Early detection of ocular abnormalities in a Chinese multicentre neonatal eye screening programme-1-year result

Multimodal imaging of white preretinal lesions in atypical familial exudative vitreoretinopathy: Case report and literature review

Purpose

To report a rare clinical finding of preretinal granules associated with atypical familial exudative vitreoretinopathy (FEVR) and perform a review of the literature.

Observations

An asymptomatic 18-year-old male was referred for unilateral peripheral avascular retina evaluation in association with presumed FEVR. He was first noted to have white preretinal granules on fundus examination at five years of age. The lesions remained unchanged over the subsequent years. Genetic testing did not reveal a pathogenic or likely pathogenic variant in a known FEVR gene. A review of the literature revealed five other cases of FEVR with similar findings.

Conclusions and Importance

Literature review suggests preretinal granules may present rarely in FEVR. Negative genetic screening of known FEVR genes in our patient with atypical FEVR suggests either a molecularly distinct etiology supporting the rarity of this association with FEVR or, alternatively, the presence of granules in developmental retinal vascular anomalies that are not specific to FEVR. Future study and genetic testing is necessary to better understand the cause of these preretinal granules and the clinical manifestations of FEVR.

Implementation of optical coherence tomography in retinopathy of prematurity screening

PURPOSE OF REVIEW

In this review, we explore the investigational applications of optical coherence tomography (OCT) in retinopathy of prematurity (ROP), the insights they have delivered thus far, and key milestones for its integration into the standard of care.

RECENT FINDINGS

While OCT has been widely integrated into clinical management of common retinal diseases, its use in pediatric contexts has been undermined by limitations in ergonomics, image acquisition time, and field of view. Recently, investigational handheld OCT devices have been reported with advancements including ultra-widefield view, noncontact use, and high-speed image capture permitting real-time en face visualization. These developments are compelling for OCT as a more objective alternative with reduced neonatal stress compared to indirect ophthalmoscopy and/or fundus photography as a means of classifying and monitoring ROP.

SUMMARY

OCT may become a viable modality in management of ROP. Ongoing innovation surrounding handheld devices should aim to optimize patient comfort and image resolution in the retinal periphery. Future clinical investigations may seek to objectively characterize features of peripheral stage and explore novel biomarkers of disease activity.

Characterization of a novel heterozygous frameshift variant in NDP gene that causes familial exudative vitreoretinopathy in female patients

Familial exudative vitreoretinopathy (FEVR) is a severe inherited disease characterized by defective retinal vascular development. With genetic and clinical heterogeneity, FEVR can be inherited in different patterns and characterized by phenotypes ranging from moderate visual defects to complete vision loss. This study was conducted to unravel the genetic and functional etiology of a 4-month-old female FEVR patient. Targeted gene panel and Sanger sequencing were utilized for genetic evaluation. Luciferase assays, western blot, quantitive real-time PCR, and immunocytochemistry were performed to verify the functional defects in the identified candidate variant. Here, we report a 4-month-old girl with bilateral retinal folds and peripheral avascularization, and identified a novel frameshift heterozygous variant c.37dup (p.Leu13ProfsTer13) in NDP. In vitro experiments revealed that the Leu13ProfsTer13 variant led to a prominent decrease in protein levels instead of mRNA levels, resulting in compromised Norrin/β-catenin signaling activity. Human androgen receptor assay further revealed that a slight skewing of X chromosome inactivation could partially cause FEVR. Thus, the pathogenic mechanism by which heterozygous frameshift or nonsense variants in female carriers cause FEVR might largely result from a loss-of-function variant in one X chromosome allele and a slightly skewed X-inactivation. Further recruitment of more FEVR-affected females carrying NDP variants and genotype-phenotype correlation analysis can ultimately offer valuable information for the prognosis prediction of FEVR.

Frameshift variants in the C-terminal of CTNNB1 cause familial exudative vitreoretinopathy by AXIN1-mediated ubiquitin-proteasome degradation condensation

