Clinical Stages of Occult Macular Dystrophy Based on Optical Coherence Tomographic Findings

Biallelic occult macular dystrophy

PURPOSE

Occult macular dystrophy (OMD) is a cause of visual loss in young adults with a grossly normal fundus appearance. It is considered an autosomal dominant disorder, related to heterozygous pathogenic variants in the gene RP1L1. The purpose of this study is to report a biallelic form of the disease.

RESULTS

A 29-year-old female had undergone neurological workup and ophthalmic examinations for transient visual loss in her left eye over the past two years but there was no definitive diagnosis. The best-corrected visual acuity was 20/30, 20/20. Indirect ophthalmoscopy with a 78D lens revealed subtle central retinal pigment epithelium mottling and optical coherence tomography confirmed subtle central thickening of the ellipsoid zone. Full-field electroretinography was normal, but pattern electroretinography showed decreased p50 responses. OMD was suspected. Retinal gene panel testing was significant only for a homozygous variant in RP1L1 (NM_178857.6: c.3571 G>T; p.Glu1191*). The parents and older brother were unavailable for segregation analysis. By history they did not have visual complaints other than a need for glasses.

CONCLUSIONS

This report presents the clinical and genetic findings of a biallelic form of OMD associated with a novel pathogenic variant in RP1L1. It would be of interest to carefully assess macular function in heterozygotes with this variant.

Nationwide epidemiologic survey on incidence of macular dystrophy in Japan

PURPOSE

The aim of this study was to estimate the number of patients in Japan who had visited an ophthalmologist for macular dystrophy of various types, including Best vitelliform macular dystrophy (BVMD), Stargardt disease, occult macular dystrophy (OMD), cone (-rod) dystrophy, X-linked retinoschisis (XLRS), and central areolar choroid dystrophy (CACD).

STUDY DESIGN

Nationwide epidemiologic survey METHODS: Questionnaires were distributed to 965 major facilities, including all the university hospitals in Japan. The aim of the questionnaire was to determine the number of patients with each type of macular dystrophy who had visited an outpatient clinic during the past 5 years (January 2015 to December 2019).

RESULTS

Over 70% of the patients were diagnosed and followed up at university hospitals. The estimated annual number of newly diagnosed cases was as follows: 55.3 for BVMD, 36.7 for Stargardt disease, 35.8 for OMD, 160.6 for cone (-rod) dystrophy, 31.0 for XLRS, 29.8 for CACD, and 174.1 for other types of macular dystrophy. The total number of patients with macular dystrophy diagnosed and followed at major institutions was estimated to be 6651.

CONCLUSION

This was the first nationwide survey of macular dystrophy in Japan and provided an approximate number of affected patients. The diagnosis of macular dystrophy is primarily carried out at facilities with affiliated specialists, such as university hospitals. By examining the incidence of multiple diseases simultaneously, we were able to compare the incidence of each type of macular dystrophy.

Optical Coherence Tomography in Inherited Macular Dystrophies: A Review

Macular dystrophies (MDs) constitute a collection of hereditary retina disorders leading to notable visual impairment, primarily due to progressive macular atrophy. These conditions are distinguished by bilateral and relatively symmetrical abnormalities in the macula that significantly impair central visual function. Recent strides in fundus imaging, especially optical coherence tomography (OCT), have enhanced our comprehension and diagnostic capabilities for MD. OCT enables the identification of neurosensory retinal disorganization patterns and the extent of damage to retinal pigment epithelium (RPE) and photoreceptor cells in the dystrophies before visible macular pathology appears on fundus examinations. It not only helps us in diagnostic retinal and choroidal pathologies but also guides us in monitoring the progression of, staging of, and response to treatment. In this review, we summarize the key findings on OCT in some of the most common MD.

Distinct Clinical Effects of Two RP1L1 Hotspots in East Asian Patients With Occult Macular Dystrophy (Miyake Disease): EAOMD Report 4

Purpose

To characterize the clinical effects of two RP1L1 hotspots in patients with East Asian occult macular dystrophy (OMD).

Methods

Fifty-one patients diagnosed with OMD harboring monoallelic pathogenic RP1L1 variants (Miyake disease) from Japan, South Korea, and China were enrolled. Patients were classified into two genotype groups: group A, p.R45W, and group B, missense variants located between amino acids (aa) 1196 and 1201. The clinical parameters of the two genotypes were compared, and deep learning based on spectral-domain optical coherence tomographic (SD-OCT) images was used to distinguish the morphologic differences.

