Vitelliform Macular Dystrophy Research Articles

BEST1 associated bestrophinopathies with angle closure and post-surgical malignant glaucoma

ABSTRACT Introduction Mutations in BEST1 gene have been linked to the development of refractory angle closure glaucoma (ACG). This study aims to delineate the clinical characteristics, genetic mutations, and disease progression in patients with autosomal recessive bestrophinopathy (ARB) and autosomal dominant Best vitelliform macular dystrophy (BVMD) who are presented with treatment-resistant ACG. Methods This retrospective analysis encompasses a comprehensive ophthalmic assessment, retinal imaging, and mutational profiling of six patients diagnosed with bestrophinopathy and concurrent ACG, with a particular emphasis on the risk of post-glaucoma filtration surgery malignant glaucoma (MG). Exome sequencing was conducted utilizing a next-generation sequencing (NGS) based gene panel. Results The cohort included five patients with ARB and one with BVMD, with a mean (±SD) age at ACG diagnosis of 35.1 ± 6.9 years. NGS analysis revealed homozygous BEST1 variants in four patients (ARB; cases 1–4) and a heterozygous BEST1 variant in one patient (BVMD; case 5). One patient (ARB; case 6), despite a recessive pedigree, showed a single heterozygous variant, suggesting the presence of an undetected heterozygous variant indicative of compound heterozygous autosomal recessive inheritance. A novel non-frameshift deletion (c.841_843delTTC; p.Phe281del) was identified in case 2. Surgical intervention was required due to uncontrolled glaucoma in all cases except case 4. All five cases that underwent glaucoma filtration surgery developed MG, which was effectively managed with combined iridozonulo-hyaloido-vitrectomy (IZHV) and pars plana vitrectomy (PPV). Cases 5 and 6, harboring a heterozygous pathogenic variant (c.241 G>A; p.Val81Met), experienced refractory MG and corneal decompensation necessitating multiple interventions. Conclusion Genomic analysis plays a pivotal role in the management of bestrophinopathies with ACG. Characterization of mutational types facilitates prognostication and enables timely interventions. IZHV with PPV emerges as a promising standalone or adjunctive procedure for the management of glaucoma among patients with BEST1 mutations and ACG.

Varied clinical presentations of RP1L1 variants in Chinese patients: a study of occult macular dystrophy and vitelliform macular dystrophy

BackgroundOccult Macular Dystrophy (OMD), primarily caused by retinitis pigmentosa 1-like 1 (RP1L1) variants, is a complex retinal disease characterised by progressive vision loss and a normal fundus appearance. This study aims to investigate the diverse phenotypic expressions and genotypic correlations of OMD in Chinese patients, including a rare case of Vitelliform Macular Dystrophy (VMD) associated with RP1L1.MethodsWe analysed seven OMD patients and one VMD patient, all with heterozygous pathogenic RP1L1 variants. Clinical assessments included Best Corrected Visual Acuity (BCVA), visual field testing, Spectral Domain Optical Coherence Tomography (SD-OCT), multifocal Electroretinograms (mfERGs), and microperimetry. Next-generation sequencing was utilised for genetic analysis.ResultsThe OMD patients displayed a range of phenotypic variability. Most (5 out of 7) had the RP1L1 variant c.133 C > T; p.R45W, associated with central vision loss and specific patterns in SD-OCT and mfERG. Two patients exhibited different RP1L1 variants (c.3599G > T; p.G1200V and c.2880G > C; p.W960C), presenting milder phenotypes. SD-OCT revealed photoreceptor layer changes, with most patients showing decreased mfERG responses in the central rings. Interestingly, a unique case of VMD linked to the RP1L1 variant was observed, distinct from traditional OMD presentations.ConclusionsThis study highlights the phenotypic diversity within OMD and the broader spectrum of RP1L1-associated macular dystrophies, including a novel association with VMD. The findings emphasise the complexity of RP1L1 variants in determining clinical manifestations, underscoring the need for comprehensive genetic and clinical evaluations in macular dystrophies.

