Disease-specific variant interpretation highlighted the genetic findings in 2325 Japanese patients with retinitis pigmentosa and allied diseases.

BACKGROUND: As gene-specific therapy for inherited retinal dystrophy (IRD) advances, unified variant interpretation across institutes is becoming increasingly important. This study aims to update the genetic findings of 86 retinitis pigmentosa (RP)-related genes in a large number of Japanese patients with RP by applying the standardised variant interpretation guidelines for Japanese patients with IRD (J-IRD-VI guidelines) built upon the American College of Medical Genetics and Genomics and the Association for Molecular Pathology rules, and assess the contribution of these genes in RP-allied diseases. METHODS: We assessed 2325 probands with RP (n=2155, including n=1204 sequenced previously with the same sequencing panel) and allied diseases (n=170, newly analysed), including Usher syndrome, Leber congenital amaurosis and cone-rod dystrophy (CRD). Target sequencing using a panel of 86 genes was performed. The variants were interpreted according to the J-IRD-VI guidelines. RESULTS: A total of 3564 variants were detected, of which 524 variants were interpreted as pathogenic or likely pathogenic. Among these 524 variants, 280 (53.4%) had been either undetected or interpreted as variants of unknown significance or benign variants in our earlier study of 1204 patients with RP. This led to a genetic diagnostic rate in 38.6% of patients with RP, with EYS accounting for 46.7% of the genetically solved patients, showing a 9% increase in diagnostic rate from our earlier study. The genetic diagnostic rate for patients with CRD was 28.2%, with RP-related genes significantly contributing over other allied diseases. CONCLUSION: A large-scale genetic analysis using the J-IRD-VI guidelines highlighted the population-specific genetic findings for Japanese patients with IRD; these findings serve as a foundation for the clinical application of gene-specific therapies.

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.

ASSESSMENTS OF MACULAR FUNCTION BY FOCAL MACULAR ELECTRORETINOGRAPHY AND STATIC PERIMETRY IN EYES WITH RETINITIS PIGMENTOSA.

PURPOSE: To assess the macular function by focal macular electroretinography and static perimetry in eyes with retinitis pigmentosa. METHODS: Eighty-eight eyes of 88 retinitis pigmentosa patients were analyzed. The relationships between the focal macular electroretinography components and the mean deviations (MDs) of the Humphrey Field Analyzer 10-2 were determined. Spectral-domain optical coherence tomography was used to determine the integrity of the ellipsoid zone (EZ) and the interdigitation zone. RESULTS: Forward-backward stepwise regression analyses showed that the amplitudes (r = 0.45, P < 0.01) and implicit times (r = -0.29, P < 0.01) of the b-waves were significantly correlated with the MDs. Some of the eyes had reduced b-wave amplitudes (<1.0 µ V) and disrupted interdigitation zone, despite having a better MD (≥ -10.0 dB) and intact EZ. Subgroup analyses of eyes with better MD (≥ -10.0 dB) showed that the EZ width was correlated with the MDs but not with the b-wave amplitude. The thickness of the EZ-retinal pigment epithelium as an alternative indicator of interdigitation zone was correlated with the b-wave amplitude (r = 0.32, P = 0.04) but not with the MDs (r = -0.10, P = 0.53). CONCLUSION: The fact that the focal macular electroretinography amplitudes are reduced before the shortening of the EZ in the early stage of retinitis pigmentosa indicates that the focal macular electroretinography amplitudes are an earlier indicator of macular dysfunction than the Humphrey Field Analyzer 10-2 findings.

INTRAOPERATIVE AND POSTOPERATIVE MONITORING OF AUTOLOGOUS NEUROSENSORY RETINAL FLAP TRANSPLANTATION FOR A REFRACTORY MACULAR HOLE ASSOCIATED WITH HIGH MYOPIA.

