Selective Assembly of TRPC Channels in the Rat Retina during Photoreceptor Degeneration.

Transient receptor potential canonical (TRPC) channels are calcium channels with diverse expression profiles and physiological implications in the retina. Neurons and glial cells of rat retinas with photoreceptor degeneration caused by retinitis pigmentosa (RP) exhibit basal calcium levels that are above those detected in healthy retinas. Inner retinal cells are the last to degenerate and are responsible for maintaining the activity of the visual cortex, even after complete loss of photoreceptors. We considered the possibility that TRPC1 and TRPC5 channels might be associated with both the high calcium levels and the delay in inner retinal degeneration. TRPC1 is known to mediate protective effects in neurodegenerative processes while TRPC5 promotes cell death. In order to comprehend the implications of these channels in RP, the co-localization and subsequent physical interaction between TRPC1 and TRPC5 in healthy retina (Sprague-Dawley rats) and degenerating (P23H-1, a model of RP) retina were detected by immunofluorescence and proximity ligation assays. There was an overlapping signal in the innermost retina of all animals where TRPC1 and TRPC5 physically interacted. This interaction increased significantly as photoreceptor loss progressed. Both channels function as TRPC1/5 heteromers in the healthy and damaged retina, with a marked function of TRPC1 in response to retinal degenerative mechanisms. Furthermore, our findings support that TRPC5 channels also function in partnership with STIM1 in Müller and retinal ganglion cells. These results suggest that an increase in TRPC1/5 heteromers may contribute to the slowing of the degeneration of the inner retina during the outer retinal degeneration.

Intensity-based optoretinography reveals sub-clinical deficits in cone function in retinitis pigmentosa.

Introduction: Clinical tools have been widely used in the diagnosis, description, and monitoring the progression of retinitis pigmentosa (RP); however, many of these methods have inherently low sensitivity and specificity, and significant photoreceptor disruption can occur before RP progression has clinically manifest. Adaptive optics scanning light ophthalmoscopy (AOSLO) has shown promise as a powerful tool for assessing photoreceptor disruption both structurally and functionally due to its increased resolution. Methods: Here we assess photoreceptor structure and function at the cellular level through AOSLO by acquiring intensity based optoretinography (iORG) in 15 individuals with no reported retinal pathology and 7 individuals with a prior clinical diagnosis of RP. Photoreceptor structure was quantified by calculating cone nearest neighbor distance (NND) across different retinal eccentricities from the AOSLO images. Cone outer segment length was measured across different retinal eccentricities using optical coherence tomography (OCT) derived longitudinal reflectivity profiles (LRPs). Finally, iORG measures of photoreceptor function were compared to retinal sensitivity as measured using the macular integrity assessment (MAIA) microperimeter. Results: Broadly, participants with RP exhibited increasing cone nearest neighbor distances and decreasing cone outer segment length as a function of retinal eccentricity, consistent with prior reports for both controls and individuals with RP. Nearly all individuals with RP had reduced iORG amplitudes for all retinal eccentricities when compared to the control cohort, and the reduction was greater in eccentricities further from the fovea. Comparing iORG amplitudes to MAIA retinal sensitivity, we found that the iORG was more sensitive to early changes in photoreceptor function whereas MAIA was more sensitive to later stages of disease. Discussion: This highlights the utility of iORG as a method to detect sub-clinical deficits in cone function in all stages of disease progression and supports the future use of iORG for identifying cells that are candidates for cellular based therapies.

Exploring self-reported visual function and vision-related anxiety in patients with RPGR-associated retinal degeneration.

Variants in the retinitis pigmentosa GTPase regulator (RPGR) gene are responsible for the majority of X-linked retinitis pigmentosa cases, which not only affects male patients but also some heterozygous females. Vision-related disability and anxiety of patients with RPGR-associated retinal degeneration have never been explored before. This study aimed to evaluate self-reported visual function and vision-related anxiety in a Portuguese cohort of male and female patients with RPGR-associated retinal degeneration using two validated patient-reported outcome measures. Cross-sectional data of thirty-two genetically-tested patients was examined, including scores of the Michigan retinal degeneration questionnaire (MRDQ) and Michigan vision-related anxiety questionnaire. Patients were classified according to retinal phenotypes in males (M), females with male phenotype (FM), and females with radial or focal pattern. Both M and FM revealed higher rod-function and cone-function anxiety scores (p < 0.017). Most MRDQ disability scores were higher in M and FM (p < 0.004). Overall, positive correlations (p < 0.004) were found between every MRDQ domain and both anxiety scores. In RPGR-associated retinal degeneration, males and females with male phenotype show similar levels of increased vision-related anxiety and disability. Every MRDQ visual function domain showed a strong correlation with anxiety scores.

