Glycogen myophosphorylase loss causes increased dependence on glucose in iPSC-derived retinal pigment epithelium.

Loss of glycogen myophosphorylase (PYGM) expression results in an inability to break down muscle glycogen, leading to McArdle disease-an autosomal recessive metabolic disorder characterized by exercise intolerance and muscle cramps. While previously considered relatively benign, this condition has recently been associated with pattern dystrophy in the retina, accompanied by variable sight impairment, secondary to retinal pigment epithelial (RPE) cell involvement. However, the pathomechanism of this condition remains unclear. In this study, we generated a PYGM-null induced pluripotent stem cell (iPSC) line, and differentiated it into mature RPE to examine structural and functional defects, along with metabolite release into apical and basal media. Mutant RPE exhibited normal photoreceptor outer segment phagocytosis but displayed elevated glycogen levels, reduced transepithelial resistance, and increased cytokine secretion across the epithelial layer compared to isogenic wildtype controls. Additionally, decreased expression of the visual cycle component, RDH11, encoding 11-cis-retinol dehydrogenase, was observed in PYGM-null RPE. While glycolytic flux and oxidative phosphorylation levels in PYGM-null RPE were near normal, the basal oxygen consumption rate (OCR) was increased. OCR in response to physiological levels of lactate was significantly greater in wildtype compared to PYGM-null RPE. Inefficient lactate utilization by mutant RPE resulted in higher glucose dependence and increased glucose uptake from the apical medium in the presence of lactate, suggesting a reduced capacity to spare glucose for photoreceptor use. Metabolic tracing confirmed slower 13C-lactate utilization by PYGM-null RPE. These findings have key implications for retinal health since they likely underlie the vision impairment in individuals with McArdle disease.

Retinal cells derived from patients with DRAM2-dependent CORD21 dystrophy exhibit key lysosomal enzyme deficiency and lysosomal content accumulation.

Biallelic mutations in DRAM2 lead to an autosomal recessive cone-rod dystrophy known as CORD21, which typically presents between the third and sixth decades of life. Although DRAM2 localizes to the lysosomes of photoreceptor and retinal pigment epithelium (RPE) cells, its specific role in retinal degeneration has not been fully elucidated. In this study, we generated and characterized retinal organoids (ROs) and RPE cells from induced pluripotent stem cells (iPSCs) derived from two CORD21 patients. Our investigation revealed that CORD21-ROs and RPE cells exhibit abnormalities in lipid metabolism, defects in autophagic flux, accumulation of aberrant lysosomal content, and reduced lysosomal enzyme activity. We identified potential interactions of DRAM2 with vesicular trafficking proteins, suggesting its involvement in this cellular process. These findings collectively suggest that DRAM2 plays a crucial role in maintaining the integrity of photoreceptors and RPE cells by regulating lysosomal function, autophagy, and potentially vesicular trafficking.

Impact of treat and extend criteria on proportions that can be extended after loading phase of 2 mg aflibercept therapy for neovascular age related macular degeneration: PRECISE Report 5.

OBJECTIVE: To study the impact of definitions of various treatment extension criteria on the proportion of patients who could be extended at their first visit after the loading phase of 2 mg aflibercept therapy for neovascular age related macular degeneration (nAMD). METHODS: Patients with nAMD initiated on the loading phase of three intravitreal doses of 2 mg aflibercept in routine clinical practice were recruited from December 2019 to August 2021. The response to the loading phase was assessed at approximately 8 weeks post-loading (up to 140 days from first injection) based on different definitions of response. The proportion of patients that qualify for interval extension based on different clinical trial criteria was also evaluated. RESULTS: A total of 722 patients with visual acuity (VA) and optical coherence tomography (OCT) scans done at all 4 visits were included. Of these 32.4% of eyes responded with complete macular fluid resolution after the first injection with no recurrence through the loading phase (super-responders) while 26.9% had persistent macular fluid in all 4 visits (true non-responders). The rest were considered suboptimal responders. Change in VA showed marked variations within each of these categories of fluid resolution. For extension of next treatment interval, if presence of any macular fluid at the post-loading visit is the only criteria considered, about 50% could be extended to 8 weeks. If both VA worsening by ≥5 letters and a > 25 µm increase in central sub-field thickness (CST) are considered, 90% will be eligible for interval extension. CONCLUSION: Clinical trial designs and pre-defined treatment extension/shortening criteria determine the proportion of patients requiring treatment in the post-loading visit. The short and long-term impact of interval extension immediate post-loading on visual outcome in clinical practice is unknown.

