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Objective: To describe the spectrum of Leber congenital amaurosis (LCA) and cone-rod dystrophy (CORD) associated with the GUCY2D gene and to identify potential end points and optimal patient selection for future therapeutic trials.Design: International, multicenter, retrospective cohort study.Subjects: Eighty-two patients with GUCY2D-associated LCA or CORD from 54 families.Methods: Medical records were reviewed for medical history, best-corrected visual acuity (BCVA), ophthalmoscopy, visual fields, full-field electroretinography, and retinal imaging (fundus photography, spectral -domain OCT [SD-OCT], fundus autofluorescence).Main Outcomes Measures: Age of onset, evolution of BCVA, genotype-phenotype correlations, anatomic characteristics on funduscopy, and multimodal imaging.Results: Fourteen patients with autosomal recessive LCA and 68 with autosomal dominant CORD were included. The median follow-up times were 5.2 years (interquartile range [IQR] 2.6-8.8 years) for LCA and 7.2 years (IQR 2.2-14.2 years) for CORD. Generally, LCA presented in the first year of life. The BCVA in patients with LCA ranged from no light perception to 1.00 logarithm of the minimum angle of resolution (logMAR) and remained relatively stable during follow-up. Imaging for LCA was limited but showed little to no structural degeneration. In patients with CORD, progressive vision loss started around the second decade of life. The BCVA declined annually by 0.022 logMAR (P < 0.001) with no difference between patients with the c.2513G>A and the c.2512C>T GUCY2D variants (P = 0.798). At the age of 40 years, the probability of being blind or severely visually impaired was 32%. The integrity of the ellipsoid zone (EZ) and that of the external limiting membrane (ELM) on SD-OCT correlated signifi-cantly with BCVA (Spearman r = 0.744, P = 0.001, and r = 0.712, P < 0.001, respectively) in those with CORD.Conclusions: Leber congenital amaurosis associated with GUCY2D caused severe congenital visual impairment with relatively intact macular anatomy on funduscopy and available imaging, suggesting long pres-ervation of photoreceptors. Despite large variability, GUCY2D-associated CORD generally presented during adolescence, with a progressive loss of vision, and culminated in severe visual impairment during mid-to-late adulthood. The integrity of the ELM and EZ may be suitable structural end points for therapeutic studies of GUCY2D-associated CORD. Ophthalmology Retina 2022;6:711-722 (c) 2022 by the American Academy of Ophthalmology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

PURPOSE: To investigate the natural disease course of retinal dystrophies associated with crumbs cell polarity complex component 1 (CRB1) and identify clinical end points for future clinical trials. DESIGN: Single-center, prospective case series. METHODS: An investigator-initiated nationwide collaborative study that included 22 patients with CRB1-associated retinal dystrophies. Patients underwent ophthalmic assessment at baseline and 2 years after baseline. Clinical examination included best-corrected visual acuity (BCVA) using Early Treatment Diabetic Retinopathy Study charts, Goldmann kinetic perimetry (V4e isopter seeing retinal areas), microperimetry, full-field electroretinography, full-field stimulus threshold (FST), fundus photography, spectral-domain optical coherence tomography, and fundus autofluorescence imaging. RESULTS: Based on genetic, clinical, and electrophysiological data, patients were diagnosed with retinitis pigmentosa (19 [86%]), cone-rod dystrophy (2 [9%]), or isolated macular dystrophy (1 [5%]). Analysis of the entire cohort at 2 years showed no significant changes in BCVA (P = .069) or V4e isopter seeing retinal areas (P = .616), although signs of clinical progression were present in individual patients. Macular sensitivity measured on microperimetry revealed a significant reduction at the 2-year follow-up (P < .001). FST responses were measurable in patients with nonrecordable electroretinograms. On average, FST responses remained stable during follow-up. CONCLUSION: In CRB1-associated retinal dystrophies, visual acuity and visual field measures remain relatively stable over the course of 2 years. Microperimetry showed a significant decrease in retinal sensitivity during follow-up and may be a more sensitive progression marker. Retinal sensitivity on microperimetry may serve as a functional clinical end point in future human treatment trials for CRB1-associated retinal dystrophies.

© 2020 The Authors. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/), The cause of autosomal-dominant retinitis pigmentosa (adRP), which leads to loss of vision and blindness, was investigated in families lacking a molecular diagnosis. A refined locus for adRP on Chr17q22 (RP17) was delineated through genotyping and genome sequencing, leading to the identification of structural variants (SVs) that segregate with disease. Eight different complex SVs were characterized in 22 adRP-affected families with >300 affected individuals. All RP17 SVs had breakpoints within a genomic region spanning YPEL2 to LINC01476. To investigate the mechanism of disease, we reprogrammed fibroblasts from affected individuals and controls into induced pluripotent stem cells (iPSCs) and differentiated them into photoreceptor precursor cells (PPCs) or retinal organoids (ROs). Hi-C was performed on ROs, and differential expression of regional genes and a retinal enhancer RNA at this locus was assessed by qPCR. The epigenetic landscape of the region, and Hi-C RO data, showed that YPEL2 sits within its own topologically associating domain (TAD), rich in enhancers with binding sites for retinal transcription factors. The Hi-C map of RP17 ROs revealed creation of a neo-TAD with ectopic contacts between GDPD1 and retinal enhancers, and modeling of all RP17 SVs was consistent with neo-TADs leading to ectopic retinal-specific enhancer-GDPD1 accessibility. qPCR confirmed increased expression of GDPD1 and increased expression of the retinal enhancer that enters the neo-TAD. Altered TAD structure resulting in increased retinal expression of GDPD1 is the likely convergent mechanism of disease, consistent with a dominant gain of function. Our study highlights the importance of SVs as a genomic mechanism in unsolved Mendelian diseases.

Contains fulltext : 244059.pdf (Publisher’s version ) (Open Access) Mutations in PRPH2, encoding peripherin-2, are associated with the development of a wide variety of inherited retinal diseases (IRDs). To determine the causality of the many PRPH2 variants that have been discovered over the last decades, we surveyed all published PRPH2 variants up to July 2020, describing 720 index patients that in total carried 245 unique variants. In addition, we identified seven novel PRPH2 variants in eight additional index patients. The pathogenicity of all variants was determined using the ACMG guidelines. With this, 107 variants were classified as pathogenic, 92 as likely pathogenic, one as benign, and two as likely benign. The remaining 50 variants were classified as variants of uncertain significance. Interestingly, of the total 252 PRPH2 variants, more than half (n = 137) were missense variants. All variants were uploaded into the Leiden Open source Variation and ClinVar databases. Our study underscores the need for experimental assays for variants of unknown significance to improve pathogenicity classification, which would allow us to better understand genotype-phenotype correlations, and in the long-term, hopefully also support the development of therapeutic strategies for patients with PRPH2-associated IRD.

A substantial proportion of subjects with autosomal recessive retinitis pigmentosa (arRP) or Usher syndrome type II (USH2) lacks a genetic diagnosis due to incomplete USH2A screening in the early days of genetic testing. These cases lack eligibility for optimal genetic counseling and future therapy. USH2A defects are the most frequent cause of USH2 and are also causative in individuals with arRP. Therefore, USH2A is an important target for genetic screening. The aim of this study was to assess unscreened or incompletely screened and unexplained USH2 and arRP cases for (likely) pathogenic USH2A variants. Molecular inversion probe (MIP)-based sequencing was performed for the USH2A exons and their flanking regions, as well as published deep-intronic variants. This was done to identify single nucleotide variants (SNVs) and copy number variants (CNVs) in 29 unscreened or partially pre-screened USH2 and 11 partially pre-screened arRP subjects. In 29 out of these 40 cases, two (likely) pathogenic variants were successfully identified. Four of the identified SNVs and one CNV were novel. One previously identified synonymous variant was demonstrated to affect pre-mRNA splicing. In conclusion, genetic diagnoses were obtained for a majority of cases, which confirms that MIP-based sequencing is an effective screening tool for USH2A. Seven unexplained cases were selected for future analysis with whole genome sequencing.

PURPOSE. To investigate the role of two deep-intronic ABCA4 variants, that showed a mild splice defect in vitro and can occur on the same allele as the low penetrant c.5603A>T, in Stargardt disease (STGD1).METHODS. Ophthalmic data were assessed of 18 STGD1 patients who harbored c.769-784C>T or c.4253+43G>A in combination with a severe ABCA4 variant. Subjects carrying c.[769784C>T; 5603A>T] were clinically compared with a STGD1 cohort previously published carrying c.5603A>T noncomplex. We calculated the penetrances of the intronic variants using ABCA4 allele frequency data of the general population and investigated the effect of c.769-784C>T on splicing in photoreceptor progenitor cells (PPCs).RESULTS. Mostly, late-onset, foveal-sparing STGD1 was observed among subjects harboring c.769-784C>T or c.4253+43G>A (median age of onset, 54.5 and 52.0 years, respectively). However, ages of onset, phenotypes in fundo, and visual acuity courses varied widely. No significant clinical differences were observed between the c.[769-784C>T; 5603A>T] cohort and the c.4253+43G>A or the c.5603A>T cohort. The penetrances of c.769-784C>T (20.5%-39.6%) and c.4253+43G>A (35.8%-43.1%) were reduced, when not considering the effect of yet unidentified or known factors in cis, such as c.5603A>T (identified in 7/7 probands with c.769-784C>T; 1/8 probands with c.4253+43G>A). Variant c.769-784C>T resulted in a pseudo-exon insertion in 15% of the total mRNA (i.e., similar to 30% of the c.769-784C>T allele alone).CONCLUSIONS. Two mild intronic ABCA4 variants could further explain missing heritability in late-onset STGD1, distinguishing it from AMD. The observed clinical variability and calculated reduced penetrance urge research into modifiers within and outside of the ABCA4 gene.

