Vitelliform Macular Dystrophy Research Articles

BEST Disease and Gene Therapy.

International Ophthalmology Clinics: Fall 2021 - Volume 61 - Issue 4 - p 167-172 doi: 10.1097/IIO.0000000000000376

A Multiple Evanescent White Dot Syndrome–like Reaction to Concurrent Retinal Insults

To describe a clinical picture resembling classic multiple evanescent white dot syndrome (MEWDS) potentially triggered by previous or concurrent, apparently unrelated, ocular events and to provide a literature review of similar presentations. Retrospective chart series and literature review. Consecutive patients diagnosed with MEWDS at the Feinberg School of Medicine, Northwestern University, Chicago, Illinois, and the IRCCS San Raffaele Scientific Institute, Milan, Italy, between July 2019 and June2020. Charts of patients were reviewed. Ophthalmic history, best-corrected visual acuity, spectral-domain OCT results, OCT angiography results, fundus autofluorescence results, ultra-widefield fluorescein angiography results, and indocyanine green angiography results were collected. A PubMed-based search was carried out for similar presentations using the terms MEWDS and white spot syndromes. An ocular history positive for previous or concurrent ocular events in patients with MEWDS was sought in our cohort and the existing literature. Five eyes of 4 patients (2 females; age range, 16-81 years) were included. The first eye had a history of bilateral Best vitelliform dystrophy and unilateral choroidal neovascularization. The second eye had angioid streaks complicated by choroidal neovascularization and underwent prior thermal laser photocoagulation. The third eye had a history of high myopia and a scleral buckle procedure for retinal detachment. The fourth patient had bilateral idiopathic retinochoroiditis. We identified 16 case reports from 5 previous publications that support a MEWDS-like reaction to previous ocular insults. We suggest a MEWDS-like reaction may be elicited by ocular events in a subset of susceptible patients. We hypothesize that damage to the outer retina may play a role in triggering the local inflammatory response.

Multimodal imaging of hereditary retinal dystrophies (a series of clinical cases)

Multimodal visualization data of inherited retinal degeneration (IRD) on a Mirante platform (Nidek, Japan), used in a number of clinical cases, is compared with the data obtained by electrophysiological diagnostic methods. 4 patients with varying IRD were examined: adult-onset foveomacular vitelliform dystrophy, Stargardt disease, including those with fundus flavimaculatus, and retinitis pigmentosa. Multimodal imaging includes: colour fundus imaging, fundus autofluorescence, retro mode, and optical coherence tomography. Electroretinography was performed using an MBN electroretinograph (Russia), and electrooculography was performed using a RETIscan Science system (Roland Consult, Germany). Using non-invasive retinal imaging methods, specific patterns of inherited dystrophies were shown, which correlated well with the data of electrophysiological research methods. The combination of multimodal imaging on the Mirante platform (Nidek, Japan) in combination with electrophysiological diagnostic methods can be successfully used in complex diagnostics, monitoring of the progression, and evaluation of the results of IRD treatment.

Multimodal imaging in subclinical best vitelliform macular dystrophy

BackgroundTo analyse multimodal imaging alterations in the subclinical form of best vitelliform macular dystrophy (BVMD).MethodsThe study was designed as an observational, cross-sectional case series. Eleven eyes of 7 subclinical patients...

Predominance of hyperopia in autosomal dominant Best vitelliform macular dystrophy

Background/AimsPatients with BEST1-associated autosomal dominant Best vitelliform macular dystrophy (AD-BVMD) have been reported to be hyperopic, but the prevalence of refractive error has not been described. This study aimed to...

Cellular Changes in Retinas From Patients With BEST1 Mutations

Best disease (BD), also known as vitelliform macular dystrophy, is an inherited disease of the central retina caused by more than 300 pathogenic variants in the BEST1 gene. The phenotype of BD is variable, and there are just a few reports on the histopathology of eyes from donors with BD. Here, we describe the histopathological comparison of donor’s eyes from two patients with BD. Eyes obtained from 85-year-old (donor 1) and 65-year-old (donor 2) donors were fixed within 25 h postmortem. Perifoveal and peripheral retinal regions were processed for histology and immunocytochemistry using retinal-specific and retinal pigment epithelium (RPE)-specific antibodies. Three age-matched normal eyes were used as controls. DNA was obtained from donor blood samples. Sequence analysis of the entire BEST1 coding region was performed and identified a c.886A > C (p.Asn296His) variant in donor 1 and a c.602T > C (p.Ile201Thr) variant in donor 2; both mutations were heterozygous. Fundus examination showed that donor 1 displayed a macular lesion with considerable scarring while donor 2 displayed close to normal macular morphology. Our studies of histology and molecular pathology in the perifovea and periphery of these two BD donor eyes revealed panretinal abnormalities in both photoreceptors and RPE cellular levels in the periphery; donor 1 also displayed macular lesion. Our findings confirm the phenotypic variability of BD associated with BEST1 variants.

