Search Results (359)

Background/objectives: Obtaining a genetic diagnosis for patients with inherited retinal diseases has become even more important since gene-specific therapies have become available. When genetic screening reveals variants of uncertain significance (VUS), additional evidence is required to determine genetic eligibility for therapy. Confirming the effect on splicing that is predicted by SpliceAI could change their classification to either likely pathogenic or pathogenic and would therefore be of great importance when interpreting these variants when geneticists worldwide are trying to reach a diagnosis. Methods: Using minigene assays, we established a pipeline to assess the effect on splicing for all variants. We selected 73 RPE65 variants that were classified as either VUS or likely benign in the RPE65 Leiden Open Variant Database (LOVD) or ClinVar and were predicted to affect splicing by SpliceAI with a delta score of >0.1 and by using an analysis window of 5000 bp up- and downstream of the variant. Results: Using four wild-type vectors, we generated 59 constructs containing the variants of interest. Through these minigene assays, we assessed the effect on splicing of these VUS to enable reclassification. Upon quantification, we identified seven variants with a full, aberrant splicing effect without residual wild-type transcript. Eleven variants had between 5% and 20% remaining wild-type transcript. Forty-one variants had ≥20% residual wild-type transcript, among which fifteen variants showed no effect on splicing. Conclusions: Following the 2023 established ClinGen specific ACMG guidelines for RPE65 (Criteria Specification Registry), evidence from splice assays enabled reclassification of seven RPE65 variants from VUS to pathogenic through an assigned PVS1-very-strong criterium, as less than 5% of wild-type transcript was present. These findings contribute to the interpretation of variants observed in patients, which will in turn dictate their eligibility for gene therapy. Full article

Background: Leber’s hereditary optic neuropathy (LHON) is the most common mitochondrial disorder and an inherited optic neuropathy. Recently, two different LHON inheritance types have been discovered: mitochondrially inherited LHON (mtLHON) and autosomal recessive LHON (arLHON). Our case report is the first diagnosed case of arLHON in a patient of Lithuanian descent and confirms the DnaJ Heat Shock Protein Family (Hsp40) Member C30 (DNAJC30) c.152A>G p.(Tyr51Cys) founder variant. Case Presentation: A 34-year-old Lithuanian man complained of headache and sudden, painless loss of central vision in his right eye. On examination, the visual acuity of the right and left eyes was 0.1 and 1.0, respectively. Visual-field examination revealed a central scotoma in the right eye, and visual evoked potentials (VEPs) showed prolonged latency in both eyes. Optical coherence tomography showed thickening of the retinal nerve fiber layer in the upper quadrant of the optic disk in the left eye. Magnetic resonance imaging of the head showed evidence of optic nerve inflammation in the right eye. Blood tests were within normal range and showed no signs of inflammation. Retrobulbar neuritis of the right eye was suspected, and the patient was treated with steroids, which did not improve visual acuity. He later developed visual loss in the left eye as well. A genetic origin of the optic neuropathy was suspected, and a complete mitochondrial DNA analysis was performed, but it did not reveal any pathologic mutations. Over time, the visual acuity of both eyes slowly deteriorated, and the retinal nerve fiber layer (RNFL) thinning of the optic disks progressed. A multidisciplinary team of specialists concluded that vasculitis or infectious disease was unlikely to be the cause of the vision loss, and a genetic cause for the disease was still suspected, although a first-stage genetic test did not yield the diagnosis. Thirty-three months after disease onset, whole-exome sequencing revealed a pathogenic variant in the DNAJC30 gene, leading to the diagnosis of arLHON. Treatment with Idebenone was started 35 months after the onset of the disease, resulting in no significant worsening of the patient’s condition. Conclusion: This case highlights the importance of considering arLHON as a possible diagnosis for patients with optic neuropathy, because the phenotype of arLHON appears to be identical to that of mtLHON and cannot be distinguished by clinicians. Full article

