Nationwide epidemiologic survey on incidence of macular dystrophy in Japan

PURPOSE

The aim of this study was to estimate the number of patients in Japan who had visited an ophthalmologist for macular dystrophy of various types, including Best vitelliform macular dystrophy (BVMD), Stargardt disease, occult macular dystrophy (OMD), cone (-rod) dystrophy, X-linked retinoschisis (XLRS), and central areolar choroid dystrophy (CACD).

STUDY DESIGN

Nationwide epidemiologic survey METHODS: Questionnaires were distributed to 965 major facilities, including all the university hospitals in Japan. The aim of the questionnaire was to determine the number of patients with each type of macular dystrophy who had visited an outpatient clinic during the past 5 years (January 2015 to December 2019).

RESULTS

Over 70% of the patients were diagnosed and followed up at university hospitals. The estimated annual number of newly diagnosed cases was as follows: 55.3 for BVMD, 36.7 for Stargardt disease, 35.8 for OMD, 160.6 for cone (-rod) dystrophy, 31.0 for XLRS, 29.8 for CACD, and 174.1 for other types of macular dystrophy. The total number of patients with macular dystrophy diagnosed and followed at major institutions was estimated to be 6651.

CONCLUSION

This was the first nationwide survey of macular dystrophy in Japan and provided an approximate number of affected patients. The diagnosis of macular dystrophy is primarily carried out at facilities with affiliated specialists, such as university hospitals. By examining the incidence of multiple diseases simultaneously, we were able to compare the incidence of each type of macular dystrophy.

The Retinal Phenotype Associated with the p.Pro101Thr BEST1 Variant

PURPOSE

To describe the retinal phenotype associated with the p.Pro101Thr BEST1 variant.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Patients diagnosed with bestrophinopathies in which molecular genetic testing identified the p.Pro101Thr BEST1 as well as healthy carriers among their first-degree relatives.

METHODS

Medical records were reviewed to obtain data on family history and ophthalmic examinations, including retinal imaging. The imaging protocol included OCT and fundus autofluorescence using Spectralis HRA + OCT (Heidelberg Engineering). Genetic analysis was performed by next-generation sequencing.

MAIN OUTCOME MEASURES

Results of ophthalmic examinations and multimodal imaging features of retinal phenotypes.

RESULTS

The c.301C>A, p.Pro101Thr BEST1 missense variant was identified as the causative variant in 8 individuals (all men) from 5 families, accounting for 13% of cases (8/61) and 10% of pathogenic alleles (9/93) in our cohort of patients affected by bestrophinopathies. Seven individuals (14 eyes) had the variant in heterozygous status: all eyes had a hyperopic refractive error (median spherical equivalent of + 3.75 diopters [D]) and 4 individuals had a macular dystrophy with mildly reduced visual acuity (median of 20/25 Snellen), whereas the other 3 were asymptomatic carriers. On multimodal retinal imaging, 5 (36%) out of 14 eyes had subclinical bestrophinopathy, 4 (29%) had typical findings of adult-onset foveomacular vitelliform dystrophy (AOFVD), and the remaining 5 (36%) displayed a pattern dystrophy-like phenotype. Follow-up data were available for 6 subjects, demonstrating clinical stability up to 11 years, in both subclinical and clinical forms. An additional patient with autosomal recessive bestrophinopathy was found to harbor the p.Pro101Thr variant in homozygosity.

CONCLUSIONS

The p.Pro101Thr BEST1 variant is likely a frequent cause of bestrophinopathy in the Italian population and can result in autosomal dominant macular dystrophies with incomplete penetrance and mild clinical manifestations as well as autosomal recessive bestrophinopathy. The spectrum of autosomal dominant maculopathy includes the typical AOFVD and a pattern dystrophy-like phenotype.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Novel IMPG2 variant causing adult macular vitelliform dystrophy: A case report

INTRODUCTION

Adult-onset vitelliform macular dystrophy (AVMD) is an inherited maculopathy characterized by metamorphopsias and decrease in visual acuity occurring between the fourth and the sixth decade. It is characterized by an 'egg yolk' macular lesion eventually evolving towards foveal atrophy and fibrosis. It is usually an autosomal dominant inherited disorder with variable penetrance, mainly related to variants in BEST1, PRPH2, IMPG1, and IMPG2 genes.

CASE DESCRIPTION

A 47-year-old woman complaining of "wavy" vision was referred to our clinic. Her past medical history and reported family history did not reveal any ocular disease. Complete ophthalmological evaluation was performed. Funduscopic examination and multimodal imaging revealed a round vitelliform lesion in both eyes, leading to a diagnosis of AVMD. Genetic analysis revealed a novel, likely pathogenetic, heterozygous c.478G > T (p.Glu160Ter), (NM_016247) variant in the IMPG2 gene.

DISCUSSION

Our patient exhibits a novel pathogenetic variant in a gene associated with AVMD. Heterozygous variants in the IMPG2 gene have been reported in multiple individuals with vitelliform macular dystrophy, with an autosomal dominant mode of inheritance. Genetic screening is essential to characterize patients, to predict vision loss in patients with a positive family history and to characterize eligible patients for new potential emerging therapies. Genotype-phenotype correlation studies are needed to have a clearer picture of pathogenetic mechanisms. Our study characterizes the phenotype related to a novel IMPG2 pathogenic variant through multimodal imaging.

Novel heterozygous PRPH2 variant identified in a patient with spinocerebellar ataxia type 14 and macular dystrophy

PURPOSE

To report on a patient with spinocerebellar ataxia type 14 (SCA14) and macular dystrophy with identification of a novel PRPH2 variant.

METHODS

Case report.

RESULTS

A 63-year-old female with molecularly confirmed SCA14 presented with symmetric pigmentary disturbances in a perifoveal distribution resembling a pattern macular dystrophy. She had no history of using medications with recognized toxic macular effects. Subsequent genetic testing confirmed a novel heterozygous missense variant of unknown significance in PRPH2 (PRPH2: c.694 G>A, p.(Ala232Thr)).

CONCLUSIONS

To our knowledge, this is the first case of macular dystrophy identified in a patient with SCA14. While it is possible that the macular dystrophy observed in this patient might be an under-reported phenotype associated with SCA14, the pattern of macular changes is consistent with PRPH2-related disorders. The identified missense variant is predicted to be damaging by most in silico models, and the residue is highly conserved, adding support to a dual genetic diagnosis in this case.

Phenotype of bilateral EYS-associated occult macular dystrophies based on multimodal imaging

BACKGROUND

The study aimed to confirm the multimodal imaging of occult macular dystrophy (OMD) with two heterozygous mutations, including an unreported heterozygous EYS mutation.