Results

Groups A and B included 29 and 22 patients, respectively. The median age of onset in groups A and B was 14.0 and 40.0 years, respectively. The median logMAR visual acuity of groups A and B was 0.70 and 0.51, respectively, and the survival curve analysis revealed a 15-year difference in vision loss (logMAR 0.22). A statistically significant difference was observed in the visual field classification, but no significant difference was found in the multifocal electroretinographic classification. High accuracy (75.4%) was achieved in classifying genotype groups based on SD-OCT images using machine learning.

Conclusions

Distinct clinical severities and morphologic phenotypes supported by artificial intelligence-based classification were derived from the two investigated RP1L1 hotspots: a more severe phenotype (p.R45W) and a milder phenotype (1196-1201 aa). This newly identified genotype-phenotype association will be valuable for medical care and the design of therapeutic trials.

Adaptive optics imaging in inherited retinal diseases: A scoping review of the clinical literature

Adaptive optics (AO) imaging enables direct, objective assessments of retinal cells. Applications of AO show great promise in advancing our understanding of the etiology of inherited retinal disease (IRDs) and discovering new imaging biomarkers. This scoping review systematically identifies and summarizes clinical studies evaluating AO imaging in IRDs. Ovid MEDLINE and EMBASE were searched on February 6, 2023. Studies describing AO imaging in monogenic IRDs were included. Study screening and data extraction were performed by 2 reviewers independently. This review presents (1) a broad overview of the dominant areas of research; (2) a summary of IRD characteristics revealed by AO imaging; and (3) a discussion of methodological considerations relating to AO imaging in IRDs. From 140 studies with AO outcomes, including 2 following subretinal gene therapy treatments, 75% included fewer than 10 participants with AO imaging data. Of 100 studies that included participants' genetic diagnoses, the most common IRD genes with AO outcomes are CNGA3, CNGB3, CHM, USH2A, and ABCA4. Confocal reflectance AO scanning laser ophthalmoscopy was the most reported imaging modality, followed by flood-illuminated AO and split-detector AO. The most common outcome was cone density, reported quantitatively in 56% of studies. Future research areas include guidelines to reduce variability in the reporting of AO methodology and a focus on functional AO techniques to guide the development of therapeutic interventions.

Occult Macular Dysfunction Syndrome: Identification of Multiple Pathologies in a Clinical Spectrum of Macular Dysfunction with Normal Fundus in East Asian Patients: EAOMD Report No. 5

Occult macular dystrophy (OMD) is the most prevalent form of macular dystrophy in East Asia. Beyond RP1L1, causative genes and mechanisms remain largely uncharacterised. This study aimed to delineate the clinical and genetic characteristics of OMD syndrome (OMDS). Patients clinically diagnosed with OMDS in Japan, South Korea, and China were enrolled. The inclusion criteria were as follows: (1) macular dysfunction and (2) normal fundus appearance. Comprehensive clinical evaluation and genetic assessment were performed to identify the disease-causing variants. Clinical parameters were compared among the genotype groups. Seventy-two patients with OMDS from fifty families were included. The causative genes were RP1L1 in forty-seven patients from thirty families (30/50, 60.0%), CRX in two patients from one family (1/50, 2.0%), GUCY2D in two patients from two families (2/50, 4.0%), and no genes were identified in twenty-one patients from seventeen families (17/50, 34.0%). Different severities were observed in terms of disease onset and the prognosis of visual acuity reduction. This multicentre large cohort study furthers our understanding of the phenotypic and genotypic spectra of patients with macular dystrophy and normal fundus. Evidently, OMDS encompasses multiple Mendelian retinal disorders, each representing unique pathologies that dictate their respective severity and prognostic patterns.