Clinical exome analysis and targeted gene repair of the c.1354dupT variant in iPSC lines from patients with PROM1-related retinopathies exhibiting diverse phenotypes.

BACKGROUND: Inherited retinal dystrophies (IRD) are one of the main causes of incurable blindness worldwide. IRD are caused by mutations in genes that encode essential proteins for the retina, leading to photoreceptor degeneration and loss of visual function. IRD generates an enormous global financial burden due to the lack of understanding of a significant part of its pathophysiology, molecular diagnosis, and the near absence of non-palliative treatment options. Patient-derived induced pluripotent stem cells (iPSC) for IRD seem to be an excellent option for addressing these questions, serving as exceptional tools for in-depth studies of IRD pathophysiology and testing new therapeutic approaches. METHODS: From a cohort of 8 patients with PROM1-related IRD, we identified 3 patients carrying the same variant (c.1354dupT) but expressing three different IRD phenotypes: Cone and rod dystrophy (CORD), Retinitis pigmentosa (RP), and Stargardt disease type 4 (STGD4). These three target patients, along with one healthy relative from each, underwent comprehensive ophthalmic examinations and their genetic panel study was expanded through clinical exome sequencing (CES). Subsequently, non-integrative patient-derived iPSC were generated and fully characterized. Correction of the c.1354dupT mutation was performed using CRISPR/Cas9, and the genetic restoration of the PROM1 gene was confirmed through flow cytometry and western blotting in the patient-derived iPSC lines. RESULTS: CES revealed that 2 target patients with the c.1354dupT mutation presented monoallelic variants in genes associated with the complement system or photoreceptor differentiation and peroxisome biogenesis disorders, respectively. The pluripotency and functionality of the patient-derived iPSC lines were confirmed, and the correction of the target mutation fully restored the capability of encoding Prominin-1 (CD133) in the genetically repaired patient-derived iPSC lines. CONCLUSIONS: The c.1354dupT mutation in the PROM1 gene is associated to three distinct AR phenotypes of IRD. This pleotropic effect might be related to the influence of monoallelic variants in other genes associated with retinal dystrophies. However, further evidence needs to be provided. Future experiments should include gene-edited patient-derived iPSC due to its potential as disease modelling tools to elucidate this matter in question.

A novel small deletion in CWC27 gene associated with CWC27-related spliceosomeopathy.

BACKGROUND: CWC27-related spliceosomeopathy is a rare autosomal recessive disorder with only 14 patients have been reported. It is characterized by retinal degeneration, short stature, skeletal anomalies, and neurological defects. We described the clinical features of a Chinese patient with CWC27-related spliceosomeopathy and identified the pathogenic variant. METHODS: The affected subject underwent detailed ophthalmic examinations. Systemic abnormalities were assessed, including body height, craniofacial morphology, oral cavity, hands, feet, hair and skin. Genomic DNA was isolated from peripheral blood and sequenced by next-generation sequencing. Sanger sequencing was performed for validation and segregation. RESULTS: The patient had poor vision, nyctalopia and nystagmus from childhood. Fundoscopy revealed extensive chorioretinal atrophy with numerous scattered greyish pigmentation. Severe circular areas of macular atrophy were observed. Optical coherent tomography showed reduced retinal thickness with nearly absent ellipsoid zone and retinal pigment epithelium. In addition, craniofacial abnormalities, short statue, brachydactyly, dental anomalies, cafe-au-lait spots, scant hair, absent eyebrows and thin eyelashes were documented. Genetic analysis revealed a novel homozygous novel small deletion c.1133delG(p.G378Efs*12) in CWC27 (NM_005869.2). CONCLUSIONS: We present a patient with early-onset retinitis pigmentosa and marked syndromic features. A novel CWC27 pathogenic variant was identified. Our findings broaden the clinical and mutation spectrum of CWC27-related spliceosomeopathy, and could be helpful in diagnosis of this rare disease.

