Mutations In Von Hippel-Lindau Gene Research Articles

Carbonic Anhydrase IX (CA9) Overexpression and Negative PAX8 Staining Can Be Used to Confirm Hemangioblastomas

Abstract Introduction/Objective Hemangioblastomas are indolent brain tumors consisting histologically of atypical stromal cells and a large number of blood vessels lined by endothelial cells. The tumors are often associated with either von Hippel- Lindau (VHL) syndrome or sporadic mutation of VHL genes. As CA9 is a marker of the hypoxic inducible factor-alpha1 cascade, its overexpression has been well known to present in clear cell renal cell carcinoma that involves the mutation of VHL gene. A few studies demonstrate overexpression of CA9 in hemangioblastomas, but not in other primary brain tumors such as gliomas and meningioma. Our two cases were used to determine if positive CA9 and negative PAX8 immuno-stains were useful markers to support the diagnosis of hemangioblastomas. Methods/Case Report One patient was a 50-year-old man and the other patient was a 75-year-old man. Two lesions were identified in the cerebellum with typical appearance of vascular channels intermingled with atypical stromal cells showing clear cell cytoplasm. The endothelial cells were positive for CD34 and ERG. The stromal cells were weakly positive for inhibin but negative for the endothelial markers GFAP, pancytokeratin and PAX8, ruling out primary glioma and metastatic clear cell renal carcinoma. The atypical stromal cells with clear cytoplasm in both tumors, however, showed strong and diffuse membranous staining for CA9 (3+). The overall findings supported the morphologic diagnosis of hemangioblastomas in both patients. Results (if a Case Study enter NA) NA Conclusion Our preliminary data indicates that positive CA9 and negative PAX8 stains are a useful pair of markers to support a diagnosis of hemangioblastoma and differentiate them from metastatic clear cell renal cell carcinoma. Additionally, CA9 can help confirm the diagnosis of hemangioblastoma when inhibin is weak or nearly negative.

Genotype-phenotype correlation of ocular von Hippel-Lindau disease in Koreans.

This scientific report aims to investigate the genotype-phenotype correlations of retinal hemangioblastoma (RH) in von Hippel-Lindau (VHL) disease. The study included 77 patients with genetically confirmed VHL disease who visited an ophthalmology clinic for the evaluation of RH. The presence, location, and size of RH were evaluated, Patients were categorized into three groups based on variants: HIF-1α binding site missense (HM), non-HIF-1α binding site missense (nHM), and truncating (TR) mutations. Fifty-six patients (72.7%) had RH in either eye, and 24 had bilateral RH. Sixteen patients (20.8%) had juxtapapillary RH in either eye. Nine patients had RH ≥ 2.0 disc diameters in size. VHL c.208G>A variant was the most frequent single mutation. Compared with patients having nHM mutations (15 patients) in VHL gene, patients with HM mutations (33 patients) or TR mutations (26 patients) presented a greater number of eyes affected (p = 0.007 and 0.004, respectively), a greater number of RH (p = 0.012 and 0.003, respectively), and more frequent presentation of large RH ≥ 2.0 disc diameters (p = 0.012, and 0.013, respectively). In conclusion, this study provides a deeper understanding of the genetic spectrum of VHL disease in Korean VHL disease and highlights the importance of the location of missense mutations regarding the risk of RH.

Radiogenomics and Texture Analysis to Detect von Hippel-Lindau (VHL) Mutation in Clear Cell Renal Cell Carcinoma.

Radiogenomics, a burgeoning field in biomedical research, explores the correlation between imaging features and genomic data, aiming to link macroscopic manifestations with molecular characteristics. In this review, we examine existing radiogenomics literature in clear cell renal cell carcinoma (ccRCC), the predominant renal cancer, and von Hippel-Lindau (VHL) gene mutation, the most frequent genetic mutation in ccRCC. A thorough examination of the literature was conducted through searches on the PubMed, Medline, Cochrane Library, Google Scholar, and Web of Science databases. Inclusion criteria encompassed articles published in English between 2014 and 2022, resulting in 10 articles meeting the criteria out of 39 initially retrieved articles. Most of these studies applied computed tomography (CT) images obtained from open source and institutional databases. This literature review investigates the role of radiogenomics, with and without texture analysis, in predicting VHL gene mutation in ccRCC patients. Radiogenomics leverages imaging modalities such as CT and magnetic resonance imaging (MRI), to analyze macroscopic features and establish connections with molecular elements, providing insights into tumor heterogeneity and biological behavior. The investigations explored diverse mutations, with a specific focus on VHL mutation, and applied CT imaging features for radiogenomic analysis. Moreover, radiomics and machine learning techniques were employed to predict VHL gene mutations based on CT features, demonstrating promising results. Additional studies delved into the relationship between VHL mutation and body composition, revealing significant associations with adipose tissue distribution. The review concludes by highlighting the potential role of radiogenomics in guiding targeted and selective therapies.

