Familial exudative vitreoretinopathy (FEVR) is a severe retinal vascular disease that causes blindness. FEVR has been linked to mutations in several genes associated with inactivation of the Norrin/β-catenin signaling pathway, but these account for only approximately 50% of cases. We report that mutations in α-catenin (CTNNA1) cause FEVR by overactivating the β-catenin pathway and disrupting cell adherens junctions. We identified 3 heterozygous mutations in CTNNA1 (p.F72S, p.R376Cfs*27, and p.P893L) by exome sequencing and further demonstrated that FEVR-associated mutations led to overactivation of Norrin/β-catenin signaling as a result of impaired protein interactions within the cadherin-catenin complex. The clinical features of FEVR were reproduced in mice lacking Ctnna1 in vascular endothelial cells (ECs) or with overactivated β-catenin signaling by an EC-specific gain-of-function allele of Ctnnb1. In isolated mouse lung ECs, both CTNNA1-P893L and F72S mutants failed to rescue either the disrupted F-actin arrangement or the VE-cadherin and CTNNB1 distribution. Moreover, we discovered that compound heterozygous Ctnna1 F72S and a deletion allele could cause a similar phenotype. Furthermore, in a FEVR family, we identified a mutation of LRP5, which activates Norrin/β-catenin signaling, and the corresponding knockin mice exhibited a partial FEVR-like phenotype. Our study demonstrates that the precise regulation of β-catenin activation is critical for retinal vascular development and provides new insights into the pathogenesis of FEVR.

Purpose.: To analyze the incidence and severity of retinopathy of prematurity (ROP) in China, and to explore the workload implications of applying different criteria. Methods.: A prospective, neonatal units–based study undertaken in two tertiary level hospitals in Shanghai, China, from January 1, 2010 to December 31, 2012. All infants with birth weight (BW) of 2000 g or less and/or gestational age (GA) of 34 weeks or less were screened for ROP. Retinopathy of prematurity was classified using the international classification, and was treated in accordance with the recommendations of the Early Treatment for Retinopathy of Prematurity Cooperative Group. Results.: A total of 2825 (93.7%) of 3014 eligible infants were screened, and ROP was diagnosed in 503 infants (17.8%). One hundred ninety-one infants (6.8%) had type 1 or worse ROP and were treated with laser or vitrectomy. The mean GA of ROP patients was 29.9 ± 2.1 weeks and their mean BW was 1425 ± 266 g. Infants who needed treatment for ROP had a mean GA of 29.3 ± 2.1 weeks and mean BW of 1331 ± 330 g. Among these treated infants, 18 infants (9.4%) exceeded the United Kingdom's (UK) screening criteria, and 28 (14.7%) exceeded the criteria used in the United States (US). If narrower criteria, as in GA less than or equal to 33 weeks and/or BW less than or equal to 1750 g were adopted, almost 16.9% fewer infants would not have been examined, with no infant missing treatment. Conclusions.: Larger, older infants are at risk in China and screening criteria used in the US and UK may not be suitable for China. Further population-based studies are recommended to determine the necessity of modifying the current ROP screening protocol. Chinese Abstract

