Peripapillary Sparing With Near Infrared Autofluorescence Correlates With Electroretinographic Findings in Patients With Stargardt Disease

PURPOSE: To evaluate the correlation between the quantification of peripapillary sparing and electroretinogram (ERG) outcomes in autosomal recessive Stargardt disease (STGD1). METHODS: Near infrared fundus autofluorescence (NIR-FAF) images of 101 eyes of 101 patients were retrospectively reviewed. Peripapillary sparing was assessed both qualitatively and quantitatively. The area of spared tissue (AST) was calculated in a 1-mm-wide ring around the optic disc after binarization of the 55\ub0 NIR-FAF. These measurements were correlated with the presence of normal ERG (group I), abnormal photopic responses (group II), or abnormal photopic and scotopic responses (group III). RESULTS: AST showed significant correlations with ERG groups (R = -0.802, P < 0.001). While qualitative assessment of peripapillary sparing (i.e., present or not) also showed a significant correlation with ERG groups (R = -0.435, P < 0.001), it was weaker than by AST quantification. The ordinal regression analysis showed that the increase in AST was associated with a decrease in the odds of belonging to ERG groups II and III, with an odds ratio of 0.82 (95% confidence interval [CI] 0.78-0.87), P < 0.001. CONCLUSIONS: The AST around the optic disc in eyes with STGD1 correlates with the impairment of photoreceptors as shown in the ERG. If replicated in future longitudinal studies, the quantification of peripapillary sparing may prove to be a useful parameter for evaluating the visual prognosis of these eyes

Prevalence of ABCA4 Deep-Intronic Variants and Related Phenotype in An Unsolved "One-Hit" Cohort with Stargardt Disease

We investigated the prevalence of reported deep-intronic variants in a French cohort of 70 patients with Stargardt disease harboring a monoallelic pathogenic variant on the exonic regions of ABCA4. Direct Sanger sequencing of selected intronic regions of ABCA4 was conducted. Complete phenotypic analysis and correlation with the genotype was performed in case a known intronic pathogenic variant was identified. All other variants found on the analyzed sequences were queried for minor allele frequency and possible pathogenicity by in silico predictions. The second mutated allele was found in 14 (20%) subjects. The three known deep-intronic variants found were c.5196+1137G>A in intron 36 (6 subjects), c.4539+2064C>T in intron 30 (4 subjects) and c.4253+43G>A in intron 28 (4 subjects). Even though the phenotype depends on the compound effect of the biallelic variants, a genotype-phenotype correlation suggests that the c.5196+1137G>A was mostly associated with a mild phenotype and the c.4539+2064C>T with a more severe one. A variable effect was instead associated with the variant c.4253+43G>A. In addition, two novel variants, c.768+508A>G and c.859-245_859-243delinsTGA never associated with Stargardt disease before, were identified and a possible splice defect was predicted in silico. Our study calls for a larger cohort analysis including targeted locus sequencing and 3D protein modeling to better understand phenotype-genotype correlations associated with deep-intronic changes and patients' selection for clinical trials

Change in Cone Structure Over 24 Months in USH2A-Related Retinal Degeneration

Purpose: To describe cone structure changes using adaptive optics scanning laser ophthalmoscopy (AOSLO) in the Rate of Progression of USH2A-related Retinal Degeneration (RUSH2A) study. Design: Multicenter, longitudinal natural history study. Methods: AOSLO images were acquired at 4 centers, twice at baseline and annually for 24 months in this natural history study. For each eye, at least 10 regions of interest (ROIs) with ≥50 contiguous cones were analyzed by masked, independent graders. Cone spacing Z-scores, standard deviations from the normal mean at the measured location, were compared between graders and tests at baseline. The association of cone spacing with clinical characteristics was assessed using linear mixed effects regression models weighted by image quality score. Annual rates of change were calculated based on differences between visits. Results: Fourteen eyes of 14 participants were imaged, with 192 ROIs selected at baseline. There was variability among graders, which was greater in images with lower image quality score (P < .001). Cone spacing was significantly correlated with eccentricity, quality score, and disease duration (P < .02). On average, the cone spacing Z-score increased 0.14 annually (about 9%, P < .001). We observed no significant differences in rate of change between disease type (Usher syndrome or retinitis pigmentosa), imaging site, or grader. Conclusions: Using current methods, the analysis of quantitative measures of cone structure showed some challenges, yet showed promise that AOSLO images can be used to characterize progressive change over 24 months. Additional multicenter studies using AOSLO are needed to advance cone mosaic metrics as sensitive outcome measures for clinical trials