Multimodal imaging analysis of autosomal recessive bestrophinopathy: Case series.

Autosomal recessive bestrophinopathy (ARB) is a subtype of bestrophinopathy caused by biallelic mutations of the BEST1 gene, which affect the retinal pigment epithelium (RPE). Studying RPE abnormalities through imaging is essential for understanding ARB. This case series involved the use of multimodal imaging techniques, namely autofluorescence (AF) imaging at 488 nm [short-wavelength AF] and 785 nm [near-infrared AF (NIR-AF)] and polarization-sensitive optical coherence tomography (PS-OCT), to investigate RPE changes in 2 siblings with ARB. Two Japanese siblings (Case 1: male, followed for 20-23 years; Case 2: female, followed for 13-17 years) carried compound heterozygous mutations of the BEST1 gene. Both siblings were diagnosed with ARB. Multimodal imaging techniques were used to evaluate RPE changes. Both siblings had funduscopic changes similar to those seen in the vitelliruptive stage of Best vitelliform macular dystrophy during the follow-up period. NIR-AF imaging showed hypo-AF of the entire macular lesion in both cases, and this hypo-AF remained stable over time. PS-OCT confirmed reduced RPE melanin content in these hypo-AF areas. Additionally, hyper-NIR-AF dots were observed within hypo-NIR-AF areas. Concomitant identification of focally thickened RPE melanin on PS-OCT imaging and hyper-AF on short-wavelength AF imaging at the sites containing hyper-NIR-AF dots indicated that the hyper-NIR-AF dots had originated from either stacked RPE cells or RPE dysmorphia. We confirmed RPE abnormalities in ARB, including diffuse RPE melanin damage in the macula alongside evidence of RPE activity-related changes. This case series demonstrates that multimodal imaging, particularly NIR-AF and PS-OCT, provides detailed insights into RPE alterations in ARB.

Best Vitelliform Macular Dystrophy Presenting with Choroidal Neovascular Membrane in an Adolescent: A Case Report and a Review of the Literature

Abstract An 11-year-old boy presented to the retina outpatient clinic with a -5-year history of poor vision in the left eye. The best corrected visual acuity at presentation was 6/5 and 6/36, respectively, in the right and left eyes. Ocular examination revealed normal anterior segments in both eyes. Binocular indirect ophthalmoscopy of the right eye revealed a pink disc with a cup disc ratio (CDR) of 0.3, normal vessels while the macula had a yellowish lesion with a scrambled egg appearance and surrounding dome-shaped subretinal fluid with a flat retina and no treatable peripheral retinal lesions. The left eye had a pink disc with CDR O.3, normal vessels with a hyperpigmented lesion at the macula surrounded by a small cuff of subretinal fluid with a flat retina and no treatable peripheral retinal lesions. Optical coherence tomography scan revealed subretinal fluid in both eyes with an active choroidal neovascular membrane in the left eye. He was advised on the need for left intravitreal anti-vascular endothelial growth factor injections.

An Overview of Best Disease

The German ophthalmologist Friedrich Best named Best vitelliform macular dystrophy (BVD), sometimes referred to as Best disease, in 1905 when he discovered a family with a history of early-onset macular degeneration. A Swedish study assessed the frequency of BVMD to be 2 in 10,000, whereas a Danish examination found 1.5 in 100,000 cases. If a parent with the condition has a kid with an unaffected spouse, there is a 50% chance that the child will inherit the condition from the parent. The syndrome is caused by a mutation in the VMD2 or BEST1 gene found at chromosome 11q12-q13. It is yet unclear how bestrophinopathies pathophysiologically operate. An ionic imbalance in the RPE milieu, which BEST1 gene mutations can bring on, can lead to impaired RPE functions. The best sickness is in five phases. There is currently no recognized treatment for the best sickness. One treatment option for CNV is VEFG injections, either used alone or in conjunction with photodynamic therapy (PDT). Anti-vascular endothelial growth factor (Anti- VEGF) treatments can prevent or reduce the creation of new blood vessels. This can postpone the onset of blindness and slow down the rate at which they leak.