Retinitis pigmentosa is a group of inherited retinal dystrophies characterized by progressive photoreceptor cell loss leading to irreversible vision loss. Affecting approximately 1 in 4000 individuals worldwide, retinitis pigmentosa exhibits significant genetic heterogeneity, with mutations in genes such as RHO, PRPF31, RPE65, USH2A, and NR2E3, which contribute to its diverse clinical presentation. This review outlines the genetic basis of retinitis pigmentosa and explores cutting-edge gene-based therapeutic strategies. Luxturna (voretigene neparvovec-rzyl), the first FDA-approved gene therapy targeting RPE65 mutations, represents a milestone in precision ophthalmology, while OCU400 is a gene-independent therapy that uses a modified NR2E3 construct to modulate retinal homeostasis across different RP genotypes. Additionally, CRISPR–Cas genome-editing technologies offer future potential for the personalized correction of specific mutations, though concerns about off-target effects and delivery challenges remain. The article also highlights MCO-010, a novel optogenetic therapy that bypasses defective phototransduction pathways, showing promise for patients regardless of their genetic profile. Moreover, QR-1123, a mutation-specific antisense oligonucleotide targeting the P23H variant in the RHO gene, is under clinical investigation for autosomal dominant RP and has shown encouraging preclinical results in reducing toxic protein accumulation and preserving photoreceptors. SPVN06, another promising candidate, is a mutation-agnostic gene therapy delivering RdCVF and RdCVFL via AAV to support cone viability and delay degeneration, currently being evaluated in a multicenter Phase I/II trial for patients with various rod–cone dystrophies. Collectively, these advances illustrate the transition from symptom management toward targeted, mutation-specific therapies, marking a major advancement in the treatment of RP and inherited retinal diseases. Full article

Background/Objectives: Genetic testing is important for diagnosing inherited retinal diseases (IRDs), but further evidence is needed on the utility of singleton genetic testing in an Australian cohort. Methods: A consecutive series of individuals with clinically diagnosed IRDs without prior genetic testing underwent commercial panel-based sequencing (Invitae or Blueprint Genetics), clinical assessment, and multimodal imaging. Retinal images were graded using the Human Phenotype Ontology terms. Binary logistic regression was used to evaluate clinical predictors of a positive molecular diagnosis. Results: Among 140 participants (mean age 49 ± 19 years), genetic testing was undertaken, on average, 23 ± 17 years after the initial clinical IRD diagnosis. Of the 60% who received a probable molecular diagnosis, 40% require further phase testing, highlighting the limitations of singleton genetic testing. USH2A, ABCA4, and RPGR were the most common encountered genes; 67% of the probably solved participants had causative genes with targeted experimental treatments in ongoing human clinical trials. Symptom onset before the age of 30 (OR = 3.06 [95% CI: 1.34–7.18]) and a positive IRD family history (OR = 2.87 [95% CI: 1.27–6.78]) were each associated with higher odds of receiving a molecular diagnosis. Diagnostic rates were comparable across retinal imaging phenotypes (atrophy and autofluorescence patterns in widespread IRD, and the extent of dystrophy in macular IRDs). Conclusions: In an Australian IRD population without prior genetic testing, commercial panels yielded higher diagnostic rates in individuals with IRD onset before the age of 30 and those with an IRD family history. Further research is needed to understand the genetic basis of IRDs, especially isolated and late-onset cases, to improve diagnosis and access to emerging therapies. Full article