METHODS

The study utilised several diagnostic methods, including Optos wide-field imaging, Bruch's membrane opening-minimum rim width (BMO-MRW), optical coherence tomography (OCT), multifocal electroretinogram (mf-ERG), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), and green light autofluorescence (FAF-G) imaging, and genetic testing.

RESULTS

The mf-ERG imaging demonstrated decreased P1 amplitudes in both eyes. This was consistent with the FAF-G imaging and OCT results, confirming the bilateral discontinuity of photoreceptors in the macular region. FFA and ICGA revealed persistent macular hypoperfusion not only within the photoreceptors of the macular area but also in the choriocapillaris. Next-generation sequencing results confirmed the presence of two heterozygous mutations in the patient: RP1L1 (c.4273G>C: p. Asp1425His), a hotspot mutation for OMD, and an unreported EYS mutation (c.7382T>A: p. Leu2461Ter) commonly found in retinitis pigmentosa (RP). Analysis using AlphaFold2 further confirmed the impact of the EYS c.7382T>A: p. Leu2461Ter variant on the functional protein conformation.

CONCLUSION

We report an unreported heterozygous EYS mutation that could serve as a promising diagnostic marker for OMD.

Macular neovascularization in inherited retinal diseases: A review

Inherited retinal diseases (IRDs) are the most common cause of blindness in working-age adults. Macular neovascularization (MNV) may be a presenting feature or occurs as a late-stage complication in several IRDs. We performed an extensive literature review on MNV associated with IRDs. MNV is a well-known complication of Sorsby fundus dystrophy and pseudoxanthoma elasticum. Those with late-onset Stargardt disease may masquerade as exudative age-related macular degeneration (AMD) when MNV is the presenting feature. Peripherinopathies may develop MNV that responds well to a short course of anti-vascular endothelial growth factor (anti-VEGF) therapy, while bestrophinopathies tend to develop MNV in the early stages of the disease without vision loss. Enhanced S-cone syndrome manifests type 3 MNV that typically regresses into a subfoveal fibrotic nodule. MNV is only a rare complication in choroideraemia and rod-cone dystrophies. Most IRD-related MNVs exhibit a favorable visual prognosis requiring less intensive regimens of anti-vascular endothelial growth factor therapy compared to age-related macular degeneration. We discuss the role of key imaging modalities in the diagnosis of MNV across a wide spectrum of IRDs and highlight the gaps in our knowledge with respect to the natural history and prognosis to pave the way for future directions of research.

Genetics of Retinitis Pigmentosa and Other Hereditary Retinal Disorders in Western Switzerland

INTRODUCTION

Mutational screening of inherited retinal disorders is prerequisite for gene targeted therapy. Our aim was to report and analyze the proportions of mutations in inherited retinal disease (IRD)-causing genes from a single center in Switzerland in order to describe the distribution of IRDs in Western Switzerland.

METHODS

We conducted a retrospective study of patient records. Criteria for inclusion were residence in Western Switzerland for patients and relatives presenting a clinical diagnosis of IRDs and an established molecular diagnosis managed by the genetics service of the Jules-Gonin Eye Hospital (JGEH) of Lausanne between January 2002 and December 2022. We initially investigated the IRD phenotypes in all patients (full cohort) with a clinical diagnosis, then calculated the distribution of IRD gene mutations in the entire cohort (genetically determined cohort). We analyzed a sub-group that comprised pediatric patients (≤18 years of age). In addition, we calculated the distribution of gene mutations within the most represented IRDs. Comprehensive gene screening was performed using a combined approach of different generation of DNA microarray analysis, direct sequencing, and Sanger sequencing.

RESULTS

The full cohort comprised 899 individuals from 690 families with a clinical diagnosis of IRDs. We identified 400 individuals from 285 families with an elucidated molecular diagnosis (variants in 84 genes) in the genetically determined cohort. The pediatric cohort included 89 individuals from 65 families with an elucidated molecular diagnosis. The molecular diagnosis rate for the genetically determined cohort was 58.2% (family ratio) and the 5 most frequently implicated genes per family were ABCA4 (11.6%), USH2A (7.4%), EYS (6.7%), PRPH2 (6.3%), and BEST1 (4.6%). The pediatric cohort had a family molecular diagnosis rate of 64.4% and the 5 most common mutated genes per family were RS1 (9.2%), ABCA4 (7.7%), CNGB3 (7.7%), CACNA1F (6.2%), CEP290 (4.6%).

CONCLUSIONS

This study describes the genetic mutation landscape of IRDs in Western Switzerland in order to quantify their disease burden and contribute to a better orientation of the development of future gene targeted therapies.

Phenotypic and Genetic Alterations in Adult-Onset Cone and Cone-Rod Dystrophy

INTRODUCTION

The objective of this study was to investigate the clinical characteristics and genetic spectrum of adult-onset cone/cone-rod dystrophy (AOCD/AOCRD) in Korean individuals.

METHODS

This is a single-center, retrospective cross-sectional study. We analyzed 22 individuals with genetically confirmed cone dystrophy, with symptoms beginning after 30 years of age. All patients underwent comprehensive ophthalmic and electrophysiological examinations. Exome sequencing of 296 genes associated with inherited retinal disease was performed. The clinical features of patients with AOCD/AOCRD and the causative genes and variants detected by exome sequencing were analyzed.

RESULTS

The median age at the first visit was 52 years (range, 31-76 years), and the most common initial symptom was reduced visual acuity. In most cases, fundus photography showed a bull's eye pattern with foveal sparing, consistent with perifoveal photoreceptor loss on optical coherence tomography. We identified disease-causing variants in six genes: RP1, CRX, CDHR1, PROM1, CRB1, and GUCY2D. Pathogenic variants in RP1, CRX, and CDHR1 were identified in 77% of the AOCD/AOCRD cases, including p.Cys1399LeufsTer5, p.Arg1933Ter, and p.Ile2061SerfsTer12 in RP1; p.Ter300GlnextTer118 in CRX; and p.Glu201Lys in CDHR1. No characteristic imaging differences were observed for any of the causative genes. Most of the RP1-related AOCD/AOCRD cases showed a decreased amplitude only in the photopic electroretinogram (ERG), whereas CRX-related AOCD/AOCRD cases showed a slightly decreased amplitude in both the scotopic and photopic ERGs.

CONCLUSION

In case of visual impairment with bull's eye pattern of RPE atrophy recognized after the middle age, a comprehensive ophthalmic examination and genetic test should be considered, with the possibility of AOCD/AOCRD in East Asians.

Visual outcomes and recurrence rate of macular corneal dystrophy following phototherapeutic keratectomy in Saudi Arabia

PURPOSE

The purpose of the study was to evaluate the visual outcomes and recurrence rate of patients with macular corneal dystrophy (MCD) who have undergone phototherapeutic keratectomy (PTK).

