Phenotypic variability in PRPH2 as demonstrated by a family with incomplete penetrance of autosomal dominant cone-rod dystrophy.

INTRODUCTION: Mutations in the peripherin-2 gene (PRPH2) are a common cause of inherited retinal dystrophies well known for their phenotypic diversity. We describe a novel presentation of the c.623G > A; p.(Gly208Asp) variant in association with cone-rod dystrophy and reduced penetrance. CASE DESCRIPTION: A 39-year-old man presents with a history of decreased visual acuity, photophobia, and dyschromatopsia. Fundus examination was largely unremarkable while spectral-domain optical coherence tomography (SD-OCT) demonstrated diffuse granularity at the ellipsoid zone. Full-field electroretinogram (ffERG) revealed a cone-rod dystrophy. Genetic testing revealed a heterozygous pathogenic variant, c.623G > A; p.(Gly208Asp), in the PRPH2 gene, also found in an unaffected brother. The 50-year-old brother had no visual symptoms and no findings on fundus examination. SD-OCT showed normal retinal architecture and ffERG was within normal limits bilaterally. CONCLUSION: This case report broadens the known phenotypic presentations of PRPH2-associated retinopathy and suggests that the PRPH2 variant c.623G > A; p.(Gly208Asp) may be associated with reduced penetrance.

Prime Editing Strategy to Install the PRPH2 c.828+1G>A Mutation.

Mutations in peripherin 2 (PRPH2) are associated with a spectrum of inherited retinal diseases (IRDs) including retinitis pigmentosa (RP) and macular degeneration. As PRPH2 is localized to cone and rod outer segments, mutations in PRPH2 lead the disorganization or absence of photoreceptor outer segments. Here, we report on a patient with PRPH2-linked RP who exhibited widespread RPE atrophy with a central area of macular atrophy sparing the fovea. In future studies, we plan to model the pathobiology of PRPH2-based RP using induced pluripotent stem cell (iPSC)-derived retinal organoids. To effectively model rare mutations using iPSC-derived retinal organoids, we first require a strategy that can install the desired mutation in healthy wild-type iPSC, which can efficiently generate well-laminated retinal organoids. In this study, we developed an efficient prime editing strategy for the installation of the pathogenic PRPH2 c.828+1 G>A splice-site mutation underlying our patient's disease.

Effects of medications on hypoxia-inducible factor in the retina: A review.

Hypoxia-inducible factor (HIF) plays a critical role in the mechanisms that allow cells to adapt to various oxygen levels in the environment. Specifically, HIF-1⍺ has shown to be widely involved in cellular repair, survival, and energy metabolism. HIF-1⍺ has also been found in increased levels in cancer cells, highlighting the importance of balance in the hypoxic response. Promoting HIF-1⍺ activity as a potential therapy for degenerative diseases and inhibiting HIF-1⍺ as a therapy for pathologies with overactive cell proliferation are actively being explored. Digoxin and metformin, HIF-1⍺ inhibitors, and deferoxamine and ⍺-ketoglutarate analogues, HIF-1⍺ activators, are being studied for application in age-related macular degeneration, diabetic retinopathy, and retinitis pigmentosa. However, these same medications have retinal toxicities that must be assessed before implementation of therapeutic care. Herein, we highlight the duality of therapeutic and toxic potential of HIF-1⍺ that must be carefully assessed prior to its clinical application in retinal disorders.

Social determinants of health disparities in Staten Island compared with Manhattan, Queens, Brooklyn, and the Bronx: Contribution to COVID-19 outcomes.