Clinically Diagnosed Occult Macular Dystrophy Habouring an m.14502T>C Mitochondrial DNA Mutation Associated with Leber's Hereditary Optic Neuropathy: Case Report and Literature Review

A 29-year-old female with no family history presented with bilateral progressive blurred vision. Her symptoms appeared at 12-years-old and her visual acuity had since deteriorated from 0.6 to 0.2 bilaterally with decreased critical flicker frequency and bilateral central scotomas. She did not have a relative afferent pupillary defect. Fundoscopy revealed no distinct disc hyperaemia, atrophy, or peripapillary telangiectatic vessels. The retinal nerve fibre layer appeared normal on optical coherence tomography in each eye; however, loss of the interdigitation zone and the disruption of the ellipsoid zone at the fovea were observed in both eyes. Multifocal electroretinography revealed decreased amplitudes at both macula regions. Mitochondrial deoxyribonucleic acid analysis identified an m.14502T>C mutation, one of the primary mutations causing Leber's hereditary optic neuropathy (LHON). Despite the presence of a marked LHON mutation, however, she was clinically diagnosed as having an occult macular dystrophy. There have only been five previous case reports, all of which were sporadic, which detail the clinical characteristics of the m.14502T>C mutation. The m.14502T>C phenotype is somewhat consistent with that of the other major mutations, including young onset, bilateral progressive visual impairment, and a typical LHON fundus. Nevertheless, m.14502T>C alone has an extremely low penetrance and its phenotype may be minimal or subclinical, as seen in our case. Since little is known about the clinical course of the m.14502T>C mutation it may be possible that the LHON phenotype may appear in later stages of life. Moreover, m.14502T>C may function as a modifier gene, which alters the phenotype of other coexisting major LHON mutations, including penetrance and the severity of the disease, through synergistic effects.

Genetic characterization of 1210 Japanese pedigrees with inherited retinal diseases by whole-exome sequencing

Inherited retinal diseases (IRDs) comprise a phenotypically and genetically heterogeneous group of ocular disorders that cause visual loss via progressive retinal degeneration. Here, we report the genetic characterization of 1210 IRD pedigrees enrolled through the Japan Eye Genetic Consortium and analyzed by whole exome sequencing. The most common phenotype was retinitis pigmentosa (RP, 43%), followed by macular dystrophy/cone- or cone-rod dystrophy (MD/CORD, 13%). In total, 67 causal genes were identified in 37% (448/1210) of the pedigrees. The first and second most frequently mutated genes were EYS and RP1, associated primarily with autosomal recessive (ar) RP, and RP and arMD/CORD, respectively. Examinations of variant frequency in total and by phenotype showed high accountability of a frequent EYS missense variant (c.2528G>A). In addition to the two known EYS founder mutations (c.4957dupA and c.8805C>G) of arRP, we observed a frequent RP1 variant (c.5797C>T) in patients with arMD/CORD.

Seroreactivity against retinal proteins in a case of POC1B gene associated cone dystrophy with normal funduscopic appearance: a systematic approach to diagnosis

PURPOSE

To report a case of cone dystrophy, associated with autosomal recessive homozygote POC1B gene variant, mimicking autoimmune retinopathy.

CASE

A 45-year-old female presented with a complaint of decreased vision in both eyes. Her best corrected visual acuity was 20/32 in the right eye and 20/50 in the left eye. Anterior segment and dilated fundus examinations were unremarkable. Spectral domain optical coherence tomography showed a subfoveal blurred dome-shaped ellipsoid zone and an extinguished interdigitation zone affecting the entire macula. Full field electroretinography revealed reduced cone responses. The differential diagnosis included inflammatory chorioretinopathies, autoimmune retinopathies (paraneoplastic or nonparaneoplastic), and hereditary retinal dystrophies. No remarkable finding was observed on combined fluorescein and indocyanine green angiographies. Paraneoplastic autoimmune antibody panel revealed nothing; however, aldolase, enolase, pyruvate kinase M2, and glyceraldehyde-3-phosphate dehydrogenase antibodies were positive on autoimmune retinopathy panel. To exclude hereditary retinal dystrophies, whole-exome sequencing (WES) was applied. WES identified an autosomal recessive homozygote POC1B gene variant (c.680A>G, p.His227Arg). Cone dystrophy diagnosis was given.

CONCLUSION

Cone dystrophy associated with POC1B gene variant may present without visible fundus abnormalities. It should be kept in mind that retinal autoantibodies may be positive in such a hereditary dystrophy case due to long-term exposure of the immune system to self-antigens. Therefore, autoimmune retinopathy is a diagnosis of exclusion and should not be diagnosed until all other causes, including hereditary dystrophies, have been ruled out.