METHODS

This retrospective, single-centered study enrolled patients from King Khaled Eye Specialist Hospital who had undergone PTK for MCD between 2000 and 2020. Pre-, intra-, and post-operative data were collected, and the primary outcome measures included uncorrected visual acuity, best-corrected visual acuity (BCVA), spherical equivalent, central keratometry, keratometric astigmatism, recurrence rate, and necessity of subsequent surgery.

RESULTS

This study evaluated 42 eyes of 29 patients. BCVA improved from 0.41 (±0.17) preoperatively to 0.30 (±0.16) postoperatively. Sixteen out of 42 eyes (38%) had the recurrence of macular dystrophy deposits within the stroma; the average time from PTK to recurrence was 37 months (range: 5.5-115.4 months). The overall success rate of PTK at 2 years was 44.8%. Eleven eyes (26%) required subsequent surgery following PTK at an average of 43 months postoperatively. Deeper ablation and longer application of mitomycin C (MMC) were both found to be statistically significant factors associated with visual improvement and lower recurrence rate following PTK.

CONCLUSION

PTK can be considered a treatment modality for younger patients to defer keratoplasty to a later stage. Deeper ablation is associated with improved postoperative visual acuity, and longer application of MMC is associated with lower recurrence rates of MCD.

Vitelliform maculopathy in MELAS syndrome

Purpose

We present a unique case of foveomacular vitelliform lesions in a patient with metabolic encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS).

Observations

After performing large panel next generation sequencing genetic testing, there was no likely alternative genetic etiology for vitelliform maculopathy in this patient.

Conclusions and Importance

We present a rare case of a visually asymptomatic pediatric patient with MELAS and vitelliform maculopathy, which may be part of the spectrum of retinal manifestations in MELAS. Pediatric-onset vitelliform maculopathy in MELAS may be under-diagnosed due to its asymptomatic nature. Given the known risk of choroidal neovascularization in vitelliform maculopathy, it is important to identify these patients for proper surveillance.

Choroidal Neovascularization Is Common in Best Vitelliform Macular Dystrophy and Plays a Role in Vitelliform Lesion Evolution

OBJECTIVE

Choroidal neovascularization (CNV) is usually considered to be a late-stage complication in Best vitelliform macular dystrophy (BVMD) and can be difficult to diagnose with fluorescein angiography. This study used swept-source (SS) OCT angiography (OCTA) to evaluate the prevalence of CNV in BVMD, identify structural features associated with CNV, and provide insight into the role of CNV in vitelliform lesion evolution.

DESIGN

Institutional review board-approved, retrospective, cross-sectional, and longitudinal study.

PARTICIPANTS

Patients with molecularly confirmed BVMD.

METHODS

Charts from consecutive patients with BVMD imaged with SS-OCTA (PLEX Elite 9000, Carl-Zeiss Meditec Inc) at the University of Iowa from September 2017 to October 2021 were reviewed. Clinical data, including age, gender, best-corrected visual acuity (BCVA), and treatment with intravitreal anti-VEGF injections were recorded. The presence of CNV on SS-OCTA was determined by expert graders and correlated with structural features, such as interstitial fluid, subretinal fluid, nodular subretinal pillar, focal choroidal excavation (FCE), and subfoveal choroidal thickness, with a P value of < 0.05 considered statistically significant.

MAIN OUTCOME MEASURES

Presence of CNV on SS-OCTA and correlation with structural features on SS-OCT.

RESULTS

A total of 53 eyes from 27 patients (13 women; 48.1%) were included. The mean age was 45 years (range, 8-79 years), and the mean logarithm of the minimum angle of resolution BCVA was 0.38 (range, 0-1). Choroidal neovascularization was identified on SS-OCTA in 27 eyes (50.9%), of which 63.0% had a vitelliform (Gass stage 2) lesion. In 40.7% (11 of 27) of eyes, there was no prior clinical diagnosis of CNV. Other structural features associated with CNV included FCEs (15.1%, 8 of 53 eyes) and nodular pillars (15.1%, 8 of 53 eyes) (P < 0.01). Seven patients had available longitudinal imaging, and most of these patients had CNV visible on SS-OCTA (71.4%; 10 of 14 eyes).

CONCLUSION

Choroidal neovascularization is common in BVMD, including in the early stages of the disease. The presence of FCEs or nodular pillars should heighten the clinical suspicion of CNV, which may accelerate vitelliform lesion evolution.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Clinical-genetic findings in a group of subjects with macular dystrophies due to mutations in rare inherited retinopathy genes

PURPOSE

To describe the results of clinical and molecular analyses in a group of patients suffering from inherited macular dystrophies, in which next-generation sequencing (NGS) efficiently detected rare causative mutations.

METHODS

A total of eight unrelated Mexican subjects with a clinical and multimodal imaging diagnosis of macular dystrophy were included. Visual assessment methods included best corrected visual acuity, color fundus photography, Goldmann visual field tests, kinetic perimetry, dark/light adapted chromatic perimetry, full-field electroretinography, autofluorescence imaging, and spectral domain-optical coherence tomography imaging. Genetic screening was performed by means of whole exome sequencing with subsequent Sanger sequencing validation of causal variants.

RESULTS

All patients exhibited a predominantly macular or cone-dominant disease. Patients' ages ranged from 12 to 60 years. Three cases had mutations in genes associated with autosomal dominant inheritance (UNC119 and PRPH2) while the remaining five cases had mutations in genes associated with autosomal recessive inheritance (CNGA3, POC1B, BEST1, CYP2U1, and PROM1). Of the total of 11 different pathogenic alleles identified, three were previously unreported disease-causing variants.

CONCLUSIONS

Macular dystrophies can be caused by defects in genes that are not routinely analyzed or not included in NGS gene panels. In this group of patients, whole exome sequencing efficiently detected rare genetic causes of hereditary maculopathies, and our findings contribute to expanding the current knowledge of the clinical and mutational spectrum associated with these disorders.

CRB1-Associated Retinal Dystrophies: Genetics, Clinical Characteristics, and Natural History

PURPOSE

To analyze the clinical characteristics, natural history, and genetics of CRB1-associated retinal dystrophies.

DESIGN

Multicenter international retrospective cohort study.

METHODS

Review of clinical notes, ophthalmic images, and genetic testing results of 104 patients (91 probands) with disease-causing CRB1 variants. Macular optical coherence tomography (OCT) parameters, visual function, fundus characteristics, and associations between variables were the main outcome measures.