PRPF8-mediated dysregulation of hBrr2 helicase disrupts human spliceosome kinetics and 5´-splice-site selection causing tissue-specific defects.

The carboxy-terminus of the spliceosomal protein PRPF8, which regulates the RNA helicase Brr2, is a hotspot for mutations causing retinitis pigmentosa-type 13, with unclear role in human splicing and tissue-specificity mechanism. We used patient induced pluripotent stem cells-derived cells, carrying the heterozygous PRPF8 c.6926 A > C (p.H2309P) mutation to demonstrate retinal-specific endophenotypes comprising photoreceptor loss, apical-basal polarity and ciliary defects. Comprehensive molecular, transcriptomic, and proteomic analyses revealed a role of the PRPF8/Brr2 regulation in 5'-splice site (5'SS) selection by spliceosomes, for which disruption impaired alternative splicing and weak/suboptimal 5'SS selection, and enhanced cryptic splicing, predominantly in ciliary and retinal-specific transcripts. Altered splicing efficiency, nuclear speckles organisation, and PRPF8 interaction with U6 snRNA, caused accumulation of active spliceosomes and poly(A)+ mRNAs in unique splicing clusters located at the nuclear periphery of photoreceptors. Collectively these elucidate the role of PRPF8/Brr2 regulatory mechanisms in splicing and the molecular basis of retinal disease, informing therapeutic approaches.

Subretinal transient hyporeflectivity in neovascular age-related macular degeneration and its response to a loading phase of aflibercept: PRECISE report 4.

PURPOSE: To describe the prevalence of subretinal transient hyporeflectivity (STHR) in exudative neovascular age-related macular degeneration (nAMD) and its response to a loading phase of aflibercept. METHODS: Optical coherence tomography (OCT) scans of treatment-naïve nAMD patients captured at baseline and after a loading phase of aflibercept were graded for presence of STHR, defined as a small, well-defined, round, subretinal, hyporeflective area, delimited between the ellipsoid zone (EZ) and the retinal pigmented epithelium/Bruch membrane complex. OCT parameters recorded were macular neovascularisation (MNV) subtypes, location of retinal fluids (subretinal fluid, SRF and intraretinal fluid, IRF), central retinal and choroidal thickness. Response was defined as absence of IRF and SRF. Factors associated with completely resolved STHR versus persistent STHR post-loading phase were compared. RESULTS: 2039 eyes of 1901 patients were analysed. STHR was observed in 79 eyes of 78 patients, with an estimated prevalence of 3.87% (95% CI 3.08-4.81%). STHR were seen in 44 type 1 MNV (56%), 27 with type 2 (34%), and 8 with type 3 (10%). At baseline, a total of 303 STHR were present, ranging between 1-22 per eye. The total number of STHR reduced significantly after the loading phase to 173 (p = 0.002). Complete disappearance of STHR was seen in 44 eyes (56%) and persistent STHR in the rest (44%). CONCLUSIONS: STHR may represent a marker of low-grade exudation in nAMD eyes with good response to a loading phase of aflibercept. However, its potential role as an independent nAMD activity biomarker is limited as most resolve after the loading phase.

Improved Structure and Function in Early-Detected Second-Eye Neovascular Age-Related Macular Degeneration: FASBAT/Early Detection of Neovascular Age-Related Macular Degeneration Report 1.

