RETINAL VASCULAR ABNORMALITIES IN A LARGE COHORT OF PATIENTS AFFECTED BY NEUROFIBROMATOSIS TYPE 1

Loss of neurofibromin induces inflammatory macrophage phenotypic switch and retinal neovascularization via GLUT1 activation

Persons with neurofibromatosis type 1 (NF1) exhibit enhanced glucose metabolism, which is replicated in Nf1-mutant mice. Inflammatory macrophages invest NF1-associated tumors, and targeting macrophages appears efficacious in NF1 models. Inflammatory macrophages rely on glycolysis to generate ATP; thus, identifying whether neurofibromin, the protein encoded by NF1, controls glucose metabolism in macrophages is therapeutically compelling. Using neurofibromin-deficient macrophages and macrophage-specific Nf1-knockout mice, we demonstrate that neurofibromin complexes with glucose transporter-1 (GLUT1) to restrain its activity and that loss of neurofibromin permits Akt2 to facilitate GLUT1 translocation to the membrane. In turn, glucose internalization and glycolysis are upregulated and provoke reparative (MIL4) macrophages to undergo an inflammatory phenotypic switch. Inflammatory MLPSIFNγ macrophages and inflammatory-like MIL4 macrophages invest the perivascular stroma of tumors and induce pathologic angiogenesis in macrophage-specific Nf1-knockout mice. These studies identify a mechanism for the enhanced glycolysis associated with NF1 and provide a novel therapeutic target for NF1.

Neurofibromatosis Type 1 (NF1)-Related Ocular Signs: New Insights on Their Prevalence, Incidence, and Genotype-Phenotype Correlation in NF1 Children

PURPOSE

To assess, in a large pediatric population affected by neurofibromatosis type 1 (NF1), the prevalence, incidence, age of onset, and genotype correlation of the main NF1-related ocular signs, including optic pathway glioma (OPG), Lisch nodules (LNs), choroidal abnormalities (CAs), and retinal vascular abnormalities (RVAs).

METHODS

NF1 patients ≤16 years old followed at our institution between 2010 and 2022 were included. Presence of NF1-related ocular signs was assessed at baseline and during follow-up evaluations through slit lamp observation (LNs), near-infrared imaging (CAs and RVAs), and neuroimaging revision (OPG). Patients were categorized according to their genetic variant.

RESULTS

A total of 237 patients were enrolled. Among those, 204 underwent at least 1 follow-up and genetic test was available for 210. Prevalence of OPG, LNs, CAs, and RVAs at baseline was, respectively, 20.7%, 43.5%, 46.8%, and 6.8%. Their incidence during follow-up was 6.4%, 22.4%, 21.4%, and 5.4%, respectively, and the mean age at onset was 6.3±3.6, 7.1±3.0, 6.4±3.0, and 6.6±2.9 years. Patients with truncating mutations presented a higher number of ocular signs than those with non-truncating mutations (1.7±1.0 vs 0.9±0.9, P = .0019).

CONCLUSIONS

Data on prevalence and incidence of NF1-related ocular signs in pediatric patients evidences that the development of these signs seems negligible after the age of 7. LNs and CAs seem to develop independently and, therefore, can be considered as two separate diagnostic criteria. Truncating mutations correlate with a higher number of NF1-related ocular signs phenotype. Note: Publication of this article is sponsored by the American Ophthalmological Society.

Neurofibromatosis Type 1-Retinal Alterations Detectable with Optical Coherence Tomography Angiography

Neurofibromatosis type 1 (NF 1) is a multisystemic genetic disorder involving aberrant proliferation of multiple tissues of a neural crest origin. It represents a tumor predisposition syndrome characterized by a wide range of clinical manifestations, such as benign tumors, which primarily affect the skin and the nervous system. The most frequent clinical signs of NF 1 include café-au-lait spots all over the surface of the skin and axillary freckling; however, these signs can be accompanied by more severe manifestations such as the growth of both benign and malignant nervous system tumors and skeletal dysplasia, as well as a wide range of ocular manifestations. We report the rare case of retinal microvascular alterations and choroidal nodules in a 15 year old male patient with NF 1, detectable on optical coherence tomography angiography (OCTA). The hyperreflective choroidal nodules modified the profile of the choroidal vasculature. The retinal microvascular alterations in the form of clustered capillaries were detected in the superficial capillary plexus located nasally to the macular region. Retinal vascular abnormalities undetectable on fundus photography or fundoscopy can be present in patients with NF 1. Indirect ophthalmoscopy of our study patient was unremarkable. However, retinal vascular abnormalities were seen on OCTA scans in the superficial capillary plexus and choroidal nodules were detected on raster OCT scans. OCTA represents a useful imaging technique for detecting retinal microvascular abnormalities, which can be considered additional distinctive signs of NF 1.