RESULTS

The mean age of the cohort at the first visit was 19.8 ± 16.1 (median 15) years, with a mean follow-up of 9.6 ± 10 years. Based on history, imaging, and clinical examination, 26 individuals were diagnosed with retinitis pigmentosa (RP; 25%), 54 with early-onset severe retinal dystrophy / Leber congenital amaurosis (EOSRD/LCA; 52%), and 24 with macular dystrophy (MD; 23%). Severe visual impairment was most frequent after 40 years of age for patients with RP and after 20 years of age for EOSRD/LCA. Longitudinal analysis revealed a significant difference between baseline and follow-up best-corrected visual acuity in the 3 subcohorts. Macular thickness decreased in most patients with EOSRD/LCA and MD, whereas the majority of patients with RP had increased perifoveal thickness.

CONCLUSIONS

A subset of individuals with CRB1 variants present with mild, adult-onset RP. EOSRD/LCA phenotype was significantly associated with null variants, and 167_169 deletion was exclusively present in the MD cohort. The poor OCT lamination may have a degenerative component, as well as being congenital. Disease symmetry and reasonable window for intervention highlight CRB1 retinal dystrophies as a promising target for trials of novel therapeutics.

Longitudinal Analysis of Functional and Structural Outcome Measures in PRPH2-Associated Retinal Dystrophy

PURPOSE

To establish disease progression rates in total lesion size (TLS), decreased autofluorescence (DAF) area, total macular volume (TMV), and mean macular sensitivity (MMS) in PRPH2-associated retinal dystrophy.

DESIGN

Single-center, retrospective chart review.

PARTICIPANTS

Patients with heterozygous pathogenic or likely pathogenic PRPH2 variants.

METHODS

Patients who underwent serial ultrawide-field (UWF) fundus autofluorescence (FAF), OCT, and Macular Integrity Assessment microperimetry with at least 1 year of follow-up were included. Linear correlation was performed in eyes of all patients to determine the rate of change over time.

MAIN OUTCOME MEASURES

Outcome measures included changes in TLS, DAF area, TMV, and MMS.

RESULTS

Twelve patients (mean age, 55) from 10 unrelated families attended 100 clinic visits, which spanned over a mean (SD) of 4.7 (2.0) years. Mean (SD) TLS and DAF radius expansion were 0.14 (0.12) and 0.10 (0.08) mm/year, respectively. Mean (SD) TMV change was -0.071 (0.040) mm³/year with no interocular difference (P = 0.20) and strong interocular correlation (r² = 0.88, P < 0.01). Mean (SD) MMS change was -0.10 (1.25) dB/year. Mean macular sensitivity declined in 4 and improved in 6 patients. Mean macular sensitivity was subnormal despite a TMV within the normal range.

CONCLUSIONS

Serial measurements of UWF-FAF-derived TLS and DAF showed slow expansion. Total macular volume might be a more sensitive measure than MMS in detecting disease progression.

PRPH2-Associated Retinopathy: Novel Variants and Genotype-Phenotype Correlations

PURPOSE

A broad spectrum of autosomal-dominant inherited retinal diseases (IRDs), ranging from mild macular pattern dystrophy to severe cone-rod degeneration, is associated with PRPH2 variants (peripherinopathies). We present detailed clinical and molecular characterization of patients affected by peripherinopathies, aiming to expand the mutational spectrum, and propose novel genotype-phenotype correlations.

DESIGN

Observational, retrospective case series.

PARTICIPANTS

Patients with an IRD related to a molecularly proven PRPH2 variant.

METHODS

Data from ophthalmic examinations and retinal imaging were collected for each follow-up visit. The standard imaging protocol included OCT, blue-light autofluorescence, near-infrared autofluorescence, and ultra-widefield fundus imaging. Genetic analysis was performed with a genomic approach by next-generation sequencing.

MAIN OUTCOME MEASURES

Results of ophthalmic examination, retinal imaging, and molecular genetic analysis.

RESULTS

Overall, a total of 19 patients with an IRD and a (likely) pathogenic PRPH2 variant were identified. Their age at presentation had a median of 48 years, whereas the symptomatic disease onset was in their 30s or 40s in 74% of cases. The median follow-up time was 4 years. Clinically, 6 patients were diagnosed with cone-rod dystrophy and 13 with pattern dystrophy. Among the 13 PRPH2 pathogenic variants identified in our cohort, 7 were missense, 3 nonsense, 2 frame shifting, and 1 splice site. Missense variants in the D2 loop were associated with cone-rod dystrophies and poor visual prognosis, whereas predicted loss-of-function alleles with pattern dystrophies and retention of a good visual function into adulthood. Overall, the following 7 variants were novel and never associated to a clinical phenotype: c.68delT, c.290G>A, c.413T>G, c.642C>G, c.702_706dupCAGTT, c.771_772delinsGA, and c.850C>G.

CONCLUSIONS

Here, we report the findings of a retrospective case series that provided a detailed clinical and molecular characterization of 19 patients harboring 13 different PRPH2 pathogenic variants, 7 of which were previously unreported, expanding the mutational spectrum of the PRPH2 gene. Loss-of-function variants might be preferentially associated with mild-pattern dystrophies, whereas missense dominant-negative variants might be preferentially associated with severely blinding cone-rod degenerations. Further studies are needed to better define the pathogenetic mechanisms and the functional effects of most variants to allow the development of successful gene therapy.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

CLEC3B is a novel causative gene for macular-retinal dystrophy

PURPOSE

Macular degeneration is the leading cause of blindness worldwide. In this study, we aimed to define a new subtype of macular-retinal dystrophy and its genetic predisposition in 5 families.

METHODS

Exome sequencing was performed to determine the putative disease-causing genes in patients with inherited macular disorders confirmed through comprehensive ophthalmic examinations. To validate its functional consequence, adeno-associated virus-mediated mutant gene was delivered into the murine retina, and both structural and functional tests were performed to investigate its pathological effects in vivo.

RESULTS

In total, 5 multigenerational families diagnosed with autosomal dominant maculoretinopathy were found to carry a pathogenic variant in a new gene, CLEC3B, which encodes tetranectin, a plasminogen kringle-4 binding protein. Consistent with the disease phenotypes of patients, mice that received subretinal injections with the CLEC3B variant displayed multiple subretinal hyperreflective deposits, reduced retinal thickness, and decreased electroretinographic responses. Moreover, the optokinetic tracking response indicated that spatial frequency was significantly lower (P < .05), implying impaired visual function in these mice.

CONCLUSION

We have presented a new subtype of macular-retinal dystrophy in 5 families as well as a new pathogenic gene, CLEC3B, providing new insights into maculoretinopathy etiology.