PURPOSE: Visual acuity (VA) and structural biomarker assessment before and 24-months after early detection and routine treatment of second-eye involvement with neovascular age-related macular degeneration (nAMD) and additional comparison with the first eye affected. DESIGN: Prospective, 22-center observational study of participants with unilateral nAMD in the Early Detection of Neovascular AMD (EDNA) study, coenrolled into the Observing Fibrosis, Macular Atrophy and Subretinal Highly Reflective Material, Before and After Intervention with anti-VEGF Treatment (FASBAT) study for an additional 2-year follow-up. PARTICIPANTS: Older adults (> 50 years) with new onset nAMD in the first eye. METHODS: Assessment of both eyes with OCT, color fundus photography (CFP), clinic-measured VA, and quality of life (QoL). MAIN OUTCOME MEASURES: Prevalence of atrophy, subretinal hyperreflective material (SHRM), intraretinal fluid (IRF), subretinal fluid (SRF), and changes in VA over the study duration in both the first and second eyes affected with nAMD. Composite QoL scores over time. RESULTS: Of 431 participants recruited to the FASBAT study, the second eye converted to nAMD in 100 participants at a mean of 18.9 months. Visual acuity was 18 letters better at the time of early diagnosis in the second eye compared with conventional diagnosis in the first eye (72.9 vs. 55.6 letters). Visual acuity remained better in the second eye 24.9 months postconversion, at 69.5 letters compared with 59.7 letters at a similar matched time point in the first eye (18.9 months). A greater proportion of participants had vision > 70 letters in the second eye versus the first eye, 24.9 months postconversion (61 vs. 35). Prevalence of SHRM and IRF was lower in the second eye compared with the first eye 24.9 months postconversion. However, SRF prevalence was greater in the second eye 24.9 months postconversion. The development and progression of total area of atrophy appears similar in both eyes. Mean composite QoL scores increased over time, with a significant correlation between VA for the second eye only 24.9 months postconversion. CONCLUSION: This study has shown that early detection of exudative AMD in the second eye is associated with reduced prevalence of SHRM and IRF and greater VA, which is significantly correlated with maintained QoL. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Associations of presenting visual acuity with morphological changes on OCT in neovascular age-related macular degeneration: PRECISE Study Report 2.

PURPOSE: To study associations of optical coherence tomography (OCT) features with presenting visual acuity (VA) in treatment naive neovascular age-related macular degeneration (nAMD). METHODS: Patients with nAMD initiated on aflibercept therapy were recruited from December 2019 to August 2021. Demographic and OCT (Spectralis, Heidelberg Engineering) features associated with good VA (VA ≥ 68 ETDRS letters, Snellen ≥ 6/12) and poor VA (VA < 54 letters, Snellen < 6/18) were analysed using Generalised Estimating Equations to account for inter-eye correlation. RESULTS: Of 2274 eyes of 2128 patients enrolled, 2039 eyes of 1901 patients with complete data were analysed. Mean age was 79.4 (SD 7.8) years, female:male 3:2 and mean VA 58.0 (SD 14.5) letters. On multivariable analysis VA < 54 letters was associated with increased central subfield thickness (CST) (OR 1.40 per 100 µm; P < 0.001), foveal intraretinal fluid (OR 2.14; P < 0.001), polypoidal vasculopathy (PCV) relative to Type 1 macular neovascularisation (MNV) (OR 1.66; P = 0.049), presence of foveal subretinal hyperreflective material (SHRM) (OR 1.73; P = 0.002), foveal fibrosis (OR 3.85; P < 0.001), foveal atrophy (OR 5.54; P < 0.001), loss of integrity of the foveal ellipsoid zone (EZ) or external limiting membrane (ELM) relative to their preservation (OR 3.83; P < 0.001) and absence of subretinal drusenoid deposits (SDD) (presence vs absence; OR 0.75; P = 0.04). These features were associated with reduced odds of VA ≥ 68 letters except MNV subtypes and SDD. CONCLUSION: Presence of baseline fovea-involving atrophy, fibrosis, intraretinal fluid, SHRM, PCV EZ/ELM loss and increased CST determine poor presenting VA. This highlights the need for early detection and treatment prior to structural changes that worsen baseline VA.

Baseline characteristics of eyes with early residual fluid post loading phase of aflibercept therapy in neovascular AMD: PRECISE study report 3.