Retinal phakomatosis and Von Hippel-Lindau peripheral capillary hemangioblastoma: proposal for staged surgery.

Retinal capillary hemangioblastoma (RCH) is present in about half of the carriers of the VHL (von Hippel-Lindau) gene mutation and can lead to the evolution of blindness. Herewith is a proposal for surgical intraretinal feeder vessel ligature to induce ischemia the phakoma and to resolve the exudative secondary retinal detachment, with satisfying results at the 6 months follow-up end point. The patient underwent a chandelier-assisted 23 G pars plana vitrectomy with valved trocars. A bimanual transretinal ligature of the hemangioblastoma's feeder vessel was performed, followed by localized endolaser to ablate the surrounding retina and capillaries, and a Polydimethylsiloxane 1000 (PDMS 1000) final tamponade. After 3 months, exchange PDMS/air/balanced salt solution (BSS), phacoemulsification, and in-the-bag intraocular lens (IOL) implantation were performed. At sixth month, fundus fluorescein angiography (FFA) showed a significant reduction of blood flow in the phakoma. Final best-corrected visual acuity (BCVA) was 6/6 (9 lines gain obtained compared to the baseline time). This surgical technique seems to be effective and promising for the treatment of VHL retinal capillary hemangioblastomas and their related retinal complications.

Sunitinib Treatment of VHL C162F Cells Slows Down Proliferation and Healing Ability via Downregulation of ZHX2 and Confers a Mesenchymal Phenotype.

von Hippel-Lindau (VHL) disease, due to mutations of the tumor suppressor VHL gene, is a rare hereditary syndrome with a high risk of developing clear cell renal cell carcinoma (ccRCC). We asked whether the VHL-C162F mutation interferes with proliferation, migration, healing and forming colony ability by using wild-type VHL (WT VHL) and VHL-C162F reconstituted cells. We then analyzed the in vitro impact of the sunitinib treatment on VHL-C162F cells. We showed that VHL-C162F mutations have no impact on cell morphology, colony formation and migration ability but confer a significant higher healing ability than in WT VHL cells. RNA sequencing analysis revealed that VHL-C162F mutation upregulates genes involved in hypoxia and epithelial mesenchymal transition (EMT) pathways by comparison with VHL WT cells. We next showed a decrease in healing ability in VHL-C162F cells depleting on ZHX2, an oncogenic driver of ccRCC, highlighting the potential involvement of ZHX2 in aggressiveness of the VHL-C162F cells. Moreover, we found that sunitinib treatment inhibits ZHX2 expression and induces a reduced proliferation correlating with downregulation of P-ERK. Sunitinib treatment also conferred a more mesenchymal profile to VHL-C162F cells with significant downregulation of E-cadherin and upregulation of N-cadherin, Slug and AXL. Sunitinib therapy may therefore promote disease progression in VHL-C162F patients.

A nonsense mutation in VHL causing Von Hippel-Lindau syndrome in a large Chinese family—a genetic study of familial neoplastic disease

Von Hippel-Lindau (VHL) syndrome is a multi-organ neoplastic disease characterized by highly vascular and cystic tumors in the central nervous system (CNS), retina, and visceral lesions, which are mainly caused by germline mutations in VHL. We aimed to detect novel mutations in VHL gene in families with VHL. Here, a large consanguineous four-generation family with variant phenotypes of VHL syndrome was recruited, and its molecular genetics were tested via Sanger sequencing. And various tools and databases were used to predict the variant pathogenicity, frequency, and protein function. Genetic investigation detected a c.351G > A nonsense mutation in VHL that altered the downstream reading frame and created a premature TGA stop signal, resulting in severely truncated pVHL (p.Trp117Ter). This mutation is absent from most public databases, and functional prediction bioinformatic tools demonstrated that this residue is conserved and that this variant is highly likely to be deleterious. The c.315G > A nonsense mutation in VHL is the causal mutation of this kindred that may lead to clear familial aggregation of VHL syndrome because of the dysfunction of the truncated pVHL.

