Necl-1/CADM3 regulates cone synapse formation in the mouse retina.

In vertebrates, retinal neural circuitry for visual perception is organized in specific layers. The outer plexiform layer is the first synaptic region in the visual pathway, where photoreceptor synaptic terminals connect with bipolar and horizontal cell processes. However, molecular mechanisms underlying cone synapse formation to mediate OFF pathways remain unknown. This study reveals that Necl-1/CADM3 is localized at S- and S/M-opsin-containing cones and dendrites of type 4 OFF cone bipolar cells (CBCs). In Necl-1-/- mouse retina, synapses between cones and type 4 OFF CBCs were dislocated, horizontal cell distribution became abnormal, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors were dislocated. Necl-1-/- mice exhibited aberrant short-wavelength-light-elicited signal transmission from cones to OFF CBCs, which was rescued by AMPA receptor potentiator. Additionally, Necl-1-/- mice showed impaired optokinetic responses. These findings suggest that Necl-1 regulates cone synapse formation to mediate OFF cone pathways elicited by short-wavelength light in mouse retina.

Clinical course of two siblings with potassium voltage-gated channel modifier subfamily V member 2 (KCNV2)-associated retinopathy.

BACKGROUND: KCNV2-associated retinopathy causes a phenotype reported as "cone dystrophy with nyctalopia and supernormal rod responses (CDSRR; OMIM# 610356)," featuring pathognomonic findings on electroretinography (ERG). Here, we report the clinical courses of two siblings with CDSRR. CASE REPORTS: Patient 1: A 3-year-old boy with intermittent exophoria was referred to our hospital. The patient's decimal best-corrected visual acuity (BCVA) at age 6 was 0.7 and 0.7 in the right and left eyes, respectively. Photophobia and night blindness were also observed. Because the ERG showed a delayed and supernormal b-wave with a "squaring (trough-flattened)" a-wave in the DA-30 ERG, and CDSRR was diagnosed. The patient's vision gradually worsened, and faint bilateral bull's eye maculopathy was observed at the age of 27 years, although the fundi were initially unremarkable. Genetic examination revealed a homozygous missense variant, c.529T > C (p.Cys177Arg), in the KCNV2 gene. Patient 2: The second patient was Patient 1's younger sister, who was brought to our hospital at 3 years of age. The patient presented with exotropia, mild nystagmus, photophobia, night blindness, and color vision abnormalities. The patients' decimal BCVA at age 13 was 0.6 and 0.4 in the right and left eyes, respectively, and BCVA gradually decreased until the age of 24 years. The fundi were unremarkable. The siblings had similar ERG findings and the same homozygous missense variant in the KCNV2 gene. CONCLUSIONS: The siblings had clinical findings typical of CDSRR. High-intense flash ERG is recommended for identifying pathognomonic "squaring" a-waves in patients with CDSRR.

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.

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.

Optical coherence tomography findings of the peripheral retina in patients with congenital X-linked retinoschisis.

Introduction: Congenital X-linked retinoschisis (XLRS) presents as macular retinoschisis/degeneration in almost all patients and as peripheral retinoschisis in half the patients. Although the optical coherence tomography (OCT) findings of macular retinoschisis have been well investigated, those of peripheral retinoschisis have rarely been reported. This study aimed to report the ultra-widefield OCT findings of the peripheral retina in patients with XLRS. Methods: Medical records of 10 Japanese patients (19 eyes) with clinically and/or genetically diagnosed XLRS were retrospectively reviewed. Funduscopic, electroretinographic, and OCT findings were reviewed and evaluated. Some were also genetically evaluated for the RS1 gene. Results: OCT of the macula revealed schises and/or cystoid changes in the inner nuclear layer (INL) and outer nuclear layer. In contrast, OCT of the peripheral retina revealed schises and/or cystoid changes in the INL in eight eyes (44%), and/or splitting in the ganglion cell layer (GCL) in 10 (56%) of the 18 eyes with clear OCT images. No schisis or cystoid changes were found in the peripheral OCT images of eight eyes (44%). A 16-year-old boy presented with retinal splitting of the GCL and INL of the inferior retina, although he had no ophthalmoscopic peripheral retinoschisis. Genetic examinations were performed on three patients, all of whom had reported missense mutations in the RS1 gene. Conclusion: In XLRS, peripheral bullous retinoschisis results from GCL splitting in the retina. One of the 10 patients with XLRS showed intraretinal retinoschisis in the GCL in the inferior periphery, which was unremarkable on ophthalmoscopy (occult retinoschisis). Although both peripheral bullous retinoschisis and occult retinoschisis showed splitting/cystic changes in the GCL, further studies are needed to determine whether occult retinoschisis progresses to bullous retinoschisis.

