Genetic characterization and structural analysis of VHL Spanish families to define genotype-phenotype correlations

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.

Pheochromocytomas and paragangliomas in von Hippel-Lindau disease: not a needle in a haystack

OBJECTIVE

Pheochromocytomas are a hallmark feature of von Hippel-Lindau disease (vHL). To our knowledge, this is the first systematic review with meta-analysis evaluating the frequency of pheochromocytomas and/or paragangliomas (PPGLs) in patients with vHL, as well as among patients with different vHL subtypes.

DESIGN

Systematic review with meta-analysis.

METHODS

We searched on MEDLINE, Scopus, and Web of Science. We included primary studies assessing participants with vHL and reporting on the frequency of PPGL. We performed random-effects meta-analysis to quantitatively assess the frequency of PPGL, followed by meta-regression and subgroup analysis. Risk of bias analysis was performed to assess primary studies' methodological quality.

RESULTS

We included 80 primary studies. In 4263 patients with vHL, the pooled frequency of PPGL was 19.4% (95% CI = 15.9-23.6%, I2 = 86.1%). The frequency increased to 60.0% in patients with vHL type 2 (95% CI = 53.4-66.3%, I2 = 54.6%) and was determined to be of 58.2% in patients with vHL type 2A (95% CI = 49.7-66.3%, I2 = 36.2%), compared to 49.8% in vHL type 2B (95% CI = 39.9-59.7%, I2 = 42.7%), and 84.1% in vHL type 2C (95% CI = 75.1-93.1%, I2 = 0%). In meta-regression analysis, more recent studies were associated with a higher frequency of PPGL. All studies had at least one internal validity item classified as 'high risk of bias,' with 13% studies having low risk of bias in all external validity items.

CONCLUSIONS

PPGLs are a common manifestation of vHL. Despite methodological limitations and differences across primary studies, our results point to the importance of PPGL screening in patients with vHL.

Bilateral Pheochromocytomas in a Patient with Y175C Von Hippel-Lindau Mutation

Von Hippel-Lindau (VHL) disease, caused by germline mutations in the VHL gene, is characterized by metachronously occurring tumors including pheochromocytoma, renal cell carcinoma (RCC), and hemangioblastoma. Although VHL disease leads to reduced life expectancy, its diagnosis is often missed and tumor screening guidelines are sparse. VHL protein acts as a tumor suppressor by targeting hypoxia-inducible factors (HIFs) for degradation through an oxygen-dependent mechanism. VHL mutants with more severely reduced HIF degrading function carry a high risk of RCC, while mutants with preserved HIF degrading capacity do not cause RCC but still lead to other tumors. VHL disease is classified into clinical types (1 and 2A-2C) based on this genotype-phenotype relationship. We report a case of bilateral pheochromocytomas and no other VHL-related tumors in a patient with Y175C VHL and show that this mutant preserves the ability to degrade HIF in normal oxygen conditions but, similar to the wild-type VHL protein, loses its ability to degrade HIF under hypoxic conditions. This study adds to the current understanding of the structure-function relationship of VHL mutations, which is important for risk stratification of future tumor development in the patients.

Molecular-genetic diagnostics of von Hippel-Lindau syndrome (VHL) in Bulgaria: first complex mutation event in the VHL gene

Von Hippel-Lindau syndrome is an autosomal-dominant disease characterized by the formation of various tumours and cysts in many different parts of the body. Von Hippel-Lindau syndrome is caused by VHL gene mutations leading to production of impaired tumor suppressor Von Hippel-Lindau syndrome protein or its complete absence.

PURPOSE

To study five patients with clinically suspected Von Hippel-Lindau syndrome, who were referred for molecular genetic testing.

METHODS

Sanger sequencing of the coding regions of the VHL gene.

RESULTS

Five clinically relevant germline mutations were detected. One of the pathogenic variants has not been previously reported. This novel mutation is a complex mutation event combining a duplication and an indel, rearranging exon 3 of the VHL gene - c. [516_517dupGTCAAGCCT; 532_542delCTGGACATCGTinsATTA], p. (Glu173Serfs*4).