Stargardt disease: A clinical case report of two sisters with different clinical development

The purpose of this article is to describe the clinical manifestations and complementary diagnostic tests of two sisters aged 26 and 31 with a diagnosis of Stargardt's disease. One of them presented with an initial visual acuity of 0.7 and showed a progressive central visual loss due to the atrophy of the external layers of the retina in the subfoveal region. She was recruited to participate in a clinical trial of Avancincaptad Pegol (Zimura®), an inhibitor of C5 of the complement's system. The other sister remained asymptomatic with a visual acuity of 1 in both eyes. In both cases white-yellow pisciform lesions were observed on the posterior pole. Although there is no curative treatment for this disease, there are many lines of investigation on this topic. The clinical and diagnostic tests can confirm the disease, and provide patients with an accurate prognosis.

The second Japanese family with Malattia Leventinese/Doyne honeycomb retinal dystrophy

PURPOSE

To describe the clinical and genetic findings of patients in the second Japanese family with Malattia Leventinese/Doyne honeycomb retinal dystrophy (ML/DHRD).

METHODS

Two patients (a 41-year-old male proband and his third son) underwent comprehensive ophthalmic examinations, including full-field and multifocal electroretinography (ERG). Sanger sequencing was performed to detect an EFEMP1 gene variant (p.Arg345Trp), which was identified as the only causative pathogenic variant.

RESULTS

Genetic analysis revealed that both patients carried the heterozygous variant, but the other unaffected family members did not. Although the proband exhibited innumerable radially distributed drusen in both the posterior poles and good visual acuity at initial presentation, bilateral choroidal neovascularization (CNV) developed during the 15-year follow-up. The proband received 15 intravitreal anti-vascular endothelial growth factor (VEGF) injections in the left eye (LE) and two injections in the right eye (RE). At 56 years of age, his decimal best-corrected visual acuity was 0.1 and 1.2 in the LE and RE, respectively. Full-field ERG showed that while the rod and combined responses were within normal amplitudes, the cone and 30-Hz flicker responses had slightly decreased amplitudes. Multifocal ERG revealed attenuated central responses in the LE and decreased temporal responses in the RE. In the 20-year-old son, multifocal ERG showed normal responses in both eyes.

CONCLUSION

This is the first report of ML/DHRD in a patient who developed bilateral CNV and received anti-VEGF treatment in both eyes. Although multifocal ERG exhibited worsening of macular function, the generalized photoreceptor function was preserved until middle age.

Bilateral solar maculopathy in a patient with bipolar disorder

A case of solar maculopathy is described in a 36-year-old man with a history of bipolar disorder. The patient reported directly looking at the sun for several hours in the setting of a bipolar disorder decompensation. The visual acuity was 0.3 in both eyes (BE). Intraocular pressure and anterior segment were normal. In the fundus exam, a peri-macular halo with loss of the foveolar reflex was observed in BE. The macular optical coherence tomography revealed a disruption of the ellipsoid line and the retinal pigment epithelium. Bilateral central defects were seen in the Humphrey 24-2 visual field. After 6 months of follow-up, the visual clinical picture remains stable with the same degree of visual acuity. Solar maculopathy is a disorder due to the phototoxic effects of radiation, which cause a decrease in visual acuity by disrupting the retinal photoreceptor layer.

Deep phenotyping of the Cdhr1-/- mouse validates its use in pre-clinical studies for human CDHR1-associated retinal degeneration

PURPOSE

To validate the Cdhr1^-/- mouse as a model for human CDHR1-associated retinal degeneration, which may present as cone-rod dystrophy or geographic atrophy.

METHODS

Deep phenotyping of Cdhr1^-/-(n = 56) and C57BL6J wildtype control mice (n = 45) was undertaken using in vivo multimodal retinal imaging and dark- and light-adapted electroretinography (ERG) over 15 months to evaluate rod- and cone-photoreceptor responses and retinal morphology.

RESULTS

Cdhr1^-/- retinas exhibited outer retinal thinning on optical coherence tomography (OCT) at 1-month versus C57BL6J (mean 14.6% reduction; P < 0.0001), with progressive degeneration to 15 months. The OCT layer representing photoreceptor outer segments was more significantly shortened in Cdhr1^-/- eyes at 1 month (mean 33.7% reduction; P < 0.0001), remained stable to 3 months and was not identifiable at later timepoints. Outer retinal thinning was more pronounced at inferior versus superior retinal locations in Cdhr1^-/- eyes (P < 0.002 at 3-9 months). Dark-adapted ERG identified severe functional deficits in Cdhr1^-/- mice at 1 month of age versus C57BL6J (mean 62% reduction) that continued to decline to 15 months (P < 0.0001). Light-adapted flicker identified severe deficits in cone function at 1 month (mean 70% reduction), with improved function to 3 months followed by progressive decline (P < 0.0001).

CONCLUSIONS

The Cdhr1^-/- mouse exhibits structural and functional evidence of progressive outer retinal degeneration at a slow rate. Early functional deficits affecting both rod and cone photoreceptors in the context of relatively mild structural changes reflect the human phenotype. This study validates the use of the Cdhr1^-/- mouse for the pre-clinical evaluation of therapeutics for human CDHR1-associated retinal degeneration.

Fundus albipunctatus photoreceptor microstructure revealed using adaptive optics scanning light ophthalmoscopy

Purpose

Fundus albipunctatus is an inherited cause of congenital stationary night blindness. The objective of this report is to describe structural changes occurring in a macular phenotype of a novel RDH5 mutation producing fundus albipunctatus using high-resolution in vivo imaging. A 62-year-old male with longstanding night blindness underwent imaging and genetic evaluation. High-resolution images of the photoreceptor mosaic were compared to those of a healthy subject. Results of a comprehensive ophthalmic evaluation and genetic testing with imaging including fundus photography, spectral-domain optical coherence tomography (OCT), fluorescein angiography (FA), OCT angiography (OCT-A), and adaptive optics scanning light ophthalmoscopy (AOSLO) are described.

Observations

The patient presented with visual acuity of 20/25 in both eyes and longstanding poor dark adaptation. Anterior segment examination was unremarkable. Fundoscopy revealed well circumscribed bilateral perifoveal mottling and atrophy in both eyes. Discrete white-yellow flecks were present beyond the vascular arcades extending to the far periphery. Genetic testing revealed a novel compound heterozygous RDH5 mutation (c.388C > T, p.Gln130*; c.665T > C, p.Leu222Pro). OCT demonstrated perifoveal photoreceptor and outer retinal irregularities, which corresponded to a window defect with late staining on FA. OCT-A demonstrated normal retinal vasculature with patchy areas of non-perfusion in the choriocapillaris. Macular abnormalities in both eyes were imaged using AOSLO to assess cone and rod photoreceptor architecture. While clinical features are consistent with a primary rod disorder, confocal AOSLO showed a paucity of normal cones with a small spared central island in both eyes. Rods appeared larger and more irregular throughout the macula. Non-confocal split detection AOSLO imaging revealed the presence of cone inner segments in dark regions of confocal imaging, indicating some degree of photoreceptor preservation.

