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Mutations in the gene ABCA4 coding for photoreceptor-specific ATP-binding cassette subfamily A member 4, are responsible for Stargardts Disease type 1 (STGD1), the most common form of inherited macular degeneration. STGD1 typically declares early in life and leads to severe visual handicap. Abca4 gene-deletion mouse models of STGD1 accumulate lipofuscin, a hallmark of the disease, but unlike the human disease show no or only moderate structural changes and no functional decline. The human macula is highly enriched in cones, and reasoning that the low cone percentage in mice retinas (< 3%) might compromise faithful modelling of human maculopathies, we performed sub-retinal injections of CRISPR/Cas9-abca4 Adeno-Associated Virus constructs into young Sand Rats (Psammomys obesus), a diurnal rodent containing > 30% cones. Compared to control injections of AAV-abca4-GFP, treated eyes exhibited extensive retinal degeneration by two months. Sanger sequencing of the CRISPR targeted sequence show a clear edition of Abca4 gene. Non-invasive fundus imaging showed widespread photoreceptor loss, confirmed by ocular coherence tomography. Functional recording by single flash and flicker electroretinography showed significant decline in photopic (cone) light responses. Post-mortem real-time PCR, immunohistochemistry and western blotting showed significant decrease of cone-specific (MW cone opsin) but not rod-specific (rhodopsin) markers. Transmission electron microscopy showed large numbers of lipid inclusions in treated but not control retinal pigmented epithelium. Finally, ultra-high performance liquid chromatography analysis of whole P. obesus eyes showed the presence of all-trans retinal-dimer, not detected in rod-rich rat eyes. In conclusion, Abca4 knockout in P. obesus results in a predominantly cone degeneration phenotype, more accurately reflecting the etiology of human STGD1, and should be valuable for characterizing pathogenic pathways and exploring treatment options. [ABSTRACT FROM AUTHOR]

The purpose of this study was to analyze and molecularly describe the largest group of patients with ABCA4-associated retinal degeneration in Latin America. Pathogenic variants in ABCA4, a member of the ATP Binding Cassette (ABC) transporters superfamily, is one of the most common causes of inherited visual deficiency in humans. Retinal phenotypes associated with genetic defects in ABCA4 are collectively known as ABCA4-associated retinal degenerations (ABCA4R), a group of recessively inherited disorders associated with a high allelic heterogeneity. While large groups of Caucasian and Asiatic individuals suffering from ABCA4R have been well characterized, molecular information from certain ethnic groups is limited or unavailable, precluding a more realistic knowledge of ABCA4-related mutational profile worldwide. In this study, we describe the molecular findings of a large group of 211 ABCA4R index cases from Mexico. Genotyping was performed using either next generation sequencing (NGS) of a retinal dystrophy genes panel or exome. ABCA4 targeted mutation testing was applied to a subgroup of subjects in whom founder mutations were suspected. A total of 128 different ABCA4 pathogenic variants were identified, including 22 previously unpublished variants. The most common type of genetic variation was single nucleotide substitutions which occurred in 92.7% (408/440 alleles). According to the predicted protein effect, the most frequent variant type was missense, occurring in 83.5% of disease-causing alleles (368/440). Mutations such as p.Ala1773Val are fully demonstrated as a founder effect in native inhabitants of certain regions of Mexico. This study also gives us certain indications of other founder effects that need to be further studied in the near future. This is the largest molecularly characterized ABCA4R Latin American cohort, and our results supports the value of conducting genetic screening in underrepresented populations for a better knowledge of the mutational profile leading to monogenic diseases. [ABSTRACT FROM AUTHOR]

The escalating prevalence of retinal diseases—notably, age-related macular degeneration and hereditary retinal disorders—poses an intimidating challenge to ophthalmic medicine, often culminating in irreversible vision loss. Current treatments are limited and often fail to address the underlying loss of retinal cells. This paper explores the potential of stem-cell-based therapies as a promising avenue for retinal regeneration. We review the latest advancements in stem cell technology, focusing on embryonic stem cells (ESCs), pluripotent stem cells (PSCs), and mesenchymal stem cells (MSCs), and their ability to differentiate into retinal cell types. We discuss the challenges in stem cell transplantation, such as immune rejection, integration into the host retina, and functional recovery. Previous and ongoing clinical trials are examined to highlight the therapeutic efficacy and safety of these novel treatments. Additionally, we address the ethical considerations and regulatory frameworks governing stem cell research. Our analysis suggests that while stem-cell-based therapies offer a groundbreaking approach to treating retinal diseases, further research is needed to ensure long-term safety and to optimize therapeutic outcomes. This review summarizes the clinical evidence of stem cell therapy and current limitations in utilizing stem cells for retinal degeneration, such as age-related macular degeneration, retinitis pigmentosa, and Stargardt's disease. [ABSTRACT FROM AUTHOR]

In the retina, retinoids involved in vision are under constant threat of oxidation, and their oxidation products exhibit deleterious properties. Using pulse radiolysis, this study determined that the bimolecular rate constants of scavenging cation radicals of retinoids by taurine are smaller than 2 × 107 M−1s−1 whereas lutein scavenges cation radicals of all three retinoids with the bimolecular rate constants approach the diffusion-controlled limits, while zeaxanthin is only 1.4–1.6-fold less effective. Despite that lutein exhibits greater scavenging rate constants of retinoid cation radicals than other antioxidants, the greater concentrations of ascorbate in the retina suggest that ascorbate may be the main protectant of all visual cycle retinoids from oxidative degradation, while α-tocopherol may play a substantial role in the protection of retinaldehyde but is relatively inefficient in the protection of retinol or retinyl palmitate. While the protection of retinoids by lutein and zeaxanthin appears inefficient in the retinal periphery, it can be quite substantial in the macula. Although the determined rate constants of scavenging the cation radicals of retinol and retinaldehyde by dopa-melanin are relatively small, the high concentration of melanin in the RPE melanosomes suggests they can be scavenged if they are in proximity to melanin-containing pigment granules. [ABSTRACT FROM AUTHOR]