Vitelliform subretinal deposits: shared pathogenesis and clinical diversity

Since its initial description, Best vitelliform macular dystrophy has been strongly linked to characteristic retinal lesions—subretinal yellowish accumulations, with a hyperreflective structure on optical coherence tomography, situated above the retinal pigment epithelium layer. However, research on this topic remains scarce. It is now recognized that, within the common pathophysiological mechanism of vitelliform lesion formation, this process may contribute to the pathogenesis of a broad spectrum of both genetic and acquired conditions.The purpose of this review is to update our understanding of genetically determined and acquired retinal diseases associated with the formation of such lesions.Materials and methods. analysis of scientific publications from databases including PubMed, ScienceDirect, and Cyberleninka was conducted. The review encompasses 16 studies, predominantly from the past decade.Results. Advances in instrumental and genetic diagnostics have revealed that vitelliform subretinal changes are not exclusive to Best disease but serve as another biomarker, indicating disruption in the metabolism of outer retinal layers. It is hypothesized that, irrespective of etiology, the primary triggering factor for lesion formation is the disjunction of outer segments of photoreceptors and impairment of phagocytic function in retinal pigment epithelial cells. This article presents a contemporary perspective on the presumed etiology and pathophysiology of vitelliform lesions, alongside clinical characteristics, manifestations, and prognosis of diseases associated with this phenomenon. Diseases with identified genetic mutations in the BEST1 gene (Bestrophinopathies) and PRPH2, as well as common acquired conditions like age-related macular degeneration and vitreoretinal traction syndrome, are discussed.Conclusions. The provided clinical characteristics, supported by multimodal visualization, are expected to aid in differential diagnosis and prognostication of the disease course.

Retinal Dystrophies Associated With Peripherin-2: Genetic Spectrum and Novel Clinical Observations in 241 Patients.

To describe the clinical, electrophysiological and genetic spectrum of inherited retinal diseases associated with variants in the PRPH2 gene. A total of 241 patients from 168 families across 15 sites in 9 countries with pathogenic or likely pathogenic variants in PRPH2 were included. Records were reviewed for age at symptom onset, visual acuity, full-field ERG, fundus colour photography, fundus autofluorescence (FAF), and SD-OCT. Images were graded into six phenotypes. Statistical analyses were performed to determine genotype-phenotype correlations. The median age at symptom onset was 40 years (range, 4-78 years). FAF phenotypes included normal (5%), butterfly pattern dystrophy, or vitelliform macular dystrophy (11%), central areolar choroidal dystrophy (28%), pseudo-Stargardt pattern dystrophy (41%), and retinitis pigmentosa (25%). Symptom onset was earlier in retinitis pigmentosa as compared with pseudo-Stargardt pattern dystrophy (34 vs 44 years; P = 0.004). The median visual acuity was 0.18 logMAR (interquartile range, 0-0.54 logMAR) and 0.18 logMAR (interquartile range 0-0.42 logMAR) in the right and left eyes, respectively. ERG showed a significantly reduced amplitude across all components (P < 0.001) and a peak time delay in the light-adapted 30-Hz flicker and single-flash b-wave (P < 0.001). Twenty-two variants were novel. The central areolar choroidal dystrophy phenotype was associated with 13 missense variants. The remaining variants showed marked phenotypic variability. We described six distinct FAF phenotypes associated with variants in the PRPH2 gene. One FAF phenotype may have multiple ERG phenotypes, demonstrating a discordance between structure and function. Given the vast spectrum of PRPH2 disease our findings are useful for future clinical trials.

Correction: Srinivasan et al. Detection and Grade Classification of Diabetic Retinopathy and Adult Vitelliform Macular Dystrophy Based on Ophthalmoscopy Images. Electronics 2023, 12, 862

There was an error in the original publication [...]