Deep Learning-Based Classification of Inherited Retinal Diseases Using Fundus Autofluorescence

Background. In recent years, deep learning has been increasingly applied to a vast array of ophthalmological diseases. Inherited retinal diseases (IRD) are rare genetic conditions with a distinctive phenotype on fundus autofluorescence imaging (FAF). Our purpose was to automatically classify different IRDs by means of FAF images using a deep learning algorithm. Methods. In this study, FAF images of patients with retinitis pigmentosa (RP), Best disease (BD), Stargardt disease (STGD), as well as a healthy comparable group were used to train a multilayer deep convolutional neural network (CNN) to differentiate FAF images between each type of IRD and normal FAF. The CNN was trained and validated with 389 FAF images. Established augmentation techniques were used. An Adam optimizer was used for training. For subsequent testing, the built classifiers were then tested with 94 untrained FAF images. Results. For the inherited retinal disease classifiers, global accuracy was 0.95. The precision-recall area under the curve (PRC-AUC) averaged 0.988 for BD, 0.999 for RP, 0.996 for STGD, and 0.989 for healthy controls. Conclusions. This study describes the use of a deep learning-based algorithm to automatically detect and classify inherited retinal disease in FAF. Hereby, the created classifiers showed excellent results. With further developments, this model may be a diagnostic tool and may give relevant information for future therapeutic approaches.

Assessment of retinal vessel density in adult-onset foveomacular vitelliform dystrophy by optical coherence tomography angiography

To evaluate retinal thickness, area of foveal avascular zone (FAZ), flow area and flow density of choriocapillaris, vessel density of both superficial capillary plexus (SCP) and deep capillary plexus (DCP) of eyes with adult-onset foveomacular vitelliform dystrophy (AOFVD) using optical coherence tomography angiography (OCT-A) and compare the results with healthy controls. 17 eyes of 14 patients diagnosed with AOFVD and 17 eyes of 17 healthy subjects were enrolled in this study. All patients underwent a complete ophthalmological examination and a 6 x 6 mm macular OCT-A scanning. Quantiative results of retinal thickness, retinal vessel density of SCP and DCP, FAZ area, flow area and flow density of choriocapillaris were analyzed. No statistically significant differences were noted in the vessel density of the SCP, except for the parafoveal nasal sector (P = 0.048). Similarly, no statistically significant differences were observed in the vessel density of the DCP, except for the parafoveal (P = 0.037) and the parafoveal temporal (P = 0.048) sectors. The choriocapillaris flow area and the flow density were significantly lower in the patients with AOFVD than in the healthy controls (P = 0.001 for both). The mean FAZ area and the retinal thickness measurements were comparable in both groups. Patients with AOFVD show vascular abnormalities that can be detected with OCT-A. OCT-A, as a noninvasive imaging modality, could provide a new perspective for understanding the pathophysiology of AOFVD and could also be useful in the follow-up of these patients and in the management of the disease progression.

SHORT-TERM MODIFICATIONS OF ELLIPSOID ZONE IN BEST VITELLIFORM MACULAR DYSTROPHY

To assess ellipsoid zone (EZ) alterations in Best vitelliform macular dystrophy using spectral-domain optical coherence tomography. Prospective, observational case series. Forty-three patients (43 eyes) underwent complete ophthalmological examination at baseline and at 24 months: best-corrected visual acuity (BCVA), biomicroscopy, fundus photography, and spectral-domain optical coherence tomography were performed. Acquisition protocol included 19-line raster scan. Alterations in EZ were marked on spectral-domain optical coherence tomography, and the area was manually calculated on a near-infrared reflectance image. Three patterns were identified: A (decrease >0.25 mm2), B (±0.25 mm2), and C (increase >0.25 mm2). Primary outcome was to describe different patterns of EZ alteration. Secondary outcomes included their correlation with BCVA and the description of a central optically preserved islet. At baseline, altered EZ was identified in 40 eyes. Worse BCVA significantly correlated with larger EZ alterations but not with lesion extension on fundus photograph. Only "pattern-C" eyes unveiled BCVA worsening at follow-up. Optically preserved islet was detected in 16 eyes (37%), disclosing significantly better vision; its disappearance at follow-up (n = 7; 44% of 16 eyes) correlated with a decrease in BCVA. The assessment of EZ status might represent a valuable functional marker in Best vitelliform macular dystrophy because stable alterations and the maintenance of a central optically preserved islet are associated with better visual acuity.