Visual field (VF) testing remains a cornerstone in assessing retinal function by measuring how well different parts of the retina detect light. It is essential for early detection, monitoring, and management of many retinal diseases. By mapping retinal sensitivity, VF exams can reveal functional loss before structural changes become visible. This review summarizes how VF testing is applied across key conditions: hydroxychloroquine (HCQ) retinopathy, age-related macular degeneration (AMD), diabetic retinopathy (DR) and macular edema (DME), and inherited disorders including inherited dystrophies such as retinitis pigmentosa (RP). Traditional methods like the Goldmann kinetic perimetry and simple tools such as the Amsler grid help identify large or central VF defects. Automated perimetry (e.g., Humphrey Field Analyzer) provides detailed, quantitative data critical for detecting subtle paracentral scotomas in HCQ retinopathy and central vision loss in AMD. Frequency-doubling technology (FDT) reveals early neural deficits in DR before blood vessel changes appear. Microperimetry offers precise, localized sensitivity maps for macular diseases. Despite its value, VF testing faces challenges including patient fatigue, variability in responses, and interpretation of unreliable results. Recent advances in artificial intelligence, virtual reality perimetry, and home-based perimetry systems are improving test accuracy, accessibility, and patient engagement. Integrating VF exams with these emerging technologies promises more personalized care, earlier intervention, and better long-term outcomes for patients with retinal disease. Full article

Autosomal recessive types of both syndromic and non-syndromic inherited myopia are common in Saudi Arabia (SA) because many people marry their relatives. The prevalence of syndromic myopathies in SA, like Stickler syndrome (SS), Knobloch syndrome (KS), and Marfan syndrome (MFS), further complicates the disease spectrum. The causative genes linked to the Knobloch, Marfan, and Pierson syndromes are COL18A1, FBN1, and LAMB2, respectively. Additionally, we found recessive types of non-syndromic high myopia that have a high chance of causing retinal detachment, like those linked to LRPAP1 and LEPREL1. In these cases, regular evaluation and early intervention, including prophylactic laser photocoagulation and pars plana vitrectomy, may improve the outcome. Advancements in genetic testing for diagnosis and prevention accelerate detection, facilitate early interventions, and provide genetic counseling. The utilization of artificial intelligence (AI), machine learning (ML), and the advancement of gene therapy offer promising avenues for personalized care. We place a high value on using genetic knowledge to create a national screening program and patient registry aimed at understanding the national burden of myopia, knowing that we have a high rate of consanguinity, which reflects pathogenic homozygous alleles and founder mutations. This initiative will incorporate genetic counseling and leverage innovative technologies, which are crucial for disease management, early identification, and prevention in Saudi Arabia’s healthcare system. Full article

Fundus autofluorescence (FAF) is a non-invasive retinal imaging technique that helps visualize naturally occurring fluorophores, such as lipofuscin, and provides valuable insight into retinal diseases—particularly inherited retinal diseases (IRDs). FAF is especially useful in detecting subclinical or early-stage IRDs and in monitoring disease progression over time. In Stargardt disease, areas of decreased autofluorescence correlate with disease progression and have been proposed as a biomarker for future clinical trials. FAF can also help differentiate Stargardt disease from other macular dystrophies. In retinitis pigmentosa, hyperautofluorescent rings are a common feature on FAF and serve as an important marker for disease monitoring, especially as changes align with those seen on other imaging modalities. FAF is valuable in tracking progression of choroideremia and may help identify disease carrier status. FAF has also improved the characterization of mitochondrial retinopathies such as maternally inherited diabetes and deafness. As a rapid and widely accessible imaging modality, FAF plays a critical role in both diagnosis and longitudinal care of patients with IRDs. Full article

Bestrophinopathies are a group of inherited retinal diseases caused by mutations in the BEST1 gene. The protein encoded by this gene, bestorphin-1 (hBest1), is a calcium-dependent transmembrane channel localized on the basolateral membrane of retinal pigment epithelial (RPE) cells. We have already demonstrated the surface behavior and organization of recombinant hBest1 and its interactions with membrane lipids such as 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), sphingomyelin (SM) and cholesterol (Chol) in models of biological membranes, which affect the hBest1 structure–function relationship. The main aim of our current investigation is to integrate pure hBest1 protein into lipid bilayer nanostructures. We synthesized and characterized various hBest1-containing nanostructures based on 1,2-Dipalmitoylphosphatidylcholine (DPPC), SM, glycerol monooleate (GMO) and Chol in different ratios and determined their cytotoxicity and incorporation into cell membranes and/or cells by immunofluorescence staining. Our results show that these newly designed nanoparticles are not cytotoxic and that their incorporation into MDCK II cell membranes (used as a model system) may provide a mechanism that could be applied to RPE cells expressing mutated hBest1 in order to restore their ion transport functions, affected by mutated and malfunctioning hBest1 molecules. Full article