CONCLUSION

Overall, our results showed that the diagnosis of Von Hippel-Lindau syndrome in our country is difficult most probably because of its heterogeneous clinical manifestation and insufficient knowledge on the diagnostic criteria for the disease. From genetic point of view our results add some novel data on the mutation profile of the VHL gene. In order to prove or revise the diagnosis, early genetic testing is strongly recommended in affected patients and their family members to ensure appropriate follow-up and treatment of the malignancies.

von Hippel-Lindau development in children and adolescents

The autosomal dominant von Hippel-Lindau disease (vHL) is associated with a lifelong risk of tumor development, especially retinal and CNS hemangioblastomas, pheochromocytoma, and renal cell carcinoma. Knowledge of paediatric vHL development is limited, and current surveillance guidelines are based on expert opinions. We aimed to describe the course of vHL development in children and adolescents, focusing on age at first manifestation, manifestation frequencies, and types. The prevalence of vHL diagnosis as well as manifestations in childhood were evaluated based on 99 patients, who had started surveillance before 18 years: 37 Danish patients from the national vHL research database and 62 international patients reported in 15 articles. Overall, 70% (69 of 99) developed manifestations before 18 years (median age at first manifestation: 12 years (range: 6-17 years)). Thirty per cent (30 of 99) had developed more than one manifestation type; the most frequent were retinal (34%) and CNS (30%) hemangioblastomas. Among the 37 Danish patients, 85% (97 of 116) of their tumors were asymptomatic. Vision outcome is significantly improved in hemangioblastomas that are treated while still asymptomatic. We agree with current guidelines that retinal surveillance be performed from birth. The patients had their first CNS hemangioblastomas at the median ages of 13-14 years (range: 6-17 years). Further, 11% (4 of 37) of the Danish patients had CNS surgery in their teenage years. Although the cohort is too small to make definite conclusions about specific initiation ages, regular CNS surveillance from vHL patients' teenage years seems clinically relevant.

Genotype-Phenotype Correlation in Patients With Germline Mutations of VHL, RET, SDHB, and SDHD Genes: Thai Experience

Mutations in the VHL, RET, SDHB, and SDHD genes are responsible for von Hippel-Lindau (VHL) disease, multiple endocrine neoplasia type 2 (MEN2), and familial paraganglioma, respectively. However, genotype-phenotype correlation data are lacking in Southeast Asia. A retrospective medical chart review was performed on patients referred to the genetics service. We found 35 patients diagnosed with clinical syndromes (16 VHL, 9 MEN2, 9 paragangliomas, and 1 neurofibromatosis type 1). In patients with VHL, 5 known VHL mutations were identified: p.Trp88X, p.Ile151Thr, p.Arg161X, p.Arg167Gln, and p.Leu178Arg. The most frequent RET mutations in patients with MEN2A occurred at codon 634 on exon 11: p.Cys634Tyr, p.Cys634Trp, and p.Cys634Arg. A patient with MEN2B had p.Met918Thr RET mutation. Approximately, 90% of patients with MEN2 had medullary thyroid carcinoma. Pheochromocytoma was found in 55.6% of patients with MEN2, and 60% of them had bilateral lesions. One patient with malignant thoracic paraganglioma had p.Arg46X mutation of SDHB. This study provides mutation phenotypes that offer a useful tool for clinicians and patients to stratify disease risks and tailor screening programs.

VHL Germline Mutations in Argentinian Patients with Clinical Diagnoses or Single Typical Manifestations of Type 1 von Hippel-Lindau Disease

AIMS

von Hippel-Lindau (VHL) disease is caused by mutations in the VHL tumor suppressor gene. As tumors that develop in the context of VHL also occur in a sporadic context, the frequency of this syndrome may be underestimated. Our aim was to identify VHL gene mutations in Argentinian patients who fulfilled the clinical criteria for type 1 VHL disease and in patients with VHL-associated manifestations that did not meet these criteria.

METHODS

We performed a retrospective cohort study, including patients who met current diagnostic criteria for type 1 VHL (Group 1, n = 19) and patients with VHL-associated manifestations that did not meet these criteria (Group 2, n = 21). Genomic DNA was extracted from peripheral blood leukocytes. Mutation analysis involved DNA sequencing, while large deletions were determined by universal primer quantitative fluorescent multiplex polymerase chain reaction (UPQFM-PCR) and multiplex ligation-dependent probe amplification (MLPA) analysis.