Purpose: Using exome sequencing, the underlying variants in many persons with autosomal recessive diseases remain undetected. We explored autosomal recessive Stargardt disease (STGD1) as a model to identify the missing heritability.Methods: Sequencing of ABCA4 was performed in 8 STGD1 cases with one variant and p.Asn1868Ile in trans, 25 cases with one variant, and 3 cases with no ABCA4 variant. The effect of intronic variants was analyzed using in vitro splice assays in HEK293T cells and patient-derived fibroblasts. Antisense oligonucleotides were used to correct splice defects.Results: In 24 of the probands (67%), one known and five novel deep-intronic variants were found. The five novel variants resulted in messenger RNA pseudoexon inclusions, due to strengthening of cryptic splice sites or by disrupting a splicing silencer motif. Variant c.769-784C>T showed partial insertion of a pseudoexon and was found in cis with c.5603A>T (p.Asn1868Ile), so its causal role could not be fully established. Variant c.4253+43G>A resulted in partial skipping of exon 28. Remarkably, antisense oligonucleotides targeting the aberrant splice processes resulted in (partial) correction of all splicing defects.Conclusion: Our data demonstrate the importance of assessing noncoding variants in genetic diseases, and show the great potential of splice modulation therapy for deep-intronic variants.

textabstractPURPOSE. To assess the phenotypic variability and natural course of inherited retinal diseases (IRDs) caused by EYS mutations. METHODS. Multiethnic cohort study (N ¼ 30) with biallelic EYS variants from a clinical IRD database (retinitis pigmentosa [RP], N ¼ 27; cone-rod dystrophy [CRD], N ¼ 1; and macular dystrophy, N ¼ 2). In vitro minigene splice assay was performed to determine the effect on EYS pre-mRNA splicing of the c.1299þ5_1299þ8del variant in macular dystrophy patients. RESULTS. We found 27 different EYS variants in RP patients and 7 were novel. The rate of visual field loss of the V4e isopter area was 0.84 6 0.44 ln(deg2 ) per year, and the rate of visual acuity loss was 0.75 Early Treatment Diabetic Retinopathy Study letters per year. Ellipsoid zone width was correlated with area of the hyperautofluorescent ring, with rs ¼ 0.78 and P < 0.001. Rate of decline in ellipsoid zone width was 57 6 17 lm per year (P < 0.01) (n ¼ 14) or 3.69% 6 0.51% from baseline per year (P < 0.001). An isolated CRD patient carried a homozygous EYS variant (c.9405T>A), previously identified in RP patients. Two siblings with macular dystrophy carried compound heterozygous EYS variants: c.1299þ5_1299þ8del and c.6050G>T. The former was novel and shown to result in skipping of exon 8, and the latter was a known RP variant. CONCLUSIONS. We report on EYS-associated macular dystrophy, extending the spectrum of EYSassociated IRDs. We observed heterogeneity between RP patients in age of onset and disease progression. Identical EYS variants were found in cases with RP, CRD, and macular dystrophy. Screening for EYS variants in CRD and macular dystrophy patients might increase the diagnostic yield in previously unsolved cases.

Contains fulltext : 234995.pdf (Publisher’s version ) (Open Access) PURPOSE: To investigate the retinal structure and function in patients with CRB1-associated retinal dystrophies (RD) and to explore potential clinical endpoints. METHODS: In this prospective cross-sectional study, 22 patients with genetically confirmed CRB1-RD (aged 6-74 years), and who had a decimal best-corrected visual acuity (BCVA) ≥ 0.05 at the last visit, were studied clinically with ETDRS BCVA, corneal topography, spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence, Goldmann visual field (VF), microperimetry, full-field electroretinography (ERG) and full-field stimulus testing (FST). Ten patients were from a genetic isolate (GI). RESULTS: Patients had retinitis pigmentosa (n = 19; GI and non-GI), cone-rod dystrophy (n = 2; GI) or macular dystrophy (n = 1; non-GI). Median age at first symptom onset was 3 years (range 0.8-49). Median decimal BCVA in the better and worse-seeing eye was 0.18 (range 0.05-0.83) and 0.08 (range light perception-0.72), respectively. Spectral-domain optical coherence tomography (SD-OCT) showed cystoid maculopathy in 8 subjects; inner retinal thickening (n = 20), a well-preserved (para)foveal outer retina (n = 7) or severe (para)foveal outer retinal atrophy (n = 14). All retinal layers were discernible in 13/21 patients (62%), with mild to moderate laminar disorganization in the others. Nanophthalmos was observed in 8 patients (36%). Full-field stimulus testing (FST) provided a subjective outcome measure for retinal sensitivity in eyes with (nearly) extinguished ERG amplitudes. CONCLUSIONS: Despite the generally severe course of CRB1-RDs, symptom onset and central visual function are variable, even at advanced ages. Phenotypes may vary within the same family. Imaging and functional studies in a prospective longitudinal setting should clarify which endpoints may be most appropriate in a clinical trial.

PURPOSE: To investigate the natural history of RHO-associated retinitis pigmentosa (RP). METHODS: A multicenter, medical chart review of 100 patients with autosomal dominant RHO-associated RP. RESULTS: Based on visual fields, time-to-event analysis revealed median ages of 52 and 79 years to reach low vision (central visual field

The first ocular gene augmentation therapy, voretigene neparvovec (VN) (Luxturna®), has been approved for clinical use in an increasing number of countries (FDA USA 2017, EMA Europe 2018, MoHAP United Arab Emirates 2019, SFDA Saudi Arabia 2019, Swiss Medic Switzerland 2020, TGA Australia 2020, BFR Brazil 2020). Among the EVICR.net clinical centers, we conducted the first multinational survey to understand distribution, diagnostic work-up, and management of inherited retinal degeneration (IRD) cases in Europe with a special focus on RPE65 mutation-associated IRDs.An electronic survey questionnaire including 35 questions specifically addressing RPE65 mutation-associated IRDs was developed and sent to the 101 EVICR.net clinical centers.The overall response rate was 49%. Forty-two centers see IRD patients, and 22/42 follow patients with confirmed biallelic RPE65 mutations. Fifteen of the 22 centers (68%) and 3/22 (14%) follow 1-5 and 6-10 patients with homozygous RPE65 mutations, respectively. Additionally, 15/22 (68%) and 3/22 (14%) follow 1-5 and20 patients with compound heterozygous RPE65 mutations, respectively. Fifty-nine percent of mutations were ACMG Class 4 and 5 (at least 1 allele), 82.8% reported previously and 17.2% novel. Referral diagnoses (the mean per center) were Leber congenital amaurosis (38.2%), early-onset severe retinal degeneration (16.8%), rod-cone-dystrophy/retinitis pigmentosa (RP) (28.1%), and unclassified visual impairment (17.0%). Twenty-five percent of the centers changed the referral diagnosis in47.5% of cases; 32% follow a specific referral process for RPE65 mutation-associated IRD patients. Annual follow-up visits are done in 55% of the centers and biannual visits in 23%. In 32%, other centers also follow the patients. Kinetic perimetry is done in 82%, static perimetry in 45%, and microperimetry in 18% of the centers. Full-field light stimulus threshold testing with blue and red stimuli to quantify the rod and cone function is used in 6/22 centers (27%). A mobility course is available in one center (5%).This first multinational survey on management of patients with RPE65 mutation-associated IRDs in Europe shows that about half of the responding EVICR.net centers have such patients under care. There is heterogeneity in diagnoses and management practices. At the start of clinical practice experience with VN, these data provide a useful baseline and highlight the need for consensus/guidelines to inform standard of care in this new era of gene therapy.

Purpose: An increasing number of gene therapies are developed for Inherited Retinal Degenerations (IRD). To date, 1 treatment has been approved for clinical use (FDA USA 2017, EMA Europe 2018, MoHAP UAE 2019, SFDA Saudi Arabia 2019, Swiss Medic Switzerland 2020, TGA Australia 2020, and BFR Brazil 2020). While such therapies do not provide complete cure, they may halt degeneration or partially restore function. Identification of well-characterized patients is an emerging need. We conducted the first multinational survey to understand the management of IRDs in Europe. Methods: An electronic survey questionnaire containing 112 questions was developed and sent to the 101 EVICR.net clinical centers (14 European countries and Israel). Results: The overall response rate was 49%. Only 14% of responding centers do not see IRD patients; 52% that manage IRD patients follow ≥200 patients, 16% > 1,000. Databases exist in 86% of the centers; of these, 75% are local files, 28% local Web-based database, and 19% national Web-based. IRD patients are referred to EVICR.net centers mainly by general ophthalmologists, patient self-referrals, and medical retina specialists. Most IRD patients are first seen in adulthood. Most prominent signs and symptoms depend on the age of onset, for example, nystagmus in infancy, or night blindness, and reduced visual acuity at older age. The time from inquiring for first appointment and clinical diagnosis varies among countries: in 29% of centers, the mean time is Conclusion: At the start of this era of ocular gene therapy for IRD patients, this first international survey on management of IRDs in Europe highlights significant heterogeneity between centers and across countries and provides important baseline data for researchers, clinicians, pharmaceutical companies, and investors.

Introduction: Treatment of exudative age-related macular degeneration (ARMD) has shifted to pro re nata and treat-extend-stop strategies. However, a rational discontinuation strategy is lacking. To develop such a strategy, it is important to determine choroidal neovascularization (CNV) recurrence rates after anti-VEGF treatment is discontinued. Here we report prospective data on persistent and recurrent CNV activity after discontinuation of bevacizumab treatment. Methods: This prospective, single-center clinical trial enrolled 191 patients with exudative ARMD. Patients were randomly assigned to receiving intravitreal bevacizumab injections every 4, 6, or 8 weeks for 1 year. CNV activity was determined in the 157 patients who completed the 1-year treatment regimen. Patients with inactive CNV were then followed for signs of CNV reactivation. Results: After 1 year of treatment, 66 (42%) of the 157 patients still had signs of persistent active CNV. Of the remaining 91 (58%) patients, 61 (67%) needed retreatment for active CNV within the first year after discontinuation of treatment (mean 4.28 ± 0.29 months). CNV was reactivated in 50 (80%) of the 61 patients within 6 months after their final treatment for CNV. Conclusion: Based on quiescent disease, anti-VEGF therapy was discontinued in 58% of the patients after they received bevacizu­mab injections every 4, 6, or 8 weeks for 1 year; 67% showed reactivated CNV within a year after discontinuation. The high reactivation rate of CNV shown in this study should help clinicians to develop rational discontinuation protocols. Trial Registration: This study is registered as NTR1174 at http://www.trialregister.nl.

