Identification of Novel FZD4 Mutations in Familial Exudative Vitreoretinopathy and Investigating the Pathogenic Mechanisms of FZD4 Mutations

Purpose

The purpose of this study is to report five novel FZD4 mutations identified in familial exudative vitreoretinopathy (FEVR) and to analyze and summarize the pathogenic mechanisms of 34 of 96 reported missense mutations in FZD4.

Methods

Five probands diagnosed with FEVR and their family members were enrolled in the study. Ocular examinations and targeted gene panel sequencing were conducted on all participants. Plasmids, each carrying 29 previously reported FZD4 missense mutations and five novel mutations, were constructed based on the selection of mutations from each domain of FZD4. These plasmids were used to investigate the effects of mutations on protein expression levels, Norrin/β-catenin activation capacity, membrane localization, norrin binding ability, and DVL2 recruitment ability in HEK293T, HEK293STF, and HeLa cells.

Results

All five novel mutations (S91F, V103E, C145S, E160K, C377F) responsible for FEVR were found to compromise Norrin/β-catenin activation of FZD4 protein. After reviewing a total of 34 reported missense mutations, we categorized all mutations based on their functional changes: signal peptide mutations, cysteine mutations affecting disulfide bonds, extracellular domain mutations influencing norrin binding, transmembrane domain (TM) 1 and TM7 mutations impacting membrane localization, and intracellular domain mutations affecting DVL2 recruitment.

Conclusions

We expanded the spectrum of FZD4 mutations relevant to FEVR and experimentally demonstrated that missense mutations in FZD4 can be classified into five categories based on different functional changes.

Peripheral and central retinal vascular changes in asymptomatic family members of patients with familial exudative vitreoretinopathy

PURPOSE

To evaluate the peripheral vascular changes and effects of these on macular microvasculature in asymptomatic family members of familial exudative vitreoretinopathy (FEVR) patients.

METHODS

This is a retrospective study including 61 eyes of asymptomatic family members of FEVR patients. Retinal abnormalities were assessed via ultra-widefield fluorescein angiography (UWF-FA) and optical coherence tomography angiography (OCTA). The eyes were grouped into 3: the first group comprised of eyes with normal findings on UWF-FA; the second group comprised of eyes with abnormal findings on UWF-FA but without any retinal ischemia; and the third group involved eyes with retinal ischemia or neovascularization.

RESULTS

Best corrected visual acuity (BCVA) was 20/20 in all eyes. Forty eyes (65.6%) had abnormalities on UWF-FA. The most common feature was peripheral vascular looping, increased tortuosity, and anastomosis (63.9%). ODM/ODD ratio was higher in group 3 compared to groups 1 and 2. Deep foveal VD was lower in group 1 compared to groups 2 and 3. The mean FAZ area and perimeter were smaller in groups 2 and 3 compared to group 1.

CONCLUSION

Even asymptomatic family members of FEVR patients may have significant peripheral retinal vascular abnormalities which may be associated with smaller optic disc, macular ectopia, and macular microvascular changes.

Genetic detection of two novel LRP5 pathogenic variants in patients with familial exudative vitreoretinopathy

BACKGROUND

Familial exudative vitreoretinopathy (FEVR) is a genetic eye disorder that leads to abnormal development of retinal blood vessels, resulting in vision impairment. This study aims to identify pathogenic variants by targeted exome sequencing in 9 independent pedigrees with FEVR and characterize the novel pathogenic variants by molecular dynamics simulation.

METHODS

Clinical data were collected from 9 families with FEVR. The causative genes were screened by targeted next-generation sequencing (TGS) and verified by Sanger sequencing. In silico analyses (SIFT, Polyphen2, Revel, MutationTaster, and GERP + +) were carried out to evaluate the pathogenicity of the variants. Molecular dynamics was simulated to predict protein conformation and flexibility transformation alterations on pathogenesis. Furthermore, molecular docking techniques were employed to explore the interactions and binding properties between LRP5 and DKK1 proteins relevant to the disease.

RESULTS

A 44% overall detection rate was achieved with four variants including c.4289delC: p.Pro1431Argfs*8, c.2073G > T: p.Trp691Cys, c.1801G > A: p.Gly601Arg in LRP5 and c.633 T > A: p.Tyr211* in TSPAN12 in 4 unrelated probands. Based on in silico analysis and ACMG standard, two of them, c.4289delC: p.Pro1431Argfs*8 and c.2073G > T: p.Trp691Cys of LRP5 were identified as novel pathogenic variants. Based on computational predictions using molecular dynamics simulations and molecular docking, there are indications that these two variants might lead to alterations in the secondary structure and spatial conformation of the protein, potentially impacting its rigidity and flexibility. Furthermore, these pathogenic variants are speculated to potentially influence hydrogen bonding interactions and could result in an increased binding affinity with the DKK1 protein.

CONCLUSIONS

Two novel genetic variants of the LRP5 gene were identified, expanding the range of mutations associated with FEVR. Through molecular dynamics simulations and molecular docking, the potential impact of these variants on protein structure and their interactions with the DKK1 protein has been explored. These findings provide further support for the involvement of these variants in the pathogenesis of the disease.

OCULAR FEATURES ASSOCIATED WITH MUTATIONS IN ATOH7 GENE OVERLAP THOSE WITH FAMILIAL EXUDATIVE VITREORETINOPATHY

BACKGROUND/PURPOSE

To report the ocular findings in three patients with a mutation in the ATOH7 gene.

METHODS

The clinical findings were collected from the medical records including those for magnetic resonance imaging. Three patients of two families who had poor vision since infancy were studied. Genetic testing of the ATOH7 gene was performed.