Pathogenic variants in IMPG1 cause autosomal dominant and autosomal recessive retinitis pigmentosa

BackgroundInherited retinal disorders are a clinically and genetically heterogeneous group of conditions and a major cause of visual impairment. Common disease subtypes include vitelliform macular dystrophy (VMD) and retinitis pigmentosa...

PRPH2-Related Retinal Diseases: Broadening the Clinical Spectrum and Describing a New Mutation.

Over 175 pathogenic mutations in the Peripherin-2 (PRPH2) gene are linked to various retinal diseases. We report the phenotype and genotype of eight families (24 patients) with retinal diseases associated with seven distinct PRPH2 gene mutations. We identified a new mutation, c.824_828+3delinsCATTTGGGCTCCTCATTTGG, in a patient with adult-onset vitelliform macular dystrophy (AVMD). One family with the p.Arg46Ter mutation presented with the already described AVMD phenotype, but another family presented with the same mutation and two heterozygous pathogenic mutations (p.Leu2027Phe and p.Gly1977Ser) in the ATP Binding Cassette Subfamily A Member 4 (ABCA4) gene that cause extensive chorioretinal atrophy (ECA), which could be a blended phenotype. The p.Lys154del PRPH2 gene mutation associated with the p.Arg2030Glu mutation in the ABCA4 gene was found in a patient with multifocal pattern dystrophy simulating fundus flavimaculatus (PDsFF), for whom we considered ABCA4 as a possible modifying gene. The mutation p.Gly167Ser was already known to cause pattern dystrophy, but we also found ECA, PDsFF, and autosomal-dominant retinitis pigmentosa (ADRP) as possible phenotypes. Finally, we identified the mutation p.Arg195Leu in a large family with common ancestry, which previously was described to cause central areolar choroidal dystrophy (CACD), but we also found ADRP and observed that it caused ECA more frequently than CACD in this family.

Optical Coherence Tomography Angiography Quantitative Assessment of Macular Neovascularization in Best Vitelliform Macular Dystrophy.

PurposeTo describe quantitative characteristics of macular neovascularization (MNV) in vitelliform macular dystrophy (VMD) patients by means of optical coherence tomography angiography (OCTA).MethodsThe study design was a prospective case series. All patients underwent complete ophthalmologic assessment, optical coherence tomography, and OCTA. The quantitative OCTA parameters examined included vessel tortuosity and vessel dispersion of the MNV. The primary outcome was OCTA characterization of MNV in VMD. Secondary outcomes included the evolution of MNV over the follow-up.ResultsA total of 78 eyes were recruited for the study. MNV was identified in 50 eyes (64%) at baseline and in 51 eyes (65%) at the end of the follow-up (mean follow-up, 24.7 ± 9.7 months). MNV was detected in four out of the 30 eyes classified as stages 2 and 3 (13%), showing exudative manifestations and undergoing ranibizumab treatment, leading to clinical stabilization. OCTA detected MNV in 46 out of 48 eyes (96%) classified as stages 4 and 5, showing no evidence of exudative manifestation. All of the non-exudative MNVs were merely observed over the follow-up and received no treatment. At the end of the follow-up, 47 out of 48 eyes displayed MNV (98%). Non-exudative MNVs remained stable over the follow-up. Statistically significant differences were found when comparing vessel tortuosity and vessel dispersion in the two MNV subforms.ConclusionsVMD is characterized by two MNV subforms. Exudative MNV is rare and may develop in the early stages of the disease, in association with bleeding and fluid formation. Non-exudative MNV develops very commonly in the advanced stage of VMD, without any exudative manifestation.

Disease-causing mutations associated with bestrophinopathies promote apoptosis in retinal pigment epithelium cells.