Lack of Response to Intravitreal Ranibizumab Treatment in Adult Onset Foveomacular Vitelliform Dystrophy Complicated with Choroidal Neovascularization: A Case Report

Adult-onset foveomacular vitelliform dystrophy (AOFVD) is a rare disease characterized by accumulation of yellowish deposits in the macula. Rarely, it may be complicated by choroidal neovascularization (CNV). Cases with CNV may be confused with occult CNV in age-related macular degeneration. In our case, we will present the visual and anatomical results of a patient with AOVF-related CNV, in which we administered 3 doses of intravitreal ranibizumab (IVR). A 59-year-old female patient, who attended our clinic with the complaint of decreased vision in both eyes, was diagnosed with AOVF-related CNV in both eyes and was treated with 3 doses of IVR for 3 months. Despite the improvement in visual and anatomical functions 1 month after the first dose, vision decreased, and anatomical functions regressed to the pre-injection state in continued injections. IVR therapy is not an appropriate treatment option in the treatment of AOVF-associated CNV.

Demonstrationof CicatricialStagewith Optical CoherenceTomography in A Child with Best VitelliformMacularDystrophy

Demonstrationof CicatricialStagewith Optical CoherenceTomography in A Child with Best VitelliformMacularDystrophy

Nationwide epidemiologic survey on incidence of macular dystrophy in Japan.

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). 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). 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. 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.

Artificial Intelligence (AI) for Early Diagnosis of Retinal Diseases.

Artificial intelligence (AI) has emerged as a transformative tool in the field of ophthalmology, revolutionizing disease diagnosis and management. This paper provides a comprehensive overview of AI applications in various retinal diseases, highlighting its potential to enhance screening efficiency, facilitate early diagnosis, and improve patient outcomes. Herein, we elucidate the fundamental concepts of AI, including machine learning (ML) and deep learning (DL), and their application in ophthalmology, underscoring the significance of AI-driven solutions in addressing the complexity and variability of retinal diseases. Furthermore, we delve into the specific applications of AI in retinal diseases such as diabetic retinopathy (DR), age-related macular degeneration (AMD), Macular Neovascularization, retinopathy of prematurity (ROP), retinal vein occlusion (RVO), hypertensive retinopathy (HR), Retinitis Pigmentosa, Stargardt disease, best vitelliform macular dystrophy, and sickle cell retinopathy. We focus on the current landscape of AI technologies, including various AI models, their performance metrics, and clinical implications. Furthermore, we aim to address challenges and pitfalls associated with the integration of AI in clinical practice, including the "black box phenomenon", biases in data representation, and limitations in comprehensive patient assessment. In conclusion, this review emphasizes the collaborative role of AI alongside healthcare professionals, advocating for a synergistic approach to healthcare delivery. It highlights the importance of leveraging AI to augment, rather than replace, human expertise, thereby maximizing its potential to revolutionize healthcare delivery, mitigate healthcare disparities, and improve patient outcomes in the evolving landscape of medicine.

Макулярная неоваскуляризация при вителлиформной дистрофии: анализ эффективности антиангиогенной терапии на примере клинических случаев

Best vitelliform macular dystrophy (BVMD) is caused by BEST1 mutation and leads to the accumulation of vitelliform material in the subretinal space. The formation of subretinal neovascular membrane can be one of BVMD complications. Herein, we discuss the criteria for initiating anti-VEGF therapy and efficacy assessment in two patients (3 eyes) with vitelliform macular dystrophy. Keyword: macular neovascularization, vitelliform macular dystrophy, optical coherence tomography, anti-VEGF therapy

Clinical features and possible pathogenesis of multiple evanescent white dot syndrome with different retinal diseases and events: a narrative review.