RESULTS

VHL mutations were detected in 16/19 (84.2%) patients in Group 1 and included: gross deletions (4/16); nonsense mutations (6/16); frameshift mutations (4/16); missense mutations (1/16); and splicing mutations (1/16). Three of these mutations were novel. No alterations were found in 3 of 19 VHL patients. In Group 2, one nonsense VHL mutation was detected in a young patient with a solitary central nervous system hemangioblastoma without familial history. A study of 30 first-degree relatives revealed four carriers with VHL mutations.

CONCLUSIONS

We found three novel mutations in the VHL gene in our population. Our results emphasize the importance of a complete genetic study of VHL to confirm type 1 VHL disease, not only in patients with clinical diagnostic criteria but also in those presenting a single typical manifestation.

An integrated computational approach can classify VHL missense mutations according to risk of clear cell renal carcinoma

Mutations in the von Hippel-Lindau (VHL) gene are pathogenic in VHL disease, congenital polycythaemia and clear cell renal carcinoma (ccRCC). pVHL forms a ternary complex with elongin C and elongin B, critical for pVHL stability and function, which interacts with Cullin-2 and RING-box protein 1 to target hypoxia-inducible factor for polyubiquitination and proteasomal degradation. We describe a comprehensive database of missense VHL mutations linked to experimental and clinical data. We use predictions from in silico tools to link the functional effects of missense VHL mutations to phenotype. The risk of ccRCC in VHL disease is linked to the degree of destabilization resulting from missense mutations. An optimized binary classification system (symphony), which integrates predictions from five in silico methods, can predict the risk of ccRCC associated with VHL missense mutations with high sensitivity and specificity. We use symphony to generate predictions for risk of ccRCC for all possible VHL missense mutations and present these predictions, in association with clinical and experimental data, in a publically available, searchable web server.

DNA sequencing identifies mutation of the von Hippel-Lindau gene in tubal pregnancy

Genetic mutations in the von Hippel-Lindau (VHL) gene are common in certain diseases. The effects on the VHL gene in the tubal pregnancy tissues are unknown but with further study, it was found that the VHL gene may be related to prognosis or therapy selection. This study was conducted to analyse the VHL gene in tissues of human fallopian tube and tubal pregnancy. A total of 35 patients undergoing salpingectomy for tubal pregnancy were recruited into the experimental group. Samples of ampullary fallopian tube during mid-secretory phase were collected from 10 patients with benign uterine disease as the control group. Fluorescent dye dideoxy termination method was performed to detect three exons sequences of the VHL gene in tissues of both the human fallopian tube and tubal pregnancy. The DNA sequences of three exons of VHL gene coding region in tubal pregnancy were not found in mutations. The present study suggested that the VHL gene mutations were not related with tubal pregnancy.

VHL frameshift mutation as target of nonsense-mediated mRNA decay in Drosophila melanogaster and human HEK293 cell line

There are many well-studied examples of human phenotypes resulting from nonsense or frameshift mutations that are modulated by Nonsense-Mediated mRNA Decay (NMD), a process that typically degrades transcripts containing premature termination codons (PTCs) in order to prevent translation of unnecessary or aberrant transcripts. Different types of germline mutations in the VHL gene cause the von Hippel-Lindau disease, a dominantly inherited familial cancer syndrome with a marked phenotypic variability and age-dependent penetrance. By generating the Drosophila UAS:Upf1^D45B line we showed the possible involvement of NMD mechanism in the modulation of the c.172delG frameshift mutation located in the exon 1 of Vhl gene. Further, by Quantitative Real-time PCR (QPCR) we demonstrated that the corresponding c.163delG human mutation is targeted by NMD in human HEK 293 cells. The UAS:Upf1^D45B line represents a useful system to identify novel substrates of NMD pathway in Drosophila melanogaster. Finally, we suggest the possible role of NMD on the regulation of VHL mutations.