Fundus autofluorescence, optical coherence tomography and electroretinography abnormalities in a patient with digoxin retinopathy that resemble those in KCNV2-associated retinopathy.

BACKGROUND: Digoxin related retinal toxicity causes blurred vision, photophobia, central scotoma, color vision abnormality, and electroretinography (ERG) abnormalities. Here, we report a case with transient abnormalities in vison, in which fundus autofluorescence (FAF), optical coherence tomography (OCT), and ERG findings resembled those in KCNV2 (potassium voltage-gated channel modifier subfamily V member 2)-associated retinopathy. CASE REPORT: An 89-year-old woman presented with complaints of acute blurred vision, nyctalopia, photophobia, and color vision abnormality. She received digoxin for tachycardia induced by atrial fibrillation for a month. The fundi showed a faint white ring at the fovea, which showed hyperfluorescence in FAF. OCT showed a thickened EZ in the macula. A dark-adapted (DA)-30 ERG showed a reduced and "squaring (trough-flattened)" a-wave, and a delayed, supernormal b-wave, resulting in a high b/a-wave amplitude ratio. The digoxin dose was reduced following an elevation in serum levels. Five weeks later, her visual acuities improved, and abnormal hyperfluorescence on FAF disappeared. After 6 months, no visual symptoms were reported. The ellipsoid-zone thickening in OCT improved; however, the b/a-wave amplitude ratio on DA-30 ERG remained high. The b-wave in LA-long-flash ERG was initially reduced, which improved after correction of serum level of digoxin. CONCLUSIONS: The patient's clinical findings resembled those of patients with KCNV2-associated retinopathy or temporal hyperkalemia. These disorders appear to have a common pathogenesis, which may be related to abnormal extracellular potassium levels in the retina. The on-bipolar cells seemed to be more affected than the off-bipolar cells in digoxin related retinal toxicity.

Long-Term Visual Prognosis of Patients Following Lens-Sparing Vitrectomy for Stage 4A Retinopathy of Prematurity.

This study evaluated the long-term visual outcomes of patients in whom at least one eye underwent successful lens-sparing vitrectomy (LSV) for stage 4A retinopathy of prematurity (ROP). A retrospective chart review was conducted using the data of 61 eyes of 42 patients with a minimum 4-year follow-up after successful LSV, with or without anti-vascular endothelial growth factor (VEGF) therapy, and whose best-corrected visual acuity (BCVA) was measurable using Landolt rings at the final visit. The mean age at the final follow-up was 10.1 ± 3.3 years. Before LSV, all eyes underwent laser ablation therapy. Twenty eyes (32.8%) with high vascular activity received anti-VEGF therapy before LSV. The mean decimal BCVA at the final follow-up was 0.23 ± 0.26 (range: hand motion to 1.2). Twenty-three eyes (54.1%) had a decimal BCVA of ≥0.4. Among 49 phakic eyes at the final examination, the mean refractive error was -10.1 ± 5.0 D, with 37 eyes (75.5%) having high myopia (>-6.0 D). No significant differences were observed in terms of decimal BCVA and refractive errors between eyes with and without anti-VEGF therapy. Approximately half of the patients had a decimal BCVA of ≥0.4, despite myopic refraction after successful LSV for stage 4A ROP. LSV for stage 4A ROP seemed to be associated with good visual function, despite myopic refraction.

EFFICACY OF INNER WALL RETINECTOMY FOR BULLOUS SCHISIS CAVITY HANGING OVER OR THREATENING THE MACULA IN PATIENTS WITH CONGENITAL X-LINKED RETINOSCHISIS.