Conclusions and Importance

The AOSLO imaging of this particular macular phenotype of fundus albipunctatus demonstrates some of the structural photoreceptor abnormalities that occur in this condition, adding insight to the variable presentation of RDH5 retinopathy. The presence of preserved inner segment architecture suggests the possibility that gene therapy could play a future role in treating this condition.

Targeted next generation sequencing and family survey enable correct genetic diagnosis in CRX associated macular dystrophy - a case report

Background

We present 3 members of a family with macular dystrophy, originally diagnosed as Stargardt disease, with a significantly variable age at onset, caused by a heterozygous mutation in CRX.

Case presentation

A 43-year-old female with bull’s eye maculopathy, whose sister was diagnosed with Stargardt disease previously at another centre, was found to have a single ABCA4 variant. Further examination of the family revealed that the asymptomatic father was also affected, indicating a dominant pattern of inheritance. In addition, the ABCA4 variant was not identified in the sister originally diagnosed with Stargardt disease. Next generation sequencing identified a heterozygous c.121C > T, p.R41W missense mutation in CRX in all 3 affected members.

Conclusions

We describe a common phenotype, but with variable age at onset, with autosomal dominant inheritance and reduced penetrance in a family found to have a pathogenic sequence variant in CRX. This illustrates the importance of panel based molecular genetic testing accompanied by family studies to establish a definitive diagnosis.

Stargardt Disease: a clinical case report of two sisters with different clinical development

The purpose of this article is to describe the clinical manifestations and complementary diagnostic tests of two sisters aged 26 and 31 with a diagnosis of Stargardt's disease. One of them presented with an initial visual acuity of 0.7 and showed a progressive central visual loss due to the atrophy of the external layers of the retina in the subfoveal region. She was recruited to participate in a clinical trial of Avancincaptad Pegol (Zimura®), an inhibitor of C5 of the complement's system. The other sister remained asymptomatic with a visual acuity of 1 in both eyes. In both cases white-yellow pisciform lesions were observed on the posterior pole. Although there is no curative treatment for this disease, there are many lines of investigation on this topic. The clinical and diagnostic tests can confirm the disease, and provide patients with an accurate prognosis.

CRB1 maculopathy presenting as fenestrated sheen macular dystrophy with 15-year follow-up

INTRODUCTION

We present two patients, the proband and the affected sibling, with biallelic CRB1 mutations leading to a macular dystrophy.

CASE PRESENTATION

We present two patients, the proband and the affected sibling, with biallelic CRB1 mutations leading to a macular dystrophy. With 15 years of follow-up for the proband, we illustrate the natural history of CRB1 maculopathy based on clinical examination, multimodal imaging, and electrophysiology. In addition, we demonstrate the wide phenotypic spectrum of the condition with the affected sister harboring the same variants but with much milder phenotypic manifestations.

CONCLUSION

In addition to a previously described pathogenic variant, Ile167_Gly169del, one pathogenic missense variant in CRB1, Lys801Ter, not previously associated with macular dystrophy, is reported here. While CRB1 mutations have been more commonly described in retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA), we demonstrate that mutations in CRB1 can cause a maculopathy with initial features similar to fenestrated sheen macular dystrophy (FSMD) that later evolves into severe macular atrophy.

Bilateral solar maculopathy in a patient with bipolar disorder

A case of solar maculopathy is described in a 36-year-old man with a history of bipolar disorder. The patient reported directly looking at the sun for several hours in the setting of a bipolar disorder decompensation. The visual acuity was 0.3 in both eyes (BE). Intraocular pressure and anterior segment were normal. In the fundus exam, a peri-macular halo with loss of the foveolar reflex was observed in BE. The macular optical coherence tomography revealed a disruption of the ellipsoid line and the retinal pigment epithelium. Bilateral central defects were seen in the Humphrey 24-2 visual field. After 6 months of follow-up, the visual clinical picture remains stable with the same degree of visual acuity. Solar maculopathy is a disorder due to the phototoxic effects of radiation, which cause a decrease in visual acuity by disrupting the retinal photoreceptor layer.

Progress of macular atrophy during 30 months' follow-up in a patient with spinocerebellar ataxia type1 (SCA1)

PURPOSE

To report the 30-months' course of macular dystrophy in a patient with genetically confirmed spinocerebellar ataxia type1 (SCA1).

METHODS

Detailed ophthalmological examinations including best-corrected visual acuity (BCVA), perimetry, multimodal fundus imaging, and electrophysiological recordings were performed on a 52-year-old woman with SCA1. The number of CAG sequence repeats of the candidate gene was verified.

RESULTS

The baseline decimal BCVA was 0.2 OD and 0.3 OS. Goldman perimetry showed relative central scotomas and slight enlargements of Mariotte blind spot bilaterally. Ophthalmoscopy revealed no abnormalities in the macula and optic disk. Fundus autofluorescence (FAF) showed a circular hyperautofluorescence and round-shaped hypoautofluorescence in the macula. Optical coherence tomography (OCT) showed a loss of the interdigitation zone and ellipsoid zone (EZ) in the macula. Full-field scotopic and photopic Full-field electroretinograms (ERGs) were normal, and multifocal ERGs were decreased in the central area. After 30 months, the BCVA had not changed, but the FAF showed a spark-like hypoautofluorescence in the macula. The abnormal area of the EZ had expanded toward the periphery, and the rate of EZ loss was 199.7%/year OD and 206.8%/year OS. Genetic examinations revealed an increase in the number of heterozygous CAG repeats in the ATXN1 gene, and the CAG repeat number of the mutant allele ranged from 43 to 48.

CONCLUSIONS

The full-field scotopic and photopic ERGs were normal. The mfERGs were significantly smaller in the central region. OCT demonstrated bilateral photoreceptor atrophy in the macula, and the rate of EZ loss was more rapid than in other macular dystrophies. Spark-like hypoautofluorescence appeared during the course of the disease process which might be a specific feature of SCA1-related retinopathy.

Correlating Adaptive Optics Images to Clinical Findings in Juvenile Macular Dystrophy with Hypotrichosis in Siblings with Homozygous CDH3 Pathogenic Variation

OBJECTIVE

We report on two German siblings diagnosed with congenital hypotrichosis and juvenile macular dystrophy, an extremely rare syndrome affecting both hair growth and visual functions.