PURPOSE: To compare the baseline characteristics in patients with and without early residual fluid (ERF) after aflibercept loading phase (LP) in patients with treatment naïve neovascular age related macular degeneration (nAMD). METHODS: Patients with nAMD initiated on LP of three intravitreal aflibercept doses were recruited from December 2019 to August 2021. Baseline demographic and OCT features associated with any ERF were analysed using Generalised Estimating Equations to account for inter-eye correlation. Receiver operating characteristic (ROC) curve was performed for selection of CST threshold. RESULTS: Of 2128 patients enrolled, 1999 eyes of 1862 patients with complete data were included. After LP, ERF was present in 1000 (50.0%), eSRF in 746(37.3%) and eIRF in 428 (21.4%) eyes. In multivariable analysis of baseline features, eyes with increased central subfield thickness (CST) (OR 1.31 per 100 microns increase [95% CI 1.22 to 1.41]; P < 0.001), eyes with IRF and SRF at baseline (1.62 [95% CI 1.17 to 2.22]; P = 0.003), and those with SRF only (OR 2.26 [95% CI 1.59 to 3.20]; P < 0.001) relative to IRF only were determinants of ERF. CST ≥ 418 microns had 57% sensitivity and 58% specificity to distinguish ERF from no ERF at visit 4. CONCLUSION: On average, 50% of eyes have ERF after aflibercept LP. Clinically relevant baseline determinants of ERF include CST ≥ 418 µ and presence of only SRF. These eyes may require further monthly treatment before extending treatment intervals.

Long-Read Nanopore Sequencing of RPGR ORF15 is Enhanced Following DNase I Treatment of MinION Flow Cells.

INTRODUCTION: RPGR ORF15 is an exon present almost exclusively in the retinal transcript of RPGR. It is purine-rich, repetitive and notoriously hard to sequence, but is a hotspot for mutations causing X-linked retinitis pigmentosa. METHODS: Long-read nanopore sequencing on MinION and Flongle flow cells was used to sequence RPGR ORF15 in genomic DNA from patients with inherited retinal dystrophy. A flow cell wash kit was used on a MinION flow cell to increase yield. Findings were confirmed by PacBio SMRT long-read sequencing. RESULTS: We showed that long-read nanopore sequencing successfully reads through a 2 kb PCR-amplified fragment containing ORF15. We generated reads of sufficient quality and cumulative read-depth to detect pathogenic RP-causing variants. However, we observed that this G-rich, repetitive DNA segment rapidly blocks the available pores, resulting in sequence yields less than 5% of the expected output. This limited the extent to which samples could be pooled, increasing cost. We tested the utility of a MinION wash kit containing DNase I to digest DNA fragments remaining on the flow cell, regenerating the pores. Use of the DNase I treatment allowed repeated re-loading, increasing the sequence reads obtained. Our customised workflow was used to screen pooled amplification products from previously unsolved inherited retinal disease (IRD) in patients, identifying two new cases with pathogenic ORF15 variants. DISCUSSION: We report the novel finding that long-read nanopore sequencing can read through RPGR-ORF15, a DNA sequence not captured by short-read next-generation sequencing (NGS), but with a more reduced yield. Use of a flow cell wash kit containing DNase I unblocks the pores, allowing reloading of further library aliquots over a 72-h period, increasing yield. The workflow we describe provides a novel solution to the need for a rapid, robust, scalable, cost-effective ORF15 screening protocol.

A Multi-Modal AI-Driven Cohort Selection Tool to Predict Suboptimal Non-Responders to Aflibercept Loading-Phase for Neovascular Age-Related Macular Degeneration: PRECISE Study Report 1.