To compare the clinical characteristics of inherited retinal diseases (IRDs) caused by biallelic versus monoallelic variants in the RP1, BEST1, and PROM1 genes. A total of 52 patients (26 female) with genetically confirmed IRDs were retrospectively selected from the records of the Harkness Eye Institute Clinical Coordinating Center at Columbia University Irving Medical Center. In RP1, 3 individuals with biallelic variants and 22 patients with monoallelic variants classified as pathogenic or likely pathogenic were selected. In BEST1, eight individuals with biallelic variants and nine individuals with monoallelic variants classified as either pathogenic or likely pathogenic were included. In PROM1, four individuals with biallelic variants and six patients with monoallelic variants classified as pathogenic or likely pathogenic were selected. All patients underwent multimodal retinal imaging and, when available, full-field electroretinography (ffERG). In all three genes, individuals with biallelic variants had markedly earlier disease onset and more severe phenotypes. In RP1, on SD-OCT, foveal involvement was observed in all biallelic cases (3/3, 100%) and in 4/22 (18%) monoallelic cases. In BEST1, the average age of onset in the biallelic cohort was 7.12 years, and the average age was 32.7 years in the monoallelic cohort. Four of eight (50%) patients in the biallelic group were additionally found to have widespread serous lesions outside of the central macula. This finding was not observed in the monoallelic group. Three of eight (38%) biallelic BEST1 patients had moderate reductions in their photopic flicker. All monoallelic BEST1 patients had photopic responses within the normal range. PROM1 biallelic cases showed severe functional impairment on ffERG, while most monoallelic cases retained normal responses. In the biallelic cohort, four of four (100%) of patients had severely attenuated or extinguished photopic responses. In the monoallelic PROM1 group, four of five (80%) monoallelic PROM1 patients had normal photopic responses, and P2-2 had mildly attenuated photopic responses. Individuals with biallelic variants exhibited earlier disease onset, more severe retinal degeneration, and significantly reduced retinal function compared with those with monoallelic variants. These observations highlight the role of loss-of-function mechanisms in more aggressive disease courses and underscore the importance of considering zygosity when determining prognosis and planning gene-based therapies. Full article

Dominant Optic Atrophy (DOA) is the most common inherited optic neuropathy and presents as gradual visual loss caused by the loss of retinal ganglion cells (RGCs). Over 60% of DOA cases are caused by pathogenic variants in the OPA1 gene, which encodes a mitochondrial GTPase essential in mitochondrial fusion. Currently, there are no treatments for DOA. Here, we tested the therapeutic potential of an approach to DOA using CRISPR activation (CRISPRa). Homology directed repair was used to introduce a common OPA1 pathogenic variant (c.2708_2711TTAGdel) into HEK293T cells as an in vitro model of DOA. Heterozygous c.2708_2711TTAGdel cells had reduced levels of OPA1 mRNA transcript, OPA1 protein, and mitochondrial network alterations. The effect of inactivated Cas9 fused to an activator (dCas9–VPR) was tested with a range of guide RNAs (gRNA) targeted to the promotor region of OPA1. gRNA3 and dCas9–VPR increased OPA1 expression at the RNA and protein level towards control levels. Importantly, the correct ratio of OPA1 isoform transcripts was maintained by CRISPRa. CRISPRa-treated cells showed an improvement in mitochondrial networks compared to untreated cells, indicating partial rescue of a disease-associated phenotype. Collectively, these data support the potential application of CRISPRa as a therapeutic intervention in DOA. Full article

Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterized by progressive photoreceptor degeneration and vision loss. While current management is largely supportive—relying on visual aids, orientation training, and nutritional supplementation—these interventions offer only symptomatic relief and do not halt disease progression. Advances in molecular genetics have led to the development of targeted treatments, including gene replacement therapy, RNA-based therapies, and CRISPR/Cas9 gene editing, offering promising strategies for disease modification. The approval of voretigene neparvovec for RPE65-associated RP marked a milestone in gene therapy, while ongoing trials targeting mutations in RPGR, USH2A, and CEP290 are expanding therapeutic options. Optogenetic therapy and stem cell transplantation represent additional strategies, particularly for patients with advanced disease. Challenges persist in delivery efficiency, immune responses, and treating large or dominant-negative mutations. Non-viral vectors, nanoparticle systems, and artificial intelligence-guided diagnostics are being explored to address these limitations and support personalized care. This review summarizes the current and emerging therapeutic landscape for RP, highlighting the shift toward precision medicine and the need for continued innovation to overcome genetic and phenotypic variability. Full article

Adeno-associated virus (AAV) vectors have emerged as the leading platform for retinal gene therapy due to their favorable safety profile, low immunogenicity, and ability to mediate long-term transgene expression within the immune-privileged ocular environment. By integrating diverse strategies such as gene augmentation and gene editing, AAV-based therapies have demonstrated considerable promise in treating both inherited and acquired retinal disorders. However, their clinical translation remains limited by several key challenges, including restricted packaging capacity, suboptimal transduction efficiency, the risk of gene therapy-associated uveitis, and broader societal concerns such as disease burden and ethical oversight. This review summarizes recent advances aimed at overcoming these barriers, with a particular focus on delivery route-specific disease applicability, multi-vector systems, and capsid engineering approaches to enhance payload capacity, targeting specificity, and biosafety. By synthesizing these developments, we propose a conceptual and technical framework for a more efficient, safer, and broadly applicable AAV platform to accelerate clinical adoption in retinal gene therapy. Full article

Background: Syndromic inherited retinal diseases (IRDs) are a clinically and genetically heterogeneous group of disorders, involving the retina and additional organs. Over 80 forms of syndromic IRD have been described. Methods: We aimed to phenotypically and genotypically characterize a cohort of 171 individuals from 140 Israeli families with syndromic IRD. Ophthalmic examination included best corrected visual acuity, fundus examination, visual field testing, retinal imaging and electrophysiological evaluation. Most participants were also evaluated by specialists in fields relevant to their extra-retinal symptoms. Genetic analyses included haplotype analysis, homozygosity mapping, Sanger sequencing and next-generation sequencing. Results: In total, 51% of the families in the cohort were consanguineous. The largest ethnic group was Muslim Arabs. The most common phenotype was Usher syndrome (USH). The most common causative gene was USH2A. In 29% of the families, genetic analysis led to a revised or modified clinical diagnosis. This included confirmation of an atypical USH diagnosis for individuals with late-onset retinitis pigmentosa (RP) and/or hearing loss (HL); diagnosis of Heimler syndrome in individuals with biallelic pathogenic variants in PEX6 and an original diagnosis of USH or nonsyndromic RP; and diagnosis of a mild form of Leber congenital amaurosis with early-onset deafness (LCAEOD) in an individual with a heterozygous pathogenic variant in TUBB4B and an original diagnosis of USH. Novel genotype–phenotype correlations included biallelic pathogenic variants in KATNIP, previously associated with Joubert syndrome (JBTS), in an individual who presented with kidney disease and IRD, but no other features of JBTS. Conclusions: Syndromic IRDs are a highly heterogeneous group of disorders. The rarity of some of these syndromes on one hand, and the co-occurrence of several syndromic and nonsyndromic conditions in some individuals, on the other hand, complicates the diagnostic process. Genetic analysis is the ultimate way to obtain an accurate clinical diagnosis in these individuals. Full article