METHODS

A detailed ophthalmological examination was carried out including fundus examination, visual acuity assessment, visual field determination, color vision testing, and electrophysiology (electroretinography [ERG]). Additionally, fundus photography and autofluorescence imaging (FAF) was performed, along with optical coherence tomography (OCT) and adaptive optics (AO) fundus imaging. Targeted Sanger sequencing and next-generation gene panel sequencing were carried out.

RESULTS

Macular dystrophy was evident in the fundus of both patients, as was a central scotoma in the static visual field. The kinetic visual field was normal. The ERG recordings were also normal, but the amplitudes of the multifocal ERG were reduced in the central 4-5° of the retina. The FAF images revealed a large central hypofluorescent area surrounded by a hyperfluorescent ring. The OCT images showed atrophy in the outer layers and tubulations. The AO images depicted a loss of central photoreceptors, as well as severe central atrophy in patient 1. A cone mosaic was observable in the peripheral AO fundus images of both patients. The disrupted cone mosaic on the AO images correlated with the hypofluorescent areas on autofluorescence. DNA testing identified the homozygous, likely pathogenic variant c.1508G>A/p.(Arg503His) (chr16:68719191) in the CDH3 gene.

CONCLUSIONS

The two siblings revealed hypotrichosis and macular dystrophy in both eyes. The identification of a homozygous CDH3 mutation in each patient confirms the syndromic entity of hypotrichosis with juvenile macular degeneration.

Whole genome sequencing reveals novel mutations causing autosomal dominant inherited macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a common sight threatening condition. However, there are a number of monogenic macular dystrophies that are clinically similar to AMD, which can potentially provide pathogenetic insights.

METHODS

Three siblings from a non-consanguineous Greek-Cypriot family reported central visual disturbance and nyctalopia. The patients had full ophthalmic examinations and color fundus photography, spectral-domain ocular coherence tomography and scanning laser ophthalmoscopy. Targeted polymerase chain reaction (PCR) was performed as a first step to attempt to identify suspected mutations in C1QTNF5 and TIMP3 followed by whole genome sequencing.

RESULTS

The three patients were noted to have symptoms of nyctalopia, early paracentral visual field loss and, in older patients, central vision loss. Imaging identified pseudodrusen, retinal atrophy and RPE-Bruch's membrane separation. Whole genome sequencing of the proband revealed two novel heterozygous variants in C1QTNF5, c.556C>T, and c.569C>G. The mutation segregated with disease in this family, occurred in cis, and resulted in missense amino acid changes P186S and S190W in C1QTNF5. In silico modeling of the variants revealed that the S190W mutations was likely to have the greatest pathologic effect and that the combination of the mutations was likely to have an additive effect.

CONCLUSIONS

The novel mutations in C1QTNF5 identified here expand the genotypic spectrum of mutations causing late-onset retinal dystrophy.

Photic maculopathy: A review of the literature (ii)

The human retina, as transducer of light energy, is especially exposed to light toxicity. Solar maculopathy has been the only form of photic maculopathy for millennia, often secondary to the observation of an eclipse. During the last century, technological advances have led to the appearance of new forms of photic maculopathy, related to the exposure to new forms of artificial light, such as welding devices and lasers. In recent years the general use of laser pointers has led to an upturn in interest in this pathology. The aim of this review is to offer an integrated view of the different types of photic maculopathy. Due to the extension of the topic, the review is presented divided into 2 parts. In this second part, atomic bomb maculopathy, laser maculopathy, iatrogenic forms of photic maculopathy, and foveomacular retinitis are presented.

Photic maculopathy: A review of the literature (I)

The human retina, as transducer of light energy, is especially exposed to light toxicity. Solar maculopathy has been the only form of photic maculopathy for millennia, often secondary to the observation of an eclipse. During the last century, technological advances have led to the appearance of new forms of photic maculopathy, related to the exposure to new forms of artificial light, such as welding devices and lasers. In recent years, the general use of laser pointers has led to an upturn in interest in this pathology. The aim of this review is to offer an integrated view of the different types of photic maculopathy. Due to the extension of this topic, the review is presented divided into two parts. In this first part solar maculopathy and welding arc maculopathy are presented.

Fixation behavior in macular dystrophy assessed by microperimetry

Purpose

To investigate the fixation behavior in macular dystrophy using microperimetry.

Methods

This retrospective study included patients with macular dystrophy and unilateral macular pucker. Macular dystrophic eyes were compared based on fixation within or outside of the atrophic region. The normal fellow eyes in patients with unilateral macular pucker formed the control group. Clinical and demographic characteristics of age, sex, best-corrected visual acuity, spherical equivalent, and fixation behavior (which included foveal mean sensitivity (MS), fixation MS, MS improvement, stability, centrality, and eccentric distance of fixation) were analyzed. A total of 58 patients were recruited, comprising 29 eyes of 29 patients in the macular dystrophy group and 29 eyes of 29 patients in the control group.

Results

Compared to the control group, patients with macular dystrophy had significantly poorer visual acuity, foveal MS, fixation MS, stability, and centrality, and more eccentric preferred retinal locations (PRLs). In macular dystrophy, the PRLs were most common on the superior side (48.3%). Compared to fixation in the atrophic region, PRLs out of the atrophic lesion gained more MS (7.41 vs. 0.89 dB, p = 0.001), although with less stable fixation (10.0 vs. 47.4%, p = 0.044). By multivariate linear regression, eccentric distance was found to be significantly associated with MS improvement (p = 0.023).

Conclusions

The commonest location of PRLs in macular dystrophy is anatomically superior to the lesion. The dystrophic eye can gain better sensitivity by using PRLs outside the atrophic area.

Identification of the PROM1 Mutation p.R373C in a Korean Patient With Autosomal Dominant Stargardt-like Macular Dystrophy

Stargardt-like macular dystrophy 4 (STGD4) is a rare macular dystrophy characterized by bull's eye atrophy of the macula and the underlying retinal pigment epithelium. Patients with STGD4 show decreased central vision, which often progresses to severe vision loss. The PROM1 gene encodes prominin-1, which is a 5-transmembrane glycoprotein also known as CD133 and is involved in photoreceptor disk morphogenesis. PROM1 mutations have been identified as genetic causes for STGD4 and other retinal degenerations such as retinitis pigmentosa. We report a case of STGD4 with a PROM1 p.R373C mutation in a Korean patient. Ophthalmic examinations of a 38-yr old man complaining of decreased visual acuity revealed bilateral atrophic macular lesions consistent with STGD4. Targeted exome sequencing of known inherited retinal degeneration genes revealed a heterozygous missense mutation c.1117C>T (p.R373C) of PROM1, which was confirmed by Sanger sequencing. To the best of our knowledge, this is the first case of a PROM1 mutation causing STGD4 in Koreans.