Tumor Suppressor Gene VHL, Mechanism and Related Therapy

Von Hippel-Lindau (VHL) syndrome is a rare hereditary disorder characterized by the development of multiple tumorsin various organs. This paper provides a comprehensive overview of the VHL gene, its mechanism of action, and itsimplications in VHL-related tumorigenesis. The first section explores the role of the VHL tumor suppressor gene inregulating angiogenesis and oxygen sensing, highlighting its significance in tumor suppression. The second sectiondiscusses the association between VHL gene mutations and the development of various tumor types, emphasizing thediverse clinical manifestations of VHL syndrome. The third section examines the diagnostic methods for identifyingVHL gene mutations, including genetic testing and clinical evaluations. The fourth section delves into therapeuticapproaches for managing VHL-related tumors, encompassing surgical interventions, targeted therapies, radiotherapy,and emerging treatment strategies. This paper aims to enhance understanding of VHL syndrome, facilitate earlydiagnosis, and guide treatment decisions for individuals affected by this complex disorder.

Abstract 1719: VHLloss enables immune checkpoint blockade therapy by boosting interferon response

Abstract Background: The von-Hippel Lindau (VHL) as a part of E3 ubiquitin ligase is a key regulator of hypoxia induced factors (HIFs). It is also characterized as a tumor suppressor gene mutated in up to 80% clear cell renal cell carcinoma (ccRCC) cases. Immune checkpoint blockade (ICB) therapy has shown improved ccRCC treatment outcomes. However, the biological roles of the VHL gene in ICB therapy are to be explored. Methods: The association between VHL gene mutation and overall survival of patients receiving ICB treatments was determined by integrating multiple human datasets. CRISPR/Cas9 was used to generate VHL knockout (KO) for in vivo tumor growth and in vitro mechanistic studies. The anti-tumor responses of genetic VHL loss in combination with anti-PD1 treatment were evaluated in three syngeneic murine tumor models. Tumor infiltrated lymphocytes and intratumoral T-cell receptor (TCR) diversity were analyzed by flow cytometry and TCR sequencing, respectively. Mitochondrial defects resulted from VHL loss were tested by JC-1 mitochondrial membrane potential assay, immunofluorescence microscopy, and qRT-PCR. VHL loss-mediated downstream signaling were further examined by western blot and bulk RNA sequencing. Results: The substantial overall survival benefits among ICB-treated patients withVHL mutations across different cancers, including RCC, in multiple human cohorts. Genetic knockout of VHL enhanced anti-PD1 therapy in three murine tumor models, including those of non-RCC origins. Moreover, VHL loss caused significant infiltration of immune effector cells and increased diversity of intratumoral TCR repertoire. VHL deficiency resulted in HIFα accumulation, increased expression of pro-mitophagy factor BNIP3, and impaired mitochondrial membrane potential that led to the cytoplasmic leakage of mitochondrial DNA (mtDNA), triggering cGAS-STING activation and type I interferon production. HIFα overexpression showed similar results as demonstrated in VHL-KO cells. In contrast, double knockdown of VHL and HIFα reversed VHL-loss induced BNIP3 upregulation, rescued mtDNA leakage to the cytoplasm, and disrupted constitutive activation of cGAS-STING signaling. Furthermore, blocking type I interferon signaling abrogated VHL-deficiency induced tumor suppression. Conclusion: Our study uncovered a novel role for VHL loss in creating an immunogenic tumor microenvironment through the activation of mtDNA-cGAS-STING pathway and type I interferon signaling in tumor cells via VHL-HIFα-BNIP3 axis, making them susceptible to ICB therapy. This finding provides a mechanistic explanation for ccRCC responsiveness to ICB therapy despite a moderate tumor mutation burden and suggests potential therapeutic strategies targeting ccRCC and other VHL-deficient tumors based on constitutive cGAS-STING and type I interferon activation. Citation Format: Meng Jiao, Xuhui Bao, Mengjie Hu, Dong Pan, Jonathan Kim, Xinjian Liu, Fang Li, Chuan-Yuan Li. VHLloss enables immune checkpoint blockade therapy by boosting interferon response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1719.