Inherited retinal dystrophies (IRDs) are congenital retinal degenerative diseases that have various inheritance patterns, including dominant, recessive, X-linked, and mitochondrial. These diseases are most often the result of defects in rod and/or cone photoreceptor and retinal pigment epithelium function, development, or both. The genes associated with these diseases, when mutated, produce altered protein products that have downstream effects in pathways critical to vision, including phototransduction, the visual cycle, photoreceptor development, cellular respiration, and retinal homeostasis. The aim of this manuscript is to provide a comprehensive review of the underlying molecular mechanisms of pathogenesis of IRDs by delving into many of the genes associated with IRD development, their protein products, and the pathways interrupted by genetic mutation. [ABSTRACT FROM AUTHOR]

The accumulation of all- trans -retinal (atRAL) in photoreceptors and the retinal pigment epithelium (RPE), which is induced by chaos in visual (retinoid) cycle, is closely associated with the pathogenesis of dry age-related macular degeneration (AMD) and autosomal recessive Stargardt's disease (STGD1). Although we have reported that the induction of ferroptosis by atRAL is an important cause of photoreceptor loss, but its mechanisms still remain unclear. In this study, we identified heme oxygenase-1 (HO-1) as an inducer of photoreceptor ferroptosis elicited by atRAL. In atRAL-loaded photoreceptor cells, inhibition of Kelch-like ECH-associated protein 1 (KEAP1) at least in part by reactive oxygen species (ROS) production evoked the release of nuclear factor-erythroid 2-related factor-2 (NRF2) from KEAP1, followed by the translocation of active NRF2 into the nucleus where it promoted the transcription of the Ho-1 gene, thereby leading to HO-1 overexpression in the cytosol. A significant elevation of Fe2+ levels in photoreceptor cells resulted from activation of HO-1 by atRAL, and it facilitated ROS overproduction and then triggered ferroptotic cell death through ROS-mediated lipid peroxidation. Both treatment with HO-1 repressor Zinc protoporphyrin IX (ZnPP) and knockout of Ho-1 gene clearly rescued photoreceptor cells against ferroptosis arising from atRAL overload. Light-exposed Abca4 −/− Rdh8 −/− mice rapidly display severe defects in atRAL clearance, and serve as an acute model of dry AMD and STGD1. HO-1 activation was distinctly observed in neural retina of Abca4 −/− Rdh8 −/− mice after exposure to light, and it was visibly relieved by intraperitoneally injected ferroptosis inhibitor ferrostatin-1. More notably, intraperitoneal administration of ZnPP effectively alleviated both photoreceptor degeneration and RPE atrophy in Abca4 −/− Rdh8 −/− mice in response to light exposure by repressing HO-1-mediated ferroptosis. Our study suggests that HO-1 is a key factor that regulates atRAL-induced ferroptosis in photoreceptors and the RPE, and its inhibition may hold promises for the therapy of dry AMD and STGD1. [ABSTRACT FROM AUTHOR]

Glaucoma and Stargardt's, an inherited disease predominantly affect the retinal portion of the eye. The diagnosis of Glaucoma in a fundus image is an arduous, time consuming process. There were many research works carried out to detect early stages of Glaucoma and Stargardt's disease. However, the accuracy, diagnostic time and performance were not improved. To resolve the above said problems, a computational method called Deep Neural Perona--Malik Diffusive Mean Shift Mode Seeking Segmented Image Classification (DNP-MDMSMSIC) is introduced for the early detection of Glaucoma and Stargardt's disease with retinal fundus images. The DNP-MDMSMSIC method comprises diverse types of layers that support to identify early detection of disease with improved accuracy and less time. Process as explained; initially, numerous qualified retinal images are given as input to the input layer. These input images are transmitted further to the hidden layer 1 to perform image pre-processing. In DNP-MDMSMSIC, Space-Variant Perona--Malik Diffusive Image Preprocessing is carried out to decrease the noise from input image without removing contents like edges, lines, etc., for image interpretation with a higher peak signal-to-noise ratio. This preprocessed image is further processed in the hidden layer 2 where the feature extraction process is performed to extract features like color, texture, and intensity with a higher degree of accuracy. Based on the extracted features, an input feature image gets segmented in hidden layer 3. Mean Shift Mode Seeking Segmentation algorithm is employed to segment the pixels in image space with corresponding feature space points. Then the segmented images are given to the output layer to perform retinal fundus image classification using Bregman Divergence Function. During the image classification, the distance between two segmented regions (i.e., testing image region of particular class and training image region) with convex is measured. In this way, the retinal fundus images get classified with higher accuracy. Experimental evaluation is performed by considering the metrics such as peak signal-to-noise, disease detection accuracy, disease detection time, and error rate corresponding to the number of retina fundus images and image size. DNP-MDMSMSIC method is designed to detect Glaucoma and Stargardt's disease at an earlier stage with higher accuracy by 8% and less time by 20% with aid of ACRIMA database. [ABSTRACT FROM AUTHOR]