A Novel ABCA4 Mutation Associated with a Late-Onset Stargardt Disease Phenotype: A Hypomorphic Allele?

BACKGROUND

Stargardt disease (STGD) is the most common juvenile hereditary macular dystrophy. In the majority of cases, the diagnosis is made prior to 20 years of age and usually leads to loss of central vision. Late-onset STGD affects a smaller number of patients. Identifying genetic changes which could be associated with clinically important differences in severity or presentation of the disease is important for understanding the mechanisms of visual loss and for planning future therapeutic approaches.

METHODS

We report a patient with the classic phenotype of STGD with late-onset mild disease exhibiting a slow clinical progression over 14 months of follow-up.

RESULTS

A 37-year-old man presented with STGD and good vision of 6/24 in the right eye and of 6/6 in the left eye as well as typical electrophysiology findings. Objective and subjective visual deterioration was not noted over a period of 14 months. Macular genetic testing revealed a novel missense mutation in ABCA4 (Thr829Met) combined with Gly1961Glu, a classic STGD mutation usually associated with a moderately severe phenotype.

CONCLUSIONS

It is suggested that the Thr829Met mutation could give rise to a hypomorphic allele of the ABC transporter with a resultant phenotype of comparatively mild STGD.

New CDH3 mutation in the first Spanish case of hypotrichosis with juvenile macular dystrophy, a case report

Background

CDH3 on 16q22.1 is responsible for two rare autosomal recessive disorders with hypotrichosis and progressive macular dystrophy: Hypotrichosis with Juvenile Macular Dystrophy and Ectodermal Dysplasia, Ectrodactyly and Macular Dystrophy. We present a new case of Hypotrichosis with Juvenile Macular Dystrophy.

Case presentation

A Spanish male born in 1998 from non-consanguineous healthy parents with a suspected diagnosis of Keratosis Follicularis Spinulosa Decalvans and Retinitis Pigmentosa Inversa referred to our Genetics Department (IIS-Fundación Jiménez Díaz).

Molecular study of ABCA4 was performed, and a heterozygous missense p.Val2050Leu variant in ABCA4 was found.

Clinical revision reclassified this patient as Hypotrichosis with Juvenile Macular Dystrophy. Therefore, further CDH3 sequencing was performed showing a novel maternal missense change p.Val205Met (probably pathogenic by in silico analysis), and a previously reported paternal frameshift c.830del;p.Gly277Alafs*20, thus supporting the clinical diagnosis..

Conclusions

This is not only the first Spanish case with this clinical and molecular diagnosis, but a new mutation has been described in CDH3. Moreover, this work reflects the importance of joint assessment of clinical signs and evaluation of pedigree for a correct genetic study approach and diagnostic.

Two sisters with macular dystrophy caused by the 3243A>G mitochondrial DNA mutation

CASE REPORT

Two sisters of 54 and 60years old, with a history of diabetes and deafness, consulted for decreased visual acuity (VA). Funduscopic examination revealed patchy areas of chorioretinal atrophy with annular arrangement around the fovea. Genetic study identified the heteroplasmic mutation 3243A>G in mitochondrial DNA, which supports syndrome maternally inherited diabetes and deafness (MIDD) or Ballinger-Wallace disease.

DISCUSSION

The finding of such macular disorders, especially in the presence of diabetes mellitus and deafness, should suggest the performing of a mitochondrial genome screening to identify this unusual syndrome.

Clinical applications of fundus autofluorescence in retinal disease

Fundus autofluorescence (FAF) is a non-invasive retinal imaging modality used in clinical practice to provide a density map of lipofuscin, the predominant ocular fluorophore, in the retinal pigment epithelium. Multiple commercially available imaging systems, including the fundus camera, the confocal scanning laser ophthalmoscope, and the ultra-widefield imaging device, are available to the clinician. Each offers unique advantages for evaluating various retinal diseases. The clinical applications of FAF continue to expand. It is now an essential tool for evaluating age related macular degeneration, macular dystrophies, retinitis pigmentosa, white dot syndromes, retinal drug toxicities, and various other retinal disorders. FAF may detect abnormalities beyond those detected on funduscopic exam, fluorescein angiography, or optical coherence tomography, and can be used to elucidate disease pathogenesis, form genotype-phenotype correlations, diagnose and monitor disease, and evaluate novel therapies. Given its ease of use, non-invasive nature, and value in characterizing retinal disease, FAF enjoys increasing clinical relevance. This review summarizes common ocular fluorophores, imaging modalities, and FAF findings for a wide spectrum of retinal disorders.

Hereditary retinal eye diseases in childhood and youth affecting the central retina

Hereditary dystrophies affecting the central retina represent a heterogeneous group of diseases. Mutations in different genes may be responsible for changes of the choroid (choroideremia), of the retinal pigment epithelium [RPE] (Best's disease), of the photoreceptor outer segments (Stargardt's disease) and of the bipolar and Mueller cells (x-linked retinoschisis). The correct diagnosis of hereditary retinal dystrophies is important, even though therapeutic options are limited at the moment, as every patient should get a diagnosis and be informed about the expected prognosis. Furthermore, specific gene therapy of a number of diseases such as Leber congenital amaurosis, choroideremia, Stargardt's disease, Usher Syndrome and achromatopsia is being evaluated at present. Classic examinations for patients suffering from hereditary retinal dystrophies of the central retina are funduscopy - also using red-free light - visual-field tests, electrophysiologic tests as electro-retinogram [ERG] and multifocal ERG and tests evaluating color vision. Recently, new imaging modalities have been introduced into the clinical practice. The significance of these new methods such as high-resolution spectral-domain optic coherence tomography [SD-OCT] and fundus autofluorescence will be discussed as well as "next generation sequencing" as a new method for the analysis of genetic mutations in a larger number of patients.

Gene discovery and prevalence in inherited retinal dystrophies

Inherited retinal dystrophies are Mendelian neurodegenerative conditions classified as pigmentary retinopathies, macular dystrophies and others. Over a 21-year period, from 1990 to 2011, we have screened in Montpellier 107 genes in 609 families and have identified a causal mutation in 68.5% of them. Following a gene candidate approach, we established that RPE65, the isomerohydrolase of the visual cycle, is responsible for severe childhood blindness (Leber congenital amaurosis or early onset retinal dystrophy). In an ongoing study, we screened the genes in a series of 283 families with dominant retinitis pigmentosa and we have estimated that 80% of the families have a mutation in a known gene. A similar study is currently undergoing for autosomal recessive retinitis pigmentosa. Finally, we have identified IMPG1 as a responsible gene for rare cases of macular vitelliform dystrophy with a dominant or recessive inheritance.