PURPOSE: To present the clinical characteristics, surgical outcomes, and surgical complications of patients with congenital X-linked retinoschisis who underwent vitrectomy for bullous schisis cavity hanging over or threatening the macula. METHODS: Nine patients with congenital X-linked retinoschisis (12 eyes) who underwent vitrectomy at three tertiary hospitals and completed ≥3 years of postoperative follow-up were retrospectively investigated. Data were collected from patients' charts, including age at vitrectomy, surgical procedures, and postoperative complications. RESULTS: The age at vitrectomy ranged 4 months to 103 months (median: 14 months). Inner wall retinectomy was performed during the initial vitrectomy in eight eyes. Among the eight eyes that initially underwent inner wall retinectomy, one (12.5%) required subsequent retinal surgery for postoperative complication. Furthermore, four eyes did not undergo initial inner wall retinectomy but required subsequent retinal surgeries for postoperative complications. Three of five eyes (60.0%) treated with silicone oil tamponade and two of seven eyes (28.6%) that were not treated with silicone oil tamponade during the initial vitrectomy required subsequent retinal surgeries for postoperative complications. All eyes maintained a clear central visual axis at the last examination. CONCLUSION: Inner wall retinectomy seems beneficial in achieving a clear visual axis in eyes with bullous schisis cavity hanging over or threatening the macula in patients with congenital X-linked retinoschisis.

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.

The Effect of an Additional Core Suture During Pulvertaft Tendon Repair: A Fresh-Frozen Cadaver Study.

PURPOSE: Pulvertaft tendon repair is a strong suture technique; however, proper tendon tension is impaired by repair site elongation. Therefore, methods to reduce postoperative elongation are warranted. This study aimed to determine the effects of additional core sutures during Pulvertaft tendon repair on repair site elongation and rupture strength. METHODS: A total of 48 finger extensor tendons were harvested from fresh-frozen cadavers, and tendons with similar diameters were paired. The 24 pairs of tendons were divided into the following 4 groups: group I, 3 interlaced weaves only; group II, 3 interlaced weaves and 2 core suture strands with 4-0 nylon; group III, 3 interlaced weaves and 2 core suture strands with 4-0 FiberWire; and group IV, 4 interlaced weaves only. Each sutured tendon was placed in a Universal Testing Machine, and repair site elongation after repeated traction loads and rupture strength were measured. RESULTS: The mean elongation values were 2.74 ± 0.84 mm, 1.80 ± 0.16 mm, 1.60 ± 0.18 mm, and 1.92 ± 0.18 mm for groups I, II, III, and IV, respectively. The elongation values were significantly lower in groups II, III, and IV than in group I. The mean rupture strengths were 64.9 ± 16.0 N, 94.8 ± 17.2 N, 110.9 ± 21.3 N, and 104.9 ± 17.5 N for groups I, II, III, and IV, respectively. Rupture strengths were significantly higher for groups III and IV than for group I. CONCLUSIONS: After adding core sutures during Pulvertaft tendon repair, the elongation amount decreased, and the rupture strength improved. CLINICAL RELEVANCE: The study showed the effect of additional core sutures during Pulvertaft tendon repair, suggesting that it could be useful in reducing postoperative tendon elongation when extensor tendon transfers are performed.

STRUCTURAL OUTCOME AFTER SURGERY FOR STAGE 5 RETINOPATHY OF PREMATURITY BASED ON THE NEW INTERNATIONAL CLASSIFICATION: ICROP 3.