Aim: to study genotype-phenotype correlations in patients with inherited retinal diseases with mutations in ABCA4 gene in Russian Federation.Patients and methods. 21 patients from Russian population aged from 7 to 51 years old (mean age 20 ± 11 years with best-corrected visual acuity from 0,02 to 0,6 (0,14 ± 0,11) with ABCA4-associated retinopathy, verified by molecular genetics methods. All patients besides standard ophthalmic examination and photodocumentation were performed Spectral-Domain OCT and fundus autofluorescence on Spectralis ®HRA+OCT (Heidelberg Engineering, Germany). Full-field electroretinogram (ERG), 30-Hz flicker ERG and macular chromatic ERG (MERG) to red stimulus were recorded on electroretinographic system MBN (MBN, Russia). (Russia) Molecular genetic studies were performed using Next Generation Sequencing (NGS) and Sandger direct sequencing. Results: In ABCA4-associated Stargardt disease 1 type (STGD1) genotype [p.L541P, p.A1038V] of «frequent» mutations was revealed in 9 patients, in 2 cases in was associated another “frequent” mutation p.G1961E. In 4 patients with genotype [p.L541P, p.A1038V] “severe” phenotype of Stargardt disease was found: with large defect of the ellipsoid zone and large zone of central reduced autofluorescence, severely subnormal macular ERG (MERG) to red stimulus and subnormal 30 Hz flicker and full-field maximal ERG. In one patient with these mutations in homozygous state ABCA4-associated cone-rod dystrophy (CORD3, clinically looking alike secondary retinal dystrophy is diagnosed. In 2 patients with genotype [p.L541P, p.A1038V] and mutation p.G1961E was found mild phenotype. One patient with homozygous mutation p.R653C autosomal recessive ABCA4-associated retinitis pigmentosa (RP19) was diagnosed. Clinical picture and autofluorescence were polymorphic in all patients.Conclusions. Our study with ophthalmological, molecular genetics and instrumental methods widens the spectrum of clinical signs of inherited eye diseases associated with mutations in АВСА4 gene, widens the spectrum mutations in Russian Federation and reveals clinicо-genetic genotype-phenotype correlations.

The first discovered vitamin, vitamin A, exists in a range of forms, primarily retinoids and provitamin carotenoids. The bioactive forms of vitamin A, retinol and retinoic acid, have many critical functions in body systems including the eye and immune system. Vitamin A deficiency is associated with dysfunctional immunity, and presents clinically as a characteristic ocular syndrome, xerophthalmia. The immune functions of vitamin A extend to the gut, where microbiome interactions and nutritional retinoids and carotenoids contribute to the balance of T cell differentiation, thereby determining immune status and contributing to inflammatory disease around the whole body. In the eye, degenerative conditions affecting the retina and uvea are influenced by vitamin A. Stargardt’s disease (STGD1; MIM 248200) is characterised by bisretinoid deposits such as lipofuscin, produced by retinal photoreceptors as they use and recycle a vitamin A-derived chromophore. Age-related macular degeneration features comparable retinal deposits, such as drusen featuring lipofuscin accumulation; and is characterised by parainflammatory processes. We hypothesise that local parainflammatory processes secondary to lipofuscin deposition in the retina are mediated by T cells interacting with dietary vitamin A derivatives and the gut microbiome, and outline the current evidence for this. No cures exist for Stargardt’s or age-related macular degeneration, but many vitamin A-based therapeutic approaches have been or are being trialled. The relationship between vitamin A’s functions in systemic immunology and the eye could be further exploited, and further research may seek to leverage the interactions of the gut-eye immunological axis.

Stargardt's disease (STGD1) is caused by mutations in the ABCA4 gene. Different lesions characterised by decreased autofluorescence levels are found in fundus autofluorescence (FAF) from STGD1 patients and could be used as outcome indicators for disease progression. We investigated the fate of foci with reduced autofluorescence (FRA) within the heterogeneous background of STGD1 patients using FAF imaging. Genetically confirmed STGD1 patients presenting heterogeneous background autofluorescence on high-quality FAF images at a minimum of two visits at least 12 months apart were chosen. A grid centred on the fovea was used to define five different zones. Within each zone, five FRA were randomly selected for each eye. The eccentricity of foci was determined at different time points for each patient. Analysis of 175 randomly chosen FRA showed consistent centrifugal displacement over time, most notably in eyes showing areas with definitely decreased autofluorescence. Interestingly, FRA did not leave an area of hypo-autofluorescence on FAF in locations where they were previously located. These findings may help to better understand STGD1 progression, improve FAF interpretation, and shed light on the nature of heterogeneous background. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives To assess depression and quality of life in individuals with Stargardt’s disease (SD), macular dystrophy whose central vision loss begins in the first decades of life. Methods This observational, cross-sectional study included 41 SD patients and 46 healthy controls, aged 18 to 63 years old, in Minas Gerais, Brazil. Major depression episode was assessed by the Mini International Neuropsychiatric Interview, depressive symptomatology by the Beck Depression Inventory (BDI) and Hamilton Depression Scale (HAM-D) and quality of life by the National Eye Institute Visual Function Questionnaire. The comparison between sociodemographic variables, quality of life and depression was performed using Fisher’s exact test and Mann-Whitney-Wilcoxon test. Results The prevalence of depression was 12.2% in the sample with SD while in the control group was 8.7% (p = 0.614). No significant differences were observed between patients and the control group regarding the prevalence of depression and sociodemographic variables. Patients with SD had overall lower quality of life scores (59.7 vs. 88.7, p < 0.001), and presented inverse correlation between depressive symptoms, as assessed by BDI (Rho = -0.49, p < 0.001) and by HAM-D (Rho = -0.45, p = 0.003) with quality of life scores. Conclusion Depressive symptoms were the major factors affecting quality of life, regardless of sociodemographic data. Individuals with SD may develop copying strategies, seek mental care to prevent the increase of depression and decrease of quality of life.