RESULTS

The three patients had varying degrees of intraocular vascular proliferation associated with advanced retinal detachments as falciform retinal folds or total retinal detachments. This state is referred to as congenital retinal nonattachment. One eye of a sibling had fluorescein angiographic findings of excessive branching of the retinal vessels and fluorescent dye leakage that were consistent with those of familial exudative vitreoretinopathy. Bilateral hypoplasia of the optic nerve was found in all three patients by magnetic resonance imaging. Genetic analysis showed a known in-frame deletion of the ATOH7 gene in all three patients.

CONCLUSION

This is the first report of a patient with a mutation in the ATOH7 gene that had typical vascular patterns of familial exudative vitreoretinopathy in the peripheral retina. The ocular features associated with mutations in the ATOH7 gene overlap those with familial exudative vitreoretinopathy at the early and advanced stages.

Refractive Status and Biometric Characteristics of Children With Familial Exudative Vitreoretinopathy

Purpose

To compare biometric characteristics between patients with early-stage familial exudative vitreoretinopathy (FEVR) and healthy controls.

Methods

This case-control study included 50 FEVR eyes in stage 1-2 and 50 control eyes matched by age, gender and spherical equivalent (SE). Biometric parameters including axial length (AL), white-to-white diameter (WTW), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), pupil diameter, vitreous chamber depth, anterior and posterior corneal surface curvature radius (ACR and PCR), anterior lens surface curvature radius (ALR) and posterior lens surface curvature radius were measured using IOLMaster 700 and compared between cases and controls using paired t-test. Correlations between SE and biometric measures were assessed using Pearson correlation coefficient (r) in cases and controls.

Results

Both FEVR cases and matched controls had a mean age of 7.6 years, 48% female and mean SE of -5.3 D (80% myopia). Compared to controls, FEVR eyes had smaller AL (P = 0.009), WTW (P = 0.001), ACD (P < 0.001), and ALR (P = 0.03), but larger CCT (P = 0.02) and LT (P = 0.01). In FEVR eyes, SE was negatively correlated with AL (r = -0.79, P < 0.001), positively correlated with ACR (r = 0.29, P = 0.04) and PCR (r = 0.33, P = 0.02), whereas in controls, SE was negatively correlated with AL (r = -0.82, P < 0.001) and LT (r = -0.34, P = 0.02), positively correlated with ALR (r = 0.29, P = 0.04).

Conclusions

Patients at early stage of FEVR exhibited a unique eye morphology resembling ocular development arrest, which may help to develop screening and early detection tools for FEVR. In FEVR patients, myopia is very prevalent and significantly associated with corneal curvature increase.

The Characteristic of Optical Coherence Tomography Angiography and Retinal Arteries Angle in Familial Exudative Vitreoretinopathy with Inner Retinal Layer Persistence

PURPOSE

To compare the angle of retinal arteries and macular vessel density and foveal avascular zone (FAZ) in early stage familial exudative vitreoretinopathy (FEVR) patients with inner retinal layer (IRL) persistence with FEVR patients without IRL persistence and normal people.

METHODS

This study enrolled 113 early stage FEVR patients and 55 age-matched normal subjects. FEVR patients were divided into IRL group and non-IRL group based on the presence or absence of IRL in fovea. The angle of superior temporal and inferior temporal branch retinal arteries on ultra-wide-field fundus images were measured. Superficial and deep vessel density of whole image, fovea and parafovea, the area and perimeter of FAZ, A-circularity index (AI, perimeter/standard circle perimeter with equal area) and vessel density around the 300-μm width of the FAZ (FD), central macular thickness (CMT) on 3 mm × 3mm OCTA were measured.

RESULTS

30 FEVR patients in IRL group, 83 FEVR patients in non-IRL group, 55 normal people in control group were evaluated. BCVA were worst in IRL group (p < .001). The angle of retinal arteries was smaller in FEVR groups (p < .001) and were smallest in IRL group (p < .001). Superficial and deep vessel density of whole and parafovea area in FEVR patients were significantly lower than that in normal people (p < .05), AI were biggest (p = .01) and FD were smallest in IRL group (p < .001). CMT in IRL group were thicker than non-IRL group and control group (p < .05).

CONCLUSION

Worse BCVA, smaller angle of retinal arteries (more vessels traction), lower macular vessel density, smaller and more irregular FAZ and thicker CMT were observed in FEVR patients with IRL persistence even in early stage.

Two types of childhood glaucoma secondary to familial exudative vitreoretinopathy

BACKGROUND

Glaucoma secondary to familial exudative vitreoretinopathy presents as angle closure by either neovascular or non-neovascular mechanisms. We analyze the presentation and outcomes of two types of childhood glaucoma secondary to familial exudative vitreoretinopathy (FEVR).

METHODS

This retrospective cross-sectional study included all patients <18 years of age diagnosed with glaucoma after or concurrently with a diagnosis of FEVR between 2010 and 2020 from Queen Sirikit National Institute of Child Health in Bangkok, Thailand. Two groups were analyzed: neovascular or non-neovascular angle-closure status. Primary outcome measures were final visual acuity and intraocular pressure (IOP) in both groups.

RESULTS

Of 144 FEVR patients, 8 children (5.5%; 11 eyes, 3 bilateral cases) developed childhood glaucoma. Mean time between FEVR presentation and glaucoma was 42.2 ± 40.0 months. In the neovascular group, 3 of 9 eyes presented with glaucoma at FEVR diagnosis; 3 of 9 eyes (33%) required glaucoma surgery. In the non-neovascular group, 2 eyes presented with acute angle closure secondary to a phacomorphic lens. Both were treated with trabeculectomy, with resolution of pupillary block. All eyes had stage 4B FEVR or greater. Six of 8 eyes had stable or better visual acuity, and 10 eyes (91%) had IOP <21 mm Hg at final follow-up.