Impacts of X-linked Retinitis Pigmentosa and Patient Pathways in European Countries: Results from the Cross-sectional EXPLORE XLRP-1 Physician Survey.

INTRODUCTION: X-linked retinitis pigmentosa (XLRP) is a rare, incurable, vision-threatening, genetic disease. In this study, we aimed to reveal the real-world burden of this disease from the viewpoint of retina specialists and geneticists involved directly in XLRP care and to identify unique insights that may not otherwise be available through typical clinical studies or health economic research. METHODS: In this exploratory, cross-sectional study (EXPLORE XLRP-1), retina specialists (n = 20) and geneticists (n = 5) in France, Germany, Italy, Spain, and the UK provided anonymized insights on their experiences managing patients with XLRP (n = 80) via an online survey and 60-min telephone interview. RESULTS: Survey respondents reported that patient independence decreased over time, where 37% of patients were considered "completely autonomous" at diagnosis versus 23% at the last consultation. At their last visit, 45% of patients were active in the workforce; 67% (12/18) of "completely autonomous" patients had active working status compared with 13% (1/8) of "completely dependent" patients. The average time from onset of symptoms to diagnosis was 4 years and varied among countries. In 78% of patients, XLRP was confirmed by genetic testing, the rate of which varied among countries (range, 50-94%), taking up to 6 months to receive results. Specialists identified unmet needs in XLRP management including more standardized assessments of quality of life (QoL) as well as easier and earlier access to specialists, genetic testing, patient support programs, and effective treatment options. CONCLUSIONS: The diagnosis, genetic testing, and management pathways among patients with XLRP can vary considerably. There is a need for more standardized diagnosis and management pathways, and QoL assessments, due to the major impact that XLRP has on patients' lives.

The role of ultra-widefield imaging with navigated central and peripheral cross-sectional and three-dimensional swept source optical coherence tomography in ophthalmology: Clinical applications.

PURPOSE: To assess central and peripheral retinal and choroidal diseases using ultra-widefield (UWF) fundus imaging in combination with navigated central and peripheral cross-sectional and three-dimensional (3D) swept source optical coherence tomography (SS-OCT) scans. METHODS: Retrospective study involving 332 consecutive patients, with a nearly equal distribution of males and females. The mean age of patients was 52 years (range 18-92 years). Average refractive error was -3.80 D (range +7.75 to -20.75 D). RESULTS: The observations in this study demonstrate the efficacy of peripheral navigated SS-OCT in assessing various ocular conditions. The technology provides high-quality images of the peripheral vitreous, vitreoretinal interface, retina, and choroid, enabling visualization of vitreous floaters and opacities, retinal holes and tears, pigmented lesions, and peripheral retinal degenerations. 3D OCT scans enhance the visualization of these abnormalities and improve diagnostic and therapeutic decisions. CONCLUSION: Navigated central and peripheral cross-sectional and 3D SS-OCT scans offer significant complementary benefits in the assessment and management of retinal diseases. Their addition to UWF imaging provides a comprehensive view of central and peripheral ocular structures, aiding in early detection, precise anatomical measurements, and objective monitoring of disease progression. In addition, this technology serves as a valuable tool for patient education, a teaching tool for trainees, and documentation for medico-legal purposes.

High prevalence of exon-13 variants in USH2A-related retinal dystrophies in Taiwanese population.