Ser80Ile mutation and a concurrent Pro25Leu variant of the VHL gene in an extended Hungarian von Hippel-Lindau family

Von Hippel-Lindau disease (VHL) is a rare autosomal dominant disease characterized by development of cystic and tumorous lesions at multiple sites, including the brain, spinal cord, kidneys, adrenals, pancreas, epididymis and eyes. The clinical phenotype results from molecular abnormalities of the VHL tumor suppressor gene, mapped to human chromosome 3p25-26. The VHL gene encodes two functionally active VHL proteins due to the presence of two translational initiation sites separated by 53 codons. The majority of disease-causing mutations have been detected downstream of the second translational initiation site, but there are conflicting data as to whether few mutations located in the first 53 codons, such as the Pro25Leu could have a pathogenic role. In this paper we report a large Hungarian VHL type 2 family consisting of 32 members in whom a disease-causing AGT80AAT (Ser80Ile) c.239G>A, p.Ser80Ile mutation, but not the concurrent CCT25CTT (Pro25Leu) c.74C>T, p.Pro25Leu variant co-segregated with the disease. To our knowledge, the Ser80Ile mutation has not been previously described in VHL type 2 patients with high risk of pheochromocytoma and renal cell cancer. Therefore, this finding represents a novel genotype-phenotype association and VHL kindreds with Ser80Ile mutation will require careful surveillance for pheochromocytoma. We concluded that the Pro25Leu variant is a rare, neutral variant, but the presence such a rare gene variant may make genetic counseling difficult.

Loss of the actin regulator HSPC300 results in clear cell renal cell carcinoma protection in Von Hippel-Lindau patients

Clear cell renal cell carcinoma (ccRCC) is the most common malignant neoplasm of the kidney. The majority of hereditary and sporadic ccRCC cases are associated with germline and somatic mutations in the Von Hippel-Lindau gene (VHL), respectively. Gross deletions at the VHL locus can result either in ccRCC or in a mild clinical phenotype, with the absence of ccRCC development. Our goal in this study was to identify the molecular basis responsible for these differences in the clinical behavior in order to predict patients' phenotype. Using multiplex ligation-dependent amplification (MLPA), we identified and characterized gross VHL deletions in Spanish VHL families. A candidate gene related to this clinical association, HSPC300, was identified and depleted by RNA interference. It was possible to narrow the susceptibility region related to the mild clinical phenotype down to approximately 14 kb that included HSPC300 (C3orf10), a regulator of actin dynamics and cytoskeleton organization. Whereas 9 out of 10 families with ccRCC retained HSPC300 in the germline, loss of the HSPC300 locus was associated with mild clinical presentation of the disease in 6 out of 8 families. In fact, genetic depletion of HSPC300 resulted in cytoskeleton abnormalities and cytokinesis arrest in several tumor cell lines including ccRCC cells, suggesting that tumor cell proliferation was compromised in the absence of HSPC300. These clinical and functional data indicate a relevant function of HSPC300 in tumor cell progression, and suggest future therapeutic strategies based upon the inhibition of HSPC300 in renal cell carcinoma and possibly on other cancers.

Genotype-phenotype correlations in von Hippel-Lindau disease

von Hippel-Lindau (VHL) disease is a dominantly inherited familial cancer syndrome resulting from mutations in the VHL tumor suppressor gene. VHL disease displays marked variation in expression and the presence of pheochromocytoma has been linked to missense VHL mutations. We analyzed genotype-phenotype correlations in 573 individuals with VHL disease. Routine clinical and radiological surveillance of VHL patients and at-risk relatives was associated with increased detection of retinal angiomatosis (73 vs. 59% of cases) and a reduction in age at diagnosis of renal cell carcinoma (RCC) (44.0+/-10.9 vs. 39.7+/-10.3 years). We confirmed the association of pheochromocytoma with missense mutations described previously, but stratifying missense mutations into those that resulted in substitution of a surface amino acid and those that disrupted structural integrity demonstrated that surface amino acid substitutions conferred a higher pheochromocytoma risk. Age at first manifestation of VHL disease was significantly earlier (P=0.001), and age-related risks of retinal angiomas and RCC were higher (P=0.022 and P=0.0008, respectively) in individuals with a nonsense or frameshift mutation than in those with deletions or missense mutations that disrupted the structural integrity of the VHL gene product (pVHL). These results extend genotype-phenotype-protein structure correlations in VHL disease and provide a baseline for future chemoprevention studies in VHL disease.