Best vitelliform macular dystrophy (BVMD) and autosomal recessive bestrophinopathy (ARB) are two kinds of bestrophinopathies which are caused by BEST1 mutations and characterized by accumulation of lipofuscin-like materials on the retinal pigment epithelium cell-photoreceptor interface. In the past two decades, research about the pathogenesis of bestrophinopathies was mainly focused on the anion channel and intracellular Ca2+ signaling, but seldom concentrated on the function of retinal pigment epithelium (RPE) cells. In this study, we explored the possible effect of the three BEST1 mutations p.V143F, p.S142G, and p.A146T on the apoptosis in human fetal RPE cells. Wild-type plasmid and mutant plasmids BEST1-pcDNA3.1 p.V143F, p.S142G, and p.A146T were transfected to human fetal RPE cells. The molecules caspase-3, phospho-Bcl-2, BAX, PARP, and AIF associated with apoptosis were determined by quantitative PCR and Western blot. Apoptotic rate and active Caspase-3 staining were analyzed by flow cytometry. Caspase-3 and PARP expression were significantly increased in BEST1-pcDNA3.1 p.S142G and p.A146T group. Flow cytometry showed that the apoptosis rates were significantly increased in the BEST1-pcDNA3.1 p.V143F, p.S142G, and p.A146T group compared with the wild-type group. For the first time, we found that the three mutations promoted RPE cell apoptosis. Furthermore, the results indicated that BEST1 mutations p.S142G and p.A146T may contribute apoptosis of RPE cells by targeting Caspase 3. Our observations suggested that the apoptosis of RPE cells may be one of the mechanisms in bestrophinopathies, which may provide a new potential therapeutic target for the treatment of this disease.

Adult Onset Best Vitelliform Macular Dystrophy: A Case Report

Introduction: Best disease or vitelliform macular dystrophy is a rare autosomal dominant disorder with bilateral presentation characterized by subretinal accumulation of yellowish material in the macular area. Macular findings range from a small yellow spot, multiple vitelliform or atrophic lesions to a chorio-retinal scar. Case report: A 35 years male presented to our outpatient department with chief complaint of blurring of vision of both eyes for the past three months. His visual acuity was 6/12 in both right and left eyes. On slit-lamp bio-examination anterior segments of both eyes were normal. On fundus examination, both eyes revealed a single, circular, yellow-opaque egg yolk-like macular lesion with no other abnormalities. Optical coherence tomography of both eyes revealed deposits of homogenous hyper- reflective material beneath retinal pigment epithelium at fovea. Fundus fluorescence angiography showed blocked fluorescence at the site of vitelliform lesion of both eyes. Conclusion: Best vitelliform macular dystrophy is a rare genetic disorder with incomplete penetrance. Optical coherence tomography and fundus fluorescence angiography support the diagnosis.

Small Molecules Restore Bestrophin 1 Expression and Function of Both Dominant and Recessive Bestrophinopathies in Patient-Derived Retinal Pigment Epithelium.

PurposeBestrophinopathies are a group of untreatable inherited retinal dystrophies caused by mutations in the retinal pigment epithelium (RPE) Cl− channel bestrophin 1. We tested whether sodium phenylbutyrate (4PBA) could rescue the function of mutant bestrophin 1 associated with autosomal dominant and recessive disease. We then sought analogues of 4PBA with increased potency and determined the mode of action for 4PBA and a lead compound 2-naphthoxyacetic acid (2-NOAA). Lastly, we tested if 4PBA and 2-NOAA could functionally rescue bestrophin 1 function in RPE generated from induced pluripotent stem cells (iPSC-RPEs) derived from patients with a dominant or recessive bestrophinopathy.MethodsGlobal and plasma membrane expression was determined by Western blot and immunofluorescent microscopy, respectively. The effect of 4PBA and 2-NOAA on transcription was measured by quantitative RT-PCR and the rate of protein turnover by cycloheximide chase and Western blot. Channel function was measured by whole-cell patch clamp.Results4PBA and 2-NOAA can rescue the global and membrane expression of mutant bestrophin 1 associated with autosomal dominant disease (Best vitelliform macular dystrophy [BVMD]) and autosome recessive bestrophinopathy (ARB), and these small molecules have different modes of action. Both 4PBA and 2-NOAA significantly increased the channel function of mutant BVMD and ARB bestrophin 1 in HEK293T and iPSC-RPE cells derived from patients with BVMD and ARB. For 4PBA, the increased mutant channel function in BVMD and ARB iPSC-RPE was equal to that of wild-type iPSC-RPE bestrophin 1.ConclusionsThe restoration of bestrophin 1 function in patient-derived RPE confirms the US Food and Drug Administration–approved drug 4PBA as a promising therapeutic treatment for bestrophinopathies.