INTRODUCTION: Social determinants of health (SDH) negatively affected Coronavirus disease-2019 (COVID-19) outcomes within the five boroughs of New York City. The goal of this study was to determine whether differences in social demographics within the borough of Staten Island, compared with the other four boroughs, may have contributed to poor COVID-19 outcomes in Staten Island. METHODS: Data were obtained from public data sources. Social demographics obtained included age, household income, poverty status, and education level. COVID-19 infection, hospitalization, and death rates reported from Staten Island were compared with rates from Manhattan, Queens, Brooklyn, and the Bronx (February 29, 2020-October 31, 2022). Mean differences in case rates of COVID-19 were higher in Staten Island compared to all four boroughs. RESULTS: Mean differences in hospitalization and death rates were higher than Manhattan but similar to the other four boroughs. Within Staten Island, case rates were highest in zip codes 10306 and 10309. Hospitalization and death rates were highest in Staten Island zip code 10304. We found that the zip codes of Staten Island with poorer COVID-19 outcomes had more individuals with less than a high school degree, lower mean household income, higher proportion of households earning less than $25,000 a year, and a greater proportion of individuals using public transportation. CONCLUSION: Differences in COVID-19 infection, hospitalization, and death rates exist between the five boroughs and between the 12 zip codes within Staten Island. These differences in COVID-19 outcomes can be attributed to different SDH.

RBP3-Retinopathy-Inherited High Myopia and Retinal Dystrophy: Genetic Characterization, Natural History, and Deep Phenotyping.

PURPOSE: To examine the genetic and clinical features and the natural history of RBP3-associated retinopathy. DESIGN: Multi-center international, retrospective, case series of adults and children, with moleculraly confirmed RBP3-asociated retinopathy. METHODS: The genetic, clinical, and retinal imaging findings, including optical coherence tomography (OCT) and fundus autofluorescence (FAF), were investigated both cross-sectionally and longitudinally. The results of international standard full-field electroretinography (ERG) and pattern electroretinography (PERG) were reviewed. RESULTS: We ascertained 12 patients (5 female and 7 male) from 10 families (4 patients previously reported). Ten novel disease-causing RBP3 variants were identified. Ten patients were homozygous. The mean age (±SD, range) of the group was 21.4 years (±19.1, 2.9-60.5 years) at baseline evaluation. All 12 patients were highly myopic, with a mean spherical equivalent of -16.0D (range, -7.0D to -33.0D). Visual acuity was not significantly different between eyes, and no significant anisometropia was observed. Mean best-corrected visual acuity (BCVA) was 0.48 logMAR (SD, ±0.29; range, 0.2-1.35 logMAR); at baseline. Eleven patients had longitudinal BCVA assessment, with a mean BCVA of 0.46 logMAR after a mean follow-up of 12.6 years. All patients were symptomatic with reduced VA and myopia by the age of 7 years old. All patients had myopic fundi and features in keeping with high myopia on OCT, including choroidal thinning. The 4 youngest patients had no fundus pigmentary changes, with the rest of the patients presenting with a variable degree of mid-peripheral pigmentation and macular changes. FAF showed variable phenotypes, ranging from areas of increased signal to advanced atrophy in older patients. OCT showed cystoid macular edema at presentation in 3 patients, which persisted during follow-up in 2 patients and resolved to atrophy in the third patient. The ERGs were abnormal in 9 of 9 cases, revealing variable relative involvement of rod and cone photoreceptors with additional milder dysfunction post-phototransduction in some. All but 1 patient had PERG evidence of macular dysfunction, which was severe in most cases. CONCLUSIONS: This study details the clinical and functional phenotype of RBP3-retinopathy in the largest cohort reported to date. RBP3-retinopathy is a disease characterized by early onset, slow progression over decades, and high myopia. The phenotypic spectrum and natural history as described herein has prognostic and counseling implications. RBP3-related disease should be considered in children with high myopia and retinal dystrophy.

Clinical and Therapeutic Evaluation of the Ten Most Prevalent CRB1 Mutations.