PURPOSE: To describe the intraoperative and postoperative morphological and functional outcomes after autologous neurosensory retinal flap transplantation (ART) for a high myopia-related refractory macular hole (MH). METHODS: This prospective interventional study enrolled five eyes of five patients (age range 54-84 years) with highly myopic refractory MHs who underwent ART. All cases were evaluated with intraoperative optical coherence tomography and postoperative optical coherence tomography, optical coherence tomography angiography, and microperimetry for at least 6 months postoperatively. RESULTS: Intraoperatively, the MH was covered by an ART flap with a persistent small subretinal space that was filled with the ART flap after 4 days to 6 days. Optical coherence tomography discriminated the original from the transplanted retina. The mean basal diameter of the original MH decreased from 1,504 ± 684 µm preoperatively to 1,111 ± 356 µm postoperatively. The best-corrected visual acuity improved in two cases, was stable in two cases, and deteriorated in one case. Microperimetry demonstrated no obvious postoperative changes in the fixation points and the absolute scotoma corresponding to the base of MHs with chorioretinal atrophy. In two eyes, choroidal neovascularization developed beneath the transplanted retinas. CONCLUSION: Transplanted tissue was in a fixed position by 1 week postoperatively with a decreased diameter of the original MH. Postoperative fixation points were on the original retina at the MH edge. Because choroidal neovascularization may develop, detailed monitoring is required.

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.

CHANGES OF CONE PHOTORECEPTOR MOSAIC IN AUTOSOMAL RECESSIVE BESTROPHINOPATHY.

PURPOSE: To assess the morphological changes of cone photoreceptors in eyes with autosomal recessive bestrophinopathy. METHODS: Both eyes of five patients with autosomal recessive bestrophinopathyunderwent spectral domain optical coherence tomography and adaptive optics fundus imaging. The cone photoreceptor densities were measured at intervals of 100 µm between 500 µm nasal and temporal eccentricities from the foveal center. RESULTS: The median age of the patients was 30 years (range, 23-45 years), and the best-corrected visual acuity ranged from 20/20 to 20/80. Adaptive optics fundus images showed reduced cone photoreceptor densities corresponding to the damages of the photoreceptor layer in the spectral domain optical coherence tomography images in four patients with relatively good best-corrected visual acuity. The cone photoreceptor densities at the center of the fovea were less than one-third of the normal cone densities (range 11,600-30,400 cells/mm). Cone photoreceptor mosaics were visible over the lesions with serous retinal detachment and retinal edema, although they were partially hyporeflective. CONCLUSION: There is a significant cone photoreceptor loss in the macular region of patients with autosomal recessive bestrophinopathy, although they had relatively good visual acuity. Monitoring cone photoreceptors by adaptive optics fundus imaging should provide accurate assessments of the disease status and indications for future therapeutic interventions.

Samd7 is a cell type-specific PRC1 component essential for establishing retinal rod photoreceptor identity.

Precise transcriptional regulation controlled by a transcription factor network is known to be crucial for establishing correct neuronal cell identities and functions in the CNS. In the retina, the expression of various cone and rod photoreceptor cell genes is regulated by multiple transcription factors; however, the role of epigenetic regulation in photoreceptor cell gene expression has been poorly understood. Here, we found that Samd7, a rod-enriched sterile alpha domain (SAM) domain protein, is essential for silencing nonrod gene expression through H3K27me3 regulation in rod photoreceptor cells. Samd7-null mutant mice showed ectopic expression of nonrod genes including S-opsin in rod photoreceptor cells and rod photoreceptor cell dysfunction. Samd7 physically interacts with Polyhomeotic homologs (Phc proteins), components of the Polycomb repressive complex 1 (PRC1), and colocalizes with Phc2 and Ring1B in Polycomb bodies. ChIP assays showed a significant decrease of H3K27me3 in the genes up-regulated in the Samd7-deficient retina, showing that Samd7 deficiency causes the derepression of nonrod gene expression in rod photoreceptor cells. The current study suggests that Samd7 is a cell type-specific PRC1 component epigenetically defining rod photoreceptor cell identity.

Course of loss of photoreceptor function and progressive Müller cell gliosis in rhodopsin P347L transgenic rabbits.