The β-catenin has two intrinsically disordered regions in both C- and N-terminal domains that trigger the formation of phase-separated condensates. Variants in its C-terminus are associated with familial exudative vitreoretinopathy (FEVR), yet the pathogenesis and the role of these variants in inducing abnormal condensates, are unclear. In this study, we identified a novel heterozygous frameshift variant, c.2104-2105insCC (p.Gln703ProfsTer33), in CTNNB1 from a FEVR-affected family. This variant encodes an unstable truncated protein that was unable to activate Wnt signal transduction, which could be rescued by the inhibition of proteasome or phosphorylation. Further functional experiments revealed the propensity of the Gln703ProfsTer33 variant to form cytoplasmic condensates, exhibiting a lower turnover rate after fluorescent bleaching due to enhanced interaction with AXIN1. LiCl, which specifically blocks GSK3β-mediated phosphorylation, restored signal transduction, cell proliferation, and junctional integrity in primary human retinal microvascular endothelial cells over-expressed with Gln703ProfsTer33. Finally, experiments on two reported FEVR-associated mutations in the C-terminal domain of β-catenin exhibited several functional defects similar to the Gln703ProfsTer33. Together, our findings unravel that the C-terminal region of β-catenin is pivotal for the regulation of AXIN1/β-catenin interaction, acting as a switch to mediate nucleic and cytosolic condensates formation that is implicated in the pathogenesis of FEVR.

Defective EMC1 drives abnormal retinal angiogenesis via Wnt/β-catenin signaling and may be associated with the pathogenesis of familial exudative vitreoretinopathy

Endoplasmic reticulum (ER) membrane protein complex (EMC) is required for the co-translational insertion of newly synthesized multi-transmembrane proteins. Compromised EMC function in different cell types has been implicated in multiple diseases. Using inducible genetic mouse models, we revealed defects in retinal vascularization upon endothelial cell (EC) specific deletion of Emc1, the largest subunit of EMC. Loss of Emc1 in ECs led to reduced vascular progression and vascular density, diminished tip cell sprouts, and vascular leakage. We then performed an unbiased transcriptomic analysis on human retinal microvascular endothelial cells (HRECs) and revealed a pivotal role of EMC1 in the β-catenin signaling pathway. Further in-vitro and in-vivo experiments proved that loss of EMC1 led to compromised β-catenin signaling activity through reduced expression of Wnt receptor FZD4, which could be restored by lithium chloride (LiCl) treatment. Driven by these findings, we screened genomic DNA samples from familial exudative vitreoretinopathy (FEVR) patients and identified one heterozygous variant in EMC1 that co-segregated with FEVR phenotype in the family. In-vitro expression experiments revealed that this variant allele failed to facilitate the expression of FZD4 on the plasma membrane and activate the β-catenin signaling pathway, which might be a main cause of FEVR. In conclusion, our findings reveal that variants in EMC1 gene cause compromised β-catenin signaling activity, which may be associated with the pathogenesis of FEVR.

Congenital coralliform cataract is the predominant consequence of a recurrent mutation in the CRYGD gene

BACKGROUND

Congenital cataract is a leading cause of treatable childhood blindness and both clinically and genetically heterogeneous. Among the already characterized phenotypes, coralliform cataract is a rare special form of congenital cataracts. Although previous studies had shown that mutations in the γD-crystallin (CRYGD) can result in congenital coralliform cataracts, no conclusive genotype-phenotype correlation might be drawn. Here we aimed to identify the spectrum and frequency of CRYGD gene mutations in congenital coralliform cataracts of Chinese origin.

METHODS

The medical records of 392 Chinese families with congenital cataracts were reviewed between January 2011 and December 2021. The families, clinically documented to have congenital coralliform cataracts, were screened for mutations in candidate CRYGD gene. The genomic DNA of all subjects was extracted from peripheral blood leukocytes. PCR amplified and direct sequencing were performed to identify the disease-causing mutation.

RESULTS

A total of 12 families with coralliform cataracts were recruited in this study in the past 10 years, accounting for 3.1% of the families with congenital cataracts. Of the 12 families, all affected individuals presented with bilateral non-progressive coralliform cataracts since birth, with the best-corrected Snellen visual acuities ranging from 20/200 to 20/25. A recurrent c.70 C > A (p. P24T) mutation in CRYGD was identified in 10 families (83.3%) with congenital cataract, which co-segregated with all affected individuals and was not observed in unaffected family members or ethnically matched normal controls.

CONCLUSIONS

The coralliform cataract is characterized by being bilateral, non-progressive and present at birth. A recurrent p.P24T CRYGD mutation occurs independently in 83.3% of the Chinese families with congenital coralliform cataracts and most likely represents a mutational hot spot, which underscore the relations between coralliform cataract and p.P24T CRYGD.

Incomplete retinal vascularization with retinopathy of prematurity-like ridges in healthy full-term newborns

PURPOSE

To describe the characteristics and clinical course of retinopathy of prematurity (ROP)-like ridges in healthy full-term newborns.