Multiple evanescent white dot syndrome (MEWDS) is a rare fundus disease, characterized by acute vision loss and visual field defects. Many previous studies have explained the possible pathogenesis and clinical features of primary MEWDS. However, as the number of reported cases increases, secondary MEWDS occurs in other related retinal diseases and injuries, exhibiting some special characteristics. The associated retinal diseases include multifocal choroiditis/punctate inner choroidopathy (MFC/PIC), acute zonal occult outer retinopathy, best vitelliform macular dystrophy, pseudoxanthoma elasticum, and ocular toxoplasmosis. The related retinal injury is laser photocoagulation, surgery, and trauma. Although primary MEWDS often have a self-limiting course, secondary MEWDS may require treatment in some cases, according to the severity of concomitant diseases and complications. Notably, MEWDS secondary to MFC/PIC that is prone to forming choroidal neovascularization and focal choroidal excavation, needs positive treatment with corticosteroids. The possible underlying pathogenesis of secondary MEWDS is the exposure of choroidal antigen after the disruption of Bruch's membrane. The MEWDS-related features in secondary MEWDS are still evanescent under most circumstances. Its prognosis and treatment depend on the severity of complications. Current studies propose that the etiology is associated with immune factors, including viral infection, inflammation in choroid and Bruch's membrane, and antigen exposure caused by retinal and/or choroidal insults. More pathogenic studies should be conducted in the future. Accurate diagnosis for secondary MEWDS could benefit patients in aspects of management and prognosis.

Risk Factors for Worsening Morphology and Visual Acuity in Eyes with Adult-Onset Foveomacular Vitelliform Dystrophy

PurposeTo explore clinical risk factors and optical coherence tomography (OCT) features associated with worse visual acuity (VA), progression of disease, choroidal neovascularization (CNV), and atrophy in eyes with adult-onset foveomacular vitelliform dystrophy (AOFVD). DesignSingle-center, retrospective, observational cohort study ParticipantsPatients seen at Duke Eye Center between January 2012 and May 2023 with a diagnosis of AOFVD confirmed via OCT and fundus autofluorescence. MethodsBaseline and final visit images from eyes with AOFVD were examined. Disease stage was assigned, and presence of atrophy or CNV was determined. Clinical and OCT features associated with progression to atrophy and CNV were determined using t-tests and chi-square analysis. Correlation with lower VA was determined using linear regression. Outcome MeasuresAssociation of clinical characteristics and OCT features with worse VA, progression of disease, CNV, and atrophy as determined by independent t-tests, chi-square analysis, and linear regression (p<0.05). Results101 eyes (63 patients) met inclusion criteria for this study, with mean follow-up duration of 48 months (SD 31 months). 51% of eyes progressed beyond baseline staging during follow-up; among baseline stage 1 eyes, incidence of atrophy was 0.068/person-year; incidence of CNV was 0.022/person-year. Risk factors for worse final VA were baseline presence of vitreomacular traction (VMT) (p=0.006), ellipsoid zone attenuation (p=0.024), increased lesion height and width (p<0.001). Predictors of progression include diabetes mellitus (p=0.012), statin use (p=0.031), presence of hyperreflective foci (p=0.012), and increased lesion width and volume (p=0.034, p=0.040). Predictors of atrophy include the baseline presence of VMT (p=0.018), decreased choroidal thickness (p=0.027), and greater maximal height, width, and volume of the lesion (p=0.031, p=0.020, p=0.009, respectively). Lower baseline VA (p=0.031) and increased lesion volume (p=0.042) were associated with CNV. ConclusionsClinical and OCT imaging features at baseline may prove useful in stratifying patient risk for progression, atrophy, CNV, and worse VA. Features such as statin use, diabetes, baseline VA, and laterality should be accounted for. OCT features such as lesion size, VMT, ellipsoid zone attenuation, choroidal thickness and hyperreflective foci may impart greater risk of poor outcomes. Future prospective analysis accounting for the time to development of atrophy and CNV is needed.

Best Vitelliform Macular Dystrophy Natural History Study Report 1: Clinical Features and Genetic Findings