von Hippel-Lindau gene mutation in non-syndromic familial pheochromocytomas

Approximately 50% of patients with non-syndromic familial pheochromocytomas had germline von Hippel-Lindau (VHL) gene mutations, but no reports on the subject were available in China. A total of five unrelated Chinese families with non-syndromic familial pheochromocytomas were screened for VHL gene mutation by polymerase chain reaction (PCR) and subsequent direct sequencing. Missense germline mutations of VHL gene were detected in four of the five families. Arg161Gln (695G-A) mutation was found in two families, and the other two families had Leu163Phe (700C-T) and Arg167Trp (712C-T) mutation, respectively. In conclusion, VHL gene may have frequent mutation in Chinese patients with non-syndromic familial pheochromocytomas.

The N131S mutation in the von Hippel-Lindau gene in a Japanese family with pheochromocytoma and hemangioblastomas

von Hippel-Lindau (VHL) disease (VHLD) is a hereditary autosomal dominant syndrome that causes various benign and malignant tumors. VHLD is caused by mutations in the VHL tumor suppressor gene. Here, we report a mutation in the VHL gene in a Japanese family with VHLD type 2A, characterized by pheochromocytoma (PHE), and hemangioblastomas (HAB) in both the retina and thoracic spinal cord but without renal cell carcinoma (RCC). We identified a heterozygous A to G point mutation at the second base of codon 131 of the VHL protein (pVHL). This mutation was predicted to convert codon 131 from asparagine to serine (N131S). Although most mutations in VHLD type 2A have been detected in the alpha domain of pVHL, the present mutated amino acid was located at the region encoding the beta domain of pVHL. Previous patients with the N131K or N131T mutation in pVHL developed VHLD type 2B with RCC or VHLD type 1 without PHE, respectively. We also identified somatic loss of heterozygosity (LOH) at chromosome 3p25-26 in the adrenal tumor of the patient. The results of our study suggest that not only the location of mutation but also the altered amino acid may be critical for determining the clinical phenotype of VHLD. LOH was associated with the development of PHE in a patient with the N131S mutation in pVHL.

Genetic and epigenetic analysis of von Hippel-Lindau (VHL) gene alterations and relationship with clinical variables in sporadic renal cancer

Genetic and epigenetic changes in the von Hippel-Lindau (VHL) tumor suppressor gene are common in sporadic conventional renal cell carcinoma (cRCC). Further insight into the clinical significance of these changes may lead to increased biological understanding and identification of subgroups of patients differing prognostically or who may benefit from specific targeted treatments. We have comprehensively examined the VHL status in tissue samples from 115 patients undergoing nephrectomy, including 96 with sporadic cRCC. In patients with cRCC, loss of heterozygosity was found in 78.4%, mutation in 71%, and promoter methylation in 20.4% of samples. Multiplex ligation-dependent probe amplification identified intragenic copy number changes in several samples including two which were otherwise thought to be VHL-noninvolved. Overall, evidence of biallelic inactivation was found in 74.2% of patients with cRCC. Many of the mutations were novel and approximately two-thirds were potentially truncating. Examination of these and other published findings confirmed mutation hotspots affecting codons 117 and 164, and revealed a common region of mutation in codons 60 to 78. Gender-specific differences in methylation and mutation were seen, although not quite achieving statistical significance (P = 0.068 and 0.11), and a possible association between methylation and polymorphism was identified. No significant differences were seen between VHL subgroups with regard to clinicopathologic features including stage, grade, tumor size, cancer-free and overall survival, with the exception of a significant association between loss of heterozygosity and grade, although a possible trend for survival differences based on mutation location was apparent.