Occult Macular Dystrophy: a case report and major review

BACKGROUND

Occult Macular Dystrophy (OMD), a rare autosomal dominant disorder caused by mutations in the retinitis pigmentosa 1-like protein 1 gene (RP1L1), is characterized by loss of central visual acuity in the absence of fundoscopic abnormalities. In patients suspected of having OMD based on unexplained central vision loss and/or photophobia, changes may be detected with spectral-domain optical coherence tomography. Subsequently, the diagnosis can be confirmed with genetic analysis.We report a case of an 18-year-old White male whose suspected diagnosis of OMD was confirmed by molecular testing. We conducted an extensive review of the literature of previously reported patients with OMD to date.

METHODS

A PubMed search of "RP1L1 and Occult Macular Dystrophy" revealed 34 papers. There were 225 individuals with genetically confirmed, symptomatic OMD; an additional 15 had a confirmed mutation but were asymptomatic and discovered incidentally.

RESULTS

Our patient presented with a 10-year history of unexplained loss of central visual acuity and photophobia. Genetic analysis confirmed the presence of a p.R45W substitution on the RP1L1 gene, the most common pathologic mutation in OMD.

CONCLUSIONS

Due to the lack of appreciable fundoscopic changes, correct identification of the disease can be difficult. Incomplete penetrance has been associated with the condition, and the age of onset is highly variable. Much of the research discussing OMD has come from Eastern Asia, but whether this is due to a heightened awareness and screening protocols, or increased incidence is unclear. Additional research and increased awareness globally will help with more timely and accurate diagnoses.

Rare occult macular dystrophy with a pathogenic variant in the RP1L1 gene in a patient of Swiss descent

Purpose

We report a first case of bilateral occult macular dystrophy (OMD) with a c.133C>T (p.Arg45Trp) pathogenic variant in the retinitis pigmentosa 1-like 1 (RP1L1) gene in a patient of Caucasian Swiss decent.

Observations

A 34-year-old man presented with decreased visual acuity known since childhood. Fundus examination of both eyes revealed no pathology other than mildly increased granularity of the foveal retinal pigment epithelium. The full-field electroretinogram (ffERG) presented with normal findings while the multifocal electroretinogram (mfERG) showed severely reduced amplitudes of the foveal response. Optical coherence tomography (OCT) showed foveal outer retinal atrophy. Fundus autofluorescence (FAF) imaging demonstrated near-normal findings with minimal mottling at the posterior pole. The genetic analysis revealed a heterozygous pathogenic variant (c.133C>T, p.Arg45Trp) in the RP1L1 gene.

Conclusion and importance

Our present case suggests that OMD shows a wide range of clinical presentations with a variety of ophthalmological findings, age of disease onset, visual acuity, and genetic diversity.

Detailed analyses of microstructure of photoreceptor layer at different severities of occult macular dystrophy by ultrahigh-resolution SD-OCT

Purpose

To analyze the microstructures of the photoreceptor layer in detail in eyes with occult macular dystrophy (OMD, Miyake's disease) by ultrahigh-resolution spectral-domain optical coherence tomography (UHR-SD-OCT).

Observations

Twenty-eight normal subjects and 5 patients with OMD of different severities were studied. Cross-sectional images through the fovea were recorded with a UHR-SD-OCT system with a depth resolution of <2.0 μm. In patients with OMD, the UHR-SD-OCT images revealed abnormal photoreceptor microstructures which were not detected in the conventional SD-OCT images. The UHR-SD-OCT images showed that the interdigitation zone (IZ) was not present and the outer segments were hyperreflective with hyperreflective dots (HRDs) aligned like string of pearls during the earlier stages. There was a disruption of the ellipsoid zone (EZ) which appeared as clusters of larger HRDs, and these HRDs became less apparent with increasing time. The outer segments became hyporeflective and rod IZ became apparent with longer duration of the disease process.

Conclusions and Importance

The UHR-SD-OCT images show detailed characteristics of the photoreceptor microstructures of different severities during the progression of OMD. These detailed observations will help in understanding the mechanisms involved in the retinal pathology and should provide important information for their treatments.

Multimodal imaging evaluation of occult macular dystrophy associated with a novel RP1L1 variant

Purpose

Occult Macular Dystrophy (OMD) is an autosomal dominant inherited retinal dystrophy caused by mutations in the retinitis pigmentosa 1-like 1 (RP1L1) gene. The present study describes a novel RP1L1 variant, identified for the first time in two Italian sisters diagnosed with OMD, along with multimodal imaging features, including Optical Coherence Tomography (OCT) Angiography.