CONCLUSIONS

Childhood glaucoma secondary to FEVR is a rare complication caused by later stages of the disease. It may present as neovascular or non-neovascular angle closure, often requiring complex care. Therefore, awareness and adequate management of FEVR can help prevent additional morbidity from childhood glaucoma.

Quantitative Analysis of Vascular Abnormalities in Full-Term Infants With Mild Familial Exudative Vitreoretinopathy

Purpose

Our goal was to build a system that combined deep convolutional neural networks (DCNNs) and feature extraction algorithms, which automatically extracted and quantified vascular abnormalities in posterior pole retinal images of full-term infants clinically diagnosed with mild familial exudative retinopathy (FEVR).

Methods

Using posterior pole retinal images taken from 4628 full-term infants with a total of 9256 eyes, we created data sets, trained DCNNs, and performed tests and comparisons. With the segmented images, our system extracted peripapillary vascular densities, mean tortuosities, and maximum diameter ratios within the region of interest. We also compared them with normal eyes statistically.

Results

In the test data set, the trained system obtained a sensitivity of 0.78 and a specificity of 0.98 for vascular segmentation, with 0.94 and 0.99 for optic disc, respectively. While in the comparison data set, compared with normal, we found a significant increase in vascular densities in retinal images with mild FEVR (5.3211% ± 0.7600% vs. 4.5998% ± 0.6586%) and a significant increase in the maximum diameter ratios (1.8805 ± 0.3197 vs. 1.5087 ± 0.2877), while the mean tortuosities significantly decreased (2.1018 ± 0.2933 [104 cm-3] vs. 3.3344 ± 0.3890 [104 cm-3]). All values were statistically significantly different.

Conclusions

Our system could automatically segment the posterior pole retinal images and extract from vascular features associated with mild FEVR. Quantitative analysis of these parameters may help ophthalmologists in the early detection of FEVR.

Translational Relevance

This system may contribute to the early detection of FEVR and facilitate the promotion of artificial intelligence-assisted diagnostic techniques in clinical applications.

FAMILIAL EXUDATIVE VITREOTINOPATHY-LIKE FEATURES IN STICKLER TYPE IV ASSOCIATED WITH NOVEL VARIANTS IN COL9A1

BACKGROUND/PURPOSE

To report a case of Stickler Type IV with familial exudative vitreoretinopathy phenotype.

METHODS

Retrospective case report.

RESULTS

A 24-year-old woman presented with right eye exotropia and decreased vision. She had no facial or typical retinal features of Stickler syndrome but complained of right-sided hearing loss and right-sided neck pain. Examination of the right eye showed a chronic combined exudative and traction retinal detachment with temporal retinal dragging associated with far temporal retinal exudations and fibrovascular proliferations. The left eye had an attached retina with large areas of peripheral temporal retinal nonperfusion on fluorescein angiography, sharply demarcated by end circulation vascular pruning and mild peripheral vascular leakage, consistent with familial exudative vitreoretinopathy phenotype. Genetic analysis identified two heterozygous c.1052C>A and c.1349A>G variants in COL9A1, but did not disclose any mutation in genes classically associated with familial exudative vitreoretinopathy.

CONCLUSION

Familial exudative vitreoretinopathy-like retinal vascular features can be the presenting sign in patients with Stickler syndrome Type IV.

Genotype-phenotype associations in familial exudative vitreoretinopathy: A systematic review and meta-analysis on more than 3200 individuals

Objective

To systematically review the relationship between genotypes and clinical phenotypes of Familial exudative vitreoretinopathy (FEVR) to support risk estimation and therapeutic decisions.

Design

Systematic review with meta-analysis.

Data sources

The data of our study were collected from PubMed, Embase, Web of Science, Cochrane, CBM, China National Knowledge Infrastructure (CNKI), WAN FANG and VIP databases since inception to August 2021.

Results

A total of 3257 patients from 32 studies were included according to the inclusion and exclusion criteria. Among all the cases, the mutation frequencies of LRP5, FZD4, NDP, TSPAN12, ZNF408 and KIF11 were 13.6%, 11.5%, 4.6%, 6.7%, 1.6%, and 5.7%, respectively. We found that the patients with NDP and FZD4 suffer more severe symptoms, among which 86.4% patients of NDP and 78.6% patients of FZD4 were in the advanced stage of FEVR. Retinal detachment is the most frequent symptom with patients of LRP5 and NDP mutations, accounting for 51.9% and 64.5%, respectively. For the patients with the mutation of TSPAN12, retinal fold is the most common clinical manifestation, and suffer the mildest clinical phenotypes compared with the other three genes.

Conclusion

The results of the meta-analysis indicate that different types of genetic mutations occur at different frequencies. In addition, the clinical manifestations of FEVR are related to the type of gene mutation. Therefore, targeted treatment strategies and follow-up recommendations should be adopted for different pathogenic genes of FEVR.

CTNNB1 (β-CATENIN) VITREORETINOPATHY: IMAGING CHARACTERISTICS AND SURGICAL MANAGEMENT

PURPOSE

We report a patient with CTNNB1-associated vitreoretinopathy. We discuss imaging findings and surgical management.

METHODS

Case report.

RESULTS

An 18-month-old girl with microcephaly, failure to thrive, developmental delay, and chronic rhinitis presented with bilateral central and peripheral tractional retinal detachments and an anomalous retinal vasculature. She underwent multimodal imaging and genetic testing, and we discuss successful surgical management.

CONCLUSION

CTNNB1 mutations can cause a vision-threatening vitreoretinopathy. We recommend CTNNB1 to be considered as part of the workup of patients presenting with familial exudative vitreoretinopathy-like clinical findings, especially if there are systemic manifestations.