About the origin and development of hereditary conventional renal cell carcinoma in a four-generation t(3;8)(p14.1;q24.23) family

Conventional renal cell carcinoma (CRCC) may appear in families with germline translocations involving chromosome 3, although a recurrent responsible gene has not been found. We recently described a family with CRCC and a constitutional t(3;8)(p14.1;q24.23), and we demonstrated that no genes were disrupted by the translocation breakpoints. In order to investigate the genetic origin and features of the CRCC tumors that occurred in this family, we have extended the pedigree up to four generations, and analyzed peripheral blood samples from 36 members, CRCC tumors, normal renal tissues, and a gastric tumor. (1) By means of comparative genomic hybridization (CGH), we have detected loss of the derivative chromosome carrying 3p in all CRCC but not in the corresponding normal renal tissue. In addition, by means of the fluorescence in situ hybridization technique, we have observed that not all tumoral cells lose the der(3p), which suggests that, previous to this loss, another hit should occur to initiate the transformation of normal into tumoral cells. (2) All known mechanisms of inactivation of the candidate von Hippel-Lindau (VHL) gene have been studied in the tumors, detecting alterations in 65% of them. This confirms that inactivation of the VHL gene is not always required to develop CRCC, and that (an)other suppressor gene(s) on 3p could be involved. (3) We discard FHIT as an alternative pathway to VHL. We have not found new candidate regions along 3p by using a 1-Mb resolution array-based CGH. (4) The tumorigenesis mechanism of a second gastric tumor developed in the probandus is different from that of CRCC.

Molecular genetics of familial renal cell carcinoma syndromes

RCC represents a group of clinically and genetically diverse diseases. Familial RCC syndromes, although rare, provide an invaluable model to study the molecular mechanisms of renal carcinogenesis. Many causative oncogenes and tumor suppressor genes have been identified and it is now possible to identify the affected individuals and carriers by genetic testing. Understanding of the molecular pathways of these genes will have a significant impact on the diagnosis and treatment of familial and sporadic RCC.

Hemangioblastomas of Central Nervous System: Molecular Genetic Analysis and Clinical Management

OBJECTIVE

Hemangioblastomas of the central nervous system (CNS) are benign neoplasms that may occur sporadically or in association with von Hippel-Lindau (VHL) disease. The proportion of primary symptomatic hemangioblastomas associated with VHL disease is estimated to be from 10 to 40%, but it seems to be underestimated. We investigated the frequency of VHL germline mutation in patients with symptomatic CNS hemangioblastoma without evidence of VHL disease to define the role of molecular genetic analysis in the management of such patients and their relatives.

METHODS

We analyzed 14 patients (6 female and 8 male; mean age, 43.5 yr) with no family history and no other clinical manifestations of VHL disease who had been operated on for symptomatic CNS hemangioblastoma. Exons 1, 2, and 3 of the VHL gene and their immediately flanking sequences were amplified by use of polymerase chain reaction followed by analysis with denaturing high-performance liquid chromatography and sequencing the anomalous samples.

RESULTS

Germline mutations of the VHL gene were identified in 2 (14%) of 14 patients. VHL gene mutation analysis was performed in both patients' family members, which showed another affected asymptomatic subject for VHL disease. The affected subjects were recommended for VHL disease surveillance protocol.

CONCLUSION

Molecular genetic analysis is a safer and more specific instrument to confirm or exclude VHL disease in patients with CNS hemangioblastoma, a negative family history, or absence of other known manifestations of the disease. Early identification of VHL mutation gene carriers is important for reducing disease morbidity and mortality. Nonsymptomatic family members will benefit from early VHL disease diagnosis or by being excluded as at-risk subjects, reducing the psychological and economic burden of screening and surveillance protocols.

Neuro-ophthalmology of von Hippel-Lindau

von Hippel-Lindau (VHL) disease is a multisystem inherited cancer syndrome with characteristic tumors and a known genetic basis. Patients with VHL develop, among other tumors, retinal capillary hemangiomas, central nervous system hemangioblastomas, renal clear cell carcinomas, and pheochromocytomas. Nearly all patients can be shown to have a mutation in the VHL gene, which is located on chromosome 3p25. Genetic abnormalities result in abnormal levels of pVHL, which in turn lead to the different tumors. Four distinct phenotypes of VHL disease have been identified based on the relative frequency of and propensity for the development of different VHL tumors. Aggressive screening of patients with VHL disease can prevent morbidity and mortality from these tumors. Although these tumors typically have been treated with observation or surgery, trials of newer medical therapies that target some of the cellular dysregulation caused by mutation in pVHL are ongoing. Even though these trials have not been wholly successful, they present an exciting direction for future research. This article presents a summary of new developments in VHL disease with a focus on ophthalmic and neuro-ophthalmic practice.