METHODS

A retrospective medical record review was performed on newborns who underwent fundus photography within 72 h of birth between January 1^st and December 31^st, 2019 at Women & Children's Health Care Hospital of Huantai, China. The RetCam 3 wide-field digital imaging system was used for fundus photography. ROP-like ridges were discovered and described.

RESULTS

Total of 5507 full-term infants underwent fundus photography. ROP-like ridges were discovered in 90 eyes from 57 infants (1.0%). Stage 1 ROP-like was seen in 63 of the eyes (70%), Stage 2 ROP-like in 26 of the eyes (28.9%), and Stage 3 ROP-like in 1 eye (1.1%). These ROP-like ridges were found in Zone II (41.1%) and Zone III (58.9%), but not in Zone I. Eight (8.9%) of the eyes had pre-plus-like diseases. No eyes had plus disease. All ROP-like ridges and pre-plus-like diseases were spontaneously regressed with a mean duration of 39.0 ± 8.2 days. Male sex (P = 0.003) was positively associated with ROP-like changes.

CONCLUSION

Healthy full-term newborns may have incomplete retinal vascularization and ROP-like ridges at birth. These ROP-like ridges showed signs of spontaneous regression.

A comprehensive functional analysis on the pathogenesis of novel TSPAN12 and NDP variants in familial exudative vitreoretinopathy

Familial exudative vitreoretinopathy (FEVR) is an inherited blinding disorder; however, the known FEVR-associated variants account for approximately only 50% cases. Currently, the pathogenesis of most reported variants is not well studied, we aim to identify novel variants from FEVR-associated genes and perform a comprehensive functional analysis to uncover the pathogenesis of variants that cause FEVR. Using targeted gene panel and Sanger sequencing, we identified six novel and three known variants in TSPAN12 and NDP. These variants were demonstrated to cause significant inhibition of Norrin/β-catenin pathway by dual-luciferase reporter assay and western blot analysis. Structural analysis and co-immunoprecipitation revealed compromised interactions between missense variants and binding partners in the Norrin/β-catenin pathway. Immunofluorescence and subcellular protein extraction were performed to reveal the abnormal subcellular trafficking. Additionally, over-expression of TSPAN12 successfully enhanced the Norrin/β-catenin signaling activity by strengthening the binding affinity of mutant Norrin with FZD4 or LRP5. Together, these observations expanded the spectrum of FEVR-associated variants for the genetic counseling and prenatal diagnosis of FEVR, as well providing a potential therapeutic strategy for the treatment of FEVR.

Time to Treatment of Pediatric Retinal Detachments: A US Claims-based Analysis

PURPOSE

To characterize delays in diagnosis and treatment of retinal detachments (RDs) in a pediatric population.

DESIGN

Retrospective cohort study using insurance claims data.

SUBJECTS

Pediatric patients with RD who underwent repair in the outpatient setting.

METHODS

A retrospective analysis of commercially insured patients from a national cohort (IBM MarketScan Research Databases) aged ≤ 18 years with an incident diagnosis of RD between 2007 and 2016. Patients with preceding eye-related visits, time to diagnosis, and time to repair were calculated and compared between patients with pre-existing ocular diagnosis and those without.

MAIN OUTCOME MEASURES

The time from diagnosis to specialist consultation, time from diagnosis to repair, time from specialist consultation to repair, number of preceding visits, and presence of previous eye-related diagnosis.

RESULTS

Our sample consisted of 826 patients, the majority (77%) of whom were diagnosed with rhegmatogenous RD. Only 40% of patients had at least 1 preceding eye-related visit, and 33% had at least 2 visits before RD diagnosis, with a median time from the last eye-related visit of 32 days (4-197 days) and median time from the second to last visit of 118 days (24-437 days). The median time from RD diagnosis to repair was 2 days (0-9 days). The 323 (37.9%) patients with pre-existing ocular diagnoses more frequently had at least 1 (44% vs. 37%; P = 0.079) or 2 preceding eye-related visits (40% vs. 29%; P = 0.002) compared with those without and also had a shorter time to RD diagnosis (median, 14.5 days vs. 44.5 days; P = 0.011) and repair (1 day vs. 3 days; P = 0.003).