The road to systemic therapy in von Hippel-Lindau (VHL) disease: Are we there yet?

Pathogenic germline mutations in VHL gene cause von Hippel-Lindau (VHL) disease, an autosomal dominant hereditary cancer syndrome associated with high penetrance of benign and malignant neoplasms, including clear cell renal cell carcinoma (ccRCC), central nervous system haemangioblastomas (CNS-HB), retinal angiomas, phaeochromocytomas and pancreatic neuroendocrine tumours (pNET). Management of VHL disease involves lifelong radiological and biochemical surveillance, often leading to repeat surgical intervention causing significant morbidity and mortality. Systemic therapy that prevents or reduces the need for surgical intervention could improve clinical outcomes and quality of life for affected individuals. Belzutifan is a second-generation small molecule hypoxia-inducible factor 2α (HIF-2α) inhibitor recently approved by US and UK regulators for the treatment of VHL (disease)-associated ccRCC, CNS-HB and pNET. While this is a welcome step forward, it is vital that we consider in what circumstances these drugs are recommended and how they fit into the overall management of VHL disease. In this personal view article, we reflect on the history of the use of systemic therapy in localised VHL disease and consider open questions relating to the use of HIF-2α inhibitors, including the need to involve medical oncologists in the multidisciplinary team moving forward. Indeed, VHL disease is the perfect paradigm for similar settings in the future.

BELZUTIFAN-INDUCED HYPERSENSITIVITY PNEUMONITIS

BELZUTIFAN-INDUCED HYPERSENSITIVITY PNEUMONITIS

A meta-analysis of different von Hippel Lindau mutations: are they related to retinal capillary hemangioblastoma?

Retinal capillary hemangioblastomas (RCH) is a benign tumor that represents the initial manifestation in roughly half of Von Hippel Lindau (VHL) patients. They may also occur sporadically without systemic involvement. A first meta-analysis study was investigated to estimate the prevalence of Retinal capillary hemangioblastoma (RCH) in Von Hippel Lindau (VHL) syndrome, and its relation to type and location of mutations in VHL gene. The electronic databases of PubMed, Scopus, Embase, and Google Scholar were utilized to find eligible papers published up to May 2020. Lastly, after the different prevalence of RCH in Europe compared to other continents was noted, we decided to consider European and non-European patients separately. The Random effect model was used to evaluate the relation between developing RCH and types of mutations. The overall prevalence of RCH among VHL patients is about 47%. The prevalence of RCH was significantly higher in Europe in comparison with non-Europeans (p value < 0.001). Overall, the differences between the prevalence of RCH among different mutation types were not statistically significant. However, in Europe, the prevalence of RCH was significantly higher in patients with truncation mutation (p value = 0.007). In Europe, the RCH in VHL patients who had a mutation in exon 2 was significantly lower in comparison with exon 1 (p value = 0.001); but in non-Europeans, the prevalence of RCH in VHL patients that involved exon 2 was significantly higher in comparison with VHL patients with a mutation in exon1 (p value = 0.012). The highest risk of developing RCH was reported among Europeans. Overall, this study showed that the prevalence of RCH in VHL syndrome is not related to type or location of mutations and difference of RCH prevalence is probably depends on other genetic or environmental factor that should be considered in subsequent studies.