Patients diagnosed with exudative neovascular age-related macular degeneration are commonly treated with anti-vascular endothelial growth factor (anti-VEGF) agents. However, response to treatment is heterogeneous, without a clinical explanation. Predicting suboptimal response at baseline will enable more efficient clinical trial designs for novel, future interventions and facilitate individualised therapies. In this multicentre study, we trained a multi-modal artificial intelligence (AI) system to identify suboptimal responders to the loading-phase of the anti-VEGF agent aflibercept from baseline characteristics. We collected clinical features and optical coherence tomography scans from 1720 eyes of 1612 patients between 2019 and 2021. We evaluated our AI system as a patient selection method by emulating hypothetical clinical trials of different sizes based on our test set. Our method detected up to 57.6% more suboptimal responders than random selection, and up to 24.2% more than any alternative selection criteria tested. Applying this method to the entry process of candidates into randomised controlled trials may contribute to the success of such trials and further inform personalised care.

Haplotyping Using Long-Range PCR and Nanopore Sequencing to Phase Variants: Lessons Learned From the ABCA4 Locus.

Short-read next-generation sequencing has revolutionized our ability to identify variants underlying inherited diseases; however, it does not allow the phasing of variants to clarify their diagnostic interpretation. The advent of widespread, increasingly accurate long-read sequencing has opened up new applications not currently available through short-read next-generation sequencing. One such use is the ability to phase variants to clarify their diagnostic interpretation and to investigate the increasingly prevalent role of cis-acting variants in the pathogenesis of the inherited disease, so-called complex alleles. Complex alleles are becoming an increasingly prevalent part of the study of genes associated with inherited diseases, for example, in ABCA4-related diseases. We sought to establish a cost-effective method to phase contiguous segments of the 130-kb ABCA4 locus by long-read sequencing of overlapping amplification products. Using the comprehensively characterized CEPH sample, NA12878, we verified the accuracy and robustness of our assay. However, in-field assessment of its utility using clinical test cases was hampered by the paucity and distribution of identified variants and by PCR chimerism, particularly where the number of PCR cycles was high. Despite this, we were able to construct robust phase blocks of up to 94.9 kb, representing 73% of the ABCA4 locus. We conclude that, although haplotype analysis of variants located within discrete amplification products was robust and informative, the stitching together of larger phase blocks using overlapping single-molecule reads remained practically challenging.

Targeted nanopore sequencing enables complete characterisation of structural deletions initially identified using exon-based short-read sequencing strategies.

BACKGROUND: The widespread adoption of exome sequencing has greatly increased the rate of genetic diagnosis for inherited conditions. However, the detection and validation of large deletions remains challenging. While numerous bioinformatics approaches have been developed to detect deletions from whole - exome sequencing and targeted panels, further work is typically required to define the physical breakpoints or integration sites. Accurate characterisation requires either expensive follow - up whole - genome sequencing or the time - consuming, laborious process of PCR walking, both of which are challenging when dealing with the repeat sequences which frequently intersect deletion breakpoints. The aim of this study was to develop a cost-effective, long-range sequencing method to characterise deletions. METHODS: Genomic DNA was amplified with primers spanning the deletion using long-range PCR and the products purified. Sequencing was performed on MinION flongle flowcells. The resulting fast5 files were basecalled using Guppy, trimmed using Porechop and aligned using Minimap2. Filtering was performed using NanoFilt. Nanopore sequencing results were verified by Sanger sequencing. RESULTS: Four cases with deletions detected following comparative read-depth analysis of targeted short-read sequencing were analysed. Nanopore sequencing defined breakpoints at the molecular level in all cases including homozygous breakpoints in EYS, CNGA1 and CNGB1 and a heterozygous deletion in PRPF31. All breakpoints were verified by Sanger sequencing. CONCLUSIONS: In this study, a quick, accurate and cost - effective method is described to characterise deletions identified from exome, and similar data, using nanopore sequencing.

Associations with Non-Persistence with Intra-Vitreal Therapy for Neovascular Age-Related Macular Degeneration at 24 Months.