Long living animal models of retinitis pigmentosa (RP) can provide important information on the retinal changes that occur at the late stages of photoreceptor degeneration. The rhodopsin Pro347Leu transgenic rabbit (P347L Tg) is a model of RP, and it has been used to analyze the functional and morphological changes in the retina following the degeneration of the photoreceptors. They have also been used to test newly-developed therapies to treat eyes with photoreceptor degeneration. However, assessments of the retinal changes in P347L Tg rabbits older than 1-year have not been reported even though the data are important for research on developing new therapies to restore vision at the end stages of RP. The purpose of this study was to determine the time course of the loss of photoreceptor function and the changes in the morphology of the retina of P347L Tg rabbits. The experiments were performed on 26 older P347L Tg rabbits. The results showed that the amplitudes of the ERGs of the P347L Tg rabbits gradually decreased and reached <10 µV between 30- and 54-months-of-age. Histological analysis at these later stages showed a loss of the photoreceptor layer, and OCT analysis showed absence of the layering of the retina. However, the thickness between the inner limiting membrane and the outer plexiform layer was about 1.7 times thicker than the corresponding thickness of WT rabbits in the OCT images. This thickening was caused by a marked gliosis of the entire retina which was confirmed by light and transmission electron microscopy. In addition, immunohistochemical analysis showed there was excessive staining of the glial fibrillary acid protein in the older P347L Tg rabbits although the rod ON bipolar cells and horizontal cells were still present in the inner nuclear layer. Our results indicate that the P347L Tg rabbit progressed to complete photoreceptor loss within 30- and 54-months-of-age and severe gliosis altered the morphology of the retina.

CLINICAL COURSE OF PARANEOPLASTIC RETINOPATHY WITH ANTI-TRPM1 AUTOANTIBODY IN JAPANESE COHORT.

PURPOSE: To report the clinical course of eyes with paraneoplastic retinopathy caused by an autoantibody against transient receptor potential cation channel, subfamily M, member 1 (TRPM1). METHODS: Ten paraneoplastic retinopathy patients with retinal ON-bipolar cell dysfunction, including six melanoma-associated retinopathy, from eight institutions in Japan were evaluated for the presence of an anti-TRPM1 antibody. The results of ophthalmic examinations and the presence of anti-TRPM1 antibody were analyzed. RESULTS: Five patients were positive for the anti-TRPM1 antibody. These patients had similar clinical findings in both eyes at the time of diagnosis; relatively preserved best-corrected visual acuity, absence of fundus and optical coherence tomography abnormalities, and specific abnormalities of the electroretinography (ERG); and negative-type ERGs with bright stimulus flashes. One patient whose retinal ON-bipolar cells remained dysfunctional for the entire testing period, although the anti-TRPM1 antibody had disappeared. On the other hand, the ERGs recovered in 2 cases within 2 years after the onset. One case progressed to additional impairment of the photoreceptors with deterioration of ERGs. One case died and the clinical course was unavailable. CONCLUSION: Paraneoplastic retinopathy patients with retinal ON-bipolar cell dysfunction possess autoantibodies against TRPM1 at the onset of the disease process; however, the clinical course of these eyes can be different.

Differences in ocular findings in two siblings: one with complete and other with incomplete achromatopsia.

PURPOSE: Patients with complete achromatopsia (ACHM) lack cone function, and patients with incomplete ACHM have relatively good visual acuity with residual color vision. The pathological mechanism(s) underlying incomplete ACHM has not been determined. The purpose of this study was to determine the pathophysiology of ACHM in two siblings: one with complete ACHM and the other with incomplete ACHM. METHODS: The medical charts of the two siblings were reviewed. RESULTS: The sibling with incomplete ACHM had decimal visual acuities that ranged from 0.4 to 0.6 and had moderate color blindness in both eyes. Her younger brother was diagnosed with complete ACHM and was not able to hold fixation, had severe pendular nystagmus, visual acuity that ranged from 0.08 to 0.1, and severe color vision abnormalities in both eyes. Optical coherence tomography (OCT) showed that the ellipsoid zone (EZ) was disruptive in the macular region in both patients. However, careful examination of the OCT images in the incomplete ACHM patient showed a high-density EZ in the central fovea. Adaptive optics (AO) fundus imaging of the sibling with incomplete ACHM revealed sparse cone mosaics remaining within 1° of the foveal center with no mosaics visible outside the central fovea. AO fundus imaging could not be performed in Case 2 because of the severe nystagmus. CONCLUSION: Our results showed that cone mosaics were present in the central fovea in the sibling with incomplete ACHM patient. This may explain the better visual acuity and color vision in this sibling.