Methods

We performed multimodal imaging including spectral-domain OCT, blue light autofluorescence (BAF), infrared autofluorescence (IRAF), swept-source OCT Angiography (OCTA), full-field and multifocal electroretinography. Genetic analysis was performed using Next-Generation Sequencing. Pathogenic potential of nonsynonymous novel variants was scored with two in silico algorithms.

Results

Proband 1 (P1) and proband 2 (P2) were two Italian sisters of 61 and 56 years old. Both reported a history of progressive visual loss without fundoscopic alterations. P1 reported a 4-year history of rapid visual function worsening, and her best-corrected visual acuity (BCVA) was counting fingers in both eyes. P2 reported a 20-year history of mild but progressive visual acuity loss, and her BCVA was 1/10 and 2/10 respectively in her right and left eye. Structural OCT displayed disorganization of outer retinal bands at the macula and foveal cavitation; loss of foveal photoreceptors was remarkably evident on en-face OCT slabs. OCTA quantitative analysis found that vessel density was reduced both at SCP and DCP while choriocapillaris blood flow was relatively spared. Genetic analysis found the same rare dominant c.2873G > C, p.Arg958Pro variant in the RP1L1 gene. The substitution was regarded as moderately radical according to Grantham score while PolyPhen2 classified the amino acidic substitution as probably damaging.

Conclusions and importance

Our study expands the mutational spectrum of RP1L1 gene: the rare c.2873G > C, p.Arg958Pro missense variant may be considered a new pathogenic variant for OMD, the first to be identified exclusively in an Italian family. Moreover, our quantitative OCTA data suggest that OMD is characterized by a rarefaction of superficial and deep capillary plexus.

Case Report: Occult Macular Dystrophy

SIGNIFICANCE

This case report discusses a case of suspected occult macular dystrophy, which is an underrecognized but not rare subtype of cone dystrophy. Increasing clinician recognition of occult macular dystrophy will lead to increased accurate diagnosis of affected patients.

PURPOSE

A clinical presentation and diagnosis of a case of suspected occult macular dystrophy, as well as background information and management, are reported.

CASE REPORT

A 44-year-old Caucasian male reported longstanding decreased vision and photophobia in both eyes. Exam revealed a bilateral reduction in best corrected visual acuity, abnormal color vision, central visual field defects, and subtle disruption of sub foveal photoreceptor integrity on optical coherence tomography with a normal fundus appearance. The multi-focal electroretinogram showed decreased perifoveal responses, while both the photopic and scotopic full-field electroretinograms were normal. This distinctive electroretinogram response pattern was critical in the diagnosis of occult macular dystrophy.

CONCLUSIONS

Reduced visual acuity with a normal clinical exam is commonly encountered in patients with occult macular dystrophy. Therefore, clinicians must be aware of occult macular dystrophy and order appropriate testing to accurately identify cases of occult macular dystrophy. Without thorough evaluation, patients may be easily misdiagnosed with other etiologies of vision loss.

Visual Field Characteristics in East Asian Patients With Occult Macular Dystrophy (Miyake Disease): EAOMD Report No. 3

Purpose

The purpose of this study was to investigate the perimetric features and their associations with structural and functional features in patients with RP1L1-associated occult macular dystrophy (OMD; i.e. Miyake disease).

Methods

In this international, multicenter, retrospective cohort study, 76 eyes of 38 patients from an East Asian cohort of patients with RP1L1-associated OMD were recruited. Visual field tests were performed using standard automated perimetry, and the patients were classified into three perimetric groups based on the visual field findings: central scotoma, other scotoma (e.g. paracentral scotoma), and no scotoma. The association of the structural and functional findings with the perimetric findings was evaluated.

Results

Fifty-four eyes (71.1%) showed central scotoma, 14 (18.4%) had other scotomata, and 8 (10.5%) had no scotoma. Central scotoma was mostly noted in both eyes (96.3%) and within the central 10 degrees (90.7%). Among the three perimetric groups, there were significant differences in visual symptoms, best-corrected visual acuity (BCVA), and structural phenotypes (i.e. severity of photoreceptor changes). The central scotoma group showed worse BCVA often with severe structural abnormalities (96.3%) and a pathogenic variant of p.R45W (72.2%). The multifocal electroretinogram (mfERG) groups largely corresponded with the perimetric groups; however, 8 (10.5%) of 76 eyes showed mfERG abnormalities preceding typical central scotoma.