Visual Deficits and Diagnostic and Therapeutic Strategies for Neurofibromatosis Type 1: Bridging Science and Patient-Centered Care

Neurofibromatosis type 1 (NF1) is an inherited autosomal dominant disorder primarily affecting children and adolescents characterized by multisystemic clinical manifestations. Mutations in neurofibromin, the protein encoded by the Nf1 tumor suppressor gene, result in dysregulation of the RAS/MAPK pathway leading to uncontrolled cell growth and migration. Neurofibromin is highly expressed in several cell lineages including melanocytes, glial cells, neurons, and Schwann cells. Individuals with NF1 possess a genetic predisposition to central nervous system neoplasms, particularly gliomas affecting the visual pathway, known as optic pathway gliomas (OPGs). While OPGs are typically asymptomatic and benign, they can induce visual impairment in some patients. This review provides insight into the spectrum and visual outcomes of NF1, current diagnostic techniques and therapeutic interventions, and explores the influence of NF1-OPGS on visual abnormalities. We focus on recent advancements in preclinical animal models to elucidate the underlying mechanisms of NF1 pathology and therapies targeting NF1-OPGs. Overall, our review highlights the involvement of retinal ganglion cell dysfunction and degeneration in NF1 disease, and the need for further research to transform scientific laboratory discoveries to improved patient outcomes.

Optic Pathway Gliomas in Pediatric Population-Current Approach in Diagnosis and Management: Literature Review

In this paper, the authors present a clinical picture of the diagnosis and current treatment regimens of optic pathway glioma in the pediatric population, with an emphasis on the role of an ophthalmic diagnosis in the differentiation and monitoring of lesions. Glioma is the most common optic nerve tumor in children.

MATERIAL

Articles in PubMed, Scholar and Website were reviewed, taking into account current standards of management related to sporadic or NF1-related optic glioma, epidemiology, location, course of the disease, clinical manifestations, histological types of the tumor, genetic predisposition, diagnostic ophthalmic tests currently applicable in therapeutic monitoring of the tumor, neurological diagnosis, therapeutic management and prognosis. The importance of current screening recommendations, in line with standards, was emphasized.

RESULTS

Glioma occurs in children most often in the first decade of life. Initially, they may be asymptomatic, and clinically ophthalmic changes are associated with the organ of vision or with systemic changes. Gliomas associated with the NF1 mutation have a better prognosis for sporadic gliomas. Diagnosis includes radiological imaging methods/MRI/ophthalmology/OCT and visual acuity log MAR assessment. The basis of treatment is clinical observation. In the case of disease progression, surgical treatment, chemotherapy and targeted therapy are used.

CONCLUSION

Further research into novel techniques for detecting gliomas would allow for early monitoring of the disease.

Insights into Novel Choroidal and Retinal Clinical Signs in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a rare inherited neurocutaneous disorder with a major impact on the skin, nervous system and eyes. The ocular diagnostic hallmarks of this disease include iris Lisch nodules, ocular and eyelid neurofibromas, eyelid café-au-lait spots and optic pathway gliomas (OPGs). In the last years, new manifestations have been identified in the ocular district in NF1 including choroidal abnormalities (CAs), hyperpigmented spots (HSs) and retinal vascular abnormalities (RVAs). Recent advances in multi-modality imaging in ophthalmology have allowed for the improved characterization of these clinical signs. Accordingly, CAs, easily detectable as bright patchy nodules on near-infrared imaging, have recently been added to the revised diagnostic criteria for NF1 due to their high specificity and sensitivity. Furthermore, subclinical alterations of the visual pathways, regardless of the presence of OPGs, have been recently described in NF1, with a primary role of neurofibromin in the myelination process. In this paper, we reviewed the latest progress in the understanding of choroidal and retinal abnormalities in NF1 patients. The clinical significance of the recently revised diagnostic criteria for NF1 is discussed along with new updates in molecular diagnosis. New insights into NF1-related neuro-ophthalmic manifestations are also provided based on electrophysiological and optical coherence tomography (OCT) studies.

Quantitative OCT angiography of the retinal and choroidal vascular circulation in pediatric patients with neurofibromatosis type 1

PURPOSE

To investigate retinal and choroidal microvascular changes in neurofibromatosis type 1 (NF1) pediatric patients using optical coherence tomography angiography (OCTA).

METHODS

This study was performed on 21 eyes of 21 NF1 patients and 30 eyes of 30 healthy subjects. Foveal avascular zone (FAZ) parameters, including area, perimeter, acircularity index, and foveal density, were measured using OCTA. Superficial (SCP) and deep (DCP) capillary plexus and radial peripapillary capillary (RPC) vessel densities and choriocapillaris flow were also evaluated. Choroidal nodules and thickness were detected using infrared reflectance and enhanced-depth imaging OCT.

RESULTS

No significant differences were observed for FAZ parameters or SCP and RPC vessel densities between groups. DCP vessel densities in the perifovea were significantly lower in the NF1 group than in the control group (P = 0.001). A significantly lower choriocapillaris flow area (P < 0.001) and increased subfoveal and nasal perifoveal choroidal thickness (P < 0.001) were observed in the NF1 group. Choriocapillaris flow area tended to be inversely related to the number of choroidal nodules in the NF1 group.

CONCLUSIONS

Perifoveal DCP vessel density and choriocapillaris flow significantly differed between NF1 patients and controls, suggesting that retinal and choroidal vascular microcirculation is affected in the former, potentially by choroidal nodules. Further longitudinal studies are required to determine the effects of these differences on circulation in the posterior segment of the eye.