Von Hippel–Lindau (VHL) disease and VHL-associated tumors in Indian subjects: VHL gene testing in a resource constraint setting

BackgroundVon Hippel–Lindau (VHL) syndrome is a familial cancer syndrome caused by mutations in VHL gene. It is characterized by the formation of benign and malignant tumors like retinal angioma, cerebellar hemangioblastoma, spinal hemangioblastoma, renal cell carcinoma, pheochromocytoma, pancreatic and renal cysts, and endolymphatic sac tumors. Germline mutations in VHL gene have also been reported in isolated VHL-associated tumors. VHL gene is a small gene with 3 coding exons and can be easily tested even in a resource constraint setting.ObjectiveTo describe clinical presentation and estimate the diagnostic yield of in VHL and VHL-associated tumors.MethodsThis is a descriptive study in a hospital setting. Here, we describe the clinical and molecular data of 69 patients with suspected VHL or having VHL-associated tumors. Sanger sequencing of coding sequences and conserved splice sites of VHL gene were done in all patients. Multiplex ligation-dependent probe amplification (MLPA) of VHL gene to detect large deletions/duplications was performed for 18 patients with no pathogenic sequence variations.ResultsAmong tumor types at presentation, pheochromocytoma was seen in 49% (34/69), hemangioblastoma was seen in 30% (21/69), and renal cell carcinoma was seen in 7% (5/69). Rest had other tumors like paraganglioma, endolymphatic sac papillary tumors, cerebellar astrocytoma and pancreatic cyst. Seven patients (10%) had more than one tumor at the time of diagnosis. Pathogenic variations in VHL gene were identified in 31probands by Sanger sequencing; 18 were missense, 2 nonsense and 2 small indels. A heterozygous deletion of exon 3 was detected by MLPA in one patient among 18 patients for whom MLPA was done. Overall, the molecular yield was 46% cases (32/69). Family history was present in 7 mutation positive cases (22%). Overall, 11 families (16%) opted for pre-symptomatic mutation testing in the family.ConclusionsMutation testing is indicated in VHL and VHL-associated tumors. The testing facility is easy and can be adopted easily in developing countries like India. The yield is good, and with fairly high incidence of familial cases, molecular testing can help in pre-symptomatic testing and surveillance.

Multidisciplinary integrated care pathway for von Hippel-Lindau disease.

BACKGROUNDClinical pathways are care plans established to describe essential steps in the care of patients with a specific clinical problem. They translate (inter)national guidelines into local applicable protocols and clinical practice. The purpose of this article is to establish a multidisciplinary integrated care pathway for specialists and allied health care professionals in caring for individuals with von Hippel–Lindau (VHL) disease.METHODSUsing a modified Delphi consensus‐making process, a multidisciplinary panel from 5 Dutch University Medical Centers produced an integrated care pathway relating to the provision of care for patients with VHL by medical specialists, specialized nurses, and associated health care professionals. Patient representatives cocreated the pathway and contributed quality criteria from the patients' perspective.RESULTSThe panel agreed on recommendations for the optimal quality of care for individuals with a VHL gene mutation. These items were the starting point for the development of a patient care pathway. With international medical guidelines addressing the different VHL‐related disorders, this article presents a patient care pathway as a flowchart that can be incorporated into VHL expertise clinics or nonacademic treatment clinics.CONCLUSIONSMedical specialists (internists, urologists, neurosurgeons, ophthalmologists, geneticists, medical oncologists, neurologists, gastroenterologists, pediatricians, and ear‐nose‐throat specialists) together with specialized nurses play a vital role alongside health care professionals in providing care to people affected by VHL and their families. This article presents a set of consensus recommendations, supported by organ‐specific guidelines, for the roles of these practitioners in order to provide optimal VHL care. This care pathway can form the basis for the development of comprehensive, integrated pathways for multiple neoplasia syndromes.

Identification of a VHL gene mutation in atypical Von Hippel-Lindau syndrome: genotype\u2013phenotype correlation and gene therapy perspective

BackgroundClassical von Hippel Lindau (VHL) disease/syndrome includes CNS hemangioblastoma, renal or pancreatic cysts, pheochromocytoma, renal carcinoma and exodermic cystadenoma. The syndrome is caused by mutation of VHL tumor suppressor gene. The most prevalent mutations are present in VHL syndrome. To date, > 500 mutations of gene related to the progression of VHL syndrome have been reported. VHL gene mutation presented in single lung or pancreatic tumor has been reported occasionally, but there is no report of both.MethodsIn this paper, we used CT scan, pathological and genetic examination methods to diagnose a rare atypical VHL syndrome.ResultsWe reported a rare case of atypical VHL syndrome with authenticated VHL mutation at p.Arg167Gln, that was associated with not only bilateral pheochromocytoma but also lung carcinoid and neuroendocrine tumor of pancreas. Based on literature reviews, the patient was recommended to be further subjected to octreotide-based radionuclide therapy.ConclusionsCombined with gene detection and clinical diagnosis, we found the inherent relationship between VHL genotype and phenotype, and constructed the standard diagnosis and treatment process of disease with rare VHL mutation from the perspective of gene therapy.