CONCLUSIONS

Retinal detachment is an important cause of morbidity in children. This work highlighted how pediatric patients without previous ocular diagnoses and visits with eye care professional may have a delayed diagnosis and repair of their RD.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Prevalence, Characteristics, and Risk Factors of Retinal Hemorrhage among Full-Term Neonates in Southern China

Neonatal retinal hemorrhage (RH) is the most common ocular fundus disease among newborns. Early detection and timely intervention are vital for reducing the risk of visual impairment caused by RH. However, little is known about the prevalence, characteristics, and risk factors of RH in southern China. Full-term infants born in Qingyuan City during the first 10 days of each month in 2021 were included in this study. All infants underwent RetCam III retinal examinations. Detailed information on retinal hemorrhage, including involved eyes, bleeding severity, and affected area (extrafoveal macula, fovea, or optic disc), and clinical information on the neonates and their mothers was collected. The results showed that among the 1072 eligible neonates, 266 (24.8%) had neonatal retinal hemorrhage. Consistent bilateral retinal hemorrhage severity was observed in 83.2% of the cases. The prevalence of optic disc involved RH, extrafoveal macular involved RH and foveal involved RH were 23.7%, 81.2% and 2.63%, respectively. Multivariate logistic regression analysis showed that lower birth weight (OR, 0.63; 95% CI, 0.40-0.99; p < 0.05) and vaginal delivery (OR, 20.6; 95% CI, 9.10-46.5; p < 0.001) were risk factors of neonatal RH. The area under the ROC curve of vaginal delivery, combined with birth weight, as predictors of neonatal RH was 0.73, with 85.3% sensitivity and 23.9% specificity. The birth weight cutoff was 3460 g. Our results suggested that neonatal RH is common in full-term neonates in southern China. It usually has the same severity in both eyes and mostly involves the extrafoveal macular region. Vaginal delivery and low birth weight are risk factors for neonatal RH.

CTNND1 variants cause familial exudative vitreoretinopathy through Wnt/Cadherin axis

Familial exudative vitreoretinopathy (FEVR) is a hereditary disorder that can cause vision loss. The CTNND1 gene encodes a cellular adhesion protein p120-catenin (p120), which is essential for vascularization, yet the function of p120 in postnatal physiological angiogenesis remains unclear. Here, we applied whole-exome sequencing (WES) on 140 probands of FEVR families and identified three candidate variants in the human CTNND1 gene. We performed inducible deletion of Ctnnd1 in the postnatal mouse endothelial cells (ECs) and observed typical phenotypes of FEVR. Immunofluorescence of retina flat mounts also revealed immune responses, including reactive astrogliosis and microgliosis accompanied by abnormal Vegfa expression. Using an unbiased proteomics analysis in combination with in vivo or in vitro approaches, we propose that p120 is critical for the integrity of cadherin/catenin complex, and that p120 activates Wnt signaling activity by protecting β-catenin from Gsk3β-ubiquitin-guided degradation. Treatment of CTNND1-depleted HRECs with Gsk3β inhibitors LiCl or CHIR-99021 successfully enhanced cell proliferation by preventing β-catenin from degradation. Moreover, LiCl treatment increased vessel density in Ctnnd1-deficient mouse retinas. Functional analysis also revealed that variants in CTNND1 cause FEVR by compromising the expression of adherens junctions (AJs) and Wnt signaling activity. Additionally, genetic interactions between p120 and β-catenin or α-catenin revealed by double heterozygous deletion in mice further confirmed that p120 regulates vascular development through the Wnt/Cadherin axis. Together, we propose that CTNND1 is a novel candidate gene associated with FEVR, and that variants in CTNND1 can cause FEVR through the Wnt/Cadherin axis.

Portable wide-field digital imaging for screening of neonatal visual impairment causes in Rio de Janeiro, Brazil: a budget impact analysis

OBJECTIVE

To estimate the budget impact of portable wide-field digital imaging incorporation on screening neonatal causes of childhood blindness and visual impairment in Rio de Janeiro, Brazil.

DESIGN

Budget impact analysis.

SETTING

Rio de Janeiro, Brazil.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the direct cost of indirect binocular ophthalmoscopy, red reflex test and portable wide-field digital image screening comprising all babies born in Rio de Janeiro's government maternity wards. The secondary outcome was the budget impact of implementing portable wide-field digital image screening in Rio de Janeiro, Brazil.

RESULTS

Considering 100% coverage of maternity wards, the total budget impact between 2020 and 2024 would be US$3 820 706.04, ranging from US$3 139 844.34 to US$6 099 510.35. The additional cost would be US$3 124 457.28, ranging from US$2 714 492.26 to US$4 880 608.63.

CONCLUSION

The cost of universal digital imaging screening corresponds to less than 1% of the government health budget of the city of Rio de Janeiro. The information provided in this study may help government decision-makers evaluate the feasibility of implementing this new strategy in the municipal setting. Further health economic evaluations should be performed to verify the affordability of the implementation of this screening strategy in the Brazilian scenario, taking into account scarce human resources.