An update on choroidal abnormalities and retinal microvascular changes in neurofibromatosis type 1

Neurofibromatosis Type 1 (NF1) is a rare neurocutaneous disorder transmitted in an autosomal dominant fashion, mainly affecting the nervous system, the eye and skin. Ocular diagnostic hallmarks of NF1 include iris Lisch nodules, optic gliomas, orbital and eyelid neurofibromas, eyelid café-au-lait spots. In recent years, a new ocular sign represented by choroidal abnormalities (CAs) has been characterized in NF1. The CAs, identified with near-infrared reflectance, have been reported with a frequency of up to 100% in NF1, and have recently been added to the actual diagnostic criteria for NF1. The present Letter to the journal is intended to provide an update on features and clinical significance of CAs in NF1. Moreover, the relation with other ocular manifestations recently described in NF1 including hyperpigmented spots and retinal microvascular abnormalities is discussed.

Anti-Vascular Endothelial Growth Factor Drug Conbercept-Loaded Peptide Hydrogel Reduced Angiogenesis in the Neovascular Age-Related Macular Degeneration

Age-related macular degeneration (AMD) accounts for 8.7% of the global blindness and neovascular form of AMD (nAMD) occupies a large proportion of severe visual loss and legal blindness caused by AMD with a relatively low incidence rate. Choroidal neovascularization (CNV) is overwhelmingly responsible for the occurrence of nAMD as bleeding and fluid leakage followed by abnormal formation of blood vessels could directly lead to loss of central vision so that reduce the choroidal angiogenesis is an ideal treatment method of nAMD. VEGF is an important cytokine which promote the signaling pathway of angiogenesis and the abnormal expression of VEGF is verified in great many CNV cases. Several anti-VEGF drugs have been widely used in clinical treatments such as ranibizumab, bevacizumab and aflibercept. Conbercept, as an originally developed drug in China, has attracted great attention. For the purpose of better treatment efficacy, our group designed a short chain peptide (Sequence: DDIIIRH-NH₂, M.W.880.99) for controlled drug release to remedy the drawback of the short half-time period. The peptide could self-assembled into a stable 'hydrogel under pH 7.4 condition and the 3D structure was clearly observed in TEM study. Rheological study exhibited its great injectability so that the hydrogel was a material for intravitreal injection. Statistics exhibited that the hydrogel could release approximately 50% of total conbercept. The In vitro experiments showed that either dose-dependent or the time-dependent incubation with peptide would not decrease the cell viability of HREC, revealing that the peptide was biocompatible. The most important is that co-incubation with HREC obviously reduced the HREC proliferation and tube formation induced by VEGF, ensuring its potential for the treatment efficacy of nAMD.

RETINAL VASCULAR ABNORMALITIES IN CHILDREN WITH NEUROFIBROMATOSIS TYPE 1

PURPOSE

Retinal vascular abnormalities (RVAs) have been recently described in patients with neurofibromatosis Type 1 (NF1) as vascular tortuosity, best visible on infrared imaging. This study assessed clinical RVA's characteristics in a large series of children with NF1.

METHODS

This retrospective observational study was conducted in children (0-18 years) with an NF1 diagnosis. Using near-infrared imaging, RVAs were classified according to the nature of vessels involvement and their degree of tortuosity.

RESULTS

Retinal imaging from 140 children, with a median age of 8.8 years (1.5-18), was included; 52 patients (37.1%) (81 eyes) exhibited RVAs. These RVAs comprised 96% (50/52) of simple vascular tortuosity and 17% (9/52) of a corkscrew pattern. A corkscrew pattern involved only small veins, whereas simple vascular tortuosity could affect both arteries and veins. No statistically significant age correlation was observed, but evolution of RVAs from simple vascular tortuosity to corkscrew pattern was observed in 5 cases.

CONCLUSION

Retinal vascular abnormalities occurred in 37.1% of children with NF1. These abnormalities may result from NF1 promoting localized tortuosity in both small arteries and veins, whereas only small second-order or tertiary-order venules evolve to a highly tortuous pattern.

Optical coherence tomography angiography of choroidal nodules in neurofibromatosis type-1: A case series

PURPOSE

To describe optical coherence tomography angiography (OCTA) findings in the retina and choroid of patients with neurofibromatosis type 1 (NF1).

METHODS

We describe a series of four patients diagnosed with NF1 and choroidal nodules who underwent a comprehensive ophthalmic evaluation including a retinal multimodal imaging study based on retinography, near-infrared reflectance imaging (NIR), enhanced depth imaging (EDI) optical coherence tomography (OCT) and OCTA.

RESULTS

Patients were three women and one man aged 36-47 years. In all patients, the choroidal nodules were not visible in retinographies but easily detectable with NIR, appearing as multiple bright patches. On OCTA, we observed reduced vessel density in the choriocapillaris in zones where choroidal nodules appeared in OCT images. In one patient, a corkscrew vessel was visible in the superficial capillary plexus.

CONCLUSION

Choriocapillaris vessel density was reduced in zones where choroidal nodules occur in NF1 patients. Further work is needed to clarify the clinical relevance of this finding.

Ocular biometric parameters changes and choroidal vascular abnormalities in patients with neurofibromatosis type 1 evaluated by OCT-A

Purpose

To analyze ocular biometric parameters alterations of the posterior pole and choroidal abnormalities in patients with neurofibromatosis type 1 (NF1) by adopting multimodal imaging, especially focusing on the role of novel diagnostic devices like swept-source optical coherence tomography angiography (SS-OCTA).