Precision genome engineering, with targeted therapy towards patient-specific mutations is predicted to be the future of personalized medicine. Ophthalmology is in the frontiers of development of targeted therapy since the eye is an accessible organ and has the ease of both delivery as well as monitoring effects of therapy. We reviewed literature using keywords CRISPR, precision medicine, genomic editing, retinal dystrophies, retinitis pigmentosa, Usher syndrome, Stargardt's Disease. Further, we collated data on current clinical trials. There is growing evidence on the role of genomic editing in retinal dystrophies, the various methods used, and stage of development of different therapies have been summarized in this paper. The CRISPR-Cas9 system has revolutionized genome editing, and opened avenues in drug discovery. It is important to understand the role of this system along with its applicability in the field of ophthalmology. In this review article, we briefly describe its methodology, the strategies of employing it for making genetic perturbations, and explore its applications in inherited retinal dystrophies. [ABSTRACT FROM AUTHOR]

Abstract Age‐related macular degeneration (AMD) is the leading cause of blindness in older people in the developed world while Stargardt's disease (SD) is a juvenile macular degeneration and an orphan disease. Both diseases are untreatable and are marked by accumulation of lipofuscin advancing to progressive deterioration of the retinal pigment epithelium (RPE) and retina and subsequent vision loss till blindness. We discovered that a small molecule belonging to the tetrahydropyridoether class of compounds, soraprazan renamed remofuscin, is able to remove existing lipofuscin from the RPE. This study investigated the drug penetration, distribution, and elimination into the eyes of a mouse model for increased lipofuscinogenesis, following a single intravitreal injection. We measured the time course of concentrations of remofuscin in different eye tissues using high‐performance liquid chromatography combined with mass spectroscopy (HPLC‐MS). We also visualized the penetration and distribution of 3H‐remofuscin in eye sections up to 20 weeks post‐injection using transmission electron microscopic (TEM) autoradiography. The distribution of silver grains revealed that remofuscin accumulated specifically in the RPE by binding to the RPE pigments (melanin, lipofuscin and melanolipofuscin) and that it was still detected after 20 weeks. Importantly, the melanosomes in choroidal melanocytes only rarely bind remofuscin emphasizing its potential to serve as an active ingredient in the RPE for the treatment of SD and dry AMD. In addition, our study highlights the importance of electron microscopic autoradiography as it is the only method able to show drug binding with a high intracellular resolution.

Age-related macular degeneration (AMD) is the leading cause of blindness in older people in the developed world while Stargardt's disease (SD) is a juvenile macular degeneration and an orphan disease. Both diseases are untreatable and are marked by accumulation of lipofuscin advancing to progressive deterioration of the retinal pigment epithelium (RPE) and retina and subsequent vision loss till blindness. We discovered that a small molecule belonging to the tetrahydropyridoether class of compounds, soraprazan renamed remofuscin, is able to remove existing lipofuscin from the RPE. This study investigated the drug penetration, distribution, and elimination into the eyes of a mouse model for increased lipofuscinogenesis, following a single intravitreal injection. We measured the time course of concentrations of remofuscin in different eye tissues using high-performance liquid chromatography combined with mass spectroscopy (HPLC-MS). We also visualized the penetration and distribution of 3H-remofuscin in eye sections up to 20 weeks post-injection using transmission electron microscopic (TEM) autoradiography. The distribution of silver grains revealed that remofuscin accumulated specifically in the RPE by binding to the RPE pigments (melanin, lipofuscin and melanolipofuscin) and that it was still detected after 20 weeks. Importantly, the melanosomes in choroidal melanocytes only rarely bind remofuscin emphasizing its potential to serve as an active ingredient in the RPE for the treatment of SD and dry AMD. In addition, our study highlights the importance of electron microscopic autoradiography as it is the only method able to show drug binding with a high intracellular resolution. [ABSTRACT FROM AUTHOR]

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The rapid development of digital imaging and computer vision has increased the potential of using the image processing technologies in ophthalmology. Image processing systems are used in standard clinical practices with the development of medical diagnostic systems. The retinal images provide vital information about the health of the sensory part of the visual system. Retinal diseases, such as glaucoma, diabetic retinopathy, age-related macular degeneration, Stargardt's disease, and retinopathy of prematurity, can lead to blindness manifest as artifacts in the retinal image. An automated system can be used for offering standardized large-scale screening at a lower cost, which may reduce human errors, provide services to remote areas, as well as free from observer bias and fatigue. Treatment for retinal diseases is available; the challenge lies in finding a cost-effective approach with high sensitivity and specificity that can be applied to large populations in a timely manner to identify those who are at risk at the early stages of the disease. The progress of the glaucoma disease is very often quiet in the early stages. The number of people affected has been increasing and patients are seldom aware of the disease, which can cause delay in the treatment. A review of how computer-aided approaches may be applied in the diagnosis and staging of glaucoma is discussed here. The current status of the computer technology is reviewed, covering localization and segmentation of the optic nerve head, pixel level glaucomatic changes, diagonosis using 3-D data sets, and artificial neural networks for detecting the progression of the glaucoma disease.