Analysis of non-retinopathy of prematurity (ROP)-related fundus hemorrhage in preterm infants in China

OBJECTIVE

To determine the incidence of fundus hemorrhage (FH) not associated with retinopathy of prematurity (ROP) during ocular screening and report their clinical features, risk factors, therapies, and prognosis in a large population of premature newborns.

METHODS

The medical records of all preterm newborns admitted to the Department of Ophthalmology, Peking University People's Hospital, Beijing, from January 1, 2016 through August 31, 2021 were retrospectively reviewed. Fundus examinations were carried out by experienced retinal experts. Examination under anesthesia was carried out in newborns with abnormal fundus including vitreous hemorrhage (VH) or retinal hemorrhage (RH) >2 disks' diameter by a Retcam 2 system. A lens-preserving vitrectomy was performed in infants requiring a vitrectomy. A comprehensive medical history was also recorded and analyzed.

RESULTS

During the 5-year period, a total of 7,260 preterm babies were screened. There were 82 (1.13%) newborns and 104 (0.72) eyes with FH, including VH or RH.Twelve (14.63%) newborns (16 eyes, 15.38%) had VH; 56 (68.29%) (74 eyes, 71.15%) had flame-shaped, superficial hemorrhages; six (7.31%) (6 eyes, 5.77%) had small, round, deep hemorrhages (<2 disk diameters in size); and eight (9.76%) (8 eyes, 7.69%) had large, round hemorrhages (>2 disk diameters). In all, there were 10 (12.20%) cases of intracranial hemorrhage. The mode of delivery was not found to be a significant factor in the occurrence of birth-related retinal hemorrhage (P = 0.22).Six newborns (eyes) with large, round retinal hemorrhage at the posterior pole while the macular was not impacted and 11 cases (15 eyes) with vitreous hemorrhage were required to receive close follow-up with average follow-up time of 105 days. A lens-sparing vitreous surgery was conducted in three patients without any complications.

CONCLUSION

Preterm newborns with FH that are not caused by ROP are more likely to have superficial, peripheral hemorrhages. Vaginal delivery compression and forceps may be associated with hemorrhage. A lens-preserving vitrectomy is required and considered safe for dense FH involving the refractive media.

Referable Macular Hemorrhage-A Clinically Meaningful Screening Target in Newborn Infants. Position Statement of the Association of Pediatric Retina Surgeons

Universal newborn eye screening facilitates early diagnosis of ocular abnormalities and mitigates vision loss. "Referral warranted" eye disease is present at birth in about 5.5% of term infants, with "macular hemorrhage impinging on the fovea" representing about 50% of referral warranted disease. The Association of Pediatric Retina Surgeons held a symposium on February 9, 2021 that culminated in a position statement on "referable macular hemorrhage" (RMH) in newborn infants. RMH is meaningful in that in can cause amblyopia through deprivation, can be readily captured with wide-angle photography in a safe and efficient manner, and may lead to early intervention with mitigation of vision loss. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:3-6.].

Newborn Eye Screening as an Application of AI

Artificial intelligence (AI) applications are diverse and serve varied functions in clinical practice. The most successful products today are clinical decision tools used by physicians, but autonomous AI is gaining traction. Widespread use of AI is limited in part because of concerns about bias, fault-tolerance, and specificity. Adoption of AI often depends on removing cost and complexity in clinical workflow integration, providing clear incentives for use, and providing clear demonstration of clinical outcome. Existing wide-angle photographic screening could be integrated into the clinical workflow based on prior implementations for premature babies and linked with AI interpretation with existing technology. Incidence of retinal abnormality, clinical considerations, AI performance, grading variation for AI-augmented human grading, and cost and policy aspects play a significant role. Improved outcomes for newborns and a relatively high estimated incidence of abnormality have been named as benefits to counterweigh costs in the long term. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:S17-S22.].

The Utility of Universal Newborn Eye Screening: A Review

Universal newborn eye screening can identify ocular abnormalities early and help mitigate long-term visual impairment. Traditional neonatal and infant eye screening is administered by neonatologists and pediatricians using the red reflex test. If this test identifies an ocular abnormality, then the patient is examined by an ophthalmologist. Notably, the red reflex test may be unable to detect amblyogenic posterior segment pathology. Recent studies using fundus imaging and telemedicine show reduced cost of human resources and increased sensitivity compared with traditional approaches. In this review, the authors discuss universal newborn eye screening pilot programs with regard to disease prevalence, referral-warranted disease, and cost-effectiveness. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:S6-S16.].