To analyze the genetic findings, clinical spectrum, and natural history of Best vitelliform macular dystrophy (BVMD) in a cohort of 222 children and adults. Single-center retrospective, consecutive, observational study. Patients with a clinical diagnosis of BVMD from pedigrees with a likely disease-causing monoallelic sequence variant in the BEST1 gene. Data were extracted from electronic and physical case notes. Electrophysiologic assessment and molecular genetic testing were analyzed. Molecular genetic test findings and clinical findings including best-corrected visual acuity (BCVA), choroidal neovascularization (CNV) rates, and electrophysiologic parameters. Two hundred twenty-two patients from 141 families were identified harboring 69 BEST1 variants. Mean age at presentation was 26.8 years (range, 1.3-84.8 years) and most patients (61.5%) demonstrated deterioration of central vision. Major funduscopic findings included 128 eyes (30.6%) with yellow vitelliform lesions, 78 eyes (18.7%) with atrophic changes, 49 eyes (11.7%) with fibrotic changes, 48 eyes (11.5%) with mild pigmentary changes, and 43 eyes (10.3%) showing a vitelliruptive appearance. Mean BCVA was 0.37 logarithm of the minimum angle of resolution (logMAR; Snellen equivalent, 20/47) for the right eye and 0.33 logMAR (Snellen equivalent, 20/43) for the left eye at presentation, with a mean annual loss rate of 0.013 logMAR and 0.009 logMAR, respectively, over a mean follow-up of 9.7 years. Thirty-seven patients (17.3%) received a diagnosis of CNV over a mean follow-up of 8.0 years. Eyes with CNV that received treatment with an anti-vascular endothelial growth factor (VEGF) agent showed better mean BCVA compared with eyes that were not treated with an anti-VEGF agent (0.28 logMAR [Snellen equivalent, 20/38] vs. 0.62 logMAR [Snellen equivalent, 20/83]). Most eyes exhibited a hyperopic refractive error (78.7%), and 13 patients (6.1%) received a diagnosis of amblyopia. Among the 3 most common variants, p.(Ala243Val) was associated with a later age of onset, better age-adjusted BCVA, and less advanced Gass stages compared with p.(Arg218Cys) and p.(Arg218His). BVMD shows a wide spectrum of phenotypic variability. The disease is very slowly progressive, and the observed phenotype-genotype correlations allow for more accurate prognostication and counselling. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Choroidal neovascularization as first sign of Best's vitelliform dystrophy in a child

Aims/Purpose: To report a case of choroidal neovascularization secondary to Best's vitelliform dystrophy in a child managed by intravitreal aflibercept.Methods: Interventional, case report.Results: A 9‐year‐old boy reported decreased visual acuity (VA) with metamorphopsia in his right eye (RE) for the previous month. VA was RE 20/100 and left eye (LE) 20/20. Funduscopy revealed right‐eye macular oedema with deep macular haemorrhage associated to a bilateral orange‐yellowish deposit. Optical coherence tomography (OCT) showed sub‐ and intraretinal fluid in the foveal area along with a hyperreflective subretinal deposit and a localized retinal pigment epithelium (RPE) elevation. Blue autofluorescence (BAF) imaging disclosed a central hyper autofluorescence area as well as a larger defect corresponding to the haemorrhage and the subretinal deposit. The LE was positive for a central deposit located under the RPE with hyper autofluorescence at BAF. Familiar history was unknown for ocular conditions and the clinical history was irrelevant for fever, inflammation, adenopathy, articular, neurological or respiratory conditions. The condition was diagnosed as choroidal neovascularization (CNV) secondary to Best's vitelliform dystrophy and a single intravitreal injection of aflibercept was performed under general anaesthesia. Genetic study revealed a likely pathogenic mutation c.874G&gt;C (p.Glu292Gln) in the BEST1 gene (missense change, not previously published) affecting a functional dominion. The subretinal bleeding and fluid resolved after one single injection of aflibercept and VA improved to 20/20. No recurrences have been observed during the subsequent five years in either eye.Conclusions: We report a case of CNV as first manifestation of a previously not reported mutation of Best's vitelliform dystrophy in a 9‐year‐old boy that was successfully treated with one single intravitreal injection of aflibercept.