Purpose: To investigate timing and risk factors of recurrent retinopathy of prematurity (ROP) after intravitreal ranibizumab (IVR) monotherapy. Methods: Fifty eyes (the more severe eye) of 50 infants treated with IVR monotherapy for type 1 ROP were studied retrospectively. The mean follow-up time was 31 weeks after IVR. Recurrent ROP (recurrence of extraretinal fibrovascular proliferation [EFP]) was determined by RetCam wide-angle fundus imaging and binocular indirect ophthalmoscopy. Risk time of recurrence was estimated by Kaplan-Meier survival analysis with recurrence as the endpoint. Time-varying recurrence hazard rate was determined using the hazard function of life-table analysis. The risk factors of recurrence were explored by logistic regression analysis. Results: Recurrence of ROP occurred in 32 (64%) of 50 eyes at 7.9 ± 2.7 weeks after IVR. Most of recurrence (94%) occurred in 2.5 to 12.0 weeks following IVR treatment. The recurrence hazard rate reached its maximum at 8 weeks. Recurrence affecting the initial site of EFP occurred significantly earlier than recurrence only at the new vascular advancing edge (4.5 ± 1.4 weeks versus 9.1 ± 2.0 weeks after IVR, P < 0.001). The independent risk factors of recurrence included extensive retinal neovascularization (P = 0.005) and oxygen requirement after IVR (P = 0.016). Conclusions: Recurrence of type 1 ROP should be carefully watched in a long-term follow-up after IVR monotherapy, particularly in the first 12 weeks after IVR and for those with extensive retinal neovascularization or prolonged oxygen therapy.

Purpose: To identify potentially pathogenic variants (PPVs) in Chinese familial exudative vitreoretinopathy (FEVR) patients in FZD4, LRP5, NDP, TSPAN12, ZNF408, and KIF11 genes. Methods: Blood samples were collected from probands and their parent(s). Genomic DNA was analyzed by next-generation sequencing, and the sequence of selected variants were validated by Sanger sequencing. The potential pathogenicity of a variant was evaluated by in silico analysis and by cosegregation of the variant with disease. Each proband was subjected to comprehensive retinal examinations, and the severity of FEVR was individually graded for each eye. Whenever possible, fundus fluorescein angiography was obtained and analyzed for parent(s) of each proband. Variation in mutation expressivity was analyzed. Results: Three hundred eighty-nine consecutive FEVR patients from 389 families participated in this study. About 74% of the probands were children younger than 7 years old. One hundred one PPVs, 49 variants with unknown significance (VUS), were identified, including 73 novel PPVs and 38 novel VUS. One hundred ten probands carried PPV (28.3%), and 51 probands carried VUS (13.1%). PPVs in FZD4, LRP5, TSPAN12, NDP, ZNF408, and KIF11 were found in 8.48%, 9.00%, 5.91%, 4.63%, 0.77%, and 0.77% of the cohort, respectively. Probands carrying PPVs in NDP and KIF11 had more severe FEVR in general than those carrying PPVs in other genes. Overall, variants in LRP5 and FZD4 showed more significant variation in phenotype than variants in TSPAN12 and NDP genes. Conclusions: Our study expanded the spectrum of PPVs associated with FEVR.

Increased oxidative stress, which can lead to the retinal pigment epithelium (RPE) cell death by inducing ATP depletion and DNA repair, is believed to be a prominent pathology in age-related macular degeneration (AMD). In the present study, we showed that and 0.1 mM nicotinamide adenine dinucleotide (NAD⁺) administration significantly blocked RPE cell death induced by 300 μM H₂O₂. Further investigation showed that H₂O₂ resulted in increased intracellular ROS level, activation of PARP-1 and subsequently necrotic death of RPE cells. Exogenous NAD⁺ administration significantly decreased intracellular and intranuclear ROS levels in H₂O₂-treated RPE cells. In addition, NAD⁺ administration to H₂O₂-treated RPE cells inhibited the activation of PARP-1 and protected the RPE cells against necrotic death. Moreover, exogenous NAD⁺ administration up-regulated autophagy in the H₂O₂-treated RPE cells. Inhibition of autophagy by LY294002 blocked the decrease of intracellular and intranuclear ROS level. Besides, inhibition of autophagy by LY294002 abolished the protection of exogenous NAD⁺ against H₂O₂-induced cell necrotic death. Taken together, our findings indicate that that exogenous NAD⁺ administration suppresses H₂O₂-induced oxidative stress and protects RPE cells against PARP-1 mediated necrotic death through the up-regulation of autophagy. The results suggest that exogenous NAD⁺ administration might be potential value for the treatment of AMD.