Mutations in the Crumbs homolog 1 (CRB1) gene lead to severe inherited retinal dystrophies (IRDs), accounting for nearly 80,000 cases worldwide. To date, there is no therapeutic option for patients suffering from CRB1-IRDs. Therefore, it is of great interest to evaluate gene editing strategies capable of correcting CRB1 mutations. A retrospective chart review was conducted on ten patients demonstrating one or two of the top ten most prevalent CRB1 mutations and receiving care at Columbia University Irving Medical Center, New York, NY, USA. Patient phenotypes were consistent with previously published data for individual CRB1 mutations. To identify the optimal gene editing strategy for these ten mutations, base and prime editing designs were evaluated. For base editing, we adopted the use of a near-PAMless Cas9 (SpRY Cas9), whereas for prime editing, we evaluated the canonical NGG and NGA prime editors. We demonstrate that for the correction of c.2843G>A, p.(Cys948Tyr), the most prevalent CRB1 mutation, base editing has the potential to generate harmful bystanders. Prime editing, however, avoids these bystanders, highlighting its future potential to halt CRB1-mediated disease progression. Additional studies investigating prime editing for CRB1-IRDs are needed, as well as a thorough analysis of prime editing's application, efficiency, and safety in the retina.

Clinical characteristics of high myopia in female carriers of pathogenic RPGR mutations: a case series and review of the literature.

BACKGROUND: RPGR mutations are the most common cause of X-linked retinitis pigmentosa (XLRP). High myopia has been described as a very frequent feature among affected female carriers of XLRP. However, the clinical phenotype of female patients presenting with X-linked RPGR-related high myopia has not been well described. MATERIALS AND METHODS: Retrospective case series of four female patients with RPGR mutations and a diagnosis of high myopia, who presented to two academic eye centers. Clinical data, including age, family history, visual acuity, refractive error, dilated fundus exam, fundus photography, optical coherence tomography, electroretinography, and results of genetic testing, were collected. RESULTS: Three RPGR variants identified in the present study have not been previously associated with myopia in female carriers. One variant (c.2405_2406delAG, p.Glu802Glyfs *32) has been previously associated with a myopic phenotype in a female patient. Patients became symptomatic between the first and sixth decades of life. Myopia-associated tilted optic discs and posterior staphyloma were present in all patients. Two patients presented with intraretinal migration of the retinal pigment epithelium. CONCLUSION: RPGR-related high myopia has been associated with mutations in exons 1-14 and ORF15 in heterozygous females. There is a wide range of visual function among carriers. Although the exact mechanism of RPGR-related high myopia is still unclear, continued molecular diagnosis and description of phenotypes remain a crucial step in understanding the impact of RPGR mutations on visual function in female XLRP carriers.

Correlations of Full-Field Stimulus Threshold With Functional and Anatomical Outcome Measurements in Advanced Retinitis Pigmentosa.

PURPOSE: To compare full-field stimulus (FST) threshold values to conventional functional and anatomical measures commonly used in clinical practice. DESIGN: Cross-sectional study. METHODS: Patients with retinitis pigmentosa with nondetectable electroretinogram rod-mediated responses and light-adapted 3.0 cd·s·m2 30-Hz flicker (LA 3.0 flicker) amplitudes of 15 mV or less were included in this study. The threshold values for blue, white, and red stimuli on FST were correlated with best-corrected visual acuity, LA 3.0 flicker amplitude and implicit times, length of the ellipsoid zone (EZ) band and thickness of outer nuclear layer measurements on optical coherence tomography, and the vertical and horizontal diameters of the autofluorescent ring on autofluorescence imaging. RESULTS: Forty-two eyes of 21 patients were included in the study. The mean FST thresholds were -22.5 ± 15.5 dB, -17.6 ± 11.5 dB, and -12.7 ± 6.0 dB for the blue, white, and red stimuli, respectively. The threshold values for the 3 FST stimuli were significantly correlated with selected functional and anatomical outcome measures. Specifically, they were strongly correlated with LA 3.0 flicker amplitude and EZ band length measured on optical coherence tomography. Using linear regression, blue and white stimulus values on FST were found to be predictive of EZ band length (R2 = 0.579 and 0.491, respectively), and the vertical (R2 = 0.694 and 0.532, respectively) and horizontal (R2 = 0.626 and 0.400, respectively) diameters of the hyperautofluorescent ring. CONCLUSIONS: The significant correlations between FST and other clinical outcome measures highlight its potential as an adjunct outcome measure.