PURPOSE: This study investigated the outcomes of vitrectomy for Stage 5 retinopathy of prematurity (ROP) based on the International Classification of Retinopathy of Prematurity third edition, in which Stage 5 ROP is divided into three subgroups. METHODS: Fifty-four eyes of 34 patients with Stage 5 ROP who underwent vitrectomy between 2004 and 2020 were retrospectively analyzed. Data including sex, gestational age and weight at birth, International Classification of Retinopathy of Prematurity 3 subcategories, perioperative use of intravitreal bevacizumab injection and laser photocoagulation, surgical procedure and complications, final retinal reattachment, and follow-up period were collected. RESULTS: Complete retinal reattachment was achieved in 16 eyes (88.9%) with Stage 5A and 13 eyes (39.4%) with Stage 5B ( P = 0.0003, Wilcoxon rank-sum test). Three patients with Stage 5C were considered inoperable. Postoperative anatomical failure was significantly associated with stage (Stage 5B vs. 5A; odds ratio, 17.986; 95% confidence interval, 3.712-148.502; P = 0.0001, multivariate logistic regression analysis). Intraoperative intravitreal bevacizumab was significantly associated with lower postoperative incidence of vitreous hemorrhage and glaucoma ( P = 0.041, chi-square test). CONCLUSION: Staging of preoperative anatomical features based on International Classification of Retinopathy of Prematurity 3 is a useful predictor for final anatomical success. Intraoperative intravitreal bevacizumab might reduce postoperative complication risks.

Characteristics of Eyes Developing Retinal Detachment After Anti-vascular Endothelial Growth Factor Therapy for Retinopathy of Prematurity.

Background: We investigated the incidence and clinical characteristics of eyes showing retinal detachment (RD) after anti-vascular endothelial growth factor (VEGF) for retinopathy of prematurity (ROP). Methods: A retrospective chart review of 76 consecutive eyes of 45 patients (18 girls and 27 boys) with stage 3 ROP who received anti-VEGF therapy between January 2012 and August 2020 with a minimum follow-up of 6 months was conducted. Eyes were divided into two groups: the vitrectomy (V) group that required vitrectomy for RD after anti-VEGF therapy and the non-vitrectomy (non-V) group that did not require vitrectomy. Data were collected from patient charts, including sex, postmenstrual age (PMA) at birth, birth weight, PMA at anti-VEGF therapy, comorbidities, reactivation, examination interval, and subsequent vitrectomies. Results: The median PMA at birth was 24.7 (range, 22.1-29.3) weeks. Twenty-seven eyes (35.1%) exhibited ROP reactivation at 6.4 ± 3.1 weeks after anti-VEGF therapy. The V group included six eyes of five patients, all of whom exhibited reactivation and developed RD 10.1 ± 6.5 weeks after anti-VEGF therapy. The types of RD were conventional (classic) in two eyes and circumferential (unique to RD after anti-VEGF) in four eyes. Three eyes required repeated vitrectomy. All eyes, except one eye in the V group, achieved retinal attachment at the last examination. The non-V group included 70 eyes of 40 patients, of which 21 exhibited reactivation and were treated successfully with laser (17 eyes) or second anti-VEGF (4 eyes). The proportion of eyes with plus disease was significantly higher in the V group (50.0%) than in the non-V group (10.0%) (P = 0.035). V group included 3 of 22 eyes (13.6%) in which the interval between the last examination and the diagnosis of reactivation was <1 week and 3 of 5 eyes (60.0%) in which the interval was more than 1 week (P = 0.024). The two groups showed no significant differences in the other factors. Conclusion: Approximately 8% of eyes developed RD about 10 weeks after anti-VEGF therapy for ROP. Eyes with history of plus disease should be carefully monitored at appropriate intervals after anti-VEGF therapy for ROP.

Pars plana vitrectomy for vitreoretinal complications in only seeing eyes after treatment for retinoblastoma.

