perimetry results, ERG responses, OCT images, FAF imaging, color vision test reports and DNA sequence variants., Results: The mean age at onset was 10.5 years (range, 4-20 years). Initial symptoms included night blindness in 59% of patients, a decreased visual acuity in 35%, and visual field loss in 6%. Fundus abnormalities were typical of RP: optic disc pallor, attenuated vessels, bone spicules, and generalized atrophy of the retina and choriocapillaris. Additionally, we observed macular abnormalities in all patients, ranging from subtle mottling of the macular pigment epithelium (two patients) and a bull's eye maculopathy (seven patients) to macular chorioretinal atrophy (seven patients)., Conclusions: Mutations in IMPG2 cause a severe form of RP with symptoms manifesting in the first 2 decades of life. IMPG2-associated RP is frequently accompanied by macular involvement, ranging from mild pigment alterations to profound chorioretinal atrophy. The resulting decrease in central vision in combination with the severe tunnel vision leads to severe visual impairment in patients with IMPG2-associated RP., (Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.)

Purpose: To provide the clinical features in patients with retinal disease caused by C8orf37 gene mutations., Methods: Eight patients--four diagnosed with retinitis pigmentosa (RP) and four with cone-rod dystrophy (CRD), carrying causal C8orf37 mutations--were clinically evaluated, including extensive medical history taking, slit-lamp biomicroscopy, ophthalmoscopy, kinetic perimetry, electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), autofluorescence (AF) imaging, and fundus photography., Results: In families A and D, respectively, one and three patients showed a classic RP phenotype with night blindness followed by concentric loss of visual field. Severe visual loss to light perception occurred early in the course of the disease. The symptoms initiated during infancy (family A) or adolescence (family D). Ophthalmoscopy revealed macular atrophy, bone spicules, attenuated vessels, and waxy pale optic discs. SD-OCT showed profound photoreceptor degeneration and AF demonstrated atrophy of the retinal pigment epithelium (RPE). ERG responses were nonrecordable in these patients. In families B and C, the patients were diagnosed with CRD. Initial symptoms were photophobia or loss of visual acuity and occurred during infancy (family B) or adolescence (family C). Ophthalmoscopy and AF revealed profound macular RPE atrophy and SD-OCT demonstrated macular photoreceptor degeneration. ERG responses were severely reduced in a cone-rod pattern or were nonrecordable. Interestingly, both patients in family B demonstrated polydactyly., Conclusions: Mutations in C8orf37 give rise to an early or adolescent-onset autosomal recessive CRD or RP phenotype with early macular atrophy. The occurrence of postaxial polydactyly in one family suggests a syndromic phenotype, which may indicate C8orf37 has a ciliary function.

Molecular diagnostics for patients with retinitis pigmentosa (RP) has been hampered by extreme genetic and clinical heterogeneity, with 52 causative genes known to date. Here, we developed a comprehensive next-generation sequencing (NGS) approach for the clinical molecular diagnostics of RP. All known inherited retinal disease genes (n = 111) were captured and simultaneously analyzed using NGS in 100 RP patients without a molecular diagnosis. A systematic data analysis pipeline was developed and validated to prioritize and predict the pathogenicity of all genetic variants identified in each patient, which enabled us to reduce the number of potential pathogenic variants from approximately 1,200 to zero to nine per patient. Subsequent segregation analysis and in silico predictions of pathogenicity resulted in a molecular diagnosis in 36 RP patients, comprising 27 recessive, six dominant, and three X-linked cases. Intriguingly, De novo mutations were present in at least three out of 28 isolated cases with causative mutations. This study demonstrates the enormous potential and clinical utility of NGS in molecular diagnosis of genetically heterogeneous diseases such as RP. De novo dominant mutations appear to play a significant role in patients with isolated RP, having major implications for genetic counselling., (© 2012 Wiley Periodicals, Inc.)

Cone-rod dystrophy (CRD) and retinitis pigmentosa (RP) are clinically and genetically overlapping heterogeneous retinal dystrophies. By using homozygosity mapping in an individual with autosomal-recessive (ar) RP from a consanguineous family, we identified three sizeable homozygous regions, together encompassing 46 Mb. Next-generation sequencing of all exons, flanking intron sequences, microRNAs, and other highly conserved genomic elements in these three regions revealed a homozygous nonsense mutation (c.497T>A [p.Leu166(∗)]) in C8orf37, located on chromosome 8q22.1. This mutation was not present in 150 ethnically matched control individuals, single-nucleotide polymorphism databases, or the 1000 Genomes database. Immunohistochemical studies revealed C8orf37 localization at the base of the primary cilium of human retinal pigment epithelium cells and at the base of connecting cilia of mouse photoreceptors. C8orf37 sequence analysis of individuals who had retinal dystrophy and carried conspicuously large homozygous regions encompassing C8orf37 revealed a homozygous splice-site mutation (c.156-2A>G) in two siblings of a consanguineous family and homozygous missense mutations (c.529C>T [p.Arg177Trp]; c.545A>G [p.Gln182Arg]) in siblings of two other consanguineous families. The missense mutations affect highly conserved amino acids, and in silico analyses predicted that both variants are probably pathogenic. Clinical assessment revealed CRD in four individuals and RP with early macular involvement in two individuals. The two CRD siblings with the c.156-2A>G mutation also showed unilateral postaxial polydactyly. These results underline the importance of disrupted ciliary processes in the pathogenesis of retinal dystrophies., (Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Purpose: Late-onset central areolar choroidal dystrophy (CACD) may easily be confused with geographic atrophy (GA) in AMD. To detect discerning features, the morphologic changes in CACD patients and in AMD patients were assessed with confocal scanning laser ophthalmoscopy (cSLO), fundus autofluorescence (FAF), and spectral-domain optical coherence tomography (SD-OCT)., Methods: A total of 30 CACD patients with identified PRPH2 gene mutations were analyzed and compared to 19 patients with early AMD and 13 patients with AMD-associated GA. The presence of drusen and pigment clumping was determined with color fundus photography. High-resolution in vivo imaging was performed with cSLO and SD-OCT. FAF images and SD-OCT volume scans were analyzed in each study eye., Results: On FAF, a speckled FAF pattern occurred significantly more often in CACD (85%) than in early AMD (5.6%; P < 0.0001). There was a significantly higher frequency of sub-RPE deposits in eyes with AMD than in eyes with CACD (36.8% versus 2.1% of scans, P = 0.0019). Reticular drusen could be visualized by SD-OCT and FAF imaging in 52.6% of the eyes with early AMD and in 100% of the eyes with GA, whereas this drusen phenotype did not manifest in eyes with CACD., Conclusions: Although outer retinal atrophy is the clinically common feature in advanced CACD as well as GA, there are microstructural alterations on high-resolution SD-OCT and FAF imaging that allow for the differentiation between CACD and AMD. The findings may help to identify patients in whom a diagnostic PRPH2 screening is warranted. (ClinicalTrials.gov number, NCT00393692.).