Methods

In this prospective, case-controlled study, patients with NF1 and age-matched control subjects were quantitatively analyzed by using multimodal imaging. All the subjects underwent confocal scanning laser ophthalmoscopy (SLO), SS-OCT and SS-OCTA examinations.

Results

SS-OCT analysis revealed a lower macular retinal nerve fiber layer (RNFL) thickness in patients with NF1 compared with those with suspected NF1 (95.0±15.9 vs 109.7±11.3 μm; P = 0.001) and control subjects (106.8±14.4 μm, P = 0.003). Retinal thickness was significantly lower in NF1 patients compared to those with suspected NF1 (280.7±23.0 vs 304.2±15.3 μm; P < 0.001) and control subjects (298.7±23.8 μm, P = 0.003). The mean vascular flow area of the SCP was significantly higher in patients with NF1 (42.6±2.2%) and suspected NF1 (43.1±2.5%) compared to control subjects (41.0±2.0%; respectively, P = 0.017 and P = 0.002). In the second choroidal layer, the flow area was significantly lower in patients with NF1 compared to control subjects (45.4±4.8 vs 49.0±4.0%,; P = 0.011).

Conclusions

Retinal thicknesses alterations and choroidal nodules are described as ocular manifestations in patients with NF1. In addition, OCTA could represent an important novel advanced imaging technique, capable of detecting early altered retinal and choroidal vascular flow area in patients with NF1.

RETINAL VASCULAR ABNORMALITIES RELATED TO NEUROFIBROMATOSIS TYPE 1: Natural History and Classification by Optical Coherence Tomography Angiography in 473 Patients

PURPOSE

To analyze and classify neurofibromatosis Type 1 (NF1)-related retinal vascular abnormalities (RVAs), their natural history and correlation with disease severity, in a large cohort of patients.

METHODS

This was an observational longitudinal study with prospective enrollment. Four hundred and seventy-three patients affected by NF1 and 150 age-matched healthy subjects were consecutively enrolled. Retinal vascular abnormalities were detected by means of near-infrared reflectance and studied by optical coherence tomography angiography. The superficial vascular plexus and the deep vascular complex (DVC) were quantitatively and qualitatively analyzed.

RESULTS

We identified RVAs in 82 of 473 (17%) NF1 patients, but in none of the 150 healthy subjects. A comparison revealed that NF1 patients with RVAs showed a higher number of NF1 diagnostic criteria (4.3 ± 1.5 vs. 3.9 ±1.5, respectively; P = 0.02) than patients without RVAs. Three different RVA types were identified on optical coherence tomography angiography: macrovascular angiomatosis of the sole superficial vascular plexus; macrovascular angiomatosis of the superficial vascular plexus combined with microvascular angiomatosis of the deep vascular complex; and combined macrovascular angiomatosis of both superficial vascular plexus and deep vascular complex. The prospective analysis of optical coherence tomography angiography images showed no significant longitudinal evolution of RVAs (mean follow-up: 3.7 ± 2.8 years). A single patient developed a de novo single RVA, and two RVAs showed detectable changes during follow-up.

CONCLUSION

In NF1 patients, RVAs are a characteristic sign that correlates with a more severe systemic disease expression, usually remaining stable during time. Optical coherence tomography angiography allows for the identification of different RVAs subtypes.

Current concepts on ocular vascular abnormalities in the phakomatoses

BACKGROUND

Neurofibromatosis, Von Hippel Lindau disease, and tuberous sclerosis complex are classified under the term phakomatoses. They are characterized by ocular vascular abnormalities such as vascular tortuosity, corkscrew retinal vessel configuration, moyamoya-like aspect, microaneurysms, hemangioblastomas, and focal sheathing of retinal arteries, possibly due to abnormal formation, migration, and differentiation of neural crest cells. These alterations can be the first sign or the hallmark of disease and can be related to vasoproliferative tumors.

PURPOSE

Novel imaging technologies in ophthalmology, such as near-infrared reflectances and spectral domain optical coherence tomography, have improved our knowledge in the diagnosis of these pathologies. Previously undetected macular vascular alterations have been reported in phakomatoses using optical coherence tomography angiography. This review will summarize the ophthalmic vascular abnormalities and novel imaging methods in the phakomatoses.

CONCLUSION

Active research is being led into the ophthalmic management of these conditions and their complications, and owing to elevated vascular endothelial growth factor production from hemangioblastoma, hamartoma, and retinal vascular proliferative tumors, increasing interest in this line of therapy has been conducted although research is still ongoing in this area.

Hyperpigmented spots at fundus examination: a new ocular sign in Neurofibromatosis Type I

BACKGROUND

Neurofibromatosis Type I (NF1), also termed von Recklinghausen disease, is a rare genetic disorder that is transmitted by autosomal dominant inheritance, with complete penetrance and variable expressivity. It is caused by mutation in the NF1 gene on chromosome 17 encoding for neurofibromin, a protein with oncosuppressive activity, and it is 50% sporadic or inherited. The disease is characterized by a broad spectrum of clinical manifestations, mainly involving the nervous system, the eye and skin, and a predisposition to develop multiple benign and malignant neoplasms. Ocular diagnostic hallmarks of NF1 include optic gliomas, iris Lisch nodules, orbital and eyelid neurofibromas, eyelid café-au-lait spots. Choroidal nodules and microvascular abnormalities have recently been identified as additional NF1-related ocular manifestations. The present study was designed to describe the features and clinical significance of a new sign related to the visual apparatus in NF-1, represented by hyperpigmented spots (HSs) of the fundus oculi.