Inherited Macular Dystrophies in a Tertiary Care Centre.

Inherited macular dystrophies constitute a group of diseases characterized by bilateral central visual loss with symmetrical macular abnormalities usually presenting in the first two decades of life. The aim of this study were to find out the demographic characteristics and disease pattern of inherited retinal dystrophies in subjects attending retina outpatient department in a tertiary care center. An observational study among twenty-six participants diagnosed as macular dystrophy visiting a tertiary care centre in Nepal, during January 2018 to June 2018 were included in the study. Detailed history, slit lamp examination, dilated fundus examination, coloured fundus photography, full field electroretinogram, multifocal electroretinogram, automated visual field and colour vision were done. A total of 52 eyes of 26 subjects were diagnosed with macular dystrophy. The male to female ratio was 1:1. The mean age of presentation was 28.38 years. Most common symptom was blurring of vision seen in 96.15%.The mean visual acuity was 0.67 log mar units in right eye and 0.71 log mar units in the left eye. The most common macular dystrophy was cone dystrophy followed by adult vitelliform macular dystrophy and Stargardts dystrophy. Cone dystrophy is the most common followed by Stargardt's disease and adult vitelliform macular dystrophy. Most presented in the first two decades of life and the most common presenting symptom was blurring of vision.

The Clinical Features and Genetic Spectrum of a Large Cohort of Chinese Patients With Vitelliform Macular Dystrophies

To provide the clinical and genetic characteristics of a large cohort of Chinese patients with vitelliform macular dystrophies. Cross-sectional study. One hundred and thirty-four unrelated Chinese patients diagnosed with Best vitelliform macular dystrophy (BVMD), autosomal recessive bestrophinopathy (ARB), or adult vitelliform macular dystrophy (AVMD) were enrolled. Detailed ophthalmic examinations and genetic testing on vitelliform macular dystrophy-related genes were performed. Genotype and phenotype association were analyzed among different diagnostic groups. In total, 87 BVMD, 30 AVMD, and 17 ARB patients were enrolled in this study. Genetic analysis identified 37 BEST1 mutations in 53 patients with BVMD and ARB. Of these, 5 variants (c.254A>C, c.291C>G, c.722C>G, c.848_850del, c.1740-2A>C) were novel. The variant c.898G>A was a hotspot mutation, which was identified in 13 patients with BVMD and 1 patient with ARB. There were significant differences of ocular biometric parameters among patients with homozygous or compound heterozygous mutations, heterozygous mutations, and those without mutations of BEST1. Homozygous or compound heterozygous patients had shortest axial length (AL), shallowest anterior chamber depth (ACD), and highest intraocular pressure (IOP); patients without mutations had longest AL, deepest ACD, and lowest IOP; and heterozygous patients were in between. Moreover, 7 patients harboring heterozygous mutations in BEST1 and 3 patients without BEST1 mutations showed similar clinical appearance to ARB in our cohort. This is the largest sample size study of Chinese vitelliform macular dystrophy patients. Our results indicated that assessment of angle-closure risk is a necessary consideration for all types of BEST1-related vitelliform macular dystrophies. The study expanded both the clinical and genetic findings of 3 common types of vitelliform macular dystrophies in a Chinese population.

INTRARETINAL HYPERREFLECTIVE LINES.

To report intraretinal hyperreflective lines related to various macular conditions. All cases were imaged with color photographs, autofluorescence images, and spectral-domain optical coherence tomography, some with fluorescein and/or indocyanine green angiography. Demographic data, imaging, course and outcome were retrospectively analyzed. Forty-nine eyes of 43 patients (16 men and 27 women) were included. Hyperreflective vertical lines (38 eyes) or curvilinear lines along the Henle fiber layer (11 eyes) were present in association with various macular conditions: adult vitelliform dystrophy or pattern dystrophy (24 eyes) frequently associated with an epiretinal membrane (six eyes) and/or thick choroid (nine eyes), age-related maculopathy or macular degeneration (nine eyes), partial resorption of subretinal or intraretinal hemorrhages (five eyes), idiopathic macular microhole (two eyes), vitreomacular traction (three eyes), multiple evanescent white dot syndrome (three eyes), fundus flavimaculatus (two eyes), and pachychoroid pigment epitheliopathy (one eye). The lines fully vanished in cases of hemorrhages, multiple evanescent white dot syndrome or resolution of vitreomacular traction, but usually persisted with gradual thinning in the other conditions. The present series showed that intraretinal hyperreflective lines could occur in various inflammatory, degenerative, or tractional conditions. They could reflect a previously unrecognized reaction to various photoreceptor, Müller cell, and/or retinal pigment epithelium damage.