PURPOSE: To report the outcomes of two only seeing eyes of two cases with retinoblastoma in which vitrectomy was performed to treat vitreous hemorrhage or rhegmatogenous retinal detachment after treatment for retinoblastoma. OBSERVATIONS: Case 1 was an 8-month-old girl whose bilateral retinoblastoma (group D, OU) was treated by chemotherapy and focal ablation therapy. As the tumor size increased, enucleation was required in the right eye. At 4 years of age, about 1 year after the last treatment for retinoblastoma, lens-sparing vitrectomy was performed for dense, nonclearing vitreous hemorrhage, which had occurred 6 months previously. No recurrence of the tumor was found, and the patient's visual acuity improved to 0.9 postoperatively. Case 2 was a 4-month-old boy who was diagnosed with bilateral retinoblastoma (group D, OD; group C, OS) and underwent treatment, including systemic and local chemotherapy and proton beam therapy. Because large, regressed tumor masses were present in the posterior pole of the right eye, the left eye was the only seeing eye. At the age of 1 year 7 months, retinal detachment developed in the left eye 1 month after cryotherapy was performed for tumor recurrence. Although a scleral buckling procedure without drainage was performed, the retina was not reattached. The retina was reattached after vitrectomy with melphalan irrigation and silicone oil tamponade. However, recurrence was noted 6 months after the operation, and enucleation was required. CONCLUSION AND IMPORTANCE: Vitrectomy appears to be beneficial for the treatment of vision-threatening complications after retinoblastoma treatment. However, vitrectomy may be associated with the potential spread of tumor cells and/or tumor recurrence and therefore should be reserved as the last treatment modality for only seeing eyes. Careful postoperative follow-up is mandatory.

Recurrent proliferative vitreoretinopathy in a patient with morning glory syndrome and intellectual disability.

PURPOSE: To report a case of morning glory syndrome (MGS) with retinal detachment, in whom unusually severe proliferative vitreoretinopathy (PVR) developed after surgery. OBSERVATIONS: A 6-year-old boy with intellectual disability underwent vitrectomy for retinal detachment associated with MGS in the left eye. Vitrectomy was performed five times. C3F8 gas tamponade was used for the first and second surgeries. However, the retina developed PVR with a nearly 360-degree giant retinal tear after the second surgery. The third surgery required 360-degree retinotomy, followed by short-term perfluoro-n-octane (PFO) tamponade, which was removed ten days later. During the fourth surgery, the retina was found to be flipped over in a funnel-shape on the retinal pigment epithelium under the PFO. Silicone oil (SO) tamponade was used. During the fifth surgery, the retina was flipped over under the SO again. We found that the patient shook his head rapidly and vigorously while crying. CONCLUSIONS AND IMPORTANCE: We speculate that excessive head shaking associated with the patient's intellectual disability induced an unusual shape of the retina under PFO or SO. Although difficult to achieve, postoperative resting seems important in preventing such complications in intellectually disabled patients with retinal detachment.

Identification of Interphotoreceptor retinoid-binding protein in the Schisis cavity fluid of a patient with congenital X-linked Retinoschisis.

BACKGROUND: This case report describes the surgical outcome in a patient with congenital X-linked retinoschisis (CXLRS) and the results of proteomic analysis of surgically extracted samples from both vitreous and intraschisis cavities by mass spectrometry. CASE PRESENTATION: A 3-month-old boy presented with extensive retinoschisis involving macula and retinal periphery in both eyes. Genetic analysis confirmed retinoschisin 1 mutation (c.554C > T), and an electroretinogram showed significant reduction of b-wave and decreased cone and rod responses, which led to a diagnosis of CXLRS. By performing pars plana vitrectomy, including inner wall retinectomy, clear visual axes with stable retinal conditions and functional vision in both eyes were obtained during the 4 years of follow-up. Proteomic analysis of surgically retrieved fluid from the intraschisis cavity revealed a higher expression of interphotoreceptor retinoid-binding protein (IRBP) than that from the vitreous humor. However, both samples showed equal levels of albumin, transferrin, and pigment epithelium-derived factor. CONCLUSIONS: Cellular adhesive imperfection in CXLRS may cause IRBP diffusion from the interphotoreceptor matrix, resulting in the strong expression of IRBP in the intraschisis cavity. An impaired retinoid cycle caused by an absence of IRBP in the retina may potentially underlie the pathology of CXLRS.

Clinical course of a Japanese girl with Leber congenital amaurosis associated with a novel nonsense pathogenic variant in NMNAT1: a case report and mini review.

Leber congenital amaurosis (LCA), although rare, is one of the most severe forms of early-onset inherited retinal dystrophy (IRD). Here, we review the molecular genetics and phenotypic characteristics of patients with NMNAT1-associated IRD. The longitudinal clinical and molecular findings of a Japanese girl diagnosed with LCA associated with pathogenic variants in NMNAT1 c.648delG, (p.Trp216Ter*) and c.709C>T (p.Arg237Cys) have been described to highlight the salient clinical features of NMNAT1-associated IRD.