Planned Preterm Delivery and Treatment of Severe Infantile FEVR With Osteoporosis-Pseudoglioma Syndrome

Familial exudative vitreoretinopathy (FEVR) is a rare hereditary vitreoretinopathy resulting from mutations in the wnt signaling pathway leading to abnormalities in fetal retinal vasculogenesis, angiogenesis, and retinal vascular maintenance. Severe FEVR may result in congenital retinal detachment resembling Norrie disease. The authors report the first case of planned preterm delivery and treatment of a patient with severe FEVR from biallelic LRP5 mutations whose siblings had congenital tractional retinal detachments with light perception vision outcomes after conventional care. Early intervention allowed laser ablation of avascular retina and functional visual outcome despite a successfully repaired unilateral tractional retinal detachment. [Ophthalmic Surg Lasers Imaging Retina. 2022;53(4):228-232.].

Reaching a FEVR Pitch: A Case Series of Familial Exudative Vitreoretinopathy in Northern Ireland

PURPOSE

To evaluate the heterogeneity of both the clinical features and genetics of familial exudative vitreoretinopathy (FEVR) in a Northern Irish population.

METHODS

A retrospective trawl of a secure pediatric database was completed, as well as communication with all Northern Ireland ophthalmologists to identify adult cases. Cases were cross-referenced with a regional genetics database. Data on patient demographics, clinical findings, genetic testing, and patient treatment were collected.

RESULTS

Sixteen patients were identified. Average age at presentation was 11.8 years (range: 4 months to 38 years). Earlier age at presentation was associated with more advanced disease and those presenting later had more subtle signs such as retinal tear or vitreous hemorrhage. Four types of gene mutations were identified in 7 patients (NDP, TSPAN12, FZD4, and KIF11). Thirteen patients had complications associated with FEVR and associated systemic conditions were found in 5 patients. Twelve eyes received active treatment to control disease.

CONCLUSIONS

FEVR is a sight-threatening disease affecting prenatal retinal angiogenesis with a spectrum of disease and diverse genetic basis. Clinicians should look for signs of systemic and other ophthalmic sequelae in patients with FEVR because this could point to a genetic cause. Vigilance should also be exercised in older patients with unexplained vitreous hemorrhage or retinal tear with consideration of widefield angiography if FEVR is suspected. [J Pediatr Ophthalmol Strabismus. 2022;59(2):102-109.].

Whole-Exome Sequencing Reveals Novel NDP Variants in X-Linked Familial Exudative Vitreoretinopathy

PURPOSE

To investigate causative variants in three Chinese families affected with familial exudative vitreoretinopathy (FEVR).

METHODS

Three unrelated Chinese families were recruited in this study. The three probands and their family members experienced a comprehensive age-appropriate eye examination and genetic analysis. Luciferase assay was performed to evaluate impacts of variants on Norrin/β-catenin signaling activity.

RESULTS

Here we report two novel NDP variants associated with FEVR in three families, including c.17T>C (p.Leu6Pro) in family 1 and c.58G>A (p.Gly20Arg) in family 2 and 3. These two variants were co-segregated with the disease phenotypes within each family. In addition, both variants resulted in compromised Norrin/β-catenin signaling activity.

CONCLUSION

Our study identified two FEVR-associated pathogenic variants in NDP, which expanded the variant spectrum and provided information for the genetic diagnosis of FEVR.

Macular Retinal Pigment Epithelial Clumping Leading to a Diagnosis of FEVR

Familial exudative vitreoretinopathy (FEVR) is a rare hereditary disorder characterized by abnormal or incomplete retinal angiogenesis. The peripheral avascularity, irregular neovascularization, and vascular leakage seen in FEVR are similar to changes that may be seen in retinopathy of prematurity (ROP). The authors report a case of atypical macular pigment clumping leading to the diagnosis of ROPER (ie, ROP vs FEVR) in a premature infant born at 23 weeks of gestation with a birth weight of 451 grams, who presented with atypical aggressive posterior ROP and a heterozygous variant in the LRP5 gene. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:505-508.].

Serpiginous Intraretinal Lesions Associated With Familial Exudative Vitreoretinopathy

Familial exudative vitreoretinopathy (FEVR) is a rare inherited disorder affecting retinal angiogenesis that may present with a wide range of phenotypic characteristics. In this report, the authors describe an atypical presentation of FEVR in a healthy 9-year-old male with progressive decreased visual acuity in the left eye. Fundus examination showed an avascular retina in the temporal periphery bilaterally. The left eye also revealed serpiginous hypopigmented lesions in the superior quadrant, which showed intraretinal location on optical coherence tomography and hyperautofluorescence. Genetic testing revealed LRP5 mutation, confirming a diagnosis of FEVR. The serpiginous lesions represent an unusual finding associated with FEVR not previously described in the literature. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:155-159.].

Persistent vasa hyaloidea propria/retinae in familial exudative vitreoretinopathy

The vasa hyaloidea propria, a component of the fetal hyaloidal vasculature, is characterized by multiple persistent fetal vasculatures branching into the vitreous. We present a 4-month-old girl with stage 4 familial exudative vitreoretinopathy, with multiple ectopic retinal vessels extending into the vitreous, confirmed with fluorescein angiography, which was consistent with persistent vasa hyaloidea propia/retinae making contact with the retina. The patient underwent vitreoretinal surgery to address the retinal detachment, during which the patent stalks of the persistent vasa hyaloidea propia/retinae were transected.