RESULTS

HSs were detected in 60 (24.1%) out of 249 patients with NF1, with a positive predictive value of 100% and a negative predictive value of 44.2%. None of the healthy subjects (150 subjects) showed the presence of HSs. HSs were visible under indirect ophthalmoscopy, ultra-wide field (UWF) pseudocolor imaging and red-only laser image, near-infrared reflectance (NIR)-OCT, but they were not appreciable on UWF green reflectance. The location and features of pigmentary lesions matched with the already studied NF1-related choroidal nodules. No significant difference was found between the group of patients (n = 60) with ocular HSs and the group of patients (n = 189) without ocular pigmented spots in terms of age, gender or severity grading of the disease. A statistically significant association was demonstrated between the presence of HSs and neurofibromas (p = 0.047), and between the presence of HSs and NF1-related retinal microvascular abnormalities (p = 0.017).

CONCLUSIONS

We described a new ocular sign represented by HSs of the fundus in NF1. The presence of HSs was not a negative prognostic factor of the disease. Following multimodal imaging, we demonstrated that HSs and choroidal nodules were consistent with the same type of lesion, and simple indirect ophthalmoscopy allowed for screening of HSs in NF1.

Rubeosis iridis and macular hemorrhages from multiple Corkscrew retinal vessels in a patient with NF1

PURPOSE

To report a case of a patient with NF1 presenting with ocular findings of AV malformation, multiple retinal hemorrhages, and neovascular glaucoma in the absence of retinal ischemia.

METHODS

Review of the medical record was conducted in accordance with the local IRBt.

RESULTS

A 60-year-old female patient with diagnosis of Neurofibromatosis type1 (NF1) and sudden decrease of vision in her left eye was found to have rubeosis iridis and high intraocular pressure (IOP). On fundus exam multiple corkscrew retinal vessels and retinal hemorrhages were present in her left eye. On Optical Coherence Tomography (OCT) the foveal hemorrhages appeared as outer layer hyperreflective retinal infiltrates whereas in the parafoveal area the hyperreflectivity was present between the RPE and neurosensory retina. Fluorescein Angiogram (FA) showed normal perfusion and no areas of leakage or ischemia. Treatment with anti-angiogenics in a timely manner correlated with a good visual outcome.

CONCLUSIONS

We present a unique patient with NF1, rubeosis iridis, high IOP, and macular hemorrhages from multiple corkscrew retinal vessels in a well perfused retina, who underwent treatment with a single dose of intravitreal Bevacizumab and had an excellent response.

Structural and microvascular changes of the peripapillary retinal nerve fiber layer in Von Hippel-Lindau disease: an OCT and OCT angiography study

Von Hippel–Lindau (VHL) disease is an autosomal dominant genetic disease caused by VHL gene mutation. Retinal hemangioblastomas (RH) are vascularized tumors and represent the main ocular manifestation of the disease. Histopathologically, RH are composed of capillary vessels and stromal cells, the neoplastic population of the lesion. The origin of these stromal cells remains controversial, even if they are hypothesized to be glial cells. The aim of the present study was to investigate neuronal and microvascular changes of the peripapillary retinal nerve fiber layer, in which glial cells, neurons and capillaries (the radial peripapillary capillary plexus) interact. VHL patients with or without peripheral RH were enrolled and compared to healthy controls. Mean peripapillary retinal nerve fiber layer (pRNFL) thickness was measured by means of optical coherence tomography (OCT). The following vascular parameters of the radial peripapillary capillary plexus were quantified using OCT angiography: Vessel Area Density,Vessel Length Fraction, Vessel Diameter Index and Fractal Dimension. One hundred and nine eyes of 61 patients, and 56 eyes of 28 controls were consecutively studied. Mean pRNFL was significantly thinner in VHL eyes without RH versus eyes with RH and controls. Mean pRNFL thickness did not differ between VHL eyes with RH and controls. All OCTA vascular parameters were reduced in VHL eyes with or without RH versus controls, with significative difference for Vessel Diameter Index. The same OCTA parameters did not significantly differ between VHL eyes with or without RH. In VHL eyes without RH, pRNFL thinning may be the consequence of impaired perfusion of the radial peripapillary capillary plexus, while the increase of pRNFL thickness in VHL eyes with RH may depend on possible activation and proliferation of the other RNFL resident cells, the glial cells.

Diagnosis and clinical course of ocular ischemic syndrome with retinal vascular abnormalities due to unilateral ocular artery and internal carotid artery stenosis in a child with neurofibromatosis type 1: a case report

Background

Neurofibromatosis type 1 (NF1) is a hereditary disease that causes neurofibromas generally, but it has been reported to sometimes be associated with various forms of blood vessel stenosis, occlusion and vascular abnormalities of unknown mechanism. However, a symptomatic case with simultaneous ophthalmic artery stenosis and internal carotid artery stenosis is an extremely rare pathogenesis in a child with NF1. In this report, we performed the diagnosis and observation using various imaging modalities for this rare pediatric case.