Purpose: Missing heritability in human diseases represents a major challenge, and this is particularly true for ABCA4-associated Stargardt disease (STGD1). We aimed to elucidate the genomic and transcriptomic variation in 1054 unsolved STGD and STGD-like probands. Methods: Sequencing of the complete 128-kb ABCA4 gene was performed using single-molecule molecular inversion probes (smMIPs), based on a semiautomated and cost-effective method. Structural variants (SVs) were identified using relative read coverage analyses and putative splice defects were studied using in vitro assays. Results: In 448 biallelic probands 14 known and 13 novel deep-intronic variants were found, resulting in pseudoexon (PE) insertions or exon elongations in 105 alleles. Intriguingly, intron 13 variants c.1938-621G>A and c.1938-514G>A resulted in dual PE insertions consisting of the same upstream, but different downstream PEs. The intron 44 variant c.6148-84A>T resulted in two PE insertions and flanking exon deletions. Eleven distinct large deletions were found, two of which contained small inverted segments. Uniparental isodisomy of chromosome 1 was identified in one proband. Conclusion: Deep sequencing of ABCA4 and midigene-based splice assays allowed the identification of SVs and causal deep-intronic variants in 25% of biallelic STGD1 cases, which represents a model study that can be applied to other inherited diseases. Fil: Khan, Mubeen. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Cornelis, Stéphanie S.. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Del Pozo Valero, Marta. Hospital Universitario Fundación Jiménez Díaz; España. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Whelan, Laura. Trinity College; Estados Unidos Fil: Runhart, Esmee H.. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Mishra, Ketan. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Bults, Femke. Radboud University Nijmegen Medical Centre; Países Bajos Fil: AlSwaiti, Yahya. St John of Jerusalem Eye Hospital Group; Palestina (ANP) Fil: AlTalbishi, Alaa. St John of Jerusalem Eye Hospital Group; Palestina (ANP) Fil: De Baere, Elfride. University of Ghent; Bélgica Fil: Banfi, Sandro. Seconda Universita Degli Studi Di Napoli; Italia Fil: Banin, Eyal. The Hebrew University of Jerusalem; Israel Fil: Bauwens, Miriam. University of Ghent; Bélgica Fil: Ben Yosef, Tamar. The Ruth And Bruce Rappaport Faculty Of Medicine; Israel Fil: Boon, Camiel J. F.. Leiden University. Leiden University Medical Center; Países Bajos Fil: van den Born, L. Ingeborgh. Rotterdam Ophthalmic Institute; Países Bajos Fil: Defoort, Sabine. Universite Lille; Francia Fil: Devos, Aurore. Universite Lille; Francia Fil: Dockery, Adrian. Trinity College; Estados Unidos Fil: Dudakova, Lubica. Charles University and General University Hospital; República Checa Fil: Fakin, Ana. Charles University and General University Hospital; República Checa Fil: Farrar, G. Jane. Trinity College; Estados Unidos Fil: Ferraz Sallum, Juliana Maria. Universidade Federal de Sao Paulo; Brasil Fil: Fujinami, Kaoru. UCL Institute of Ophthalmology; Reino Unido Fil: Gilissen, Christian. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Glavac, Damjan. University of Ljubljana; Eslovenia Fil: Gorin, Michael B.. University of California at Los Angeles. School of Medicine; Estados Unidos Fil: Greenberg, Jacquie. University of Cape Town; Sudáfrica Fil: Hayashi, Takaaki. The Jikei University School of Medicine; Japón Fil: Hettinga, Ymkje M.. Bartiméus Diagnostic Center for Complex Visual Disorders; Países Bajos Fil: Hoischen, Alexander. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Hoyng, Carel B.. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Hufendiek, Karsten. University Eye Hospital Hannover Medical School; Alemania Fil: Jägle, Herbert. University Regensburg; Alemania Fil: Kamakari, Smaragda. OMMA Ophthalmological Institute of Athens; Grecia Fil: Karali, Marianthi. Seconda Universita Degli Studi Di Napoli; Italia Fil: Kellner, Ulrich. No especifíca; Fil: Klaver, Caroline C. W.. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Kousal, Bohdan. Charles University and General University Hospital; República Checa Fil: Lamey, Tina M.. University of Western Australia; Australia Fil: MacDonald, Ian M.. University of Alberta; Canadá Fil: Matynia, Anna. University of California at Los Angeles. School of Medicine; Estados Unidos Fil: McLaren, Terri L.. University of Western Australia; Australia Fil: Mena, Marcela D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina Fil: Meunier, Isabelle. Université Montpellier II; Francia Fil: Miller, Rianne. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Newman, Hadas. Universitat Tel Aviv; Israel Fil: Ntozini, Buhle. University of Cape Town; Sudáfrica Fil: Oldak, Monika. No especifíca; Fil: Pieterse, Marc. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Podhajcer, Osvaldo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina Fil: Puech, Bernard. Universite Lille; Francia Fil: Ramesar, Raj. University of Cape Town; Sudáfrica Fil: Rüther, Klaus. No especifíca; Fil: Salameh, Manar. No especifíca; Fil: Salles, Mariana Vallim. Universidade de Sao Paulo; Brasil Fil: Sharon, Dror. The Hebrew University of Jerusalem; Israel Fil: Simonelli, Francesca. Seconda Universita Degli Studi Di Napoli; Italia Fil: Spital, Georg. No especifíca; Fil: Steehouwer, Marloes. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Szaflik, Jacek P.. No especifíca; Fil: Thompson, Jennifer A.. No especifíca; Fil: Thuillier, Caroline. Universite Lille; Francia Fil: Tracewska, Anna M.. No especifíca; Fil: van Zweeden, Martine. Radboud University Nijmegen Medical Centre; Países Bajos Fil: Vincent, Andrea L.. University of Auckland; Nueva Zelanda Fil: Zanlonghi, Xavier. No especifíca; Fil: Liskova, Petra. Charles University and General University Hospital; República Checa Fil: Stöhr, Heidi. Universitat Regensburg; Alemania Fil: De Roach, John N.. University of Western Australia; Australia Fil: Ayuso, Carmen. Hospital Universitario Fundación Jiménez Díaz; España Fil: Roberts, Lisa. University of Cape Town; Sudáfrica Fil: Weber, Bernhard H. F.. Universitat Regensburg; Alemania Fil: Dhaenens, Claire Marie. Universite Lille; Francia Fil: Cremers, Frans P. M.. Radboud University Nijmegen Medical Centre; Países Bajos

Contains fulltext : 225467.pdf (Publisher’s version ) (Closed access) PURPOSE: To study the disease course of RPE65-associated inherited retinal degenerations (IRDs) as a function of the genotype, define a critical age for blindness, and identify potential modifiers. METHODS: Forty-five patients with IRD from 33 families with biallelic RPE65 mutations, 28 stemming from a genetic isolate. We collected retrospective data from medical charts. Coexisting variants in 108 IRD-associated genes were identified with Molecular Inversion Probe analysis. RESULTS: Most patients were diagnosed within the first years of life. Daytime visual function ranged from near-normal to blindness in the first four decades and met WHO criteria for blindness for visual acuity and visual field in the fifth decade. p.(Thr368His) was the most common variant (54%). Intrafamilial variability and interfamilial variability in disease severity and progression were observed. Molecular Inversion Probe analysis confirmed all RPE65 variants and identified one additional variant in LRAT and one in EYS in two separate patients. CONCLUSION: All patients with RPE65-associated IRDs developed symptoms within the first year of life. Visual function in childhood and adolescence varied but deteriorated inevitably toward blindness after age 40. In this study, genotype was not predictive of clinical course. The variance in severity of disease could not be explained by double hits in other IRD genes.

PURPOSE. The purpose of this study was to investigate the phenotype and long-term clinical course of female carriers of RPGR mutations. METHODS. This was a retrospective cohort study of 125 heterozygous RPGR mutation carriers from 49 families. RESULTS. Eighty-three heterozygotes were from retinitis pigmentosa (RP) pedigrees, 37 were from cone-/cone-rod dystrophy (COD/CORD) pedigrees, and 5 heterozygotes were from pedigrees with mixed RP/CORD or unknown diagnosis. Mutations were located in exon 1-14 and in ORF15 in 42 of 125 (34%) and 83 of 125 (66%) subjects, respectively. The mean age at the first examination was 34.4 years (range, 2.1 to 86.0 years). The median follow-up time in heterozygotes with longitudinal data (n = 62) was 12.2 years (range, 1.1 to 52.2 years). Retinal pigmentary changes were present in 73 (58%) individuals. Visual symptoms were reported in 51 (40%) cases. Subjects with both symptoms and pigmentary fundus changes were older than the other heterozygotes (P = 0.01) and had thinner foveal outer retinas (P = 0.006). Complete expression of the RP or CORD phenotype was observed in 29 (23%) heterozygotes, although usually in milder forms than in affected male relatives. Best-corrected visual acuity (BCVA) was < 20/40 and < 20/400 in at least one eye in 45 of 116 (39%) and 11 of 116 (9%) heterozygotes, respectively. Myopia was observed in 74 of 101 (73%) subjects and was associated with lower BCVA (P = 0.006). Increasing age was associated with lower BCVA (P = 0.002) and decreasing visual field size (P = 0.012; I4e isopter). CONCLUSIONS. RPGR mutations lead to a phenotypic spectrum in female carriers, with myopia as a significantly aggravating factor. Complete disease expression is observed in some individuals, who may benefit from future (gene) therapeutic options.