Conclusions

The patterns of scotoma with different clinical severity were first identified in occult macular dystrophy, and central scotoma, a severe pattern, was most frequently observed. These perimetric patterns were associated with the severity of BCVA, structural phenotypes, genotype, and objective functional characteristics which may precede in some cases.

An extended phenotype of RP1L1 maculopathy - case report

BACKGROUND

To report the ophthalmological findings of a new phenotypical variant of RP1L1 maculopathy in an Indian patient with a homozygous variant in the RP1L1 gene.

MATERIALS AND METHODS

A 39-year-old male presented with complaints of disturbance in the central field of vision in both eyes (BE) for a duration of 6 months. He underwent ophthalmic examinations and diagnostic imaging. A complete retinal degeneration panel consisting of 228 genes was evaluated for pathologic variations using next-generation sequencing (NGS), which showed a variant in the RP1L1 gene.

RESULTS

On fundus examination, he was found to have ill-defined foveal mottling in BE. Spectral domain optical coherence tomography (SD-OCT) showed sub-foveal hyper-reflective deposits and outer retinal layer disruption. A provisional diagnosis of the atypical variant of adult-onset foveomacular vitelliform dystrophy (AOFVD) was made on the basis of clinical, OCT, Fundus autofluorescence (FAF) and electrophysiological features. Genetic assessment of the proband revealed the presence of a homozygous base pair deletion in exon 4 of RP1L1 gene (chr8:g.10468194_10468195del), which results in frameshift and premature truncation of the protein 24 amino acids downstream to codon 1138 (p.Lys1138SerfsTer24). This variant was confirmed in the proband's parents by Sanger sequencing. The diagnosis was revised to RP1L1 maculopathy, as the RP1L1 gene variant is most commonly associated with this entity.

CONCLUSION

This report presents the multimodal imaging of a previously unreported phenotype of RP1L1 maculopathy associated with a genetic variant of RP1L1 gene, thereby expanding the spectrum associated with RP1L1 maculopathy.

NPHP1 gene-associated nephronophthisis is associated with an occult retinopathy

Biallelic deletions in the NPHP1 gene are the most frequent molecular defect of nephronophthisis, a kidney ciliopathy and leading cause of hereditary end-stage kidney disease. Nephrocystin 1, the gene product of NPHP1, is also expressed in photoreceptors where it plays an important role in intra-flagellar transport between the inner and outer segments. However, the human retinal phenotype has never been investigated in detail. Here, we characterized retinal features of 16 patients with homozygous deletions of the entire NPHP1 gene. Retinal assessment included multimodal imaging (optical coherence tomography, fundus autofluorescence) and visual function testing (visual acuity, full-field electroretinography, color vision, visual field). Fifteen patients had a mild retinal phenotype that predominantly affected cones, but with relative sparing of the fovea. Despite a predominant cone dysfunction, night vision problems were an early symptom in some cases. The consistent retinal phenotype on optical coherence tomography images included reduced reflectivity and often a granular appearance of the ellipsoid zone, fading or loss of the interdigitation zone, and mild outer retinal thinning. However, there were usually no obvious structural changes visible upon clinical examination and fundus autofluorescence imaging (occult retinopathy). More advanced retinal degeneration might occur with ageing. An identified additional CEP290 variant in one patient with a more severe retinal degeneration may indicate a potential role for genetic modifiers, although this requires further investigation. Thus, diagnostic awareness about this distinct retinal phenotype has implications for the differential diagnosis of nephronophthisis and for individual prognosis of visual function.