Background/Objectives: Inherited retinal diseases (IRDs) are a heterogeneous group of rare eye disorders characterized by progressive photoreceptor degeneration, leading to severe visual impairment or even blindness. This study aims to investigate the prevalence, types, and clinical significance of ophthalmic comorbidities in Portuguese patients with IRDs. Methods: This nationwide Portuguese population-based retrospective study was based on the IRD-PT registry (retina.com.pt). Statistical analysis was conducted using Microsoft^® Excel^® for Microsoft 365 and IBM SPSS Statistics version 29.0.2.0. Informed consent was obtained from all participants. Results: A total of 1531 patients (1254 families) from six centers were enrolled. The cohort consisted of 51% males, with a mean age of 45.8 ± 19.3 years and a mean age at diagnosis of 39.4 ± 19.5 years. Overall, ocular comorbidities were reported in 644 patients (42.1%). In 176 individuals (11.5%), multiple concurrent comorbidities were found. Cataract was the most common comorbidity (21.3%), followed by amblyopia (6.3%) and high myopia (5.9%). Statistically significant associations with ocular comorbidities were observed in isolated progressive IRDs. Specifically, AR RP was associated with cataract (p < 0.001), and gene analysis revealed several significant associations. CRB1 was statistically linked to epiretinal membrane (ERM) (p = 0.003), EYS with cataract (p = 0.001), PROM1 with choroidal neovascularization (CNV) (p = 0.0026), and USH2A with macular hole (p = 0.01). Patients with the RPE65 mutation in Leber congenital amaurosis were associated with ERM (p = 0.019). There was also a significant association between X-linked RP and high myopia (p < 0.001) and CNV in Best disease (p < 0.001); in syndromic IRDs, cataract, cystoid macular edema, and ERM were observed in Usher syndrome, p = 0.002, p = 0.002, and p = 0.005, respectively, and the MYO7A gene was linked to cataract (p = 0.041) and strabismus (p = 0.013); pseudoxanthoma elasticum was significantly associated with CNV (p = 0.002); and foveal hypoplasia was associated with anterior segment dysgenesis (p < 0.001). Conclusions: This study enhances the current understanding of ocular comorbidities in IRDs in Portuguese patients. Common findings were cataract, refractive error, and CME. Stationary IRDs and pattern dystrophies showed fewer concomitant comorbidities, supporting their classification as non-progressive or benign conditions. The significance of registries like IRD-PT cannot be overstated, particularly in the context of rare diseases. These databases serve multiple crucial functions in enabling detailed documentation of disease characteristics and long-term monitoring of disease progression. Full article

Background: The prevalence of foveal hypoplasia in different inherited retinal diseases (IRDs) has not been compared in a large patient cohort. We aimed to investigate the prevalence and visual significance of foveal hypoplasia in IRDs. Methods: Participants included patients with IRDs and control subjects. All patients had macular optical coherence tomography (OCT). Results: Among our 357 patients, 123 had rod-cone dystrophy (34.5%), 22 had cone/cone-rod dystrophy (6.2%), 30 had macular dystrophy (8.4%), and 182 (51%) were controls. Having a phenotype of rod-cone (OR = 12.9, p < 0.001) or cone/cone-rod dystrophy (OR = 10.2, p < 0.001) was associated with higher odds of having foveal hypoplasia. Males had higher odds of having foveal hypoplasia (OR = 2.4, p = 0.006). The prevalence of foveal hypoplasia in the retinitis pigmentosa GTPase regulator (RPGR) group (8/15 (53.3%)) was significantly higher than in matched controls (0/15, 0.0%) (p = 0.002). Atypical foveal hypoplasia had the highest LogMAR of 0.50 (±0.37), which was higher than grade one 0.16 (±0.17) (p = 0.038). Grade one LogMAR was not different from normal fovea 0.20 (±0.28) (p = 0.572). Conclusions: We report that rod-cone and cone/cone-rod IRDs are associated with foveal hypoplasia. Based on our findings, detection of foveal hypoplasia in a patient with reduced vision should prompt consideration of an IRD. Full article