Purpose: To describe the phenotypic spectrum of retinal disease caused by the c.2991+1655A>G mutation in CEP290 and to compare disease severity between homozygous and compound heterozygous patients. Methods: Medical records were reviewed for best-corrected visual acuity (BCVA), age of onset, fundoscopy descriptions. Foveal outer nuclear layer (ONL) and ellipsoid zone (EZ) presence was assessed using spectral-domain optical coherence tomography (SD-OCT). Differences between compound heterozygous and homozygous patients were analyzed based on visual performance and visual development. Results: A total of 66 patients were included. The majority of patients had either light perception or no light perception. In the remaining group of 14 patients, median BCVA was 20/195 Snellen (0.99 LogMAR; range 0.12-1.90) for the right eye, and 20/148 Snellen (0.87 LogMAR; range 0.22-1.90) for the left. Homozygous patients tended to be more likely to develop light perception compared to more severely affected compound heterozygous patients (P = 0.080) and are more likely to improve from no light perception to light perception (P = 0.022) before the age of 6 years. OCT data were available in 12 patients, 11 of whom had retained foveal ONL and EZ integrity up to 48 years (median 23 years) of age. Conclusions: Homozygous patients seem less severely affected compared to their compound-heterozygous peers. Improvement of visual function may occur in the early years of life, suggesting a time window for therapeutic intervention up to the approximate age of 17 years. This period may be extended by an intact foveal ONL and EZ on OCT.

PURPOSE: It is unknown which retinal cells are involved in the retina-to-sclera signaling cascade causing myopia. As inherited retinal dystrophies (IRD) are characterized by dysfunction of a single retinal cell type and have a high risk of refractive errors, a study investigating the affected cell type, causal gene, and refractive error in IRDs may provide insight herein. DESIGN: Case-control study. METHODS: STUDY POPULATION: Total of 302 patients with IRD. from 2 ophthalmogenetic centers in the Netherlands. REFERENCE POPULATION: Population-based Rotterdam Study-III and Erasmus Rucphen Family Study (N = 5550). Distributions and mean spherical equivalent (SE) were calculated for main affected cell type and causal gene; and risks of myopia and hyperopia were evaluated using logistic regression. RESULTS: Bipolar cell-related dystrophies were associated with the highest risk of SE high myopia 239.7; odds ratio (OR) mild hyperopia 263.2, both P

Purpose: To examine the long-term clinical course and variability in a large pedigree segregating CRB1 type autosomal recessive retinitis pigmentosa. Methods: An observational case study of 30 patients with CRB1 type autosomal recessive retinitis pigmentosa, homozygous for the CRB1 c.3122T > C; p.(Met1041Thr) mutation from a Dutch genetically isolated population in which the CRB1 gene was originally identified. The authors evaluated medical records, analyzed a questionnaire, and performed a comprehensive ophthalmic examination, including optical coherence tomography. Results: Mean follow-up was 19 years (range 0-45 years, SD 15 years). With aging, patients showed progressive visual decline, deterioration of visual fields, increasing narrowing of the anterior chamber, increased prevalence of cataract, and an increase in the amount of intraretinal pigmentations. Fifty percent of patients had a visual acuity of ≤0.3 at Age 18 and of ≤0.1 at Age 35. Electroretinogram responses were severely reduced or absent already at a young age and optical coherence tomography showed increased retinal thickness with often cystoid maculopathy at young age, and thinning of the retina and disorientation of the photoreceptor layer in the late stages. The clinical course showed considerable interindividual variability, but intraindividual similarity between both eyes was the rule. Conclusion: The wide and variable clinical spectrum in patients with the same CRB1 mutation supports the hypothesis that the CRB1 type autosomal recessive retinitis pigmentosa-phenotype is modulated by other factors. The clinical variability will make it harder to evaluate the effect of (upcoming) therapies for retinitis pigmentosa, although because of the intraindividual similarity between both eyes, the contralateral eye can be used as an excellent internal control.

Item does not contain fulltext PURPOSE: To describe the phenotype and clinical course of patients with RPGR-associated retinal dystrophies, and to identify genotype-phenotype correlations. METHODS: A multicenter medical records review of 74 male patients with RPGR-associated retinal dystrophies. RESULTS: Patients had retinitis pigmentosa (RP; n = 52; 70%), cone dystrophy (COD; n = 5; 7%), or cone-rod dystrophy (CORD; n = 17; 23%). The median follow-up time was 11.6 years (range 0-57.1). The median age at symptom onset was 5.0 years (range 0-14 years) for patients with RP and 23.0 years (range 0-60 years) for patients with COD/CORD. The probability of being blind (best-corrected visual acuity

Background: Transcorneal electrical stimulation (TES) has been suggested as a possible treatment for retinitis pigmentosa (RP). Objective: To expand the safety assessment of repeated applications of an electrical current from a DTL-like electrode in patients with RP. Methods: This single-arm open label interventional safety trial included a total of 105 RP patients from 11 European centers, who received weekly TES for 6 months on 1 eye followed by observation for another 6 months without stimulation. The primary outcome measure was safety, indicated by the frequency and severity of adverse events. Secondary measures included intraocular pressure and central retinal thickness. Visual field and visual acuity were examined using the methods available at each site. Results: Dry eye sensation was the most common adverse event recorded (37.5%). Serious adverse events secondary to TES were not observed. Most adverse events were mild and all resolved without sequelae. The secondary outcome measures revealed no significant or clinically relevant changes. Conclusion: The present results confirm the excellent safety profile of TES. Transient dry eye symptoms were the most common adverse event.

Purpose To analyse intraocular cytokine levels and prevalence of intraocular antiretinal antibodies (ARAs) in patients with retinitis pigmentosa (RP), age‐related macular degeneration (AMD), glaucoma and cataract, and correlate the results to clinical manifestations. Methods We collected intraocular fluid samples from patients with RP (n = 25), AMD (n = 12), glaucoma (n = 28) and cataract (n = 22), and serum samples paired with the intraocular fluids from patients with RP (N = 7) and cataract (n = 10). Interleukin (IL)‐1β, IL‐1ra, IL‐2, IL‐6, IL‐6rα, IL‐7, IL‐8, IL‐10, IL‐17A, IL‐23, thymus‐ and activation‐regulated chemokine (TARC), monocyte chemoattractant protein‐1 (MCP‐1), tumour necrosis factor‐alpha (TNF‐α), placental growth factor (PlGF) and vascular endothelial growth factor (VEGF) were measured using a multiplex assay. Antiretinal antibodies (ARA) detection was performed by indirect immunofluorescence. Results Increasing age was associated with increasing levels of IL‐6, IL‐8, TNF‐α and VEGF. All patient groups exhibited distinct profiles of intraocular cytokines. Intraocular levels of IL‐8 were highest in patients with AMD and glaucoma. Cataract patients exhibited high intraocular levels of IL‐23. Intraocular levels of IL‐2, IL‐6, MCP‐1 and PlGF in RP patients exceeded the levels of serum, indicating intraocular production. Intraocular ARAs were found in only one patient with AMD. Conclusion Increased levels of inflammatory cytokines in intraocular fluid of patients with originally noninflammatory ocular diseases show that intraocular inflammation is involved in their pathogenesis of these entities. Moreover, we show that increasing age is associated with increasing levels of intraocular cytokines and conclude that future studies on intraocular mediators should be corrected for age of patients.

Item does not contain fulltext PURPOSE: To elucidate the functional effect of the ABCA4 variant c.5461-10T-->C, one of the most frequent variants associated with Stargardt disease (STGD1). DESIGN: Case series. PARTICIPANTS: Seventeen persons with STGD1 carrying ABCA4 variants and 1 control participant. METHODS: Haplotype analysis of 4 homozygotes and 11 heterozygotes for c.5461-10T-->C and sequence analysis of the ABCA4 gene for a homozygous proband. Fibroblasts were reprogrammed from 3 persons with STGD1 into induced pluripotent stem cells, which were differentiated into photoreceptor progenitor cells (PPCs). The effect of the c.5461-10T-->C variant on RNA splicing by reverse-transcription polymerase chain reaction was analyzed using PPC mRNA. In vitro assays were performed with minigene constructs containing ABCA4 exon 39. We analyzed the natural history and ophthalmologic characteristics of 4 persons homozygous for c.5461-10T-->C. MAIN OUTCOME MEASURES: Haplotype and rare variant data for ABCA4, RNA splice defects, age at diagnosis, visual acuity, fundus appearance, visual field, electroretinography (ERG) results, fluorescein angiography results, and fundus autofluorescence findings. RESULTS: The frequent ABCA4 variant c.5461-10T-->C has a subtle effect on splicing based on prediction programs. A founder haplotype containing c.5461-10T-->C was found to span approximately 96 kb of ABCA4 and did not contain other rare sequence variants. Patient-derived PPCs showed skipping of exon 39 or exons 39 and 40 in the mRNA. HEK293T cell transduction with minigenes carrying exon 39 showed that the splice defects were the result of the c.5461-10T-->C variant. All 4 subjects carrying the c.5461-10T-->C variant in a homozygous state showed a young age of STGD1 onset, with low visual acuity at presentation and abnormal cone ERG results. All 4 demonstrated severe cone-rod dystrophy before 20 years of age and were legally blind by 25 years of age. CONCLUSIONS: The ABCA4 variant c.5461-10T-->C is located on a founder haplotype lacking other disease-causing rare sequence variants. In vitro studies revealed that it leads to mRNA exon skipping and ABCA4 protein truncation. Given the severe phenotype in persons homozygous for this variant, we conclude that this variant results in the absence of ABCA4 activity.

Retinitis pigmentosa (RP) shows substantial genetic heterogeneity. It has been estimated that in approximately 60%-80% of RP cases, the genetic diagnosis can be found using whole exome sequencing (WES). In this study, the purpose was to identify causative variants in individuals with genetically unexplained retinal disease, which included one consanguineous family with two affected siblings and one case with RP.To identify the genetic defect, WES was performed in both probands, and clinical analysis was performed. To obtain insight into the function of KIAA1549 in photoreceptors, mRNA expression, knockdown and protein localisation studies were performed.Through analysis of WES data, based on population allele frequencies, and in silico prediction tools, we identified a homozygous missense variant and a homozygous frameshift variant inIn conclusion, our results underscore the causality of segregating variants in

Contains fulltext : 190679.pdf (Publisher’s version ) (Open Access) Leber congenital amaurosis (LCA) is a rare inherited retinal disorder affecting approximately 1:50,000 people worldwide. So far, mutations in 25 genes have been associated with LCA, with CEP290 (encoding the Centrosomal protein of 290 kDa) being the most frequently mutated gene. The most recurrent LCA-causing CEP290 mutation, c.2991+1655A>G, causes the insertion of a pseudoexon into a variable proportion of CEP290 transcripts. We previously demonstrated that antisense oligonucleotides (AONs) have a high therapeutic potential for patients homozygously harbouring this mutation, although to date, it is unclear whether rescuing one single allele is enough to restore CEP290 function. Here, we assessed the AON efficacy at RNA, protein and cellular levels in samples that are compound heterozygous for this mutation, together with a protein-truncating mutation in CEP290. We demonstrate that AONs can efficiently restore splicing and increase protein levels. However, due to a high variability in ciliation among the patient-derived cell lines, the efficacy of the AONs was more difficult to assess at the cellular level. This observation points towards the importance of the severity of the second allele and possibly other genetic variants present in each individual. Overall, AONs seem to be a promising tool to treat CEP290-associated LCA, not only in homozygous but also in compound heterozygous carriers of the c.2991+1655A>G variant.