Role of LINC01592 in TGF-β1-induced epithelial-mesenchymal transition of retinal pigment epithelial cells

Regulation of long-chain non-coding RNA01592 (LINC01592) in the process of transforming retinal pigment epithelial (RPE) cells into mesenchymal cells following induction by transforming growth factor beat 1 (TGF-β1) was investigated by interfering with LINC01592 expression in human RPE (hRPE) cells. LINC01592 expression in hRPE cells was significantly increased following treatment with 10 ng/mL TGF-β1 for 48 h. Expression of E-cadherin and Snail were decreased in hRPE cells following induction with TGF-β1 compared with the control group (P < 0.05). Following induction by TGF-β1, expression of E-cadherin, alpha-smooth muscle actin (α-SMA), and Snail were significantly lower in the LINC01592-knockdown group compared with the negative control group (P < 0.05). LINC01592 overexpression significantly enhanced the viability, proliferation, and migration of hRPE cells induced by TGF-β1 (P < 0.05). Following induction by TGF-β1, E-cadherin expression was significantly decreased and α-SMA and Snail expression were significantly increased in the LINC01592-overexpression group compared with the negative control group (P < 0.05). RPE cells induced by TGF-β1 exhibited epithelial-mesenchymal transition (EMT). Inhibiting LINC01592 expression could significantly reduce TGF-β1-induced EMT of hRPE cells. The regulatory effect of LINC01592 on EMT in hRPE cells induced by TGF-β1 provides a novel treatment for proliferative vitreoretinopathy.

Spatial Functional Characteristics of East Asian Patients With Occult Macular Dystrophy (Miyake Disease); EAOMD Report No. 2

PURPOSE

To describe the functional phenotypic features of East Asian patients with RP1L1-associated occult macular dystrophy (ie, Miyake disease).

DESIGN

An international multicenter retrospective cohort study.

METHODS

Twenty-eight participants (53 eyes) with Miyake disease were enrolled at 3 centers (in Japan, China, and South Korea). Ophthalmologic examinations including spectral-domain optical coherence tomography (SDOCT) and multifocal electroretinogram (mfERG) were performed. Patients were classified into 3 functional groups based on mfERG: Group 1, paracentral dysfunction with relatively preserved central/peripheral function; Group 2, homogeneous central dysfunction with preserved peripheral function; and Group 3, widespread dysfunction over the recorded area. Three functional phenotypes were compared in clinical parameters and SDOCT morphologic classification (severe phenotype, blurred/flat ellipsoid zone and absence of the interdigitation zone; mild phenotype, preserved ellipsoid zone).

RESULTS

There were 8 eyes in Group 1, 40 eyes in Group 2, and 5 eyes in Group 3. The patients in Group 1 showed significantly later onset (P = .005) and shorter disease duration (P = .002), compared with those in Group 2. All 8 eyes in Group 1 showed the mild morphologic phenotype, while 43 of 45 eyes in Groups 2 and 3 presented the severe phenotype, which identified a significant association between the functional grouping and the morphologic classification (P < .001).

CONCLUSIONS

A spectrum of functional phenotypes of Miyake disease was first documented with identification of 3 functional subtypes. Patients with paracentral dysfunction had the mildest phenotype, and those with homogeneous central or widespread dysfunction showed overlapping clinical findings with severe photoreceptor changes, suggesting various extents of visual impairment.

RP2-associated retinal disorder in a Japanese cohort: Report of novel variants and a literature review, identifying a genotype-phenotype association

The retinitis pigmentosa 2 (RP2) gene is one of the causative genes for X-linked inherited retinal disorder. We characterized the clinical/genetic features of four patients with RP2-associated retinal disorder (RP2-RD) from four Japanese families in a nationwide cohort. A systematic review of RP2-RD in the Japanese population was also performed. All four patients were clinically diagnosed with retinitis pigmentosa (RP). The mean age at examination was 36.5 (10-47) years, and the mean visual acuity in the right/left eye was 1.40 (0.52-2.0)/1.10 (0.52-1.7) in the logarithm of the minimum angle of resolution unit, respectively. Three patients showed extensive retinal atrophy with macular involvement, and one had central retinal atrophy. Four RP2 variants were identified, including two novel missense (p.Ser6Phe, p.Leu189Pro) and two previously reported truncating variants (p.Arg120Ter, p.Glu269CysfsTer3). The phenotypes of two patients with truncating variants were more severe than the phenotypes of two patients with missense variants. A systematic review revealed additional 11 variants, including three missense and eight deleterious (null) variants, and a statistically significant association between phenotype severity and genotype severity was revealed. The clinical and genetic spectrum of RP2-RD was illustrated in the Japanese population, identifying the characteristic features of a severe form of RP with early macular involvement.