Venous thromboembolism in critically ill patients affected by ARDS related to COVID-19 in Northern-West Italy

OBJECTIVE: Coronavirus disease 2019 (COVID-19) is an emerging infectious disease that was first reported in Wuhan, China, and has subsequently spread worldwide. An association between increased venous thromboembolism in patients with pneumonia-related to COVID-19 has not yet been well described. PATIENTS AND METHODS: We aimed to illustrate cases of pulmonary thromboembolism in patients with acute respiratory distress syndrome related to COVID-19 treated in our intensive care unit. The medical records of patients affected by COVID-19 with acute respiratory distress syndrome in our institute from 1/3/2020 to 31/3/2020 were retrospectively reviewed. RESULTS: Our center registered a high prevalence of thromboembolic events among 62 patients affected by acute respiratory distress syndrome related to COVID-19 despite a regular antithrombotic prophylaxis. Out of these, 32 patients were transferred to other hospitals, and 30 were treated in our center. Venous thromboembolism was registered in 12 (19.3%) cases. In particular, 11 diagnoses of pulmonary embolism and 1 diagnosis of deep vein thrombosis were formulated. We described a case series of venous thromboembolism in nine patients treated in our Intensive Care Unit (ICU). Main pulmonary arteries were always involved in these patients. None of them died. CONCLUSIONS: In conclusion, critically ill patients with ARDS related to COVID-19 may have an increased risk of VTE that could be a leading cause of mortality. These patients require a high index of clinical suspicion and an accurate diagnostic approach, in order to immediately start an appropriate anticoagulant treatment

Longitudinal Changes in Scotopic and Mesopic Macular Function as Assessed with Microperimetry in Patients with Stargardt Disease: SMART Study Report No. 2: Short Title: Scotopic and Mesopic Macular Functions in Stargardt Disease

PURPOSE: To estimate and compare cross-sectional scotopic versus mesopic macular sensitivity losses measured by microperimetry, and to report and compare the longitudinal rates of scotopic and mesopic macular sensitivity losses in ABCA4 gene associated Stargardt Disease (STGD1). DESIGN: Multicenter prospective cohort study. METHODS: Participants: 127 molecular confirmed STGD1 patients enrolled from 6 centers in the USA and Europe and followed every 6 months for up to 2 years. OBSERVATION PROCEDURES: The Nidek MP-1S device was used to measure macular sensitivities of the central 20° under mesopic and scotopic conditions. The mean deviations (MD) from normal for mesopic macular sensitivity for the fovea (within 2° eccentricity) and extrafovea (4°-10° eccentricity), and the MD for scotopic sensitivity for the extrafovea were calculated. Linear mixed effects models were used to estimate mesopic and scotopic changes. MAIN OUTCOME MEASURES: Baseline mesopic mean deviation (mMD) and scotopic MD (sMD) and rates of longitudinal changes in the mMDs and sMD. RESULTS: At baseline, all eyes had larger sMD, and the difference between extrafoveal sMD and mMD was 10.7 dB (p<.001). Longitudinally, all eyes showed a statistically significant worsening trend: the rates of foveal mMD and extrafoveal mMD and sMD changes were 0.72 (95%CI: 0.37 to 1.07), 0.86 (95%CI: 0.58 to 1.14) and 1.12 (95%CI: 0.66 to 1.57) dB/year, respectively. CONCLUSIONS: In STGD1, in extrafovea, loss of scotopic macular function preceded and was faster than the loss of mesopic macular function. Scotopic and mesopic macular sensitivities using microperimetry provide alternative visual function outcomes for STGD1 treatment trials