AIMS: The aim of the study was to investigate non-persistence with treatment for neovascular age-related macular degeneration (NvAMD) before day 720 (24 months) after initiation, explore associations with baseline characteristics and variation between sites. METHODS: Anonymised demographic and clinical data were extracted from electronic medical records at treating National Health Service (NHS) Trusts for NvAMD eyes starting intra-vitreal therapy from 2017 to 2018. Time to non-persistence with treatment, defined as no recorded attendance for either monitoring or treatment for a period ≥6 months, was visualised with a Kaplan-Meier survival plot. Associations with treatment non-persistence were investigated using a Cox proportional hazards model. RESULTS: Analysis included 7,970 eyes of 7,112 patients treated at 13 NHS trusts. Censoring deaths and those eyes in which treatment was stopped permanently, the Kaplan-Meier analyses demonstrated survival figures of 77.7% for persistence with treatment to day 360 and 71.8% to day 720. Hazard ratios for non-persistence with treatment were reduced at 10 sites, relative to the reference, with first-treated eye status and with baseline acuity worse than or equal to LogMAR 1.0. Hazard ratios increased with younger age, in the presence of other ocular co-morbidities and with baseline acuity better than or equal to LogMAR 0.5. After an episode of non-persistence, visual acuity decreased by at least 0.1 and 0.3 LogMAR in 39% and 18% of eyes, respectively. CONCLUSIONS: Non-persistence with treatment was common, especially in the first year of treatment, and was often associated with a decrease in visual acuity. Treatment site, baseline visual acuity, and age were the strongest predictors of treatment non-persistence before day 720. Understanding and addressing reasons for non-persistence are important to ensure that effective but expensive treatments are used cost-effectively and to maintain acuity. Variation in non-persistence between sites, even after adjustment for other variables, suggests that local factors in treatment provision may be particularly important.

UNITED KINGDOM DATABASE STUDY OF INTRAVITREAL DEXAMETHASONE IMPLANT (OZURDEX) FOR MACULAR EDEMA RELATED TO RETINAL VEIN OCCLUSION.

PURPOSE: To study the treatment patterns, visual outcomes and safety profile of intravitreal dexamethasone implant (IDI) used for the treatment of macular edema secondary to retinal vein occlusion. METHODS: Up to 2 years of routinely collected anonymized data within electronic medical record systems were remotely extracted from 16 centers. The outcome measures include visual outcome, number of injections, and safety measures, including the rate of intraocular pressure (IOP) rise, frequency of IOP-lowering medication usage, and cataract surgery rates. RESULTS: The study included 688 eyes (44.4%) with central retinal vein occlusion and 862 eyes (55.6%) with branch retinal vein occlusion; 1,250 eyes (80.6%) were treatment naive and 28% (275/989) had high IOP or were on IOP-lowering medications before IDI use. It was found that 31% (476) of eyes received two injections, and 11.7% (182) and 3.7% (58) of eyes received three and four injections, respectively. The mean baseline Snellen visual acuity improved from 20/125 to 20/40 after the first injection. The probability of cataract surgery was 15% at 24 months. The proportion of eyes with ≥10 mmHg change from baseline was higher in phakic (14.2%) compared with pseudophakic eyes (5.4%, P = 0.004). Three eyes required IOP filtering surgery (0.2%). CONCLUSION: The visual results of IDI in eyes with macular edema secondary to retinal vein occlusion in the real world are comparable to those of clinical trial setting. Increased IOP in eyes with preexisting ocular hypertension or glaucoma can be controlled with additional medical treatment. Intraocular pressure rise with IDI may be more frequent in phakic than in pseudophakic eyes.

Cost-effective sequence analysis of 113 genes in 1,192 probands with retinitis pigmentosa and Leber congenital amaurosis.

Introduction: Retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA) are two groups of inherited retinal diseases (IRDs) where the rod photoreceptors degenerate followed by the cone photoreceptors of the retina. A genetic diagnosis for IRDs is challenging since >280 genes are associated with these conditions. While whole exome sequencing (WES) is commonly used by diagnostic facilities, the costs and required infrastructure prevent its global applicability. Previous studies have shown the cost-effectiveness of sequence analysis using single molecule Molecular Inversion Probes (smMIPs) in a cohort of patients diagnosed with Stargardt disease and other maculopathies. Methods: Here, we introduce a smMIPs panel that targets the exons and splice sites of all currently known genes associated with RP and LCA, the entire RPE65 gene, known causative deep-intronic variants leading to pseudo-exons, and part of the RP17 region associated with autosomal dominant RP, by using a total of 16,812 smMIPs. The RP-LCA smMIPs panel was used to screen 1,192 probands from an international cohort of predominantly RP and LCA cases. Results and discussion: After genetic analysis, a diagnostic yield of 56% was obtained which is on par with results from WES analysis. The effectiveness and the reduced costs compared to WES renders the RP-LCA smMIPs panel a competitive approach to provide IRD patients with a genetic diagnosis, especially in countries with restricted access to genetic testing.