Contains fulltext : 151962.pdf (Publisher’s version ) (Open Access) PURPOSE: To identify mutations in FAM161A underlying autosomal recessive retinitis pigmentosa (arRP) in the Dutch and Belgian populations and to investigate whether common FAM161A-associated phenotypic features could be identified. METHODS: Homozygosity mapping, amplification-refractory mutation system (ARMS) analysis, and Sanger sequencing were performed to identify mutations in FAM161A. Microsatellite and SNP markers were genotyped for haplotype analysis. Patients with biallelic mutations underwent detailed ophthalmologic examinations, including measuring best-corrected visual acuity, extensive fundus photography with reflectance and autofluorescence imaging, and optical coherence tomography. RESULTS: Homozygosity mapping in 230 Dutch individuals with suspected arRP yielded five individuals with a homozygous region harboring FAM161A. Sanger sequencing revealed a homozygous nonsense mutation (c.1309A>T; p.[Arg437*]) in one individual. Subsequent ARMS analysis and Sanger sequencing in Dutch and Belgian arRP patients resulted in the identification of seven additional individuals carrying the p.(Arg437*) mutation, either homozygously or compound heterozygously with another mutation. Haplotype analysis identified a shared haplotype block of 409 kb surrounding the p.(Arg437*) mutation in all patients, suggesting a founder effect. Although the age of onset was variable among patients, all eight developed pronounced outer retinal loss with severe visual field defects and a bull's eye-like maculopathy, followed by loss of central vision within 2 decades after the initial diagnosis in five subjects. CONCLUSIONS: A founder mutation in FAM161A p.(Arg437*) underlies approximately 2% of arRP cases in the Dutch and Belgian populations. The age of onset of the retinal dystrophy appears variable, but progression can be steep, with almost complete loss of central vision later in life.

Item does not contain fulltext Variants in ABCA4 are responsible for autosomal-recessive Stargardt disease and cone-rod dystrophy. Sequence analysis of ABCA4 exons previously revealed one causative variant in each of 45 probands. To identify the "missing" variants in these cases, we performed multiplex ligation-dependent probe amplification-based deletion scanning of ABCA4. In addition, we sequenced the promoter region, fragments containing five deep-intronic splice variants, and 15 deep-intronic regions containing weak splice sites. Heterozygous deletions spanning ABCA4 exon 5 or exons 20-22 were found in two probands, heterozygous deep-intronic variants were identified in six probands, and a deep-intronic variant was found together with an exon 20-22 deletion in one proband. Based on ophthalmologic findings and characteristics of the identified exonic variants present in trans, the deep-intronic variants V1 and V4 were predicted to be relatively mild and severe, respectively. These findings are important for proper genetic counseling and for the development of variant-specific therapies.

Item does not contain fulltext Primary cilia are sensory organelles present on most mammalian cells. The assembly and maintenance of primary cilia are facilitated by intraflagellar transport (IFT), a bidirectional protein trafficking along the cilium. Mutations in genes coding for IFT components have been associated with a group of diseases called ciliopathies. These genetic disorders can affect a variety of organs including the retina. Using whole exome sequencing in three families, we identified mutations in Intraflagellar Transport 172 Homolog [IFT172 (Chlamydomonas)] that underlie an isolated retinal degeneration and Bardet-Biedl syndrome. Extensive functional analyses of the identified mutations in cell culture, rat retina and in zebrafish demonstrated their hypomorphic or null nature. It has recently been reported that mutations in IFT172 cause a severe ciliopathy syndrome involving skeletal, renal, hepatic and retinal abnormalities (Jeune and Mainzer-Saldino syndromes). Here, we report for the first time that mutations in this gene can also lead to an isolated form of retinal degeneration. The functional data for the mutations can partially explain milder phenotypes; however, the involvement of modifying alleles in the IFT172-associated phenotypes cannot be excluded. These findings expand the spectrum of disease associated with mutations in IFT172 and suggest that mutations in genes originally reported to be associated with syndromic ciliopathies should also be considered in subjects with non-syndromic retinal dystrophy.

Purpose Intravitreal anti-vascular endothelial growth factor (VEGF) injections are an effective treatment for neovascular age-related macular degeneration (nARMD). Bevacizumab appears to be a cost-effective off-label anti-VEGF alternative to ranibizumab, but an optimal injection schedule has not yet been determined. In this study, we investigate whether on-demand bevacizumab treatment every 8 weeks is non-inferior to on-demand bevacizumab every 4 weeks in treating nARMD. Methods A total of 120 nARMD patients were randomly assigned to an on-demand regimen of intravitreal bevacizumab (IVB) every 4 (n = 60) or 8 weeks (n = 60). The primary outcome was visual acuity (VA) change after 1 year of treatment. Results Visual acuity (VA) improved between baseline and 1 year in both treatment groups. The mean change in the VA score at 1 year was not significantly different between bevacizumab administration on-demand every 4 weeks [5.6 ± 10.2 Early Treatment Diabetic Retinopathy Study (ETDRS) letter] or 8 weeks (4.6 ± 12.0 ETDRS letters). A reduction in the central retinal thickness was observed in both groups. At 1 year, the mean decrease in central foveal thickness ranged from 61 ± 90 μm in the 4-week group to 91 ± 83 μm in the 8-week group (p = 0.07). The mean number of IVB treatments during the study period was 8.7 ± 2.3 in the 4-week group and 5.9 ± 1.0 in the 8-week group. Conclusion At 1 year, bevacizumab administration on-demand every 8 weeks was non-inferior to administration every 4 weeks. The results strongly suggest that bevacizumab acts longer than 4 weeks in ARMD, reducing the burden of injections for patients.

Item does not contain fulltext PURPOSE: To identify the genetic cause of and describe the phenotype in 4 families with autosomal recessive retinitis pigmentosa (arRP) that can be associated with pseudocoloboma. DESIGN: Case series. PARTICIPANTS: Seven patients from 4 unrelated families with arRP, among whom 3 patients had bilateral early-onset macular pseudocoloboma. METHODS: We performed homozygosity mapping and whole-exome sequencing in 5 probands and 2 unaffected family members from 4 unrelated families. Subsequently, Sanger sequencing and segregation analysis were performed in additional family members. We reviewed the medical history of individuals carrying IDH3A variants and performed additional ophthalmic examinations, including full-field electroretinography, fundus photography, fundus autofluorescence imaging, and optical coherence tomography. MAIN OUTCOME MEASURES: IDH3A variants, age at diagnosis, visual acuity, fundus appearance, visual field, and full-field electroretinography, fundus autofluorescence, and optical coherence tomography findings. RESULTS: We identified 7 different variants in IDH3A in 4 unrelated families, that is, 5 missense, 1 nonsense, and 1 frameshift variant. All participants showed symptoms early in life, ranging from night blindness to decreased visual acuity, and were diagnosed between the ages of 1 and 11 years. Four participants with biallelic IDH3A variants displayed a typical arRP phenotype and 3 participants were diagnosed with arRP and pseudocoloboma of the macula. CONCLUSIONS: IDH3A variants were identified as a novel cause of typical arRP in some individuals associated with macular pseudocoloboma. We observed both phenotypes in 2 siblings carrying the same compound heterozygous variants, which could be explained by variable disease expression and warrants caution when making assertions about genotype-phenotype correlations.

Item does not contain fulltext BACKGROUND: Leber congenital amaurosis, caused by mutations in RPE65 and LRAT, is a severe form of inherited retinal degeneration leading to blindness. We aimed to assess replacement of the missing chromophore 11-cis retinal with oral QLT091001 (synthetic 9-cis-retinyl acetate) in these patients. METHODS: In our open-label, prospective, phase 1b trial, we enrolled patients (aged >/=6 years) with Leber congenital amaurosis and RPE65 or LRAT mutations at McGill University's Montreal Children's Hospital. Patients received 7 days of oral QLT091001 (10-40 mg/m(2) per day). We assessed patients at baseline and days 7, 9, 14, and 30, and then 2 months and every 2 months thereafter for up to 2.2 years for safety outcomes and visual function endpoints including Goldmann visual fields (GVF), visual acuity, and functional MRI assessment. We regarded patients as having an improvement in vision if we noted at least a 20% improvement in retinal area on GVF compared with baseline or a visual acuity improvement of five or more letters compared with baseline in two consecutive study visits (or any improvement from no vision at baseline). This study is registered with ClinicalTrials.gov, number NCT01014052. FINDINGS: Between December, 2009, and June, 2011, we enrolled and treated 14 patients aged 6-38 years who were followed up until March, 2012. Ten (71%) of 14 patients had an improvement in GVF areas (mean increase in retinal area of 28-683%). Six (43%) patients had an improvement in visual acuity (mean increase of 2-30 letters). Self-reported or parent-reported improvements in activities of daily living supported these findings. After 2 years, 11 (79%) patients had returned to their baseline GVF retinal area and ten (71%) had returned to baseline visual acuity letter values. Thus, three (21%) patients had a sustained GVF response and four (30%) had a sustained visual acuity response. Four patients had functional MRI scans, which correlated with visual response or absence of response to treatment. No serious adverse events occurred, although we noted transient headaches (11 patients), photophobia (11 patients), reduction in serum HDL concentrations (four patients), and increases in serum triglycerides (eight patients) and aspartate aminotransferase concentrations (two patients). INTERPRETATION: Non-invasive oral QLT091001 therapy is well tolerated, and can rapidly improve visual function in some patients with Leber congenital amaurosis and RPE65 and LRAT mutations. FUNDING: QLT, Foundation Fighting Blindness Canada, CIHR, FRSQ, Reseau Vision.