BACKGROUND: Biallelic pathogenic variants in USH2A lead to Usher syndrome or non-syndromic retinitis pigmentosa, and shown to have geographical and ethnical distribution in previous studies. This study provided a deeper understanding of the detailed clinical features using multimodal imaging, genetic spectrum, and genotype-phenotype correlations of USH2A-related retinal dystrophies in Taiwan. RESULTS: In our cohort, the mean age at first visit was 47.66 ± 13.54 years, and the mean age at symptom onset, which was referred to the onset of nyctalopia and/or visual field constriction, was 31.21 ± 15.24 years. Among the variants identified, 23 (50%) were missense, 10 (22%) were splicing variants, 8 (17%) were nonsense, and 5 (11%) were frameshift mutations. The most predominant variant was c.2802T>G, which accounted for 21% of patients, and was located in exon 13. Patients with truncated alleles had significantly earlier symptom onset and seemly poorer disease progression regarding visual acuity, ellipsoid zone line length, and hypofluorescent lesions in the macula than those who had the complete gene. However, the clinical presentation revealed similar progression between patients with and without the c.2802T>G variant. During long-term follow-up, the patients had different ellipsoid zone line progression rates and were almost evenly distributed in the fast, moderate, and slow progression subgroups. Although a younger onset age and a smaller baseline intact macular area was observed in the fast progression subgroup, the results showed no significant difference. CONCLUSIONS: This is the first cohort study to provide detailed genetic and longitudinal clinical analyses of patients with USH2A-related retinal dystrophies in Taiwan. The mutated allele frequency in exon 13 was high in Taiwan due to the predominant c.2802T>G variant. Moreover, truncated variants greatly impacted disease progression and determined the length of therapeutic windows. These findings provide insight into the characteristics of candidates for future gene therapies.

Clinical and Genetic Findings in a Cohort of Patients with PRPF31-associated Retinal Dystrophy.

PURPOSE: The purpose of our study was to assess the phenotypic and genotypic spectrum in a large cohort of patients with PRPF31-associated retinal dystrophy. DESIGN: Retrospective cohort study METHODS: In this retrospective chart review study, we collected cross-sectional data on the phenotype and genotype of patients with PRPF31-associated retinal dystrophy from the clinics for inherited retinal dystrophies at the University of Tuebingen and the local RetDis database and biobank. Patients underwent thorough ophthalmological examinations and genetic testing. RESULTS: Eighty-six patients from 61 families were available for clinical assessment, while genomic DNA was available for 111 individuals (index patients and family members). Fifty-three different disease-associated variants were observed in our cohort. Point mutations were the most common class. All but two patients exhibited features of a typical Retinitis pigmentosa (RP). One patient showed a cone-rod-dystrophy pattern. One mutation carrier revealed no signs of a retinal dystrophy. There was a statistically significant better visual acuity for patients with large deletions in the 20-39 age group. Cystoid macular edema was common in those with preserved central retina and showed an association with female sex. CONCLUSION: Our study confirms high phenotypic variability in disease onset and age at which legal blindness is reached in PRPF31-linked RP. Non-penetrance is commonly documented in family history, although poorly represented in our study, possibly indicating that true asymptomatic mutation carriers are rare if followed-up over lifetime with thorough ophthalmologic workup.

Pigmentary retinal dystrophy associated with peroxisome biogenesis disorder-Zellweger syndrome spectrum.

Pigmentary retinal dystrophy (PRD) is a group of inherited disorders involving the progressive degeneration of rod and cone photoreceptors and the retinal pigment epithelium (RPE), which can progress to pigmentary retinopathy (PR). We present a case of PRD in a female pediatric patient who has pathogenic variants in the PRPH2 and PEX1 genes. The patient has associated macular edema and secondary visual impairment. Treatment has included serial dexamethasone intravitreal implant injections and topical dorzolamide. The PEX1 gene mutation is associated with peroxisome biogenesis disorder-Zellweger syndrome spectrum (PBD-ZSS) and resulting retinal dystrophies. The PRPH2 mutation may play a role in macular edema and PRD, as it is implicated in macular degeneration, choroid defects, and photoreceptor dysfunction. In this case, we review multiple gene mutations playing potential etiologic roles for PRD and discuss care management.

Multimodal Imaging of Optic Nerve Head in Retinitis Pigmentosa.