Association of Clinical and Genetic Heterogeneity With BEST1 Sequence Variations

Detailed phenotypic information on the spectrum of fundus abnormalities and clinical variability of all phenotypes associated with sequence variations in BEST1 is limited. To report a detailed phenotypic and genetic analysis of a patient cohort with sequence variations in BEST1. This retrospective case series took place at the Oxford Eye Hospital in Oxford, UK. Thirty-six patients from a single center with disease-causing sequence variations in BEST1 from 25 different families were analyzed. Data were collected from November 2017 to June 2018, and analysis began April 2018. Results of ocular phenotyping and genetic testing using targeted next-generation sequencing to identify BEST1 sequence variations. Thirty-six patients from 25 families with disease-causing sequence variations in BEST1 were included. Of 36 patients, 20 (55.6%) were female. Three distinct clinical phenotypes were identified: autosomal recessive bestrophinopathy (ARB), best vitelliform macular dystrophy (BVMD), and adult-onset vitelliform macular dystrophy. The ARB phenotype group comprised 18 patients from 9 families with age in years at symptom onset ranging from less than 10 to 40s. All patients showed a common phenotype of fundus autofluorescence abnormalities, and spectral-domain optical coherence tomography features were similar in all patients with schitic and cystoid changes. A phenotype of a beaten metallic retinal appearance extending from the mid periphery to the far periphery was identified in 8 patients. Four patients from 1 family with ARB were previously reported to have autosomal recessive retinitis pigmentosa but were reclassified as having ARB as part of this study. The BVMD phenotype group comprised 16 patients from 14 families with age at symptom onset ranging from less than 10 to 70s. Fundus features were localized to the macula and consistent with the stage of BVMD. In the adult-onset vitelliform macular dystrophy phenotype group, the age in years at symptom onset varied from 50s to 70s in 2 patients from 2 families. Fundus features included small vitelliform lesions. Where available, electro-oculogram results demonstrated a reduced or absent light rise in all patients with ARB and BVMD. Genetic testing identified 22 variants in BEST1. These findings support the notion that ARB, BVMD, and adult-onset vitelliform macular dystrophy are clinically distinct and recognizable phenotypes and suggest that the association of autosomal recessive retinitis pigmentosa with sequence variations in BEST1 should be rereviewed.

Deletion of the Impg2 gene causes the degeneration of rod and cone cells in mice.

Variants in interphotoreceptor matrix proteoglycans (IMPG2) have been reported in retinitis pigmentosa (RP) and vitelliform macular dystrophy (VMD) patients. However, the underlying molecular mechanisms remain elusive due to a lack of suitable disease models. We developed two independent Impg2 knockout (KO) mouse models using the CRISPR/Cas9 technique to assess the in vivo functions of Impg2 in the retina. Impg2 ablation in mice recapitulated the RP phenotypes of patients, including an attenuated electroretinogram (ERG) response and the progressive degeneration of photoreceptors. The histopathological examination of Impg2-KO mice revealed irregularly arranged rod cells and mislocalized rhodopsin protein in the inner segment at 6months of age. In addition to the pathological changes in rod cells, cone cells were also affected in KO retinas. KO retinas exhibited progressive cone cell death and impaired cone cell elongation. Further immunoblotting analysis revealed increased levels of endoplasmic reticulum (ER) stress-related proteins, including C/EBP homologous protein (CHOP), immunoglobulin heavy-chain-binding protein (BIP) and protein disulfide isomerase (PDI), in Impg2-KO mouse retinas. Increased gliosis and apoptotic cell death were also observed in the KO retinas. As autophagy is closely associated with ER stress, we then checked whether autophagy was disturbed in Impg2-KO mouse retinas. The results showed that autophagy was impaired in KO retinas, as revealed by the increased accumulation of SQSTM1 and other proteins involved in autophagy. Our results demonstrate the essential roles of Impg2 in the retina, and this study provides novel models for mechanistic investigations and development of therapies for RP caused by IMPG2 mutations.