Case presentation

A 6-year-old girl diagnosed with NF1 presented with gradual visual loss in the right eye. Best corrected visual acuity (BCVA) was 20/40 OD and the intraocular pressure (IOP) was normal in both eyes. Retinal vascular abnormalities with tortuous vessels and optic disc pallor were observed in the right fundus. Widefield fluorescein angiography revealed multiple sites of neovascularization and a large non-perfusion area in the peripheral retina. Optical coherence tomography angiography showed retinal vascular abnormalities in the right eye and revealed differences in inner retinal thickness and blood flow signal between the left and right eyes. Laser speckle flowgraphy showed that chorioretinal blood flow was significantly decreased in the right eye. Cerebral angiography revealed the right ophthalmic artery was significantly narrowed throughout. In addition, Magnetic resonance angiography revealed that the right internal carotid artery was significantly narrowed in the ophthalmic segment. We diagnosed ophthalmic artery and internal carotid artery stenosis with retinal vascular abnormalities and ocular ischemic syndrome in NF1. Because IOP increased to 35 mmHg, due to neovascular glaucoma in addition to mild vitreous hemorrhage occurred, panretinal photocoagulation was performed after intravitreal bevacizumab injection. After treatments, IOP normalized, but BCVA decreased to 20/100 OD. Arterial spin labeling showed normal cerebral blood flow. The patient is currently being carefully monitored.

Conclusions

We have described the diagnosis and treatment of ocular ischemic syndrome due to multiple arteries stenosis in a child with NF 1. Utilization of various imaging modalities was helpful in diagnosing the complicated pathogenesis. However, since direct intervention by neurosurgery is not possible in this case, it is expected that treatment will be extremely difficult in the future.

Retinal manifestations of the neurocutaneous disorders

PURPOSE OF REVIEW

The neurocutaneous disorders are a genetically and phenotypically diverse group of congenital syndromes characterized by cutaneous, ocular, and central nervous system manifestations. This review provides an overview of the clinical features and retinal findings in selected neurocutaneous disorders.

RECENT FINDINGS

Advances in genetics and diagnostic retinal and neuroimaging allow for the recognition of retinal features of common neurocutaneous syndromes and for improved characterization of rarer entities based on previously underdiagnosed or unrecognized retinal findings.

SUMMARY

Better characterization of the neurocutaneous disorders allows for earlier recognition and the potential for expeditious vision-saving and life-saving treatment.

Congenital abnormalities of the retinal vasculature in neurofibromatosis type I

The aim of this cross-sectional study was to investigate congenital abnormalities of the retinal vasculature (CARVs) in patients with neurofibromatosis type I (NF-1). Forty-eight patients (96 eyes) with NF-1 diagnosed according to the National Institutes of Health (NIH) criteria and 48 healthy controls were included in this study. Standard fundus photographs were obtained for each subject to evaluate the presence and frequency of CARVs. The sensitivity, specificity, and diagnostic accuracy of different cut-off numbers of CARVs were compared with those of the NIH criteria. Forty-four (91.7%) patients in the NF-1 group demonstrated either supranumeraty optic disc vessels or triple branching of the retinal vasculature, and 22 patients (45.8%) demonstrated both findings. The frequencies of these two CARVs were significantly different between the two groups (p < 0.00001). A cut-off value of either one for supranumerary optic disc vessels or triple branching showed the highest accuracy along with sensitivity and specificity of 91.7% and 87.5%. CARVs such as supranumerary optic disc vessels or triple branching were frequently observed in NF-1 patients, and their occurrence was unrelated to the age of patients. Thus, these CARVs could be added as new ophthalmologic manifestions for NF-1 and may potentially enable early diagnosis of NF-1.

Ocular surface involvement in patients with neurofibromatosis type 1 syndrome

PURPOSE

The aim of this study is to evaluate ocular surface morphological and functional changes in patients with neurofibromatosis type 1 (NF1).

METHODS

Twenty-eight patients with NF1 and 14 healthy subjects were included in this study. All participants underwent a medical history collection, a complete ophthalmological examination including slit lamp exam and assessment of best-corrected visual acuity (BCVA), corneal sensitivity, and lacrimal function (Schirmer test and fluorescein tear break-up time test). Corneal nerves' morphology and endothelial cells density were evaluated by in vivo corneal confocal microscopy (IVCM). Tear and conjunctiva epithelium samples were collected to evaluate nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) tear levels and conjunctival expression of their receptors TrkA and p75NTR.

RESULTS

Patients with NF1 showed a significant decrease of FTBUT when compared with healthy subjects (p < 0.001). Corneal sensitivity was ≤ 50 mm in 46% of NF1 patients. IVCM showed a significant increase of corneal nerve branching and of corneal endothelial cells density. No significant difference was observed between the two groups on NGF and BDNF tear levels and conjunctival expression of their receptors.

CONCLUSION

This study demonstrated the presence of ocular surface changes in NF-1 patients including decrease of tear stability and of corneal sensitivity. Patients with NF1 also showed changes of corneal endothelial cells' density.