BACKGROUND: A pallor optic nerve head (ONH) is one of the three features of retinitis pigmentosa (RP). This study aimed to assess the ONH prospectively by color tone, presence of hyper-reflective tissue, blood flow, retinal nerve fiber layer (RNFL) thickness, ganglion cell complex (GCC) and investigate the change in these parameters with and without ONH pallor. METHODS: The presence of ONH pallor was assessed by three independent examiners through careful examination using fundus photographs. The presence of a hyper-reflective structure on the ONH was carefully evaluated using a volume scan optical coherence tomography (OCT). RNFL thickness and ellipsoid zone (EZ) width around the macula were also evaluated by OCT. Laser speckle flowgraphy was used to measure the mean blur rate of the entire ONH area, which was subsequently divided into the vessel area (MV) and tissue area (MT). RESULTS: Twenty-eight eyes of 28 patients with RP (55.4 ± 16.23 years of age) were included. The pale ONH was observed in 10 (35%) eyes. Hyper-reflective structures were observed in seven (25%) eyes. No significant correlation was found between the pale ONH and the presence of a hyper-reflective structure (Pearson's chi-squared test, p = .364). The average of the ONH area, MV, and MT was 8.65 ± 3.08 AU, 17.81 ± 7.54 AU, and 6.4 ± 2.66 AU, respectively, which significantly decreased in patients with pallor ONH (all p < .05). The global RNFL thickness was 73.54 ± 18.82 µm. The nasal and superior quadrants and global RNFL thickness in patients with a pale ONH were significantly thinner than in patients without a pale ONH (all p < .05). The global and superior and inferior GCC thickness in patients with a pale ONH were significantly thinner than in patients without a pale ONH(all p < .05).There was no difference in the EZ width between patients with and without a pale ONH (p = .107). CONCLUSION: We conducted multiple assessments of the ONH in RP patients and investigated its clinical significance. Our findings suggest that ONH pallor may indicate a comprehensive change that emerges alongside the progression of retinal degeneration in RP. TRIAL REGISTRATION: This trial was retrospectively registered in the UMIN Clinical Trial Registry (UMIN ID: 000048168).

Mutant dominant-negative rhodopsin∆I256 causes protein aggregates degraded via ERAD and prevents normal rhodopsin from proper membrane trafficking.

Dominant mutations in the rhodopsin gene (Rho) contribute to 25% of autosomal dominant retinitis pigmentosa (adRP), characterized by photoreceptor loss and progressive blindness. One such mutation, Rho ∆I256 , carries a 3-bp deletion, resulting in the loss of one of two isoleucines at codons 255 and 256. Our investigation, using recombinant expression in HEK293 and COS-7 cells, revealed that Rho ∆I256, akin to the known adRP mutation Rho P23H, induces the formation of rhodopsin protein (RHO) aggregates at the perinuclear region. Co-expression of Rho ∆I256 or Rho P23H with wild-type Rho WT, mimicking the heterozygous genotype of adRP patients, demonstrated the dominant-negative effect, as all isoforms were retained in perinuclear aggregates, impeding membrane trafficking. In retinal explants from WT mice, mislocalization of labeled adRP isoforms at the outer nuclear layer was observed. Further analysis revealed that RHO∆I256 aggregates are retained at the endoplasmic reticulum (ER), undergo ER-associated degradation (ERAD), and colocalize with the AAA-ATPase escort chaperone valosin-containing protein (VCP). These aggregates are polyubiquitinated and partially colocalized with the 20S proteasome subunit beta-5 (PSMB5). Pharmacological inhibition of proteasome- or VCP activity increased RHO∆I256 aggregate size. In summary, RHO∆I256 exhibits dominant pathogenicity by sequestering normal RHOWT in ER aggregates, preventing its membrane trafficking and following the ERAD degradation.

Bardet-Biedl syndrome in a 19-year-old male: the first case report from Palestine.

Bardet-Biedl syndrome (BBS) is a rare genetic disorder characterized by retinitis pigmentosa, polydactyly, type 2 diabetes mellitus, and obesity. This case report presents a 19-year-old male from Palestine with BBS, exhibiting delayed diagnosis and variable phenotypic expression. The patient had familial BBS history and presented with obesity, type 2 diabetes mellitus, retinitis pigmentosa, and cryptorchidism. Genetic analysis identified heterozygous missense variants in the FBN3 gene, yet additional genetic factors may contribute to the phenotype. Renal abnormalities included kidney shrinkage and mild hydronephrosis. Management of this patient involves a multidisciplinary approach with lifestyle modifications, surgical interventions, and supportive care. Early diagnosis, genetic counseling, and regular follow-up are crucial for improving outcomes in BBS. This report highlights diagnostic and therapeutic challenges and underscores the need for further research on this complex disorder.