Phenotypic Variability of Retinal Disease Among a Cohort of Patients With Variants in the CLN Genes.

Purpose: To describe the phenotype of CLN-associated retinal dystrophy in a subset of patients at the Columbia University Medical Center, United States, and the Hospital das Clínicas de Pernambuco, Brazil, in comparison to the published literature. Methods: Eleven patients with confirmed biallelic variants in the CLN genes were evaluated via dilated fundus examination, clinical imaging, and full-field electroretinogram. A thorough literature search was conducted to determine previously published variants and associated phenotypes. Results: Genetic testing confirmed the presence of variants in CLN3, CLN7/MFSD8, CLN8, and GRN/CLN11. Five novel variants were identified, and four novel phenotypes of previously published alleles were described. The phenotype differed among patients with variants in the same gene and sometimes among patients with the same allele. Conclusions: Substantial phenotypic variability among variants in the CLN genes makes identification of genotype-phenotype or allele-phenotype correlations challenging. Further study is required to establish an extensive database for adequate patient counseling.

Chorioretinal atrophy following voretigene neparvovec despite the presence of fundus autofluorescence.

INTRODUCTION: Leber congenital amaurosis (LCA) type 2, due to disease-causing variants in RPE65, is characterized by severe visual loss in early infancy. Current treatments include voretigene neparvovec-rzyl (VN) for RPE65-associated LCA. Herein, we present the long-term follow-up of a patient treated with VN using quantitative autofluorescence (488 nm excitation). CASE REPORT: A 9-year-old girl with a diagnosis of LCA with biallelic variants in RPE65 presented for evaluation. The patient underwent VN treatment at the age of 11. The patient returned to clinic at age of 19 at which time imaging revealed evidence of chorioretinal atrophy. Quantitative autofluorescence performed prior to gene therapy and at 6- and 8-year follow-up revealed a central area of fundus autofluorescence. DISCUSSION: This case report demonstrates acquisition of fundus autofluorescence at 6- and 8-year follow-up despite the development of chorioretinal atrophy.

Foveolar thickness as potential standardized structural outcome measurement in studies of Bietti crystalline dystrophy.

Bietti crystalline dystrophy (BCD) is an ultra-rare orphan disorder that can lead to blindness. Because of the variable rates of progression of the disease, it is necessary to identify suitable outcome measurements for tracking progression in BCD. A retrospective analysis of patients with a clinical and genetic diagnosis of BCD was conducted. Four measurements of spectral domain-optical coherence tomography were compared to patients' best corrected visual acuity. We observed that patients with higher measurements of foveolar thickness, choroidal thickness in the foveolar region, ellipsoid zone band length and the outer nuclear layer + area, had on average better visual acuity. Future studies are needed to validate the structural-functional correlations we observed in BCD and to propose a sensitive and clinically meaningful outcome measurement for tracking this rare, variable disease.

A pathogenic in-frame deletion-insertion variant in BEST1 phenocopies Stargardt disease.

Here, we describe affected members of a 2-generation family with a Stargardt disease-like phenotype caused by a 2-base pair deletion insertion, c.1014_1015delGAinsCT;p.(Trp338_Asn339delinsCysTyr), in BEST1. The variant was identified by whole-exome sequencing, and its pathogenicity was verified through chloride channel recording using WT and transfected mutant HEK293 cells. Clinical examination of both patients revealed similar phenotypes at 2 different disease stages that were attributable to differences in their age at presentation. Hyperautofluorescent flecks along the arcades were observed in the proband, while the affected mother exhibited more advanced retinal pigment epithelium (RPE) loss in the central macula. Full-field electroretinogram testing was unremarkable in the daughter; however, moderate attenuation of generalized cone function was detected in the mother. Results from electrooculogram testing in the daughter were consistent with widespread dysfunction of the RPE characteristic of Best disease. Whole-cell patch-clamp recordings revealed a statistically significant decrease in chloride conductance of the mutant compared with WT cells. This report on a mother and daughter with a BEST1 genotype that phenocopies Stargardt disease broadens the clinical spectrum of BEST1-associated retinopathy.