A Case of Sickle Cell Retinopathy With Retinal Artery Occlusion in African-Japanese Patients.

As globalization progresses, cases of sickle cell disease (SCD) are now being seen even in Japan, where SCD did not originally exist. SCD causes not only anemia but also peripheral blood flow obstruction, which can lead to systemic complications. This report represents a case of sickle cell retinopathy (SCR) in Japan discovered with the onset of retinal artery occlusion (RAO). The patient, a 20-year-old African-Japanese male, was being monitored for SCD at the Nagoya University Hospital, Pediatrics Department, Nagoya, Japan. Following a chest pain episode, he reported a loss of vision in his right eye and was referred to the ophthalmology department. Examination showed reduced visual acuity in the right eye 20/40 compared to the left 20/20. A Goldman visual field test indicated central vision loss in the right eye, and fundoscopic examination revealed yellow-white lesions centered on the macula and peripheral salmon-patch-like lesions in the right eye, with peripheral black sunburst-like lesions in the left eye. Optical coherence tomography (OCT) of the right eye showed inner retinal edema within the macula, suggesting an SCR accompanied by branch RAO. Six months later, he complained of further vision loss in his right eye. Examination and OCT revealed sub-inner limiting membrane hemorrhage in the right eye, suggesting worsening of the SCR. SCD is exceedingly rare among native Japanese but is likely to be encountered more frequently as globalization progresses. Even in countries where SCD has traditionally been rare, attention must be paid to the occurrence of severe SCR when managing SCD.

Genetic and Clinical Features of ABCA4-Associated Retinopathy in a Japanese Nationwide Cohort.

PURPOSE: To clarify the genetic and clinical features of Japanese patients with ABCA4-associated retinopathy. DESIGN: Retrospective, multicenter cohort study. METHODS: Patients with retinal degeneration and biallelic ABCA4 variants were recruited from 13 different hospitals. Whole exome sequencing analysis was used for genetic testing. Comprehensive ophthalmic examinations were performed on matched patients. The primary outcome measure was identifying multimodal retinal imaging findings associated with disease progression. RESULTS: This study included 63 patients: 19 with missense/missense, 23 with missense/truncation, and 21 with truncation/truncation genotypes. In total, 62 variants were identified, including 29 novel variants. Six patients had a mild phenotype characterized by foveal-sparing or preserved foveal structure, including 4 with missense/missense and 2 with missense/truncation genotypes. The p.Arg212His variant was the most frequent in patients with mild phenotypes (4/12 alleles). Clinical findings showed a disease duration-dependent worsening of the phenotypic stage. Patients with the truncation/truncation genotype exhibited rapid retinal degeneration within a few years and definite fundus autofluorescence imaging patterns, including hyper autofluorescence at the macula and few or no flecks. CONCLUSIONS: Our results indicate that missense/missense or missense/truncation genotypes, including the p.Arg212His variant, are associated with a relatively mild phenotype. In contrast, the truncation/truncation genotype causes rapid and severe retinal degeneration in Japanese patients with ABCA4-associated retinopathy. These data are vital in predicting patient prognosis, guiding genetic counseling, and stratifying patients for future clinical trials.

Pathogenic variants of MFRP and PRSS56 genes are major causes of nanophthalmos in Japanese patients.