Photovoltaic, wireless wide-field epiretinal prosthesis to treat retinitis pigmentosa.

PURPOSE: To develop and evaluate a photovoltaic, wireless wide-field epiretinal prosthesis for the treatment of retinitis pigmentosa. METHODS: A mosaic array of thinned silicon-based photodiodes with integrated thin-film stimulation electrodes was fabricated with a flexible polyimide substrate film to form a film-based miniaturized electronic system with wireless optical power and signal transmission and integrated electrostimulation. Manufactured implants were characterized with respect to their optoelectronic performance and biocompatibility following DIN EN ISO 10993. RESULTS: A 14 mm diameter prosthesis containing 1276 pixels with a maximum sensitivity at a near infrared wavelength of 905 nm and maximized stimulation current density 30-50 µm below the electrodes was developed for direct activation of retinal ganglion cells during epiretinal stimulation. Fabricated prostheses demonstrated mucosal tolerance and the preservation of both metabolic activity, proliferation and membrane integrity of human fibroblasts as well as the retinal functions of bovine retinas. Illumination of the prosthesis, which was placed epiretinally on an isolated perfused bovine retina, with infrared light resulted in electrophysiological recordings reminiscent of an a-wave (hyperpolarization) and b-wave (depolarization). CONCLUSIONS: A photovoltaic, wireless wide-field epiretinal prosthesis for the treatment of retinitis pigmentosa using near infrared light for signal transmission was designed, manufactured and its biocompatibility and functionality demonstrated in vitro and ex vivo.

VDAC in Retinal Health and Disease.

The retina, a tissue of the central nervous system, is vital for vision as its photoreceptors capture light and transform it into electrical signals, which are further processed before they are sent to the brain to be interpreted as images. The retina is unique in that it is continuously exposed to light and has the highest metabolic rate and demand for energy amongst all the tissues in the body. Consequently, the retina is very susceptible to oxidative stress. VDAC, a pore in the outer membrane of mitochondria, shuttles metabolites between mitochondria and the cytosol and normally protects cells from oxidative damage, but when a cell's integrity is greatly compromised it initiates cell death. There are three isoforms of VDAC, and existing evidence indicates that all three are expressed in the retina. However, their precise localization and function in each cell type is unknown. It appears that most retinal cells express substantial amounts of VDAC2 and VDAC3, presumably to protect them from oxidative stress. Photoreceptors express VDAC2, HK2, and PKM2-key proteins in the Warburg pathway that also protect these cells. Consistent with its role in initiating cell death, VDAC is overexpressed in the retinal degenerative diseases retinitis pigmentosa, age related macular degeneration (AMD), and glaucoma. Treatment with antioxidants or inhibiting VDAC oligomerization reduced its expression and improved cell survival. Thus, VDAC may be a promising therapeutic candidate for the treatment of these diseases.

Inherited Retinal Diseases and Retinal Organoids as Preclinical Cell Models for Inherited Retinal Disease Research.

Inherited retinal diseases (IRDs) are a large group of genetically and clinically diverse blinding eye conditions that result in progressive and irreversible photoreceptor degeneration and vision loss. To date, no cures have been found, although strides toward treatments for specific IRDs have been made in recent years. To accelerate treatment discovery, retinal organoids provide an ideal human IRD model. This review aims to give background on the development and importance of retinal organoids for the human-based in vitro study of the retina and human retinogenesis and retinal pathologies. From there, we explore retinal pathologies in the context of IRDs and the current landscape of IRD treatment discovery. We discuss the usefulness of retinal organoids in this context (as a patient-derived cell model for IRDs) to precisely understand the pathogenesis and potential mechanisms behind a specific IRD-causing variant of interest. Finally, we discuss the importance and promise of retinal organoids in treatment discovery for IRDs, now and in the future.

The Clinical and Mutational Spectrum of Bardet-Biedl Syndrome in Saudi Arabia.