Genetic and Phenotypic Landscape of PRPH2-Associated Retinal Dystrophy in Japan.

Peripherin-2 (PRPH2) is one of the causative genes of inherited retinal dystrophy. While the gene is relatively common in Caucasians, reports from Asian ethnicities are limited. In the present study, we report 40 Japanese patients from 30 families with PRPH2-associated retinal dystrophy. We identified 17 distinct pathogenic or likely pathogenic variants using next-generation sequencing. Variants p.R142W and p.V200E were relatively common in the cohort. The age of onset was generally in the 40's; however, some patients had earlier onset (age: 5 years). Visual acuity of the patients ranged from hand motion to 1.5 (Snellen equivalent 20/13). The patients showed variable phenotypes such as retinitis pigmentosa, cone-rod dystrophy, and macular dystrophy. Additionally, intrafamilial phenotypic variability was observed. Choroidal neovascularization was observed in three eyes of two patients with retinitis pigmentosa. The results demonstrate the genotypic and phenotypic variations of the disease in the Asian cohort.

Neural crest stem cells can be induced in vitro from human-induced pluripotent stem cells using a novel protocol free of feeder cells.

Objective: Our knowledge of human neural crest stem cells (NCSCs) is expanding, owing to recent advances in technologies utilizing human-induced pluripotent stem cells (hiPSCs) that generate NCSCs. However, the clinical application of these technologies requires the reduction of xeno-materials. To overcome this significant impediment, this study aimed to devise a novel method to induce NCSCs from hiPSCs without using a feeder cell layer. Materials and Methods: hiPSCs were cultured in feeder-free maintenance media containing the Rho-associated coiled-coil forming kinase inhibitor Y-27632. When the cells reached 50-70% confluence, differentiation was initiated by replacing the medium with knockout serum replacement (KSR) medium containing Noggin and SB431542. The KSR medium was then gradually replaced with increasing concentrations of Neurobasal medium from day 5 to 11. Results: Immunocytochemistry and flow cytometry were performed 12 days after induction of differentiation and revealed that the cells generated from hiPSCs expressed the NCSC markers p75 and HNK-1, but not the hiPSC marker SOX2. Conclusion: These findings demonstrate that hiPSCs were induced to differentiate into NCSCs in the absence of feeder cells.

FACTORS ASSOCIATED WITH REACTIVATION AFTER INTRAVITREAL BEVACIZUMAB OR RANIBIZUMAB THERAPY IN INFANTS WITH RETINOPATHY OF PREMATURITY.

PURPOSE: To investigate the efficacy and risk factors of intravitreal antivascular endothelial growth factor injection (anti-VEGF therapy) for retinopathy of prematurity (ROP). METHODS: We retrospectively reviewed 80 consecutive eyes of 43 patients with Type 1 ROP or worse who received anti-VEGF therapy during January 2012-February 2018. Patients were divided into those who were injected with 0.25 mg of bevacizumab (IVB group, 37 eyes) and 0.25 mg of ranibizumab (IVR group, 43 eyes). Serum VEGF concentrations of 18 patients were measured before and after IVR. RESULTS: Antivascular endothelial growth factor injection therapy reduced ROP activity in all eyes; however, 14 eyes (17.5%) exhibited reactivation. The reactivation rates of the IVB and IVR groups were 13.5% and 20.9%, respectively (P = 0.556). Multivariate logistic regression analysis showed that postmenstrual age ≤35 weeks at anti-VEGF therapy (P = 0.014) and aggressive posterior ROP (P = 0.044) was significantly associated with reactivation. Serum VEGF was significantly suppressed at Days 1 (P < 0.001) and 7 (P = 0.012) after IVR and returned to the preinjection level by Day 14 (P = 0.210). CONCLUSION: Both IVR and IVB seemed effective in reducing ROP activity. Reactivation after anti-VEGF therapy may be associated with younger postmenstrual age at anti-VEGF therapy and aggressive posterior ROP.