Expression of VHL, VEGF and HIF-1α in endolymphatic sac tumors

Objective: To investigate the expression of von Hippel-Lindau (VHL), vascular endothelial growth factor (VEGF) and hypoxia inducible factor-1α (HIF-1α) in endolymphatic sac tumor (ELST) and its clinical significance, and to analyze its association with VHL gene mutation. Methods: Twenty-four cases of ELST, which were surgically resected and diagnosed by pathological examination in Beijing Tongren Hospital Affiliated to Capital Medical University, Beijing, China during 2012-2020, were recruited as the ELST group, and 24 cases of otitis media diagnosed in the same hospital were selected as the control group. The expression of VHL, VEGF, and HIF-1α was assessed using EnVision immunohistochemical staining and compared between the ELST and control groups. Sanger sequencing was performed to detect the VHL mutation status in 24 ELSTs. The correlations among VHL, VEGF and HIF-1α expression were analyzed. The associations of VHL, VEGF and HIF-1α expression with age of onset, gender, tumor size, bone invasion and clinical stage in ELST were also analyzed. Results: The expression rate of VHL in the ELST group was significantly lower than that in the control group (P<0.05), but the expression rates of VEGF and HIF-1α in the ELST group were significantly higher than those in the control group (P<0.05). VHL expression was inversely correlated with VEGF and HIF-1α expression. The expression of VEGF and HIF-1α was associated with bone invasion and clinical stage (P<0.05), but the expression of VHL, VEGF and HIF-1α had no significant associations with the age of onset, gender, or tumor size of ELST (P>0.05). Conclusions: The expression of VHL is decreased while that of VEGF and HIF-1α increased in ELST. Expression of VHL is inversely correlated with that of VEGF and HIF-1α. The expression of VEGF and HIF-1α is correlated with bone invasion and clinical stage. Thus, VEGF and HIF-1α may be therapeutic targets of ELST.

Constellation of Von Hippel-Lindau Disease-Related Findings on a 68Ga-DOTATATE PET/CT.

Von Hippel-Lindau (VHL) is a rare predominantly hereditary syndrome characterized by multiple benign and malignant tumors that can affect different organ systems. We present representative images of a 68Ga-DOTATATE PET/CT in a patient with confirmed VHL gene mutation, which demonstrates a constellation of findings commonly seen in these patients in one single imaging modality.

Multiple Hepatic and Pulmonary Tumors Combined with Bilateral Adrenal Masses in a Young Woman with von Hippel–Lindau Disease

Question: A 37-year-old woman was admitted to our center for adrenal diseases with bilateral adrenal tumors and multiple hepatic and pulmonary lesions for surgery. She was first diagnosed with von Hippel–Lindau (VHL) syndrome in April 2000, with proof of heterozygous point mutation c.292T>C in exon 1 of the VHL gene. Her father was diagnosed with a VHL gene mutation as well. She complained of a 4- to 5-kg weight loss in 4 months, increased daytime fatigue, and anxiety. She reported occasional nicotine abuse in the past.

Phthisis bulbi and retinal capillary haemangioma associated with papilloedema due to recurrent bilateral cerebellar haemangioblastomas – A case of Von Hippel Lindau syndrome