Effective smMIPs-Based Sequencing of Maculopathy-Associated Genes in Stargardt Disease Cases and Allied Maculopathies from the UK.

Macular dystrophies are a group of individually rare but collectively common inherited retinal dystrophies characterised by central vision loss and loss of visual acuity. Single molecule Molecular Inversion Probes (smMIPs) have proved effective in identifying genetic variants causing macular dystrophy. Here, a previously established smMIPs panel tailored for genes associated with macular diseases has been used to examine 57 UK macular dystrophy cases, achieving a high solve rate of 63.2% (36/57). Among 27 bi-allelic STGD1 cases, only three novel ABCA4 variants were identified, illustrating that the majority of ABCA4 variants in Caucasian STGD1 cases are currently known. We examined cases with ABCA4-associated disease in detail, comparing our results with a previously reported variant grading system, and found this model to be accurate and clinically useful. In this study, we showed that ABCA4-associated disease could be distinguished from other forms of macular dystrophy based on clinical evaluation in the majority of cases (34/36).

Outcome of Cataract Surgery in Patients With Retinitis Pigmentosa.

PURPOSE: To assess the visual outcome of cataract surgery in patients with retinitis pigmentosa (RP). DESIGN: Retrospective, noncomparative clinical study. METHODS: Preoperative, intraoperative, and postoperative data of patients with RP who were undergoing cataract surgery were collected from several expertise centers across Europe. RESULTS: In total, 295 eyes of 226 patients were included in the study. The mean age at surgery of the first eye was 56.1 ± 17.9 years. Following surgery, best-corrected visual acuity (BCVA) improved significantly from 1.03 to 0.81 logMAR (ie, 20/214 to 20/129 Snellen) in the first treated eye (-0.22 logMAR; 95% CI = -0.31 to -0.13; P < .001) and from 0.80 to 0.56 logMAR (ie, 20/126 to 20/73 Snellen) in the second treated eye (-0.24 logMAR; 95% CI = -0.32 to -0.15; P < .001). Marked BCVA improvements (postoperative change in BCVA of ≥0.3 logMAR) were observed in 87 of 226 patients (39%). Greater odds for marked visual improvements were observed in patients with moderate visual impairment or worse. The most common complications were zonular dialysis (n = 15; 5%) and (exacerbation of) cystoid macular edema (n = 14; 5%), respectively. Postoperative posterior capsular opacifications were present in 111 of 295 eyes (38%). CONCLUSION: Significant improvements in BCVA are observed in most patients with RP following cataract surgery. Baseline BCVA is a predictor of visual outcome. Preoperative evaluation should include the assessment of potential zonular insufficiency and the presence of CME, as they are relatively common and may increase the risk of complications.

Late-Onset Autosomal Dominant Macular Degeneration Caused by Deletion of the CRX Gene.