Peripheral Persistent Fetal Vasculature: A Report of Three Cases

The authors report three cases of persistent fetal vasculature (PFV) presenting with an atypical peripheral fibrovascular stalk. A 5-month-old with congenital exotropia with a vitreous hemorrhage in the right eye underwent vitrectomy, and a mid-peripheral vitreal vascular stalk was visualized within the area of hemorrhage. The second case is of an 8-year-old with two fetal vascular remnants in the right eye: (1) a stalk superotemporally extending from the pars plana to the mid-peripheral retina that was associated with a retinal break and (2) a focal lens opacity. The third case is a 12-year-old with a history of familial exudative vitreoretinopathy and peripapillary choroidal neovascular membrane found to have a peripheral vitreal stalk in the right eye. These cases demonstrate a rare form of PFV with primarily peripheral remnants. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e83-e88.].

Molecular evolutionary and structural analysis of familial exudative vitreoretinopathy associated FZD4 gene

BACKGROUND

Frizzled family members belong to G-protein coupled receptors and encode proteins accountable for cell signal transduction, cell proliferation and cell death. Members of Frizzled receptor family are considered to have critical roles in causing various forms of cancer, cardiac hypertrophy, familial exudative vitreoretinopathy (FEVR) and schizophrenia.

RESULTS

This study investigates the evolutionary and structural aspects of Frizzled receptors, with particular focus on FEVR associated FZD4 gene. The phylogenetic tree topology suggests the diversification of Frizzled receptors at the root of metazoans history. Moreover, comparative structural data reveals that FEVR associated missense mutations in FZD4 effect the common protein region (amino acids 495-537) through a well-known phenomenon called epistasis. This critical protein region is present at the carboxyl-terminal domain and encompasses the K-T/S-XXX-W, a PDZ binding motif and S/T-X-V PDZ recognition motif.

CONCLUSION

Taken together these results demonstrate that during the course of evolution, FZD4 has acquired new functions or epistasis via complex patter of gene duplications, sequence divergence and conformational remodeling. In particular, amino acids 495-537 at the C-terminus region of FZD4 protein might be crucial in its normal function and/or pathophysiology. This critical region of FZD4 protein may offer opportunities for the development of novel therapeutics approaches for human retinal vascular disease.

A Novel Pathogenic Variant in NDP Gene With Incomplete Penetrance Manifests as X-Linked Familial Exudative Vitreoretinopathy

Familial exudative vitreoretinopathy (FEVR) is a rare hereditary ocular disorder characterized by incomplete or abnormal development of peripheral retinal vasculature. The genes responsible for this disorder are associated with the wingless-related integration site (Wnt) signaling pathway, a critical pathway for the development of normal retinal vasculature. A pathogenic variant in any one of these genes may disrupt retinal vasculogenesis. Furthermore, the type and number of pathogenic variants may influence the severity of disease and clinical course. Here, the authors identify a novel pathogenic variant in the NDP gene, not previously described in the literature. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:120-124.].

Familial Exudative Vitreoretinopathy Imaged With Optical Coherence Tomography Angiography

The authors present a case of a 29-year-old man who presented to the Department of Ophthalmology at their institution to complete a peripheral laser treatment in his left eye for familial exudative vitreoretinopathy complicated by tractional macular edema. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e112-e113.].

Wnt-Spectrum Vitreoretinopathy Masquerading as Congenital Toxoplasmosis

Wnt-spectrum vitreoretinopathies are a group of rare inherited disorders of retinal angiogenesis that include familial exudative vitreoretinopathy/Norrie disease and are most commonly autosomal dominant; however, they can rarely present with other inheritance patterns that are more difficult to diagnose. The authors describe a case of an uncle misdiagnosed as congenital toxoplasmosis for decades and his 2-month-old nephew presenting with bilateral retinal detachments. Genetic analysis revealed an NDP gene mutation in the child and the uncle, as well as heterozygosity of the mother confirming a Wnt-spectrum vitreoretinopathy. This report describes the evaluation, diagnosis, and importance of early laser stabilization of this disorder. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:446-450.].

Familial exudative vitreoretinopathy complicated with full thickness macular hole: A case report

RATIONALE

To report a case of familial exudative vitreoretinopathy (FEVR) complicated with full-thickness macular hole (FTMH).

PATIENT CONCERNS

A 39-year-old male presented after becoming aware of metamorphopsia in his left eye.

DIAGNOSES

Fundus examination showed a retinal avascular area, retinal vascular abnormality, and yellow exudation at the peripheral retina in both eyes. Optical coherence tomography findings revealed impending MH (IMH) due to posterior vitreous detachment (PVD) in his left eye. Despite of the occurrence of spontaneous complete PVD, an FTMH developed at 4 months after the onset of IMH.

INTERVENTIONS

To treat the FTMH, vitreous surgery was performed. Intraoperative findings revealed that the thick posterior vitreous membrane (PVM) had no adhesions with the edge of the FTMH. However, a thin epiretinal membrane (ERM) was observed around the MH.

OUTCOMES

Postoperatively, the FTMH was closed, and the patient's corrected visual acuity improved from (0.4) to (0.8).

LESSONS

In this present case, an IMH developed via traction by a thick PVM, characteristic of FEVR, with FTMH then developing via traction by a thin ERM. Our findings reveal that it is vital to fully understand these anatomical features before performing vitreous surgery for FTMH complicated with FEVR.

Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management

Familial exudative vitreoretinopathy (FEVR) is a heritable vitreoretinopathy characterized by anomalous retinal vascular development. The principal feature of the disease is an avascular peripheral retina. This in turn can cause further pathological changes including neovascularization, exudation, hemorrhage, and retinal detachment. The biological basis of the disease is thought to be from defects in the Wnt signaling pathway. Many gene mutations have been implicated, and these can be inherited in an autosomal dominant (most common), autosomal recessive, and X-linked recessive fashion. Examination with wide-field fluorescein angiography is essential and can identify the disease in its earlier stages, enabling timely treatment, in addition to helping identify asymptomatic family members. The current treatment paradigm involves laser photocoagulation of the avascular peripheral retina for neovascular sequelae and vitreoretinal surgery for progressive retinal detachment. Further studies are underway to better characterize this complex vitreoretinopathy.