Peripheral retinal neovascularization in a patient with pilocytic astrocytoma

We described a case of papilledema complicated by peripheral retinal vessels in a 12-year-old boy affected by cerebellar astrocytoma. Opportunity to treat with photocoagulation or intravitreal anti-VEGF (vascular endothelial growth factor) injections was discussed with the parents and no treatment was done. After 5 years from surgery, retinal neovascularization was stable without vitreal hemorrhages or retinal complications, more specifically fibrosis of the neovessels increased and leakage phenomena were reduced at the fluorescein angiography. To our knowledge, this is a unique case of papilledema complicated by peripheral retinal vessels in a patient affected by cerebellar astrocytoma.

Optic Pathway Glioma in Type 1 Neurofibromatosis: Review of Its Pathogenesis, Diagnostic Assessment, and Treatment Recommendations

Type 1 neurofibromatosis (NF1) is a dominantly inherited condition predisposing to tumor development. Optic pathway glioma (OPG) is the most frequent central nervous system tumor in children with NF1, affecting approximately 15-20% of patients. The lack of well-established prognostic markers and the wide clinical variability with respect to tumor progression and visual outcome make the clinical management of these tumors challenging, with significant differences among distinct centers. We reviewed published articles on OPG diagnostic protocol, follow-up and treatment in NF1. Cohorts of NF1 children with OPG reported in the literature and patients prospectively collected in our center were analyzed with regard to clinical data, tumor anatomical site, diagnostic workflow, treatment and outcome. In addition, we discussed the recent findings on the pathophysiology of OPG development in NF1. This review provides a comprehensive overview about the clinical management of NF1-associated OPG, focusing on the most recent advances from preclinical studies with genetically engineered models and the ongoing clinical trials.

The Diagnosis and Management of Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1), NF2, and schwannomatosis are related, but distinct, tumor suppressor syndromes characterized by a predilection for tumors in the central and peripheral nervous systems. NF1 is one of the most common autosomal dominant conditions of the nervous system. NF1 has a high degree of variability in clinical presentation, which may include multiple neoplasms as well as cutaneous, vascular, bony, and cognitive features. Some of these manifestations overlap with other genetic conditions. Accurate diagnosis of NF1 is important for individualizing clinical care and genetic counseling. This article summarizes the clinical features, diagnostic work-up, and management of NF1.

Dysfunctional coping is related to impaired skin-related quality of life and psychological distress in patients with neurofibromatosis type 1 with major skin involvement

BACKGROUND

Low skin-related quality of life (QoL) is usually associated with low levels of self-confidence and self-esteem and with high levels of anxiety and depression symptoms. The way patients cope with a physical disease impacts significantly on their psychosocial adjustment to the disorder and on their emotional functioning.

OBJECTIVES

To explore how coping strategies, skin-related QoL, psychological distress and self-esteem interact in a sample of individuals with neurofibromatosis type 1 (NF1).

METHODS

Seventy-two adult patients with NF1 completed the following questionnaires: Coping Orientation to Problem Experiences (COPE), Skindex-29, Padua Skin-Related QoL questionnaire (PSRQ), State-Trait Anxiety Inventory-X2 form (STAI-X2), Depression Questionnaire (DQ) and Rosenberg Self-Esteem Scale (RSES). The k-modes algorithm was used to identify clusters of patients based on four variables: sex, NF1 severity, number and distribution of cutaneous neurofibromas. Individuals in different clusters were compared with regard to their scores; correlations between scores were analysed within each cluster.

RESULTS

Two main clusters were identified: individuals in Cluster 1 had a larger number and more widespread distribution of neurofibromas compared with Cluster 2. Patients in Cluster 1 scored higher only on several PSRQ and Skindex-29 scales. Among patients in Cluster 1, the COPE 'avoidance strategies' scale was significantly correlated with the PSRQ 'physical distress and impairments' scale, the Skindex-29 'physical symptoms' and 'functioning' scales, the STAI-X2, the DQ and the RSES.

CONCLUSIONS

Patients with major skin involvement have reduced skin-related QoL. Among them, current findings tentatively suggest that the higher the use of dysfunctional coping, the more impaired are QoL, psychological distress and self-esteem. What's already known about this topic? Neurofibromatosis type 1 (NF1) can affect the quality of life (QoL) in adolescent and adult patients. Low skin-related QoL is usually associated with low levels of self-confidence and self-esteem and with high levels of anxiety and depression symptoms. Questionnaires evaluating skin-related QoL, anxiety, depression, self-esteem and coping are available. What does this study add? Patients with a large number and a widespread distribution of cutaneous neurofibromas have reduced skin-related QoL compared with patients with minor skin involvement. The newly developed Padua Skin-Related QoL questionnaire allows the simultaneous evaluation of discomfort and comfort skin-related QoL dimensions in patients with NF1. Among patients with major skin involvement, the higher the use of dysfunctional coping, the more impaired are skin-related QoL, psychological distress and self-esteem. Our data suggest that patients with NF1 with major skin involvement who endorse dysfunctional beliefs about their own coping abilities might benefit from psychological counselling and coping skills treatments aiming to both improve perceived self-efficacy and learn more adaptive coping strategies.