BACKGROUND: Nanophthalmos (NNO) is a rare condition with significantly shorter axial length than normal. Several genes are known to cause NNO, among them the MFRP and PRSS56 genes have been reported to cause majority of NNOs. The purpose of this study was to determine the genetic basis of Japanese patients with NNO. MATERIALS AND METHODS: We studied seven patients with NNO. Whole exome sequencing (WES) and Sanger sequencing were performed to determine the variants causing the NNO. We also reviewed the medical charts of the patients to determine the phenotype of these seven patients. RESULTS: WES revealed that four patients from three families carried homozygous frameshift variants of the PRSS56 gene (c.1066dupC). Two novel variants of the MFRP gene were detected in the other two patients: one proband had a homozygous missense variant (c.1486 G>A) and the other had a compound heterozygous variant (c.1486 G>A and c.662_663insT). The axial length of the eight eyes with the PRSS56 variant was 15.69 ± 0.48 mm (mean ± SD) and that for the 4 eyes with the MFRP variant was 15.63 ± 0.69 mm. Three of the six cases with the PRSS56 or MFRP variant had the uveal effusion syndrome. CONCLUSIONS: NNOs in Japanese patients are caused by variants of the PRSS56 and MFRP genes as in other ethnic populations. In addition, two new variants of the MFRP gene were found in our cohort. The phenotypes and anomalies in Japanese patients with NNO were similar to those reported for other ethnic populations.

Assessment of factors affecting flicker ERGs recorded with RETeval from data obtained from health checkup screening.

PURPOSE: To determine the factors significantly associated with the amplitudes and implicit times of the flicker electroretinograms (ERGs) recorded with the RETeval system by analyzing the comprehensive data obtained during a health checkup screening. METHODS: Flicker ERGs were recorded with the RETeval system from 373 individuals who had a normal fundus and optical coherence tomography images. The sex, age, anthropometric, ophthalmologic, and hematologic data were collected from all participants who were 40- to 89-years-of-age. Univariable and multivariable linear mixed effects regression analyses were performed to identify factors that were significantly associated with the implicit times and amplitudes of the RETeval flicker ERGs. RESULTS: Univariable linear mixed effects regression analysis showed significant correlations between the implicit times and the best-corrected visual acuity, the age, the axial length, the blood sugar level, and the blood urea nitrogen level. Analyses by multivariable linear mixed effects regression identified that the axial length (ß = 0.28), the age (ß = 0.24), and the blood sugar level (ß = 0.092) were three independent factors that were significantly correlated with the implicit times of the RETeval flicker ERGs. Univariable linear mixed effects regression analysis also showed significant correlations between the amplitudes of the RETeval flicker ERGs and the age, the platelet count, and the creatinine level. Multivariable linear mixed effects regression models identified the age (ß = -0.092), the platelet count (ß = 0.099), and the creatinine level (ß = -0.12) as three independent factors that were significantly correlated with the amplitudes of the RETeval flicker ERGs. However, the smoking habits, body mass index, and the blood pressure were not significantly correlated with either the implicit times or amplitudes of the RETeval flicker ERGs. CONCLUSIONS: Our results indicate that the age and some ophthalmologic and hematologic findings but not the anthropometric findings were significantly associated with the implicit times and amplitudes of the RETeval flicker ERGs. Thus, clinicians should remember these factors when analyzing the RETeval flicker ERGs.

Longitudinal Changes of Macular Curvature in Patients with Retinitis Pigmentosa.

Purpose: To investigate the longitudinal changes of the macular curvature in eyes with retinitis pigmentosa (RP) and to determine the factors associated with the changes. Methods: We reviewed the medical charts of 107 RP patients, for whom the axial length of their right eyes ranged from 21.5 to 26.0 mm and who had had been followed by spectral-domain optical coherence tomography (OCT). The OCT images at the initial and the most recent examinations were compared. The mean curvature of Bruch's membrane within 6 mm of the central macula obtained from the OCT images was evaluated as the mean macular curvature index (MMCI). Changes in the MMCI and their relationships with other clinical factors, including the ellipsoid zone (EZ) width, were assessed. Results: The MMCI decreased significantly in the vertical OCT images, from -15.47 × 10-5 µm-1 to -16.36 × 10-5 µm-1 (P = 0.008) during the mean observation period of 3.4 ± 1.4 years (mean ± SD). This indicated that the macular shape became more concave. The change to a steeper shape was more prominent in eyes with less photoreceptor degeneration and for which the EZ width was preserved at >2000 µm. In three eyes, the MMCI increased markedly by >5 × 10-5 µm-1, and this was accompanied by absorption of the macular edema. Conclusions: The macular curvature in RP eyes becomes more concave in eyes with preserved EZ width. Translational Relevance: Longitudinal changes of the macular curvature in RP should be considered in future therapies, such as the implantation of the retinal prosthesis.