Clinical and next-generation sequencing findings in a Chinese family exhibiting severe familial exudative vitreoretinopathy

Familial exudative vitreoretinopathy (FEVR) is a rare hereditary retinal disorder characterized by the premature arrest of vascularization in the peripheral retina. The aim of the present study was to characterize the clinical presentations of a Chinese family affected by bilateral severe FEVR, and to identify the underlying genetic variations. One family that presented with bilateral FEVR was recruited for this study. Comprehensive ophthalmic examinations, including best‑corrected visual acuity, slit‑lamp examination, fundus photography, fundus fluorescein angiography imaging and electroretinogram were performed. Genomic DNA was extracted from leukocytes of the peripheral blood collected from the affected and unaffected family members, as well as 200 unrelated control subjects from the same population. Next‑generation sequencing of the candidate genes associated with ocular diseases was performed, and the identified mutations were validated by conventional polymerase chain reaction‑based sequencing. The functional effects of the mutations were analyzed by polymorphism phenotyping (PolyPhen) and sorting intolerant from tolerant (SIFT). One heterozygous ATP binding cassette subfamily A member 4 (ABCA4) c.5693G>A (p.R1898H) mutation in exon 40 and one heterozygous LDL receptor related protein 5 (LRP5) c.260T>G (p.I87S) mutation in exon 2 were identified in this family. To the best of our knowledge, the ABCA4 c.5693G>A (p.R1898H) mutation has not been reported in FEVR, and the LRP5 c.260T>G (p.I87S) mutation is a novel mutation. PolyPhen and SIFT predicted that the amino acid substitution R1898H in protein ABCA4 is benign, whereas the amino acid substitution I87S in protein LRP5 is damaging. A single nucleotide polymorphism c.266A>G (p.Q89R, rs41494349) was identified in exon 2 of LRP5. These findings expand the mutation spectrums of ABCA4 and LRP5, and will be valuable for genetic counseling and development of therapeutic interventions for patients with FEVR.

FEVR-like Presentation in an 11q Deletion Syndrome and 16p13.11 Microdeletion

A 7-year-old boy was diagnosed and treated for familial exudative vitreoretinopathy. Genetic testing revealed a 16p13.11 microdeletion and unbalanced translocation causing 11q deletion syndrome. This is the first report describing retinal findings associated with this combination of genetic alterations. Patients with 11q deletion syndrome or 16p13 microdeletions should undergo ophthalmologic examination. [J Pediatr Ophthalmol Strabismus. 2017;54:e71-e74.].

RETINAL VASCULAR TORTUOSITY AND EXUDATIVE RETINOPATHY IN A FAMILY WITH DYSKERATOSIS CONGENITA MASQUERADING AS FAMILIAL EXUDATIVE VITREORETINOPATHY

PURPOSE

To report a novel presentation of dyskeratosis congenita masquerading as familial exudative vitreoretinopathy.

METHODS

Observational case series involving single family and literature review.

RESULTS

A brother and sister were diagnosed with familial exudative vitreoretinopathy at ages 4 and 2, respectively. Both patients were managed with laser photocoagulation. Eight years after the initial presentation, both siblings developed pancytopenia secondary to bone marrow failure. Laboratory work-up revealed severely shortened telomere length in both patients, and genetic testing revealed a missense mutation in the gene that encodes the reverse transcriptase component of telomerase, confirming the diagnosis of dyskeratosis congenita. The father of both children was a carrier of the same mutation, who exhibited marked retinal vascular tortuosity of the second-order vessels.

CONCLUSION

Dyskeratosis congenita is a severe multisystem disorder, which should be considered in cases of pediatric exudative retinopathies with concurrent signs and/or symptoms of bone marrow failure.

[Guidance of Medical Care for Familial Exudative Vitreoretinopathy：Research on Rare and Intractable Diseases, Health and Labour Sciences Research Grants]

Familial exudative vitreoretinopathy is a hereditary insufficiency of retinal vascularture, which manifests a variety of vitreoretinal abnormalities, including nonvascularlized retina, abnormality of retinal vessel growing, dragged retina, retinal folds and total retinal detachment. While causative genes have been identified, cases are often sporadic. Periodic examination is necessary to find recurrence of the disease and late complications, including rhegmatogenous retinal detachment, cataract and glaucoma.

Familial exudative vitreoretinopathy: A report of an asymptomatic case with autosomal dominant inheritance detected using FZD4 molecular analysis

OBJECTIVE

To report a familial case of Familial Exudative Vitreoretinopathy (FEVR) with an autosomal dominant inheritance pattern identified with the molecular analysis of FZD4.

CASE REPORT

The proband is a 13 year-old boy who consulted for low vision. Fundus examination revealed a peripheral avascular zone and macular dragging, consistent with FEVR. Molecular analysis demonstrated a mutation of FZD4 in DNA from both the patient and his asymptomatic mother.

DISCUSSION

This familial case was identified with the molecular analysis of FZD4 and shows the importance to explore first degree relatives in a sporadic FEVR case.