Clinical and genetic characteristics of 10 Japanese patients with PROM1-associated retinal disorder: A report of the phenotype spectrum and a literature review in the Japanese population

Variants in the PROM1 gene are associated with cone (-rod) dystrophy, macular dystrophy, and other phenotypes. We describe the clinical and genetic characteristics of 10 patients from eight Japanese families with PROM1-associated retinal disorder (PROM1-RD) in a nationwide cohort. A literature review of PROM1-RD in the Japanese population was also performed. The median age at onset/examination of 10 patients was 31.0 (range, 10-45)/44.5 (22-73) years. All 10 patients showed atrophic macular changes. Seven patients (70.0%) had spared fovea to various degrees, approximately half of whom had maintained visual acuity. Generalized cone (-rod) dysfunction was demonstrated in all nine subjects with available electrophysiological data. Three PROM1 variants were identified in this study: one recurrent disease-causing variant (p.Arg373Cys), one novel putative disease-causing variant (p.Cys112Arg), and one novel variant of uncertain significance (VUS; p.Gly53Asp). Characteristic features of macular atrophy with generalized cone-dominated retinal dysfunction were shared among all 10 subjects with PROM1-RD, and the presence of foveal sparing was crucial in maintaining visual acuity. Together with the three previously reported variants [p.R373C, c.1551+1G>A (pathogenic), p.Asn580His (likely benign)] in the literature of Japanese patients, one prevalent missense variant (p.Arg373Cys, 6/9 families, 66.7%) detected in multiple studies was determined in the Japanese population, which was also frequently detected in the European population.

Progress of macular atrophy during 30 months' follow-up in a patient with spinocerebellar ataxia type1 (SCA1)

PURPOSE

To report the 30-months' course of macular dystrophy in a patient with genetically confirmed spinocerebellar ataxia type1 (SCA1).

METHODS

Detailed ophthalmological examinations including best-corrected visual acuity (BCVA), perimetry, multimodal fundus imaging, and electrophysiological recordings were performed on a 52-year-old woman with SCA1. The number of CAG sequence repeats of the candidate gene was verified.

RESULTS

The baseline decimal BCVA was 0.2 OD and 0.3 OS. Goldman perimetry showed relative central scotomas and slight enlargements of Mariotte blind spot bilaterally. Ophthalmoscopy revealed no abnormalities in the macula and optic disk. Fundus autofluorescence (FAF) showed a circular hyperautofluorescence and round-shaped hypoautofluorescence in the macula. Optical coherence tomography (OCT) showed a loss of the interdigitation zone and ellipsoid zone (EZ) in the macula. Full-field scotopic and photopic Full-field electroretinograms (ERGs) were normal, and multifocal ERGs were decreased in the central area. After 30 months, the BCVA had not changed, but the FAF showed a spark-like hypoautofluorescence in the macula. The abnormal area of the EZ had expanded toward the periphery, and the rate of EZ loss was 199.7%/year OD and 206.8%/year OS. Genetic examinations revealed an increase in the number of heterozygous CAG repeats in the ATXN1 gene, and the CAG repeat number of the mutant allele ranged from 43 to 48.

CONCLUSIONS

The full-field scotopic and photopic ERGs were normal. The mfERGs were significantly smaller in the central region. OCT demonstrated bilateral photoreceptor atrophy in the macula, and the rate of EZ loss was more rapid than in other macular dystrophies. Spark-like hypoautofluorescence appeared during the course of the disease process which might be a specific feature of SCA1-related retinopathy.

RP1L1 and inherited photoreceptor disease: A review

Retinitis pigmentosa 1-like 1 (RP1L1) is a component of the photoreceptor cilium. Pathogenic variants in RP1L1 lead to photoreceptor disease, suggesting an important role for RP1L1 in photoreceptor biology, though its exact function is unknown. To date, RP1L1 variants have been associated with occult macular dystrophy (a cone degeneration) and retinitis pigmentosa (a rod disease). Here, we summarize reported RP1L1-associated photoreceptor conditions and disease-causing RP1L1 variants. We also discuss novel associations between RP1L1 and additional photoreceptor conditions-besides occult macular dystrophy and retinitis pigmentosa-and fit RP1L1 into the broader scope of photoreceptor disease. RP1L1 appears to have a complex relationship with other photoreceptor proteins and may modify disease phenotype. Ultimately, further exploration of the relationship between RP1L1, other cilium components, and their impact on photoreceptor health is needed.