Macular degeneration is hallmarked by retinal accumulation of toxic retinoid species (e.g., A2E) for which there is no endogenous mechanism to eliminate it. This ultimately results in progressive dysfunction and loss of vision either in advanced age for genetically normal patients (age-related macular degeneration) or in adolescence for those with inherited genetic mutations (Stargardt's disease). In this article, we present a proof-of-concept study for an enzyme-based therapy to remove these retinoids, modeled on traditional enzyme replacement therapy. Recombinant manganese peroxidase (rMnP) is produced in Pichia pastoris. In vitro, we demonstrate that rMnP breaks down A2E and other lipofuscin fluorophores with limited cellular toxicity, and as this enzyme is mannosylated, it can be taken up into cells through mannose receptor-dependent endocytosis. In vivo, we demonstrate that rMnP can significantly reduce the A2E burden when administered by intravitreal injections. Together, these data provide encouraging results toward the development of an enzyme-based therapy for macular degeneration and indicate the need for additional work to characterize the molecular mechanism of A2E breakdown and to improve the pharmacological parameters of the enzyme. [ABSTRACT FROM AUTHOR]

Abstract Ring scotoma is an annular field defect centered on fixation. Age-related macular degeneration in the elderly and hydroxychloroquine toxicity in younger patients are usual causes of central ring scotoma. We report bilateral ring scotoma as the presentation of adult onset Stargardt's disease. Central ring scotoma has a precise localizing value, to a lesion involving macula. [ABSTRACT FROM AUTHOR]

The retinoid visual cycle is an ocular retinoid metabolism specifically dedicated to support vertebrate vision. The visual cycle serves not only to generate light-sensitive visual chromophore 11- cis- retinal, but also to clear toxic byproducts of normal visual cycle ( i.e. all- trans- retinal and its condensation products) from the retina, ensuring both the visual function and the retinal health. Unfortunately, various conditions including genetic predisposition, environment and aging may attribute to a functional decline of the all- trans- retinal clearance. To combat all- trans- retinal mediated retinal degeneration, we sought to slow down the retinoid influx from the RPE by inhibiting the visual cycle with a small molecule. The present study describes identification of CU239, a novel non-retinoid inhibitor of RPE65, a key enzyme in the visual cycle. Our data demonstrated that CU239 selectively inhibited isomerase activity of RPE65, with IC 50 of 6 μM. Further, our results indicated that CU239 inhibited RPE65 via competition with its substrate all- trans- retinyl ester. Mice with systemic injection of CU239 exhibited delayed chromophore regeneration after light bleach, and conferred a partial protection of the retina against injury from high intensity light. Taken together, CU239 is a potent visual cycle modulator and may have a therapeutic potential for retinal degeneration. [ABSTRACT FROM AUTHOR]

AIM:To compare the synthesis efficiency of n3 and n6 very long chain polyunsaturated fatty acid(VLC-PUFA)by overexpressing ELOVL4 protein, providing guidance for treating Stargardt-like macular dystrophy(STGD3).METHODS:To establish recombinant adenovirus with the ELOVL4 protein and green fluorescent protein, transferred into cultured PC12 cells. The cells were divided into 3 groups: PC12, PC12+Ad-GFP and PC12+Ad- ELOVL4, former two groups serve as controls. ELOVL4 gene expression was quantified by qRT-PCRs. ELOVL4 protein was analyzed by Western-Blot(WB). The transduced cells were treated with both EPA and AA(1:1). After 48h of incubation, cells were collected, total lipids extracted and fatty acid methyl esters prepared and analyzed by gas chromatography-mass spectrometry(GC-MS). RESULTS: When supplemented together, 20:5n3(EPA)and 20:4n6(AA)were efficiently taken up at almost the same amounts in the PC12 cells regardless of ELOVL4 expression. The ELOVL4-expressing cells elongated both EPA and AA to a series of n3 and n6 VLC-PUFAs. From 20:5n3/EPA, 34:5n3 and 36:5n3 account for 0.71% and 1.6%, respectively. From 20:4n6/DHA, 34:4n6 and 36:4n6 were only 0.46% and 0.61%, respectively. The total relative mol% of n3 VLC-PUFAs synthesized from EPA was almost two times that of n6 VLC-PUFAs synthesized from AA.CONCLUSION: ELOVL4 protein preferentially elongates n3 PUFA to VLC-PUFAs over n6 PUFA. Dietary supplementation of appropriate n3/n6 PUFAs may provide STGD3 patients with some therapeutic benefits.

60-year-old woman referring visual disability. She presented bone spicule pigmentation and retinal atrophy in all peripheral retina, as well as macular retinal flecks. Multimodal imaging showed typical findings of both inherited retinal dystrophies (IRD). Electroretinogram confirmed rod dysfunction. Biallelic mutations were found in ABCA4 and CNGA1 genes. Although not common, different IRDs may be present in a same patient at the same time. This is the first reported case of the combination of RP with late-onset Stargardt's disease. We propose the name 'Stargardt's pigmentosa' for this novel clinical entity., (Copyright © 2023 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.)

Stargardt’s disease is the most common form of juvenile macular dystrophy. The purpose of this study is to report the clinical characteristics, visual function, and retinal tomography of patients diagnosed with Stargardt’s disease in Taiwan. Methods: Retrospective case series; data collected include results of complete ophthalmic examinations: best-corrected visual acuity (BCVA), slit-lamp biomicroscopy, indirect ophthalmoscopy, fundus photography, fluorescein angiography, color sense discrimination test, electroculography (EOG), electroretinography (ERG), dark adaptation, visual field test, and optical coherence tomography (OCT) examinations focused on the macular area. Results: Twenty patients were enrolled in this study. The mean age of the patients was 32.1 years. The mean logMAR-converted visual acuity of all patients was 0.96. Maculopathy with or without flecks was evident in all patients. Fluorescein angiography revealed hyperfluorescence in the macula of all cases. Varying degrees of color sense discrimination dysfunction were noted. Electrophysiologic studies showed subnormal to abnormal responses in most patients. Decreased foveal thickness was evident on OCT and foveal thickness was inversely associated with logMAR visual acuity. Also, logMAR visual acuity was associated with total error scores on the color sense discrimination test and the Arden ratio of EOG. The Arden ratio of EOG correlated with the thickness of the outer ring of the macula. Conclusion: Typical clinical presentations of Stargardt’s disease were demonstrated in our case series. OCT findings showed a correlation between foveal thickness and visual acuity, making OCT a useful predictor for other visual function tests. Our results indicate that OCT is helpful in the evaluation of visual acuity and the progression of maculopathy in patients with Stargardt’s disease.