The importance of having a relevant model system to investigate splicing modulation in the retina: The unforeseen cases of the intronic variants in RPE65 and IMPG2 genes

Inherited retinal diseases (IRDs) are clinically and genetically heterogeneous disorders that can be caused by pathogenic variants in one of the more than 270 genes associated with IRDs. Among them, mutations in RPE65 can lead to Leber congenital amaurosis (LCA) whereas mutations in IMPG2 to vitelliform macular dystrophy (VMD).During my talk, I will provide evidence of the importance of employing the right cellular models to identify disease mechanism(s) and eventually evaluate suitable treatments. For this, I will highlight two intriguing examples of potential splicing defects studied by our group. Such defects are attractive for splicing modulation therapies using antisense oligonucleotides (AONs), a group of versatile molecules that can alter splicing by interacting with the target sequence(s) at pre‐mRNA level. Thus, characterizing the effect of a variant at the RNA level is instrumental to assess the applicability of AON‐based therapeutic intervention.We explored the effect of the homozygous variant c.11 + 5G&gt;A in RPE65 and a heterozygous complex allele consisting of c.3023‐15T&gt;A and c.3023G&gt;A (p.(Gly1008Asp)) in IMPG2. In silico predictions suggested that these variants lead to a splicing defect. To assess the pathogenic effect of these variants, splice reporter assays using midigenes were conducted in HEK293T cells. Initial results pointed towards a 124‐nt exon elongation for the RPE65 variant and an in‐frame deletion of 48‐nt at the beginning of exon 15 for the complex allele in IMPG2.To validate these results, blood cells from the patients harbouring these defects were reprogrammed to induced pluripotent stem cells (iPSCs). Subsequently, iPSCs were differentiated to the retinal cells in which these genes are endogenously expressed. For RPE65, iPSCs were differentiated into retinal pigment epithelium (RPE) cells (&gt;90 days differentiation) or, for IMPG2, into photoreceptor precursor cells (PPCs, 30 days differentiation). For the RPE65 variant, a cell specific effect was observed: while a clear exon elongation was observed in the midigene system, in RPE, the expression of the gene was highly reduced. In addition, no protein was detected and the patient‐derived cells showed differences compared to the control line. For IMPG2, the 48‐nt deletion was detected in a lower percentage in patient‐derived PPCs compared to the levels observed in the midigene system. However, aberrantly spliced IMPG2 transcripts were highly elevated in patient‐derived PPCs in comparison to control PPCs.Overall, our work shows the importance of having the right cellular context to determine the effect of genetic variants on splicing in the retina.

Multimodal imaging in fundus flavimaculatus with macular vitelliform lesion

We report a case of fundus flavimaculatus (FFM) with macular vitelliform lesion. The study was done in a center in eastern India. A 38-year-old male presented with painless diminution of vision. His best corrected visual acuity (BCVA) was 20/60 and 20/25 in the right and left eye, respectively. There were polymorphous, yellowish, mid-peripheral retinal flecks and foveal vitelliform lesions. Investigations were suggestive of FFM. We have described the various multimodal imaging modalities to differentiate FFM and vitelliform dystrophy. It is crucial to differentiate these diseases due to the difference in visual prognosis. We report a case of FFM with a foveal vitelliform lesion.

Retinal sensitivity and fundus autofluorescence in adult-onset foveomacular vitelliform dystrophy

The present study aimed to compare retinal sensitivity (RS) at each stage and to evaluate the relationship between RS and fundus autofluorescence (FAF) pattern in adult-onset foveomacular vitelliform dystrophy (AOFVD). We retrospectively reviewed 17 eyes of 13 patients with AOFVD. In addition to best-corrected visual acuity (VA), RS within the affected lesion and optical coherence tomography (OCT) measurements were carried out in each participant. All the examined eyes were classified into 4 stages and 3 FAF patterns. RS was superimposed on OCT fundus image and RS within the affected lesion was calculated in each eye. The relationships between visual functions (VA and RS within the affected lesion) and stages and also FAF patterns were analyzed using the linear mixed model. As a result, RS within the affected lesion was significantly associated with FAF pattern, but not with stage. In contrast, VA was correlated with neither stages nor FAF patterns. Our current result suggested that RS within the affected lesion was related to FAF patterns but this was not the case with VA in eyes with AOFVD, demonstrating the usefulness of measuring RS, not only VA, to comprehend the disease status in AOFVD.