Relationship Between Macular Curvature and Common Causative Genes of Retinitis Pigmentosa in Japanese Patients.

Purpose: To determine the relationship between the macular curvature and the causative genes of retinitis pigmentosa (RP). Methods: We examined the medical records of the right eyes of 65 cases with RP (31 men and 34 women; average age, 47.6 years). There were 31 cases with the EYS variants, 11 cases with the USH2A variants, six cases with the RPGR variants, 13 cases with the RP1 variants, and four cases with the RP1L1 variants. The mean curvature of Bruch's membrane was calculated within 6 mm of the fovea as the mean macular curvature index (MMCI, 1/µm). We used multiple linear regression analysis to determine the independence of the causative genes contributing to the MMCIs after adjustments for age, sex, axial length, and width of the ellipsoid zone. Results: The median MMCI was -31.2 × 10-5/µm for the RPGR eyes, -16.5 × 10-5/µm for the RP1L1 eyes, -13.0 × 10-5/µm for the RP1 eyes, -9.8 × 10-5/µm for the EYS eyes, and -9.0 × 10-5/µm for the USH2A eyes. Compared with the EYS gene as the reference gene, the RPGR gene was significantly related to the MMCI values after adjusting for the other parameters (P = 5.30 × 10-6). In contrast, the effects of the other genes, USH2A, RP1, and RP1L1, were not significantly different from that of the EYS gene (P = 0.26, P = 0.49, and P = 0.92, respectively). Conclusions: The RPGR gene had a stronger effect on the steep macular curvature than the other ciliopathy-related genes.

Changes in intraocular pressure and aqueous flare in eyes with multiple evanescent white dot syndrome.

PURPOSE: To study the changes in intraocular pressure (IOP) and aqueous flare in eyes with multiple evanescent white dot syndrome (MEWDS) during the disease course. STUDY DESIGN: Retrospective observational study. METHODS: Twenty-one patients with unilateral MEWDS were retrospectively evaluated. IOP values were compared between the affected and fellow eyes 2 weeks, 1 month, and 3 months following disease onset in 17 patients, and within 7 days from disease onset in 11 patients. Aqueous flare values measured using a laser flare-cell meter in ten eyes between 1 weeks and 1 month from disease onset were compared between the affected and fellow eyes. RESULTS: IOP values were significantly lower in the affected eyes than in the fellow eyes at both 2 weeks (P=0.002) and 1 month from disease onset (P=0.02). However, IOP values of affected eyes did not show significant differences from the fellow eyes within 7 days ((P=0.11) and 3 months of onset (P=0.30). Aqueous flare values were significantly increased in the affected eyes compared to those in the fellow eyes (P=0.010) and significantly correlated with IOP values (r=-0.67, P=0.035). CONCLUSION: IOP values mildly decreased in association with aqueous flare values in the acute phase in eyes with MEWDS.

Clinical characteristics and high resolution retinal imaging of retinitis pigmentosa caused by RP1 gene variants.

PURPOSE: To report the clinical course and high resolution images of autosomal recessive retinitis pigmentosa (RP) associated with a variant of the RP1 gene (c.4052_4053ins328/p.Tyr1352Alafs*9; m1), a high frequency founder variant in Japanese RP patients. STUDY DESIGN: Retrospective case series. METHODS: Nine patients from 5 unrelated Japanese families were studied. Five patients had the m1 variant homozygously, and 4 patients had the m1 variant compound heterozygously with another frameshift variant (c.4196delG/p.Cys1399Leufs*5). Ophthalmic examinations including adaptive optics (AO) fundus imaging were performed periodically. RESULTS: The fundus photographs, fundus autofluorescence (FAF) images, and optical coherence tomographic (OCT) images indicated severe retinal degeneration in all the patients involving the macula even at a young age (20 s). The areas of surviving photoreceptors in the central macula were seen as hyper-autofluorescent regions in the FAF images and preserved outer retinal structure in the OCT images; they were identifiable in the AO fundus images in 8 eyes. The borders of the surviving photoreceptor areas were surrounded by hyporeflective clumps, presumably containing melanin, and the size of these areas decreased progressively during the 4-year follow-up period. The disappearance of the surviving photoreceptor areas was associated with complete blindness. CONCLUSION: Patients with RP associated with the m1 variant have a progressive and severe retinal degeneration that begins at an early age. Monitoring the surviving photoreceptor areas by AO fundus imaging can provide a more precise pathological record of retinal degeneration.