Contains fulltext : 125691.pdf (Publisher’s version ) (Closed access) OBJECTIVE: Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous disorder characterized by night blindness and peripheral vision loss, and in many cases leads to blindness. Despite extensive knowledge about genes involved in the pathogenesis of RP, the genetic cause remains elusive in many patients. In this study, we aimed to identify novel genes that are involved in the cause of RP. DESIGN: We present a case series with mutations in the mevalonate kinase (MVK) gene. PARTICIPANTS: A total of 769 patients with nonsyndromic RP and 174 Dutch control individuals participated in this study. METHODS: Exome sequencing analysis was performed in a proband of Dutch origin who was initially diagnosed with nonsyndromic autosomal recessive RP. Mutations in MVK were identified and subsequently tested for segregation within the patient's family and screened in a large cohort of patients with genetically unsolved RP. Patients with mutations underwent extensive clinical reexamination. MAIN OUTCOME MEASURES: Digital fundus photography, spectral-domain optical coherence tomography (OCT), and fundus autofluorescence analysis were performed in patients with MVK mutations. Mevalonate kinase (MK) enzyme activity was analyzed in cultured lymphoblastoid cells, and mevalonic acid levels were measured in urine samples. RESULTS: Exome variant filtering and prioritization led to the identification of compound heterozygous mutations in MVK (p.I268T and p.A334T) in the proband and her affected brother. Screening of our nonsyndromic RP patient cohort revealed an additional individual who was homozygous for the p.A334T alteration. Clinical reevaluation of all 3 patients showed a classic form of RP with variable extraocular symptoms, such as history of recurrent childhood febrile crises in 2 patients, mild ataxia in 1, and renal failure in 1. All 3 affected individuals showed a significantly decreased MK activity and highly elevated levels of urinary mevalonic acid. CONCLUSIONS: Although the MK activity in cells and mevalonic acid concentrations in urine are strongly aberrant and comparable to that in patients with systemic mevalonate kinase deficiency (MKD), only mild clinical symptoms related to this syndrome were observed in our patients. In the current article, we add another phenotype to the spectrum of diverging disorders associated with mutations in MVK. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Purpose: Several clinical trials have established the efficacy of ranibizumab therapy administered every 4 weeks to treat exudative age-related macular degeneration (ARMD). Bevacizumab appears to be a cost-effective alternative to ranibizumab, although an optimal injection schedule has not yet been determined. In this study, we set out to determine whether bevacizumab treatment in exudative ARMD every 6 or 8 weeks is non-inferior to bevacizumab treatment every 4 weeks. Methods: A total of 191 patients with exudative ARMD were randomly assigned to a 1-year continuous regimen of intravitreal bevacizumab every 4 (n = 64), 6 (n = 63) or 8 weeks (n = 64). The primary outcome was visual acuity change after 1 year of treatment. Results: In all three treatment groups, visual acuity improved between baseline and 1 year. There was no statistically significant difference in the mean change of visual acuity score at 1 year for bevacizumab administered every 4 (1.96 ± 13.70), 6 (1.60 ± 10.98) or 8 weeks (5.98 ± 8.88). Reduction in central retinal thickness was observed in all three study groups. At 1 year, the mean decrease in central foveal thickness ranged from 86 ± 97 μm in the every 6 weeks group to 109 ± 90 μm in the group every 8 weeks group (p = 0.30). Conclusion: At 1 year, bevacizumab administered every 6 or 8 weeks was not inferior to therapy administered every 4 weeks.

To determine which color vision test is most appropriate for the identification of cone disorders.In a clinic-based study, four commonly used color vision tests were compared between patients with cone dystrophy (n = 37), controls with normal visual acuity (n = 35), and controls with low vision (n = 39) and legal blindness (n = 11). Mean outcome measures were specificity, sensitivity, positive predictive value and discriminative accuracy of the Ishihara test, Hardy-Rand-Rittler (HRR) test, and the Lanthony and Farnsworth Panel D-15 tests.In the comparison between cone dystrophy and all controls, sensitivity, specificity and predictive value were highest for the HRR and Ishihara tests. When patients were compared to controls with normal vision, discriminative accuracy was highest for the HRR test (c-statistic for PD-axes 1, for T-axis 0.851). When compared to controls with poor vision, discriminative accuracy was again highest for the HRR test (c-statistic for PD-axes 0.900, for T-axis 0.766), followed by the Lanthony Panel D-15 test (c-statistic for PD-axes 0.880, for T-axis 0.500) and Ishihara test (c-statistic 0.886). Discriminative accuracies of all tests did not further decrease when patients were compared to controls who were legally blind.The HRR, Lanthony Panel D-15 and Ishihara all have a high discriminative accuracy to identify cone disorders, but the highest scores were for the HRR test. Poor visual acuity slightly decreased the accuracy of all tests. Our advice is to use the HRR test since this test also allows for evaluation of all three color axes and quantification of color defects.

Background Recent findings suggesting that Abelson helper integration site 1 (AHI1) is involved in non-syndromic retinal disease have been debated, as the functional significance of identified missense variants was uncertain. We assessed whether AHI1 variants cause non-syndromic retinitis pigmentosa (RP). Methods Exome sequencing was performed in three probands with RP. The effects of the identified missense variants in AHI1 were predicted by three-dimensional structure homology modelling. Ciliary parameters were evaluated in patient’s fibroblasts, and recombinant mutant proteins were expressed in ciliated retinal pigmented epithelium cells. Results In the three patients with RP, three sets of compound heterozygous variants were detected in AHI1 (c.2174G>A; p.Trp725* and c.2258A>T; p.Asp753Val, c.660delC; p.Ser221Glnfs*10 and c.2090C>T; p.Pro697Leu, c.2087A>G; p.His696Arg and c.2429C>T; p.Pro810Leu). All four missense variants were present in the conserved WD40 domain of Jouberin, the ciliary protein encoded by AHI1, with variable predicted implications for the domain structure. No significant changes in the percentage of ciliated cells, nor in cilium length or intraflagellar transport were detected. However, expression of mutant recombinant Jouberin in ciliated cells showed a significantly decreased enrichment at the ciliary base. Conclusions This report confirms that mutations in AHI1 can underlie autosomal recessive RP. Moreover, it structurally and functionally validates the effect of the RP-associated AHI1 variants on protein function, thus proposing a new genotype–phenotype correlation for AHI1 mutation associated retinal ciliopathies.

Item does not contain fulltext PURPOSE: USH2A mutations are an important cause of retinitis pigmentosa (RP) with or without congenital sensorineural hearing impairment. We studied genotype-phenotype correlations and compared visual prognosis in Usher syndrome type IIa and nonsyndromic RP. DESIGN: Clinic-based, longitudinal, multicenter study. PARTICIPANTS: Consecutive patients with Usher syndrome type IIa (n = 152) and nonsyndromic RP (n = 73) resulting from USH2A mutations from ophthalmogenetic clinics in the Netherlands and Belgium. METHODS: Data on clinical characteristics, visual acuity, visual field measurements, retinal imaging, and electrophysiologic features were extracted from medical charts over a mean follow-up of 9 years. Cumulative lifetime risks of low vision and blindness were estimated using Kaplan-Meier survival analysis. MAIN OUTCOME MEASURES: Low vision and blindness. RESULTS: Participant groups had similar distributions of gender (48% vs. 45% males in Usher syndrome type IIa vs. nonsydromic RP; P = 0.8), ethnicity (97% vs. 99% European; P = 0.3), and median follow-up time (6.5 years vs. 3 years; P = 0.3). Usher syndrome type IIa patients demonstrated symptoms at a younger age (median age, 15 years vs. 25 years; P < 0.001), were diagnosed earlier (median age, 26 years vs. 36.5 years; P < 0.001), and became visually impaired 13 years earlier (median age, 41 years vs. 54 years; P < 0.001) based on VF and 18 years earlier based on VA (median age, 54 years vs. 72 years; P < 0.001) than nonsyndromic RP patients. The presence of 2 truncating mutations in USH2A was associated mostly with the syndromic phenotype, whereas other combinations were present in both groups. We found novel variants in Usher syndrome type IIa (25%) and nonsyndromic RP (19%): 29 missense mutations, 10 indels, 14 nonsense mutations, 9 frameshift mutations, and 5 splice-site mutations. CONCLUSIONS: Most patients with USH2A-associated RP have severe visual impairment by age 50. However, those with Usher syndrome type IIa have an earlier decline of visual function and a higher cumulative risk of visual impairment than those without nonsyndromic RP. Complete loss of function of the USH2A protein predisposes to Usher syndrome type IIa, but remnant protein function can lead to RP with or without hearing loss.