Development and application of a next-generation-sequencing (NGS) approach to detect known and novel gene defects underlying retinal diseases

<p>Abstract</p> <p>Background</p> <p>Inherited retinal disorders are clinically and genetically heterogeneous with more than 150 gene defects accounting for the diversity of disease phenotypes. So far, mutation detection was mainly performed by APEX technology and direct Sanger sequencing of known genes. However, these methods are time consuming, expensive and unable to provide a result if the patient carries a new gene mutation. In addition, multiplicity of phenotypes associated with the same gene defect may be overlooked.</p> <p>Methods</p> <p>To overcome these challenges, we designed an exon sequencing array to target 254 known and candidate genes using Agilent capture. Subsequently, 20 DNA samples from 17 different families, including four patients with known mutations were sequenced using Illumina Genome Analyzer IIx next-generation-sequencing (NGS) platform. Different filtering approaches were applied to identify the genetic defect. The most likely disease causing variants were analyzed by Sanger sequencing. Co-segregation and sequencing analysis of control samples validated the pathogenicity of the observed variants.</p> <p>Results</p> <p>The phenotype of the patients included retinitis pigmentosa, congenital stationary night blindness, Best disease, early-onset cone dystrophy and Stargardt disease. In three of four control samples with known genotypes NGS detected the expected mutations. Three known and five novel mutations were identified in <it>NR2E3, PRPF3, EYS, PRPF8, CRB1, TRPM1 </it>and <it>CACNA1F</it>. One of the control samples with a known genotype belongs to a family with two clinical phenotypes (Best and CSNB), where a novel mutation was identified for CSNB. In six families the disease associated mutations were not found, indicating that novel gene defects remain to be identified.</p> <p>Conclusions</p> <p>In summary, this unbiased and time-efficient NGS approach allowed mutation detection in 75% of control cases and in 57% of test cases. Furthermore, it has the possibility of associating known gene defects with novel phenotypes and mode of inheritance.</p

RNA-based therapies in inherited retinal diseases

Inherited retinal diseases (IRDs) are a genetically and phenotypically heterogeneous group of genetic eye disorders. There are more than 300 disease entities, and together this group of disorders affects millions of people globally and is a frequent cause of blindness or low-vision certification. However, each type is rare or ultra-rare. Characteristically, the impaired vision in IRDs is due to retinal photoreceptor dysfunction and loss resulting from mutation in a gene that codes for a retinal protein. Historically, IRDs have been considered incurable and individuals living with these blinding conditions could be offered only supportive care. However, the treatment landscape for IRDs is beginning to evolve. Progress is being made, driven by improvements in understanding of genotype-phenotype relationships, through advances in molecular genetic testing and retinal imaging. Alongside this expanding knowledge of IRDs, the current era of precision medicine is fueling a growth in targeted therapies. This has resulted in the first treatment for an IRD being approved. Several other therapies are currently in development in the IRD space, including RNA-based therapies, gene-based therapies (such as augmentation therapy and gene editing), cell therapy, visual prosthetics, and optogenetics. RNA-based therapies are a novel approach within precision medicine that have demonstrated success, particularly in rare diseases. Three antisense oligonucleotides (AONs) are currently in development for the treatment of specific IRD subtypes. These RNA-based therapies bring several key advantages in the setting of IRDs, and the potential to bring meaningful vision benefit to individuals living with inherited blinding disorders. This review will examine the increasing breadth and relevance of RNA-based therapies in clinical medicine, explore the key features that make AONs suitable for treating genetic eye diseases, and provide an overview of the three-leading investigational AONs in clinical trials

WDR34, a candidate gene for non-syndromic rod-cone dystrophy

Rod-cone dystrophy (RCD), also called retinitis pigmentosa, is characterized by rod followed by cone photoreceptor degeneration, leading to gradual visual loss. Mutations in over 65 genes have been associated with non-syndromic RCD explaining 60% to 70% of cases, with novel gene defects possibly accounting for the unsolved cases. Homozygosity mapping and whole-exome sequencing applied to a case of autosomal recessive non-syndromic RCD from a consanguineous union identified a homozygous variant in WDR34. Mutations in WDR34 have been previously associated with severe ciliopathy syndromes possibly associated with a retinal dystrophy. This is the first report of a homozygous mutation in WDR34 associated with non-syndromic RCD