Neurofibromin Deficiency Induces Endothelial Cell Proliferation and Retinal Neovascularization

Purpose

Neurofibromatosis type 1 (NF1) is the result of inherited mutations in the NF1 tumor suppressor gene, which encodes the protein neurofibromin. Eye manifestations are common in NF1 with recent reports describing a vascular dysplasia in the retina and choroid. Common features of NF1 retinopathy include tortuous and dilated feeder vessels that terminate in capillary tufts, increased endothelial permeability, and neovascularization. Given the retinal vascular phenotype observed in persons with NF1, we hypothesize that preserving neurofibromin may be a novel strategy to control pathologic retinal neovascularization.

Methods

Nf1 expression in human endothelial cells (EC) was reduced using small hairpin (sh) RNA and EC proliferation, migration, and capacity to form vessel-like networks were assessed in response to VEGF and hypoxia. Wild-type (WT), Nf1 heterozygous (Nf1^+/−), and Nf1^flox/+;Tie2cre pups were subjected to hyperoxia/hypoxia using the oxygen-induced retinopathy model. Retinas were analyzed quantitatively for extent of retinal vessel dropout, neovascularization, and capillary branching.

Results

Neurofibromin expression was suppressed in response to VEGF, which corresponded with activation of Mek-Erk and PI3-K-Akt signaling. Neurofibromin-deficient EC exhibited enhanced proliferation and network formation in response to VEGF and hypoxia via an Akt-dependent mechanism. In response to hyperoxia/hypoxia, Nf1^+/− retinas exhibited increased vessel dropout and neovascularization when compared with WT retinas. Neovascularization was similar between Nf1^+/− and Nf1^flox/+;Tie2cre retinas, but capillary drop out in Nf1^flox/+;Tie2cre retinas was significantly reduced when compared with Nf1^+/− retinas.

Conclusions

These data suggest that neurofibromin expression is essential for controlling endothelial cell proliferation and retinal neovascularization and therapies targeting neurofibromin-deficient EC may be beneficial.

Retinal microvascular abnormalities in neurofibromatosis type 1

PURPOSE

The aim of this study was to provide a classification of the different retinal vascular arrangements in neurofibromatosis 1 (NF1), with appropriate qualitative and quantitative information.

METHODS

This study was conducted on 334 consecutive patients with NF1 and 106 sex-matched and age-matched healthy control subjects. Each patient underwent a comprehensive ophthalmological examination inclusive of near-infrared reflectance retinography by using the spectral domain Optical coherence tomography (OCT), a complete dermatological examination and 1.5 T MRI scan of the brain to assess the presence of optic nerve gliomas. To evaluate the predictability and the diagnostic accuracy of our identified retinal microvascular arrangements, we calculated the diagnostic indicators for each pattern of pathology, with corresponding 95% CI. In addition, we evaluated the association between the microvascular arrangements and each National Institutes of Health diagnostic criteria.

RESULTS

Microvascular abnormalities were detected in 105 of 334 NF1 patients (31.4%), the simple vascular tortuosity was recognised in 78 of 105 cases (74.3%) and whether the corkscrew pattern and the moyamoya-like type showed a frequency of 42.8% (45 of 105 cases) and 15.2% (16 of 105 cases), respectively. We found a statistically significant correlation between the presence of retinal microvascular abnormalities and the patient age (p=0.02) and between the simple vascular tortuosity, the patient age and the presence of neurofibromas (p=0.002 and p=0.05, respectively).

CONCLUSIONS

We identified microvascular alterations in 31.4% of patients and a statistically significant association with patient age. Moreover, the most frequent type of microvascular alterations, the simple vascular tortuosity, resulted positively associated with age and with the presence of neurofibromas.

Correlation of peripapillary retinal nerve fibre layer thickness with visual acuity in paediatric patients affected by optic pathway glioma

PURPOSE

To evaluate peripapillary retinal nerve fibre layer (RNFL) thickness, measured by spectral-domain optical coherence tomography (SD-OCT), as a surrogate of visual function in a population of paediatric patients affected by optic pathway glioma (OPG) associated with neurofibromatosis type 1 (NF1).

METHODS

A total of 38 paediatric patients (66 eyes) affected by MRI-proven OPG were included. Each patient underwent complete ophthalmological examination, including age-appropriate visual acuity (VA) assessment and RNFL analysis by SD-OCT. Visual acuity was classified as normal or pathologic using age-based normative data. Visual acuity was correlated to mean RNFL thickness of the whole peripapillary area and of each single analyzed sector (nasal, superior, temporal, inferior).

RESULTS

Visual acuity was normal in 43 (65%) and pathologic in 23 (35%) eyes. Mean parapapillary RNFL thickness of each analyzed sector was significantly lower in eyes with abnormal VA (p < 0.05). The best balanced cut-off value of global RNFL thickness allowing to discriminate between eyes with normal and pathologic VA was 76.25 μm (91%, 76%, 67% and 94% of sensitivity, specificity, positive and negative predicting value, respectively). Considering best balanced cut-off values of other analyzed RNFL sectors, the superior (p = 0.0029) and the inferior (p = 0.0024) sectors reached the higher sensitivity (87% and 87%, respectively) and specificity (81% and 79%, respectively).

CONCLUSION

Retinal nerve fibre layer thickness is directly related to VA in children affected by NF1-related OPG, and should be considered as a potential surrogate marker of VA. Retinal nerve fibre layer thickness cut-off values can be used in paediatric patients to discriminate false-positive results obtained by VA measurement.