Purpose: To determine the genetic defect and to describe the clinical characteristics in patients with retinitis punctata albescens (RPA) and fundus albipunctatus (FAP). Design: Case series/observational study. Participants: We included 13 patients affected by RPA or FAP. Methods: Thirteen patients were collected from 8 families with a retinal dystrophy characterized by tiny, yellow-white dots on funduscopy, typical for FAP or RPA. All patients underwent full ophthalmologic examinations, including visual field assessment. Fundus photography, and electroretinography were performed in 12 patients, and optical coherence tomography and fundus autofluorescence were performed in 4 patients. DNA samples of all patients were screened for mutations in RLBP1 and for mutations in RDH5 in patients who did not carry mutations in RLBP1. DNA samples of 2 sibling pairs of nonconsanguineous families who carried mutations neither in RLBP1 nor in RDH5 were analyzed by genome-wide homozygosity mapping. Sequence analysis was performed of LRAT, a candidate gene in a shared homozygous region. Main Outcome Measures: We assessed DNA sequence variants, best-corrected visual acuity, fundus appearance, visual field measurements, electroretinogram responses, optical coherence tomography, and fundus autofluorescence. Results: A homozygous frameshift mutation was identified in LRAT in 4 patients with RPA. Mutations in RLBP1 were identified in 7 patients with RPA and in 1 patient with FAP and cone dystrophy. One patient had compound heterozygous mutations in RDH5 and suffered from FAP with mild maculopathy. Conclusions: A genetic defect was identified in LRAT as a novel cause of RPA. LRAT is therefore the fourth gene involved in the visual cycle that may cause a white-dot retinopathy. We also revealed that mutations in RLBP1 may lead to FAP with cone dystrophy. Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article. Ophthalmology 2012; 119: 1899-1906 (C) 2012 by the American Academy of Ophthalmology

Restoring vision in inherited retinal degenerations remains an unmet medical need. In mice exhibiting a genetically engineered block of the visual cycle, vision was recently successfully restored by oral administration of 9-cis-retinyl acetate (QLT091001). Safety and visual outcomes of a once-daily oral dose of 40 mg/m2/day QLT091001 for 7 consecutive days was investigated in an international, multi-center, open-label, proof-of-concept study in 18 patients with RPE65- or LRAT-related retinitis pigmentosa. Eight of 18 patients (44%) showed a ≥20% increase and 4 of 18 (22%) showed a ≥40% increase in functional retinal area determined from Goldmann visual fields; 12 (67%) and 5 (28%) of 18 patients showed a ≥5 and ≥10 ETDRS letter score increase of visual acuity, respectively, in one or both eyes at two or more visits within 2 months of treatment. In two patients who underwent fMRI, a significant positive response was measured to stimuli of medium contrast, moving, pattern targets in both left and right hemispheres of the occipital cortex. There were no serious adverse events. Treatment-related adverse events were transient and the most common included headache, photophobia, nausea, vomiting, and minor biochemical abnormalities. Measuring the outer segment length of the photoreceptor layer with high-definition optical coherence tomography was highly predictive of treatment responses with responders having a significantly larger baseline outer segment thickness (11.7 ± 4.8 μm, mean ± 95% CI) than non-responders (3.5 ± 1.2 μm). This structure-function relationship suggests that treatment with QLT091001 is more likely to be efficacious if there is sufficient photoreceptor integrity. Trial Registration ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01014052","term_id":"NCT01014052"}}NCT01014052

Contains fulltext : 96905.pdf (Publisher’s version ) (Closed access) A fundamental challenge in analyzing exome-sequence data is distinguishing pathogenic mutations from background polymorphisms. To address this problem in the context of a genetically heterogeneous disease, retinitis pigmentosa (RP), we devised a candidate-gene prioritization strategy called cis-regulatory mapping that utilizes ChIP-seq data for the photoreceptor transcription factor CRX to rank candidate genes. Exome sequencing combined with this approach identified a homozygous nonsense mutation in male germ cell-associated kinase (MAK) in the single affected member of a consanguineous Turkish family with RP. MAK encodes a cilium-associated mitogen-activated protein kinase whose function is conserved from the ciliated alga, Chlamydomonas reinhardtii, to humans. Mutations in MAK orthologs in mice and other model organisms result in abnormally long cilia and, in mice, rapid photoreceptor degeneration. Subsequent sequence analyses of additional individuals with RP identified five probands with missense mutations in MAK. Two of these mutations alter amino acids that are conserved in all known kinases, and an in vitro kinase assay indicates that these mutations result in a loss of kinase activity. Thus, kinase activity appears to be critical for MAK function in humans. This study highlights a previously underappreciated role for CRX as a direct transcriptional regulator of ciliary genes in photoreceptors. In addition, it demonstrates the effectiveness of CRX-based cis-regulatory mapping in prioritizing candidate genes from exome data and suggests that this strategy should be generally applicable to a range of retinal diseases.

Contains fulltext : 96984.pdf (Publisher’s version ) (Closed access) PURPOSE: To determine the genetic defects underlying autosomal recessive retinitis pigmentosa (arRP) in the Dutch population and in a subset of patients originating from other countries. The hypothesis was that, because there has been little migration over the past centuries in certain areas of The Netherlands, a significant fraction of Dutch arRP patients carry their genetic defect in the homozygous state. METHODS: High-resolution genome-wide SNP genotyping on SNP arrays and subsequent homozygosity mapping were performed in a large cohort of 186 mainly nonconsanguineous arRP families living in The Netherlands. Candidate genes residing in homozygous regions were sequenced. RESULTS: In ~94% of the affected individuals, large homozygous sequences were identified in their genome. In 42 probands, at least one of these homozygous regions contained one of the 26 known arRP genes. Sequence analysis of the corresponding genes in each of these patients revealed 21 mutations and two possible pathogenic changes, 14 of which were novel. All mutations were identified in only a single family, illustrating the genetic diversity within the Dutch population. CONCLUSIONS: This report demonstrates that homozygosity mapping is a powerful tool for identifying the genetic defect underlying genetically heterogeneous recessive disorders like RP, even in populations with little consanguinity.

Contains fulltext : 87206_pre.pdf (Author’s version preprint ) (Open Access) Contains fulltext : 87206_pub.pdf (Publisher’s version ) (Closed access) PURPOSE: To characterize the role of EYS, a recently identified retinal disease gene, in families with inherited retinal degenerations in the Israeli and Palestinian populations. METHODS: Clinical and molecular analyses included family history, ocular examination, full-field electroretinography (ERG), perimetry, autozygosity mapping, mutation detection, and estimation of mutation age. RESULTS: Autozygosity mapping was performed in 171 consanguineous Israeli and Palestinian families with inherited retinal degenerations. Large homozygous regions, harboring the EYS gene, were identified in 15 of the families. EYS mutation analysis in the 15 index cases, followed by genotyping of specific mutations in an additional 121 cases of inherited retinal degenerations, revealed five novel null mutations, two of which are founder mutations, in 10 Israeli and Palestinian families with autosomal recessive retinitis pigmentosa (arRP). The most common mutation identified was a founder mutation in the Moroccan Jewish subpopulation. The ESTIAGE program produced an estimate that the age of the most recent common ancestor was 26 generations. The retinal phenotype in most patients was typical yet relatively severe RP, with an early age of onset and nonrecordable ERGs on presentation. CONCLUSIONS: The results demonstrate that EYS is currently the most commonly mutated arRP gene in the Israeli population, mainly due to founder mutations. EYS mutations were associated with an RP phenotype in all patients. The authors concluded that the gene plays only a minor role in causing other retinal phenotypes. 01 september 2010

Contains fulltext : 81053.pdf (Publisher’s version ) (Closed access) PURPOSE: The purpose of this study was to identify the causative gene defect in two siblings with an uncharacterized cone-rod dysfunction and to describe the clinical characteristics. METHODS: Genome-wide homozygosity mapping, with a 250K SNP-array followed by a search for candidate genes, was performed. The patients underwent ophthalmic examination, including elaborate electroretinography. RESULTS: In a Dutch sib pair, a shared 9-Mb homozygous region was found on 11q13.1-q13.5 that encompasses the CABP4 gene, previously implicated in autosomal recessive incomplete congenital stationary night blindness (CSNB2) in two small families. A novel homozygous p.Arg216X mutation in CABP4 was detected in the sib pair. Quantitative RT-PCR on RNA isolated from patient lymphoblast cells showed no nonsense-mediated degradation of mutant CABP4 mRNA. Clinically, patients presented with reduced visual acuity, photophobia, and abnormal color vision, but they did not experience night blindness. Electroretinograms showed electronegative mixed rod-cone responses and severely reduced cone responses, as in CSNB2. Isolated rod responses, however, were (sub)normal. CONCLUSIONS: A novel homozygous nonsense mutation in CABP4 in two siblings resulted in a phenotype with severely reduced cone function and only negligibly reduced rod function on electroretinography and psychophysical testing. Since these patients and two of three previously described patients do not experience night blindness, the name CSNB2 is confusing for patients as well as clinicians. Therefore, the authors propose to name the phenotype congenital cone-rod synaptic disorder.

Contains fulltext : 80462.pdf (Publisher’s version ) (Closed access) Cone photoreceptor disorders form a clinical spectrum of diseases that include progressive cone dystrophy (CD) and complete and incomplete achromatopsia (ACHM). The underlying disease mechanisms of autosomal recessive (ar)CD are largely unknown. Our aim was to identify causative genes for these disorders by genome-wide homozygosity mapping. We investigated 75 ACHM, 97 arCD, and 20 early-onset arCD probands and excluded the involvement of known genes for ACHM and arCD. Subsequently, we performed high-resolution SNP analysis and identified large homozygous regions spanning the PDE6C gene in one sibling pair with early-onset arCD and one sibling pair with incomplete ACHM. The PDE6C gene encodes the cone alpha subunit of cyclic guanosine monophosphate (cGMP) phosphodiesterase, which converts cGMP to 5'-GMP, and thereby plays an essential role in cone phototransduction. Sequence analysis of the coding region of PDE6C revealed homozygous missense mutations (p.R29W, p.Y323N) in both sibling pairs. Sequence analysis of 104 probands with arCD and 10 probands with ACHM revealed compound heterozygous PDE6C mutations in three complete ACHM patients from two families. One patient had a frameshift mutation and a splice defect; the other two had a splice defect and a missense variant (p.M455V). Cross-sectional retinal imaging via optical coherence tomography revealed a more pronounced absence of cone photoreceptors in patients with ACHM compared to patients with early-onset arCD. Our findings identify PDE6C as a gene for cone photoreceptor disorders and show that arCD and ACHM constitute genetically and clinically overlapping phenotypes.