The RUSH2A Study: Best-Corrected Visual Acuity, Full-Field Electroretinography Amplitudes, and Full-Field Stimulus Thresholds at Baseline

Purpose: The purpose of this study was to evaluate baseline best corrected visual acuity (BCVA), full-field electroretinography (ERG), full-field stimulus thresholds (FST), and their relationship with baseline demographic and clinical characteristics in the Rate of Progression in Usher syndrome type 2 (USH2A)-related Retinal Degeneration (RUSH2A) multicenter study. Methods: Participants had Usher syndrome type 2 (USH2, N = 80) or autosomal recessive nonsyndromic retinitis pigmentosa (ARRP, N = 47) associated with biallelic variants in the USH2A gene. Associations of demographic and clinical characteristics with BCVA, ERG, and FST were assessed with regression models. Results: In comparison to ARRP, USH2 had worse BCVA (median 79 vs. 82 letters; P < 0.001 adjusted for age), lower rod-mediated ERG b-wave amplitudes (median 0.0 vs. 6.6 µV; P < 0.001) and 30 Hz flicker cone-mediated ERG amplitudes (median 1.5 vs. 3.1 µV; P = 0.001), and higher (white, blue, and red) FST thresholds (means [-26, -31, -23 dB] vs. [-39, -45, -28 dB]; P < 0.001 for all stimuli). After adjusting for age, gender, and duration of vision loss, the difference in BCVA between diagnosis groups was attenuated (P = 0.09). Only diagnosis was associated with rod- and cone-mediated ERG parameters, whereas both genders (P = 0.04) and duration of visual loss (P < 0.001) also were associated with FST white stimulus. Conclusions: USH2 participants had worse BCVA, ERG, and FST than ARRP participants. FST was strongly associated with duration of disease; it remains to be determined whether it will be a sensitive measure of progression. Translational Relevance: Using standardized research protocols in RUSH2A, measures have been identified to monitor disease progression and treatment response and differentiate features of prognostic relevance between USH2 and ARRP participants with USH2A mutations

Relative frequencies of inherited retinal dystrophies and optic neuropathies in Southern France: assessment of 21-year data management

PURPOSE: Inherited retinal dystrophies (IRDs) and inherited optic neuropathies (IONs) are rare diseases defined by specific clinical and molecular features. The relative prevalence of these conditions was determined in Southern France. METHODS: Patients recruited from a specialized outpatient clinic over a 21-year period underwent extensive clinical investigations and 107 genes were screened by polymerase chain reaction/sequencing. RESULTS: There were 1957 IRD cases (1481 families) distributed in 70% of pigmentary retinopathy cases (56% non-syndromic, 14% syndromic), 20% maculopathies and 7% stationary conditions. Patients with retinitis pigmentosa were the most frequent (47%) followed by Usher syndrome (10.8%). Among non-syndromic pigmentary retinopathy patients, 84% had rod-cone dystrophy, 8% cone-rod dystrophy and 5% Leber congenital amaurosis. Macular dystrophies were encountered in 398 cases (30% had Stargardt disease and 11% had Best disease). There were 184 ION cases (127 families) distributed in 51% with dominant optic neuropathies, 33% with recessive/sporadic forms and 16% with Leber hereditary optic neuropathy. Positive molecular results were obtained in 417/609 families with IRDs (68.5%) and in 27/58 with IONs (46.5%). The sequencing of 5 genes (ABCA4, USH2A, MYO7A, RPGR and PRPH2) provided a positive molecular result in 48% of 417 families with IRDs. Except for autosomal retinitis pigmentosa, in which less than half the families had positive molecular results, about 75% of families with other forms of retinal conditions had a positive molecular diagnosis. CONCLUSIONS: Although gene discovery considerably improved molecular diagnosis in many subgroups of IRDs and IONs, retinitis pigmentosa, accounting for almost half of IRDs, remains only partly molecularly defined