The retinal features of Bardet-Biedl syndrome (BBS) are insufficiently characterized in Arab populations. This retrospective study investigated the retinal features and genotypes of BBS in Saudi patients managed at a single tertiary eye care center. Data analysis of the identified 46 individuals from 31 families included visual acuity (VA), systemic manifestations, multimodal retinal imaging, electroretinography (ERG), family pedigrees, and genotypes. Patients were classified to have cone-rod, rod-cone, or generalized photoreceptor dystrophy based on the pattern of macular involvement on the retinal imaging. Results showed that nyctalopia and subnormal VA were the most common symptoms with 76% having VA ≤ 20/200 at the last visit (age: 5-35). Systemic features included obesity 91%, polydactyly 56.5%, and severe cognitive impairment 33%. The predominant retinal phenotype was cone-rod dystrophy 75%, 10% had rod-cone dystrophy and 15% had generalized photoreceptor dystrophy. ERGs were undetectable in 95% of patients. Among the 31 probands, 61% had biallelic variants in BBSome complex genes, 32% in chaperonin complex genes, and 6% had biallelic variants in ARL6; including six previously unreported variants. Interfamilial and intrafamilial variabilities were noted, without a clear genotype-phenotype correlation. Most BBS patients had advanced retinopathy and were legally blind by early adulthood, indicating a narrow therapeutic window for rescue strategies.

SCAPER-Related Autosomal Recessive Retinitis Pigmentosa with Intellectual Disability: Confirming and Extending the Phenotypic Spectrum and Bioinformatics Analyses.

Mutations in the gene SCAPER (S phase Cyclin A-Associated Protein residing in the Endoplasmic Reticulum) have recently been associated with retinitis pigmentosa (RP) and intellectual disability (ID). In 2011, a possible involvement of SCAPER in human diseases was discovered for the first time due to the identification of a homozygous mutation causing ID in an Iranian family. Later, five studies were published in 2019 that described patients with autosomal recessive syndromic retinitis pigmentosa (arRP) accompanied by ID and attention-deficit/hyperactivity disorder (ADHD). This present study describes three patients from an Arab consanguineous family in Israel with similar clinical features of the SCAPER syndrome. In addition, new manifestations of ocular symptoms, nystagmus, glaucoma, and elevator palsy, were observed. Genetic testing of the patients and both parents via whole-exome sequencing revealed the homozygous mutation c.2023-2A>G in SCAPER. Phenotypic and genotypic descriptions for all available cases described in the literature including our current three cases (37 cases) were carried out, in addition to a bioinformatics analysis for all the genetic variants that was undertaken. Our study confirms and extends the clinical manifestations of SCAPER-related disorders.

Exploring Stem-Cell-Based Therapies for Retinal Regeneration.

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.

Global trends in oxidative stress in the Retina: A bibliometric analysis of 2013-2023.

Background: Oxidative stress plays a significant role in the pathogenesis of many retinal diseases. However, only a few systematic bibliometric studies have been conducted. This study aims to visualize research hotspots and developmental trends in oxidative stress in the retina from 2013 to 2023 by analyzing bibliometric data. Methods: We retrieved papers on oxidative stress in the retina published between 2013 and 2023 from the Web of Science Core Collection. The data were visually analyzed using CiteSpace and VOSviewer software. Results: The total number of 2100 publications were included in the analysis. An overall increasing trend in the number of publications is observed between 2013 and 2023. Chinese publications were the most contributive, but United States publications were the most influential. Shanghai Jiao Tong University was the most active and prolific institution. Antioxidants was the most productive journal, while Oxidative Medicine and Cellular Longevity were the journals with the most-cited articles. Kaarniranta K, from Finland, was the most productive and influential author. Examination of co-cited references revealed that researchers in the field are primarily focused on investigating the molecular mechanisms, preventive strategies, and utilization of antioxidants to address retinal oxidative damage. Diabetic retinopathy, endothelial growth factor, retinitis pigmentosa, retinal degeneration, antioxidant response, retinal ganglion cells, and genes are the research hotspots in this field. Metabolism, sodium iodate, and system are at the forefront of research in this field. Conclusion: Attention toward retinal oxidative stress has increased over the past decade. Current research focuses on the mechanisms of retinal diseases related to oxidative stress and the experimental study of antioxidants in retinal diseases, which may continue to be a trend in the future.