Stargardt disease is the most common form of juvenile macular degeneration. Clinically, it is characterized by pisciform flecks at lhe level of the retinal pigment epithelium and a bull's-eye maculopathy. Inheritance is usually autosomal recessive, although dominantly inherited case have been described. Both sexes are affected equally. We reported here three cases of Stargardt's macular dystrophy, who are siblings and daughters of non consanguineous parents. In case-1,2 and 3 we found the typical presentation with almost same findings.

Purpose: To report on 4 patients affected by Stargardt’s disease (STGD) with fundus flavimaculatus (FFM) and ABCA4 gene mutation associated with subretinal fibrosis. Methods: Four patients with a diagnosis of STGD were clinically examined. All 4 cases underwent a full ophthalmologic evaluation, including best-corrected visual acuity measured by the Snellen visual chart, biomicroscopic examination, fundus examination, fundus photography, electroretinogram, microperimetry, optical coherence tomography and fundus autofluorescence. All patients were subsequently screened for ABCA4 gene mutations, identified by microarray genotyping and confirmed by conventional DNA sequencing of the relevant exons. Results: In all 4 patients, ophthalmologic exam showed areas of subretinal fibrosis in different retinal sectors. In only 1 case, these lesions were correlated to an ocular trauma as confirmed by biomicroscopic examination of the anterior segment that showed a nuclear cataract dislocated to the superior site and vitreous opacities along the lens capsule. The other patients reported a lifestyle characterized by competitive sport activities. The performed instrumental diagnostic investigations confirmed the diagnosis of STGD with FFM in all patients. Moreover, in all 4 affected individuals, mutations in the ABCA4 gene were found. Conclusions: Patients with the diagnosis of STGD associated with FFM can show atypical fundus findings. We report on 4 patients affected by STGD with ABCA4 gene mutation associated with subretinal fibrosis. Our findings suggest that this phenomenon can be accelerated by ocular trauma and also by ocular microtrauma caused by sport activities, highlighting that lifestyle can play a role in the onset of these lesions.

Purpose: To evaluate the ability of the preferential hyperacuity perimeter (PHP) and the Amsler grid to detect central scotomas in Stargardt's disease and age macular degeneration. Methods: Prospective, comparative, cross-section study in which 16 patients affected with AMD and Stargardt's disease were evaluated. All patients had an optometric evaluation including refraction, best corrected visual acuity, evaluation with PHP Foresee and with the Amsler grid. The sensitivity of the macular evaluation tests (The Amsler grid and PHP) for each maculopathy was calculated. Results: To detect scotomas in both macular pathologies, the PHP sensitivity is 60–70 %, while the Amsler grid sensitivity is 85–100 %. As screening methods for maculopathies, the PHP sensitivity is 83 %, while the Amsler grid sensitivity is 93 %. Conclusions: The Amsler grid and the PHP are both useful to detect scotomas in Stargardt's disease and AMD. As a disease screening method, the Amsler grid is useful in both conditions; however, the PHP is only useful in AMD, not in Stargardt's.

Background: Patients with central scotoma report difficulty with reading and many other activities of daily living. While some patients easily adopt an eccentric viewing posture, the majority of patients need to be taught both that the scotoma exists and the most effective way to view around it. Patients with strabismus and amblyopia who eccentrically fixate are taught to view with the macula through vision therapy. Patients with central scotoma can use many of these same techniques to learn to view with an eccentric point, to develop efficient eye movements, and to develop eye-hand coordination using this new eccentric location. Case Reports: Two cases are presented of patients with functional difficulties related to central scotoma. The first case involves a 66-year-old female with dry age-related macular degeneration. The second case is a 38-year-old female with Stargardt's disease. Discussion: Limitations of the peripheral vision system in terms of resolution, reduced visual span, oculomotor deficits, and slower processing all contribute to difficulties with reading and slower reading speed in patients with central scotoma. Vision therapy for oculomotor skills resulted in both patients having a modest increase in reading speed, which is consistent with the current literature. Eye care providers should consider adding optometric vision therapy techniques to other methods in place in order to help patients with central scotoma maximize their visual function. [ABSTRACT FROM AUTHOR]

Purpose: Investigation the properties and progression in Stargardt's disease. Material and Methods: The electrophysiological features of fundus flavimaculatus (FFM) in 18 cases and fundus flavimaculatus with Stargardt's disease (FFM+STGD) in 5 cases were revisited and the progression in a young patient with STGD was investigated using optical coherence tomography (OCT), electroretinography (ERG) and electrooculography (EOG). Results: EOG Arden index (EOG AI) and rod ERG amplitudes did not differ significantly between FFM and FFM+STGD (t=1.02 and p>0.05). There was a difference in cone ERG amplitudes at the level of 1% probability and was significantly decreased in FFM+STGD group (t=5.03 and p<0.01). There was a significant difference between the two groups in visually evoked cortical response latencies (t=5.56 and p<0.01) and in amplitudes (t=4.84 and p<0.01). In Stargardt's case, all ERG parameters worsened to pathological levels from subnormal values and EOG AI to subnormal-abnormal ratios from normal ratios within a three year period. Subtle changes in optical coherens tomography (OCT) were noted during this period. Conclusion: STGD may be seen in variable appearances. In FFM which is accepted as the variant of STGD, the lesions are located peripherally and the disease manifests itself in advanced ages. The electrophysiological parameters are less affected in FFM. The gross changes in ERG and EOG findings within time whereas subtle changes occurring in OCT implies that ERG and EOG can be preferred in the detection of progression. [ABSTRACT FROM AUTHOR]