Contains fulltext : 69893.pdf (Publisher’s version ) (Closed access) In patients with autosomal-recessive retinitis pigmentosa (arRP), homozygosity mapping was performed for detection of regions harboring genes that might be causative for RP. In one affected sib pair, a shared homozygous region of 5.0 Mb was identified on chromosome 6, within the RP25 locus. One of the genes residing in this interval was the retina-expressed gene EGFL11. Several genes resembling EGFL11 were predicted just centromeric of EGFL11. Extensive long-range RT-PCR, combined with 5'- and 3'- RACE analysis, resulted in the identification of a 10-kb transcript, starting with the annotated exons of EGFL11 and spanning 44 exons and 2 Mb of genomic DNA. The transcript is predicted to encode a 3165-aa extracellular protein containing 28 EGF-like and five laminin A G-like domains. Interestingly, the second part of the protein was found to be the human ortholog of Drosophila eyes shut (eys), also known as spacemaker, a protein essential for photoreceptor morphology. Mutation analysis in the sib pair homozygous at RP25 revealed a nonsense mutation (p.Tyr3156X) segregating with RP. The same mutation was identified homozygously in three arRP siblings of an unrelated family. A frame-shift mutation (pPro2238ProfsX16) was found in an isolated RP patient. In conclusion, we identified a gene, coined eyes shut homolog (EYS), consisting of EGFL11 and the human ortholog of Drosophila eys, which is mutated in patients with arRP. With a size of 2 Mb, it is one of the largest human genes, and it is by far the largest retinal dystrophy gene. The discovery of EYS might shed light on a critical component of photoreceptor morphogenesis.

Purpose To determine the efficacy of multiple versions of a commercially available arrayed primer extension (APEX) microarray chip for autosomal recessive retinitis pigmentosa (arRP). Methods We included 250 probands suspected of arRP who were genetically analyzed with the APEX microarray between January 2008 and November 2013. The mode of inheritance had to be autosomal recessive according to the pedigree (including isolated cases). If the microarray identified a heterozygous mutation, we performed Sanger sequencing of exons and exon–intron boundaries of that specific gene. The efficacy of this microarray chip with the additional Sanger sequencing approach was determined by the percentage of patients that received a molecular diagnosis. We also collected data from genetic tests other than the APEX analysis for arRP to provide a detailed description of the molecular diagnoses in our study cohort. Results The APEX microarray chip for arRP identified the molecular diagnosis in 21 (8.5%) of the patients in our cohort. Additional Sanger sequencing yielded a second mutation in 17 patients (6.8%), thereby establishing the molecular diagnosis. In total, 38 patients (15.2%) received a molecular diagnosis after analysis using the microarray and additional Sanger sequencing approach. Further genetic analyses after a negative result of the arRP microarray (n = 107) resulted in a molecular diagnosis of arRP (n = 23), autosomal dominant RP (n = 5), X-linked RP (n = 2), and choroideremia (n = 1). Conclusions The efficacy of the commercially available APEX microarray chips for arRP appears to be low, most likely caused by the limitations of this technique and the genetic and allelic heterogeneity of RP. Diagnostic yields up to 40% have been reported for next-generation sequencing (NGS) techniques that, as expected, thereby outperform targeted APEX analysis.

Item does not contain fulltext OBJECTIVE: To determine the refractive error in patients with autosomal recessive retinitis pigmentosa (arRP) caused by RP1 mutations and to compare it with that of other genetic subtypes of RP. METHODS: Twenty-six individuals had arRP with RP1 mutations, 25 had autosomal dominant RP (adRP) with RP1 mutation, 8 and 33 had X-linked RP (xlRP) with RP2 and RPGR mutations, respectively, 198 and 93 had Usher syndrome and arRP without RP1 mutations, respectively. The median of the spherical equivalent (SE) and the IQR (Q25-Q75) was determined and multiple comparisons were performed. RESULTS: arRP patients with RP1 mutations had SE median at -4.0 dioptres (D) OD (Ocula Dextra); -3.88 D OS (Ocula Sinistra), whereas arRP patients without RP1 mutations (-0.50 D OD; -0.75 D OS) and Usher syndrome patients (-0.50 D OD; -0.38 D OS) were significantly less myopic (p

Item does not contain fulltext PURPOSE: Defects in MAK, encoding a protein localized to the photoreceptor connecting cilium, have recently been associated with autosomal recessive retinitis pigmentosa (RP). The aim of this study is to describe our detailed clinical observations in patients with MAK-associated RP, including an assessment of syndromic symptoms frequently observed in ciliopathies. METHODS: In this international collaborative study, 11 patients carrying nonsense or missense mutations in MAK were clinically evaluated, including extensive assessment of the medical history, slit-lamp biomicroscopy, ophthalmoscopy, kinetic perimetry, electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), autofluorescence imaging and fundus photography. Additionally, we used a questionnaire to evaluate the presence of syndromic features and tested the olfactory function. RESULTS: MAK-associated RP is not associated with syndromic features, not even with subclinical dysfunction of the olfactory apparatus. All patients experienced typical RP symptoms of night blindness followed by visual field constriction. Symptoms initiated between childhood and the age of 43 (mean: 23 years). Although some patients experienced vision loss, the visual acuity remained normal in most patients. ERG and ophthalmoscopy revealed classic RP characteristics, and SD-OCT demonstrated thinning of the overall retina, outer nuclear layer and photoreceptor-pigment epithelium complex. CONCLUSION: Nonsense and missense mutations in MAK give rise to a non-syndromic recessive RP phenotype without apparent extra-ocular features. When compared to other retinal ciliopathies, MAK-associated RP appears to be relatively mild and shows remarkable resemblance to RP1-associated RP, which could be explained by the close functional relation of these proteins.

Purpose: This study aimed to identify the genetic defects in 2 families with autosomal recessive macular dystrophy with central cone involvement. Design: Case series. Participants: Two families and a cohort of 244 individuals with various inherited maculopathies and cone disorders. Methods: Genome-wide linkage analysis and exome sequencing were performed in 1 large family with 5 affected individuals. In addition, exome sequencing was performed in the proband of a second family. Subsequent analysis of the identified mutations in 244 patients was performed by Sanger sequencing or restriction enzyme digestion. The medical history of individuals carrying the MFSD8 variants was reviewed and additional ophthalmic examinations were performed, including electroretinography (ERG), multifocal ERG (mfERG), perimetry, optical coherence tomography (OCT), fundus autofluorescence, and fundus photography. Main Outcome Measures: MFSD8 variants, age at diagnosis, visual acuity, fundus appearance, color vision defects, visual field, ERG, mfERG, fundus autofluorescence, and OCT findings. Results: Compound heterozygous variants in MFSD8, a gene encoding a lysosomal transmembrane protein, were identified in 2 families with macular dystrophy with a normal or subnormal ERG, but reduced mfERG. In both families, a heterozygous missense variant p.Glu336Gln was identified, which was predicted to have a mild effect on the protein. In the first family, a protein-truncating variant (p.Glu381*) was identified on the other allele, and in the second family, a variant (c.1102G>C) was identified that results in a splicing defect leading to skipping of exon 11 (p.Lys333Lysfs*3). The p.Glu336Gln allele was found to be significantly enriched in patients with maculopathies and cone disorders (6/488) compared with ethnically matched controls (35/18 682; P < 0.0001), suggesting that it may act as a genetic modifier. Conclusions: In this study, we identified variants in MFSD8 as a novel cause of nonsyndromic autosomal recessive macular dystrophy with central cone involvement. Affected individuals showed no neurologic features typical for variant late-infantile neuronal ceroid lipofuscinosis (vLINCL), a severe and devastating multisystem lysosomal storage disease previously associated with mutations in MFSD8. We propose a genotype-phenotype model in which a combination of a severe and a mild variant cause nonsyndromic macular dystrophy with central cone involvement, and 2 severe mutations cause vLINCL. (C) 2015 by the American Academy of Ophthalmology.

Contains fulltext : 50306.pdf (Publisher’s version ) (Closed access) PURPOSE: To test human CRB1 heterozygotes for possible clinical or functional retinal changes and to evaluate whether a patient with Leber congenital amaurosis (LCA) with CRB1 mutations not consistent with previously described CRB1 phenotypes carried a modifier allele in another LCA gene. METHODS: Seven unrelated heterozygous carriers of CRB1 mutations underwent phenotyping by full eye examinations (indirect ophthalmoscopy and slit lamp biomicroscopy) and functional testing (standard full-field electroretinography [ERG] and multifocal ERG). For genotyping of the LCA patients and their parents, denaturing high-performance liquid chromatography (dHPLC) analyses were performed, followed by sequence analysis of CRB1, followed by sequence analysis of the AIPL1 and CRX genes to identify a putative modifier effect in a patient with an atypical CRB1 phenotype. RESULTS: Reduced full-field ERG b-wave amplitudes were observed with scotopic -2 dB flash (140 microV; P < 0.05), normal full-field cone ERGs, and significant regional retinal dysfunction on mfERG in five of seven carriers of CRB1 mutations. A known AIPL1 mutation (p. R302L) was identified as a potential modifier allele in a patient with LCA carrying two CRB1 mutations and with a prominent maculopathy. CONCLUSIONS: In human heterozygotes of CRB1 mutations (parents of offspring with LCA), distinctive regional retinal dysfunctions were found by multifocal ERG measurements that were consistent with the focal histologic abnormalities reported for the two CRB1 knockout mice models. This phenotypic finding may identify CRB1 carriers and point to the causal gene defect in affected LCA offspring, significantly facilitating the molecular diagnostic process. Evidence suggests a modifier allele in AIPL1 in a patient with LCA with prominent atrophic macular lesions and homozygous defects in CRB1.

Contains fulltext : 57334.pdf (Publisher’s version ) (Closed access) Mutations in the Crumbs homologue 1 (CRB1) gene have been reported in patients with a variety of autosomal recessive retinal dystrophies, including retinitis pigmentosa (RP) with preserved paraarteriolar retinal pigment epithelium (PPRPE), RP with Coats-like exudative vasculopathy, early onset RP without PPRPE, and Leber congenital amaurosis (LCA). We extended our investigations of CRB1 in these retinal dystrophies, and identified nine novel CRB1 sequence variants. In addition, we screened patients with "classic" RP and classic Coats disease (without RP), but no pathologic sequence variants were found in the CRB1 gene. In total, 71 different sequence variants have been identified on 184 CRB1 alleles of patients with retinal dystrophies, including amino acid substitutions, frameshift, nonsense, and splice site mutations, in-frame deletions, and large insertions. Recent studies in two animal models, mouse and Drosophila, and in vivo high-resolution microscopy in patients with LCA, have shed light on the role of CRB1 in the pathogenesis of retinal dystrophies and its function in the photoreceptors. In this article, we provide an overview of the currently known CRB1 sequence variants, predict their effect, and propose a genotype-phenotype correlation model for CRB1 mutations.