A novel missense mutation of NDP in a Chinese family with X-linked familial exudative vitreoretinopathy

Familial exudative vitreoretinopathy (FEVR) is a hereditary ocular disorder characterized by a failure of peripheral retinal vascularization. In this report, we describe a novel missense mutation of the Norrie disease gene (NDP) in a Chinese family with X-linked FEVR. Ophthalmologic evaluation was performed on four male patients and seven unaffected individuals after informed consent was obtained. Venous blood was collected from the 11 members of this family, and genomic DNA was extracted using standard methods. The coding exons 2 and 3 and their corresponding exon-intron junctions of NDP were amplified by polymerase chain reaction and then subjected to direct DNA sequencing. A novel missense mutation (c.310A>C) in exon 3, leading to a lysine-to-glutamine substitution at position 104 (p.Lys104Gln), was identified in all four patients with X-linked FEVR. Three unaffected female individuals (III2, IV3, and IV11) were found to be carriers of the mutation. This mutation was not detected in other unaffected individuals. The mutation c.310A>C (p.Lys104Gln) in exon 3 of NDP is associated with FEVR in the studied family. This result further enriches the mutation spectrum of FEVR.

Familial Exudative Vitreoretinopathy With a Novel LRP5 Mutation

This report reviews the genetics of familial exudative vitreoretinopathy (FEVR) and describes the identification of a novel variant in the LRP5 gene. A 20-month-old boy presented with reduced visual acuity in the right eye from exudative retinal detachment with mild retinal traction. Fluorescein angiography in the right eye disclosed extensive peripheral retinal non-perfusion and telangiectatic vessels and the left eye showed minimal peripheral non-perfusion. These features were suggestive of FEVR. Treatment with laser photocoagulation and cryotherapy to the region of non-perfusion was performed with resolution of the exudative retinal detachment. Fundus examination of the father revealed mild signs of FEVR, such as hyperacute retinal vascular branching and slight retinal vascular traction, whereas the mother's fundus examination was unremarkable. Genetic testing revealed that the affected boy was negative for mutations in the FZD4, NDP, and TSPAN12 genes and heterozygous for a previously unreported A745V variant in the LRP5 gene. The father was also heterozygous for the A745V variant in the LRP5 gene and the unaffected mother showed no mutation. A genetic evaluation of the known genes associated with FEVR revealed a novel variant in the LRP5 gene that co-segregated with the phenotype in the family. [J Pediatr Ophthalmol Strabismus. 2016;53:e39-e42.].

Simultaneous Novel Mutations of LRP5 and TSPAN12 in a Case of Familial Exudative Vitreoretinopathy

Familial exudative vitreoretinopathy and osteoporosis pseudoglioma syndrome are conditions that result from mutations in the LRP5 gene. Persistent fetal vasculature is a rare congenital malformation that can mimic end-stage familial exudative vitreoretinopathy. The authors report a case of familial exudative vitreoretinopathy in the spectrum of osteoporosis pseudoglioma syndrome associated with novel mutations of the LRP5 and TSPAN12 genes that resulted in a phenotype similar to bilateral persistent fetal vasculature. Both conditions can result in bilateral early-onset blindness. A high index of suspicion, dilated fundus examination and angiography of the parents, and genetic testing are necessary to ensure a correct diagnosis.

Differential diagnosis of Norrie disease and X-linked familial exudative vitreoretinopathy (XL-FEVR) based on clinical and molecular evaluation

Background: Molecular analysis of the NDP gene to confirm and precise the clinical diagnosis in two patients with X-linked familial exudative vitreoretinopathy (XL-FEVR). Material and methods: We report two patients from unrelated families with NDP gene mutations: a 14-month-old boy (p1) who was found to have severe exudative vitreoretinopathy and a 4-year-old boy with exudative vitreoretinopathy (p2). An extensive clinical examination of the probands, including slit-lamp examination, B-mode ultrasonography and magnetic resonance imaging was conducted, along with genetic analysis of NDP gene. Results: Clinical findings in patient 1 included no light perception, total retinal detachment and hyperplastic primary vitreous in both eyes. The genetic analysis of the NDP gene enabled to identify the novel frameshift mutation c.222_c223insCG in p1 leading to the premature stop codon and production of aberrant norrin protein. In P2, clinical presentation included high myopia with astigmatism, unilateral fibrous bands and retinal detachment. Genetic testing revealed known point mutation c.362G>A leading to amino-acid alteration and improper protein. Conclusions: Mutation screening of NDP gene identified two different mutations in this region, one of which has not been previously reported.

Frizzled-4 Variations Associated with Retinopathy and Intrauterine Growth Retardation: A Potential Marker for Prematurity and Retinopathy

PURPOSE

To present the association between mutations affecting the Wnt-signaling receptor protein (FZD4), inherited vitreoretinopathies, and retinopathy of prematurity (ROP).

DESIGN

Retrospective analysis of prospective samples at a tertiary referral center.

PARTICIPANTS

Patients referred to our practice for management of a variety of pediatric vitreoretinopathies were offered participation in an ophthalmic biobank (421 participants with vitreoretinopathies were included in this study). Full-term healthy infants (n = 98) were recruited to the study as controls.

METHODS

Patients with various vitreoretinopathies were prospectively enrolled in an ophthalmic biobank, approved by the Human Investigation Committee at William Beaumont Hospital. Retrospective genetic analysis of the FZD4 gene was performed (Sanger sequencing). Participants with a diagnosis of familial exudative vitreoretinopathy (FEVR), Norrie disease, Coats' disease, bilateral persistent fetal vasculature, and ROP were reviewed for the presence of a FZD4 variant. Data retrieval included status of retinopathy (including staging when possible), gestational age (GA), birth weight (BW) (when available), and family and birth histories.

MAIN OUTCOME MEASURES

The association of FZD4 variants with the presence of vitreoretinopathy.

RESULTS

The sequence variation p.[P33S(;)P168S] is the most prevalent FZD4 variant and is statistically significant for ROP and FEVR (P = 4.6E-04 and P = 2.4E-03, respectively) compared with full-term newborns (P = 1.7E-01). In addition, infants expressing the sequence variation tended to have significantly lower BWs for respective GA (P = 0.04). This suggests that the FZD4 p.[P33S(;)P168S] variant may be a risk factor for retinopathy and restricted intrauterine growth.