Von Hippel Lindau (VHL) syndrome is an autosomal dominant condition caused by mutation of VHL gene. It is characterized by vascular tumors of eye, central nervous system, visceral cysts and tumors. Here we report a case of VHL in a young male patient who presented with phthisis bulbi in the right eye and retinal capillary haemangioma in the left eye. Systemic features of raised intracranial pressure was present along with bilateral abduction deficit and florid disc edema in the left eye. There was a polypoidal reddish mass in the inferotemporal quadrant, with a dilated draining vein, indicating retinal capillary hemangioma. The phthisical right eye was speculated to result from untreated retinal capillary hemangioma, culminating in exudative retinal detachment. Urinary Vanillyl Mandelic Acid suggested pheochromocytoma. Imaging modalities revealed multiple cerebellar hemangioblastomas, pheochromocytoma and pancreatic cysts. Screening of family members revealed no evidence of systemic manifestations, suggesting the possibility of sporadic mutation. Retinal capillary hemangioma is the commonest and earliest manifestation of VHL. The ocular complications include intraretinal exudation and exudative retinal detachment, secondary angiomatosis, epiretinal membrane, vitreous hemorrhage, retinal neovascularization, tractional retinal detachment and macular ectopia. Our case report emphasizes that retinal examination in patients with suspected VHL is not only a screening tool for the presence of capillary hemangioma but also for regular monitoring and prevention of vision threatening complications. Keywords: Von Hippel Lindau (VHL) syndrome, Retinal capillary hemangioma, Cerebellar hemangioblastomas, Pheochromocytoma.

Macular Perfusion Impairment in Von Hippel-Lindau Disease Suggests a Generalized Retinal Vessel Alteration.

Background: To evaluate macular perfusion in patients with Von Hippel–Lindau (VHL) disease. Methods: VHL patients with or without peripheral retinal hemangioblastomas (RHs) were consecutively enrolled. A group of healthy subjects served as controls. Macular perfusion was analyzed by means of OCT angiography (OCTA) in the superficial vascular plexus (SVP), and in the intermediate (ICP) and deep retinal capillary (DCP) plexuses. The following OCTA parameters were measured: Vessel Area Density (VAD), Vessel Length Fraction (VLF), Vessel Diameter Index (VDI) and Fractal Dimension (FD). Results: Sixty-three VHL patients (113 eyes) and 28 healthy controls (56 eyes) were enrolled. All OCTA quantitative parameters were reduced in VHL patients vs. controls, reaching statistical significance for VAD of the SVP (0.348 ± 0.07 vs. 0.369 ± 0.06, p = 0.0368) and VDI of all plexuses (p < 0.03 for all). No significant differences were detected between eyes without or with peripheral RHs. Conclusions: Macular perfusion is reduced in VHL patients demonstrating retinal vessel changes that are independent of the presence of peripheral RHs. VHL gene mutations disrupt the hypoxia-induced (HIF)/vascular endothelium growth factors (VEGF) pathway and the Notch signaling, both essential for the normal retinal vasculogenesis and angiogenesis. Therefore, an anomalous generalized retinal vascular development may be hypothesized in VHL disease.

Isolated Paraganglioma in a Patient with VHL P.L163F Mutation

Paragangliomas (PGLs) are one of the many neoplasms associated with von Hippel-Lindau (VHL) disease. VHL disease type 2C is a unique subtype characterized by the presence of a PGL or pheochromocytoma without other VHL-associated neoplasms. This report describes a rare germline mutation in the VHL gene in a patient with isolated PGL. The clinical presentation, urinary metanephrines and normetanephrines, computed tomography scan, meta-iodobenzylguanidine scintiscan, surgical pathology, and genetic testing of a patient with PGL and a rare VHL gene mutation are described. A literature review is also presented. A 23-year-old, Indian woman was incidentally found to have an indeterminate 4.2 × 3.6 × 3.2-cm mass adjacent to the liver. A 36-year-old first cousin was recently diagnosed with a PGL. Her 24-hour urinary metanephrines were 6,886 μg/g creatinine (reference range is 81 to 330 μg/g creatinine) and normetanephrines were 6,810 μg/g creatinine (reference range is 20 to 158 μg/g creatinine). Surgical pathology revealed a PGL adjacent to a normal adrenal gland. Genetic testing revealed a mutation in VHL p.L163F. Surveillance for other tumors associated with VHL disease has been negative thus far. Her cousin has not undergone genetic testing despite recommendations to do so. We present the first reported case of PGL in a patient with VHL disease caused by a missense mutation in VHL p.L163F. To date, reports of this rare mutation have only involved patients with pheochromocytoma and without other tumors associated with VHL disease, suggesting that VHL p.L163F mutation may cause a VHL disease type 2C phenotype.