Background: Chloroquine (CQ) and hydroxychloroquine (HCQ) are used to treat auto-immune related diseases such as rheumatoid arthritis (RA) or systemic lupus erythematosus. Both drugs however can cause retinal toxicity eventually leading to irreversible maculopathy and retinopathy. Established risk factors are duration and dosage of treatment while the involvement of genetic factors contributing to toxic maculopathy is largely unclear. To address the latter issue, this study aimed to expand on earlier efforts by (1) evaluating risk-altering variants known to be associated with age-related macular degeneration (AMD), a frequent maculopathy in individuals over 55 years of age, and (2) determining the contribution of genetic variants in the coding sequence of the ABCA4 gene. Methods: The ABCA4 gene was analyzed by deep sequencing technology using a personal genome machine (Ion Torrent) with 200 bp read length. Assessment of AMD variants was done by restriction enzyme digestion of PCR products and TaqMan SNP genotyping. Effect sizes, p-values and confidence intervals of common variants were evaluated by logistic regression (Firth’s bias corrected). To account for multiple testing, p-values were adjusted according to the false discovery rate. Results: We found no effects of known AMD-associated variants on the risk of toxic maculopathy. In contrast, we report a statistically significant association of common variants in the ABCA4 gene with retinal disease, assessed by a score-based variance-component test (PSKAT = 0.0055). This association remained significant after adjustment for environmental factors like age and duration of medication and was driven by three common variants in ABCA4 (c.5682G > C, c.5814A > G, c.5844A > G), all conferring a reduced risk for toxic maculopathy. Conclusions: Our findings demonstrate that minor alleles of common genetic variants in ABCA4 significantly reduce susceptibility to develop toxic maculopathy under CQ treatment. A refined risk profile based on genetic and environmental factors may have implications for revised recommendations in CQ as well as HCQ treatment. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether the characteristics of multifocal electroretinograms (mfERGs) were correlated with the ophthalmic appearance of the fundus in patients with Stargardt's disease/fundus flavimaculatus (SFF). Methods: Full-field ERGs, mfERGs, and general ophthalmic examinations were performed on 49 eyes with SFF. Results: The SFF patients were divided into four subtypes according to the classification of Noble and Carr [Arch Ophthalmol 1979;97:1281-1285]. The patients with type 1 SFF had severely reduced mfERGs in the macular area and reduced and delayed responses in the mid-periphery. The type 2 SFF patients had reduced but recordable mfERGs from the center of the macula with more depressed responses in the paramacular area, and the type 3 SFF patients had reduced and delayed mfERGs both in the macula and periphery. The patients with type 4 SFF had normal mfERGs in the macular area and delayed responses in all outer zones. Conclusions: These mfERG findings indicate that each subtype of SFF has unique characteristics corresponding to the abnormal retinal functions. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Stem cell therapy for retinal disease is under way, and several clinical trials are currently recruiting. These trials use human embryonic, foetal and umbilical cord tissue-derived stem cells and bone marrow-derived stem cells to treat visual disorders such as age-related macular degeneration, Stargardt's disease and retinitis pigmentosa. Over a decade of analysing the developmental cues involved in retinal generation and stem cell biology, coupled with extensive surgical research, have yielded differing cellular approaches to tackle these retinopathies. Here, we review these various stem cell-based approaches for treating retinal diseases and discuss future directions and challenges for the field. [ABSTRACT FROM AUTHOR]

The retina is the light-sensitive layer of the human eye. The macula forms the central part of the retina. The character of light responsiveness is attributed to the presence of photoreceptor cells here. Stargardt's disease is the most common cause of hereditary macular dystrophy. It is linked to disease-causing sequence variations/mutations in the ABCA4 gene on chromosome 1p21-p13, which destroys rod and cone cells within the retina. The disc membranes of rod and cone outer segments include an ATP-binding cassette transport protein encoded by the ABCA4 gene. All trans-retinal conjugates are transported across disc membranes by the ABCA4 protein. Abnormally high amounts of lipofuscin pigments build up in the retinal pigment epithelium (RPE) due to mutations in the ABCA4 gene, leading to RPE cell loss and secondary photoreceptor cell degeneration. As a result of this disease, the central or detailed vision becomes blurred, and the patient may find it challenging to discern colours. The retina presents with a distinctive "beaten-bronze" appearance due to the presence of prominent yellow dots. The phenotypic form of Stargardt disease, known as fundus flavimaculatus, is characterized by the widespread distribution of flecks throughout the fundus, including the periphery. In the given case report, we present a 46-year-old male patient who presented with complaints of persistence of a blind spot in central vision, difficulty in identifying faces, distortion of letters while reading, decreased visual acuity and difficulty in adapting from light to dark settings as symptoms. The stepwise assessment of the patient led to the diagnosis of Stargardt's disease. The case report reflects the disease history, pathogenesis, manifestations, prognosis, differential diagnosis and treatment options for this rare presentation., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Maheshwari et al.)