CONCLUSIONS

Testing for FZD4 gene mutations is useful in patients with suspected FEVR and ROP. The relatively high prevalence of the p.[P33S(;)P168S] variant in ROP and intrauterine growth restriction suggests that it also may be a marker for increased risk of developing ROP and preterm birth.

Surgical outcomes of progressive tractional retinal detachment associated with familial exudative vitreoretinopathy

PURPOSE

To evaluate various surgeries for treating retinal detachment (RD) associated with familial exudative vitreoretinopathy (FEVR).

DESIGN

Retrospective, interventional case series.

METHODS

The charts of 22 patients who underwent surgery were reviewed. A complete ophthalmic examination was performed including wide-field fundus images with fluorescein angiography. The primary and secondary outcomes were fundus features (vascular activity of the fibrovascular proliferation and extent of tractional RD) and visual acuity (VA), respectively.

RESULTS

Thirty-one eyes were included (12 eyes underwent scleral buckling, 1 scleral buckling and vitrectomy, 7 vitrectomy alone, and 11 lensectomy and vitrectomy). Twenty-six eyes were reattached during 1 surgery. Scleral buckling resulted in cessation of fibrovascular proliferation and retinal reattachment; only 1 of these eyes required vitrectomy. Lens-sparing vitrectomy resulted in stabilized fibrovascular proliferation and retinal reattachment. Vitrectomy with lensectomy did not achieve retinal reattachment in 4 eyes. Fibrovascular proliferation has a rich vascular component in patients younger than 3 years, and collagen fibers were present mainly with more advanced age. The postoperative VA improved in 5 of 8 eyes examined, was unchanged in 1 eye, and decreased in 2 eyes with macular involvement.

CONCLUSIONS

FEVR-induced RDs are highly variable and require careful preoperative evaluation to determine the best surgical procedure. Vitrectomy with release of posterior traction is essential in younger patients with vascularly active fibrovascular proliferation, whereas scleral buckling may be important for cases with peripheral traction anterior to the equator. In all cases, peripheral thermal treatment applied to all ischemic areas contributed to reduced peripheral neovascularization.

Osteoporotic vertebral fractures during pregnancy: be aware of a potential underlying genetic cause

CONTEXT

Although the baby growing in its mother's womb needs calcium for skeletal development, osteoporosis and fractures very rarely occur during pregnancy.

CASE PRESENTATION

A 27-year-old woman in the seventh month of her first pregnancy contracted midthoracic back pain after lifting an object. The pain was attributed to her pregnancy, but it remained postpartum. Her past medical history was uneventful, except for severely reduced vision of her left eye since birth. Family history revealed that her maternal grandmother had postmenopausal osteoporosis and her half-brother had three fractures during childhood after minor trauma. Her height was 1.58 m; she had no blue sclerae or joint hyperlaxity. Laboratory examination including serum calcium, phosphate, alkaline phosphatase, creatinine, β-carboxyterminal cross-linking telopeptide of type I collagen, 25-hydroxyvitamin D, and TSH was normal. Multiple thoracic vertebral fractures were diagnosed on x-ray examination, and dual-energy x-ray absorptiometry scanning showed severe osteoporosis (Z-scores: L2-L4, -5.6 SD; femur neck, -3.9 SD). DNA analyses revealed two compound heterozygous missense mutations in LRP5. The patient's mother carried one of the LRP5 mutations and was diagnosed with osteoporosis. Her half-brother, treated with cabergoline for a microprolactinoma, also had osteoporosis of the lumbar spine on dual-energy x-ray absorptiometry and carried the same LRP5 mutation. The patient was treated with risedronate for 2.5 years. Bone mineral density and back pain improved. She stopped bisphosphonate use 6 months before planning a second pregnancy.

CONCLUSION

Our patient was diagnosed with osteoporosis pseudoglioma syndrome/familial exudative vitreoretinopathy. Potential underlying genetic causes should be considered in pregnancy-associated osteoporosis with implications for patients and relatives. More studies regarding osteoporosis treatment preceding conception are desirable.

Ultra-widefield imaging for the management of pediatric retinal diseases

PURPOSE

To describe the utility of using ultra-widefield digital fundus photography and ultra-widefield fluorescein angiography (UWFA) in the pediatric patient population to evaluate peripheral retinal pathology and to manage Coats' disease and familial exudative vitreoretinopathy (FEVR).

METHODS

Retrospective review of pediatric retinal patients with FEVR or Coats' disease who underwent ultra-widefield fundus photography and UWFA.

RESULTS

Eight patients were included in this case series. Five patients had the clinical diagnosis of FEVR, and two eyes of two patients with FEVR received UWFA-guided laser photocoagulation. Three patients were diagnosed as having Coats' disease and received UWFA-guided laser photocoagulation.

CONCLUSIONS

Ultra-widefield fundus photography and UWFA can be used successfully as an outpatient procedure in the pediatric patient population without the necessity of examination under anesthesia and can aid the physician in the documentation and evaluation of peripheral retinal pathology. UWFA can also assist in directing laser photocoagulation in the treatment of pediatric retinal diseases.

[Familial exudative vitreoretinopathy]

Familial exudative vitreoretinopathy (FEVR) is a progressive hereditary retinal vascular disorder of unknown etiology. The disease is associated with gene mutation and mainly has an autosomal dominant mode of inheritance. Pathogenesis of the disease consists in abnormal retinal peripheral vasculogenesis. Three classifications, detailed clinical presentation and differential diagnostic criteria of the disease are presented. Surgical options of treatment of potential retinal detachment are discussed.