PURPOSE: To characterize the phenotype observed in a case series with macular disease and determine the cause. DESIGN: Multicenter case series. PARTICIPANTS: Six families (7 patients) with sporadic or multiplex macular disease with onset at 20 to 78 years, and 1 patient with age-related macular degeneration. METHODS: Patients underwent ophthalmic examination; exome, genome, or targeted sequencing; and/or polymerase chain reaction (PCR) amplification of the breakpoint, followed by cloning and Sanger sequencing or direct Sanger sequencing. MAIN OUTCOME MEASURES: Clinical phenotypes, genomic findings, and a hypothesis explaining the mechanism underlying disease in these patients. RESULTS: All 8 cases carried the same deletion encompassing the genes TPRX1, CRX, and SULT2A1, which was absent from 382 control individuals screened by breakpoint PCR and 13 096 Clinical Genetics patients with a range of other inherited conditions screened by array comparative genomic hybridization. Microsatellite genotypes showed that these 7 families are not closely related, but genotypes immediately adjacent to the deletion breakpoints suggest they may share a distant common ancestor. CONCLUSIONS: Previous studies had found that carriers for a single defective CRX allele that was predicted to produce no functional CRX protein had a normal ocular phenotype. Here, we show that CRX whole-gene deletion in fact does cause a dominant late-onset macular disease.

Associations with visual acuity outcomes after 12 months of treatment in 9401 eyes with neovascular AMD.

OBJECTIVE: To record visual acuity outcomes after 12 months of treatment for neovascular age-related macular degeneration (NvAMD), investigate variation between sites and explore associations with baseline characteristics and care processes. METHODS AND ANALYSIS: Anonymised demographic and clinical data were extracted from electronic medical records at treating National Health Service (NHS) Trusts. Associations with acuity outcomes were investigated using multivariate linear and logistic regression. RESULTS: Analysis included 9401 eyes (7686 patients) treated at 13 NHS Trusts. From baseline to month 12, median acuity improved from LogMAR 0.50 (IQR 0.30-0.80) to 0.40 (0.22-0.74) and the proportion of eyes with LogMAR ≥0.3 increased from 34.5% to 39.8%. Baseline visual acuity was the strongest predictor of visual acuity outcomes. For each LogMAR 0.1 worsening of baseline acuity, the acuity at 12 months was improved by LogMAR 0.074 (95% CI 0.073 to 0.074) and the odds of a 'poor' acuity outcome was multiplied by 1.66 (95% CI 1.61 to 1.70). Younger age, independent living status, lower socioeconomic deprivation, timely loading phase completion and higher number of injections were associated with better acuity outcomes. Despite case-mix adjustments, there was evidence of significant variation in acuity outcomes between sites. CONCLUSIONS: Even after adjustment for other variables, variation in acuity outcomes after NvAMD treatment within the NHS remains. Meaningful comparison of outcomes between different providers requires adjustment for a range of baseline characteristics, not visual acuity alone. Identifying best practice at sites with better outcomes and adapting local care processes are required to tackle this health inequality.

Novel SIX6 mutations cause recessively inherited congenital cataract, microcornea, and corneal opacification with or without coloboma and microphthalmia.

Purpose: To investigate the molecular basis of recessively inherited congenital cataract, microcornea, and corneal opacification with or without coloboma and microphthalmia in two consanguineous families. Methods: Conventional autozygosity mapping was performed using single nucleotide polymorphism (SNP) microarrays. Whole-exome sequencing was completed on genomic DNA from one affected member of each family. Exome sequence data were also used for homozygosity mapping and copy number variation analysis. PCR and Sanger sequencing were used to confirm the identification of mutations and to screen further patients. Evolutionary conservation of protein sequences was assessed using CLUSTALW, and protein structures were modeled using PyMol. Results: In family MEP68, a novel homozygous nucleotide substitution in SIX6 was found, c.547G>C, that converts the evolutionarily conserved aspartic acid residue at the 183rd amino acid in the protein to a histidine, p.(Asp183His). This residue mapped to the third helix of the DNA-binding homeobox domain in SIX6, which interacts with the major groove of double-stranded DNA. This interaction is likely to be disrupted by the mutation. In family F1332, a novel homozygous 1034 bp deletion that encompasses the first exon of SIX6 was identified, chr14:g.60975890_60976923del. Both mutations segregated with the disease phenotype as expected for a recessive condition and were absent from publicly available variant databases. Conclusions: Our findings expand the mutation spectrum in this form of inherited eye disease and confirm that homozygous human SIX6 mutations cause a developmental spectrum of ocular phenotypes that includes not only the previously described features of microphthalmia, coloboma, and congenital cataract but also corneal abnormalities.