Background/Purpose: Stargardt’s disease is the most common form of juvenile macular dystrophy. The purpose of this study is to report the clinical characteristics, visual function, and retinal tomography of patients diagnosed with Stargardt’s disease in Taiwan. Methods: Retrospective case series; data collected include results of complete ophthalmic examinations: best-corrected visual acuity (BCVA), slit-lamp biomicroscopy, indirect ophthalmoscopy, fundus photography, fluorescein angiography, color sense discrimination test, electroculography (EOG), electroretinography (ERG), dark adaptation, visual field test, and optical coherence tomography (OCT) examinations focused on the macular area. Results: Twenty patients were enrolled in this study. The mean age of the patients was 32.1 years. The mean logMAR-converted visual acuity of all patients was 0.96. Maculopathy with or without flecks was evident in all patients. Fluorescein angiography revealed hyperfluorescence in the macula of all cases. Varying degrees of color sense discrimination dysfunction were noted. Electrophysiologic studies showed subnormal to abnormal responses in most patients. Decreased foveal thickness was evident on OCT and foveal thickness was inversely associated with logMAR visual acuity. Also, logMAR visual acuity was associated with total error scores on the color sense discrimination test and the Arden ratio of EOG. The Arden ratio of EOG correlated with the thickness of the outer ring of the macula. Conclusion: Typical clinical presentations of Stargardt’s disease were demonstrated in our case series. OCT findings showed a correlation between foveal thickness and visual acuity, making OCT a useful predictor for other visual function tests. Our results indicate that OCT is helpful in the evaluation of visual acuity and the progression of maculopathy in patients with Stargardt’s disease. [Copyright &y& Elsevier]

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Purpose: Patients with Stargardt's disease usually have a poor visual prognosis. However, in our clinical practice we have observed some patients with dark-red foveal pigmentation (sparing) who had good best corrected visual acuity (BCVA) despite the presence of a late-stage disease. The purpose of this study was to investigate the BCVA outcomes in Japanese patients with Stargardt's disease with foveal sparing. Methods: Eighteen consecutive patients (36 eyes) with Stargardt's disease underwent ophthalmoscopy, fluorescein angiography, fundus autofluorescence imaging, and near-infrared fundus autofluorescence (NIA) imaging. The patients were divided into two groups based on the presence or absence of foveal sparing. The presence of foveal sparing was determined based on ophthalmoscopy and NIA imaging results. The association between foveal sparing and BCVA was assessed statistically by Students' t test. Results: Of the 36 eyes, ten (27.8 %) had dark-red foveal sparing. The mean BCVA of the group with sparing was 0.16 ± 0.31, expressed in logarithm of the minimum angle of resolution (logMAR) units, and that of the group without sparing was 1.03 ± 0.39 logMAR units, which is a significant difference ( p = 0.0000002507). Conclusion: A subgroup of Japanese patients with late-stage Stargardt's disease and dark-red foveal sparing maintained a relatively good BCVA. The pigmentation was clearly observed using NIA and proved useful for assessing the BCVA prognosis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Optometry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Der Ophthalmologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: To evaluate multifocal electroretinographic changes in patients with Stargardt's disease. Materials and Methods: Twenty-six eyes of 13 patients with Stargardt's disease (ages, 16- 53 years) and 19 eyes of 19 normal control subjects were examined. The multifocal electroretinographic first-order kernels were extracted from the responses elicited by 61 standard hexagonal elements of a visual response imaging system. P1 amplitudes and implicit times were analyzed within five concentric ring annuli centered on the fovea. Multifocal electroretinographic P1 response amplitude and implicit times within the central 30° of the retina were compared with those of control group. Results: P1 amplitudes of the Stargardt patients was lower than that of the normal controls without an overlap of the 5-95% intervals in the ring 1 and 2. P1 amplitudes was lower than normal 25 eyes of Stargardt patients (96%) in the ring 3, 14 eyes (54%) in the ring 4 and 10 eyes (38%) in the ring 5. The peak time was not delayed. Conclusion: Our results showed that although the macular atrophic area was ophthalmoscopically well demarcated in patients with Stargardt's disease, the abnormality of retinal function extended beyond the borders of ophthalmoscopic lesions. [ABSTRACT FROM AUTHOR]

Background: Recessive Stargardt disease is due to mutations in the retina-specific ABC transporter gene. Established strategies for molecular characterization of this gene include direct detection by a microarray interrogating approximately 500 DNA variations and a scanning denaturing HPLC methodology. Methods: Because 11 mutations were reported to account for approximately 50% of molecular defects in the Italian population, we evaluated an alternative open microchip-based assay for a fast and simplified level 1 screening for these mutations. Results: This approach allowed the characterization of both mutated alleles in 4% and one mutated allele in 43% of cases when applied to a cohort of 47 Stargardt patients. In the same patients, further investigation by denaturing HPLC for complete characterization identified both mutated alleles in 51% and one mutated allele in 19% of cases, allowing the detection of 38 different mutations, five of which had never been described. Notably, new mutations account for a high proportion (13%) of molecular defects in our patient cohort. Conclusions: This finding raises the question about the choice of the optimal diagnostic strategy for complete genotyping of the ABCA4 gene, as new mutations could not be identified by any direct detection technology, irrespective of the total number of variations screened. Clin Chem Lab Med 2008;46:1250–5. [ABSTRACT FROM AUTHOR]

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The visual evoked cortical potential (VECP) is widely used to verify complaints of reduced visual performance and to identify the site of the disorder. In this study, we investigated the correlation between reduced visual acuity and VECP in volunteers with normal corrected visual acuity and in patients suffering from inherited macular degeneration or from age related macular degeneration (ARMD). Flash evoked VECP was not affected by the visual acuity in the cases of refractive error and in ARMD patients but was reduced in amplitude and delayed in implicit time in the patients suffering from inherited macular degeneration. The VECP elicited by pattern reversal checkerboard (PVECP) was not affected by the quality of the visual image in volunteers with uncorrected refractive error when checks of 60′ or larger were used but were considerably reduced in size and prolonged in implicit time for checks smaller than 15′. In both groups of patients suffering from macular dysfunction, pattern reversal VECP was very subnormal and was characterized by prolonged implicit time compared to values expected from their visual acuity. These findings indicate that the PVECP does not directly correlate with visual acuity but rather with foveal function. Therefore, we suggest that recordings of PVECP can be used to differentiate between refractive error and macular disorders as causing reduction in visual acuity when other clinical signs are missing or not available. [ABSTRACT FROM AUTHOR]