Clinical and Genetic Characteristics of 15 Affected Patients From 12 Japanese Families with GUCY2D-Associated Retinal Disorder.

Purpose: To determine the clinical and genetic characteristics of patients with GUCY2D-associated retinal disorder (GUCY2D-RD). Methods: Fifteen patients from 12 families with inherited retinal disorder (IRD) and harboring GUCY2D variants were ascertained from 730 Japanese families with IRD. Comprehensive ophthalmological examinations, including visual acuity (VA) measurement, retinal imaging, and electrophysiological assessment were performed to classify patients into three phenotype subgroups; macular dystrophy (MD), cone-rod dystrophy (CORD), and Leber congenital amaurosis (LCA). In silico analysis was performed for the detected variants, and the molecularly confirmed inheritance pattern was determined (autosomal dominant/recessive [AD/AR]). Results: The median age of onset/examination was 22.0/38.0 years (ranges, 0-55 and 1-73) with a median VA of 0.80/0.70 LogMAR units (ranges, 0.00-1.52 and 0.10-1.52) in the right/left eye, respectively. Macular atrophy was identified in seven patients (46.7%), and two had diffuse fundus disturbance (13.3%), and six had an essentially normal fundus (40.0%). There were 11 patients with generalized cone-rod dysfunction (78.6%), two with entire functional loss (14.3%), and one with confined macular dysfunction (7.1%). There were nine families with ADCORD, one with ARCORD, one with ADMD, and one with ARLCA. Ten GUCY2D variants were identified, including four novel variants (p.Val56GlyfsTer262, p.Met246Ile, p.Arg761Trp, p.Glu874Lys). Conclusions: This large cohort study delineates the disease spectrum of GUCY2D-RD. Diverse clinical presentations with various severities of ADCORD and the early-onset severe phenotype of ARLCA are illustrated. A relatively lower prevalence of GUCY2D-RD for ADCORD and ARLCA in the Japanese population was revealed. Translational Relevance: The obtained data help to monitor and counsel patients, especially in East Asia, as well as to design future therapeutic approaches.

Clinical and Genetic Characteristics of 18 Patients from 13 Japanese Families with CRX-associated retinal disorder: Identification of Genotype-phenotype Association.

Inherited retinal disorder (IRD) is a leading cause of blindness, and CRX is one of a number of genes reported to harbour autosomal dominant (AD) and recessive (AR) causative variants. Eighteen patients from 13 families with CRX-associated retinal disorder (CRX-RD) were identified from 730 Japanese families with IRD. Ophthalmological examinations and phenotype subgroup classification were performed. The median age of onset/latest examination was 45.0/62.5 years (range, 15-77/25-94). The median visual acuity in the right/left eye was 0.52/0.40 (range, -0.08-2.00/-0.18-1.70) logarithm of the minimum angle of resolution (LogMAR) units. There was one family with macular dystrophy, nine with cone-rod dystrophy (CORD), and three with retinitis pigmentosa. In silico analysis of CRX variants was conducted for genotype subgroup classification based on inheritance and the presence of truncating variants. Eight pathogenic CRX variants were identified, including three novel heterozygous variants (p.R43H, p.P145Lfs*42, and p.P197Afs*22). A trend of a genotype-phenotype association was revealed between the phenotype and genotype subgroups. A considerably high proportion of CRX-RD in ADCORD was determined in the Japanese cohort (39.1%), often showing the mild phenotype (CORD) with late-onset disease (sixth decade). Frequently found heterozygous missense variants located within the homeodomain underlie this mild phenotype. This large cohort study delineates the disease spectrum of CRX-RD in the Japanese population.