KLF9-dependent ROS regulate melanoma progression in stage-specific manner.

Although antioxidants promote melanoma metastasis, the role of reactive oxygen species (ROS) in other stages of melanoma progression is controversial. Moreover, genes regulating ROS have not been functionally characterized throughout the entire tumor progression in mouse models of cancer. To address this question, we crossed mice-bearing knock-out of Klf9, an ubiquitous transcriptional regulator of oxidative stress, with two conditional melanocytic mouse models: BrafCA mice, where BrafV600E causes premalignant melanocytic hyperplasia, and BrafCA/Pten-/- mice, where BrafV600E and loss of Pten induce primary melanomas and metastases. Klf9 deficiency inhibited premalignant melanocytic hyperplasia in BrafCA mice but did not affect formation and growth of BrafCA/Pten-/- primary melanomas. It also, as expected, promoted BrafCA/Pten-/- metastasis. Treatment with antioxidant N-acetyl cysteine phenocopied loss of Klf9 including suppression of melanocytic hyperplasia. We were interested in a different role of Klf9 in regulation of cell proliferation in BrafCA and BrafCA/Pten-/- melanocytic cells. Mechanistically, we demonstrated that BRAFV600E signaling transcriptionally upregulated KLF9 and that KLF9-dependent ROS were required for full-scale activation of ERK1/2 and induction of cell proliferation by BRAFV600E. PTEN depletion in BRAFV600E-melanocytes did not further activate ERK1/2 and cell proliferation, but rendered these phenotypes insensitive to KLF9 and ROS. Our data identified an essential role of KLF9-dependent ROS in BRAFV600E signaling in premalignant melanocytes, offered an explanation to variable role of ROS in premalignant and transformed melanocytic cells and suggested a novel mechanism for suppression of premalignant growth by topical antioxidants.

FOXQ1 controls the induced differentiation of melanocytic cells.

Oncogenic transcription factor FOXQ1 has been implicated in promotion of multiple transformed phenotypes in carcinoma cells. Recently, we have characterized FOXQ1 as a melanoma tumor suppressor that acts via repression of N-cadherin gene, and invasion and metastasis. Here we report that FOXQ1 induces differentiation in normal and transformed melanocytic cells at least partially via direct transcriptional activation of MITF gene, melanocytic lineage-specific regulator of differentiation. Importantly, we demonstrate that pigmentation induced in cultured melanocytic cells and in mice by activation of cAMP/CREB1 pathway depends in large part on FOXQ1. Moreover, our data reveal that FOXQ1 acts as a critical mediator of BRAFV600E-dependent regulation of MITF levels, thus providing a novel link between two major signal transduction pathways controlling MITF and differentiation in melanocytic cells.

Melanoma Suppressor Functions of the Carcinoma Oncogene FOXQ1.

Lineage-specific regulation of tumor progression by the same transcription factor is understudied. We find that levels of the FOXQ1 transcription factor, an oncogene in carcinomas, are decreased during melanoma progression. Moreover, in contrast to carcinomas, FOXQ1 suppresses epithelial-to-mesenchymal transition, invasion, and metastasis in melanoma cells. We find that these lineage-specific functions of FOXQ1 largely depend on its ability to activate (in carcinomas) or repress (in melanoma) transcription of the N-cadherin gene (CDH2). We demonstrate that FOXQ1 interacts with nuclear ß-catenin and TLE proteins, and the ß-catenin/TLE ratio, which is higher in carcinoma than melanoma cells, determines the effect of FOXQ1 on CDH2 transcription. Accordingly, other FOXQ1-dependent phenotypes can be manipulated by altering nuclear ß-catenin or TLE proteins levels. Our data identify FOXQ1 as a melanoma suppressor and establish a mechanism underlying its inverse lineage-specific transcriptional regulation of transformed phenotypes.