Germline mutations in the von Hippel–Lindau gene in Italian patients

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.

Frequent Mutations of VHL Gene and the Clinical Phenotypes in the Largest Chinese Cohort With Von Hippel-Lindau Disease

Von Hippel–Lindau (VHL) disease is a rare autosomal-dominant inherited tumor syndrome. We aimed to analyze the correlations between frequent VHL mutations and phenotypes in Chinese VHL families. We screened 540 patients from 187 unrelated Chinese VHL families for 19 frequent VHL mutations. The penetrance and mean age at onset for VHL-associated susceptible organs were calculated and compared. The overall survival of VHL patients was described with Kaplan–Meier curves. Among the 19 frequent germline mutations, there were four hotspot mutation sites (194, 481, 499, and 500). Missense mutations were the most common types of mutations (70.0%) followed by nonsense mutations (20.0%) and splicing mutations (10.0%). Due to the diversity of these mutations, the penetrance for each organ and the age at onset are distinct. Even in cases of similar mutations, variance in the penetrance and age at onset was observed. The mean age at death for the patients in this cohort was 42.4 ± 13.5 years, and variability was observed in the Kaplan–Meier curves. We present a precise summary of the phenotypes for the frequent VHL mutations in the largest Chinese VHL cohort, which provides valuable strategies for genetic counseling and clinical surveillance of VHL individuals.

Novel genotype-phenotype correlations in five Chinese families with Von Hippel-Lindau disease

CONTEXT

Von Hippel-Lindau (VHL) disease manifests as a variety of benign and malignant neoplasms. Previous studies of VHL disease have documented several genotype-phenotype correlations; however, many such correlations are still unknown. Increased identification of new mutations and patients with previously described mutations will allow us to better understand how VHL mutations influence disease phenotypes.

PATIENTS AND DESIGN

A total of 45 individuals from five unrelated families were evaluated, of which 21 patients were either diagnosed with VHL disease or showed strong evidence related to this disease. We compared the patients' gene sequencing results with their medical records including CT or MRI scans, eye examinations and laboratory/pathological examinations. Patients were also interviewed to obtain information regarding their family history.

RESULTS

We identified four missense mutations: c.239G>T (p.Ser80Ile), linked with VHL Type 2B, was associated with renal cell carcinoma, pheochromocytoma and hemangioma in the cerebellum; c.232A>T (p.Asn78Tyr) manifested as RCC alone and likely caused VHL Type 1; c.500G>A (p.Arg167Gln) mutation was more likely to cause VHL Type 2 than Type 1 as it preferentially induced Pheo and HB in the retina, cerebellum and spinal cord; c.293A>G (p.Try98Cys) was associated with Pheo and thus likely induced VHL Type 2.

CONCLUSIONS

Characterizing VHL disease genotype-phenotype correlations can enhance the ability to predict the risk of individual patients developing different VHL-related phenotypes. Ultimately, such insight will improve the diagnostics, surveillance and treatment of VHL patients.

PRECIS

Four missense mutations in VHL have been identified in 21 individuals when five unrelated Chinese families with VHL disease were analyzed; VHL mutations are highly associated with unique disease phenotypes.

Pedigree analysis, diagnosis and treatment in Von Hippel-Lindau syndrome: A report of three cases

The objective of the present study was to systematically investigate the clinical features, diagnosis and therapeutic treatment of Von Hippel-Lindau (VHL) syndrome in order to improve understanding of this disease. A total of 3 cases of VHL syndrome treated at the Affiliated Hospital of Zunyi Medical College (Zunyi, China) between September 2014 and October 2015 were retrospectively analyzed. The associated literature was reviewed, and the diagnostic and therapeutic features were discussed. Case 1 was diagnosed as VHL syndrome accompanied by a renal tumor on the right side, and radical tumor resection in the right kidney was performed. Postoperative pathological examination indicated clear cell carcinoma. Case 2 was diagnosed as VHL syndrome accompanied by bilateral adrenal pheochromocytoma. The left-side adrenal tumor was removed, and postoperative pathological analysis was suggestive of adrenal pheochromocytoma. Case 3 visited the hospital due to the presence of masses on the left and right sides of the kidney, but did not undergo surgery for personal reasons. Follow-ups were scheduled subsequent to surgery at another hospital. The diagnosis in all 3 cases was confirmed by genetic testing, where VHL mutations were detected in all patients. Following surgery, pedigree and genetic analysis was performed in all 3 pedigrees and VHL mutations were identified in 7 family members. The diagnosis of VHL syndrome should be based on the clinical manifestation of the patients and the results of genetic tests. DNA analysis of mutations is the main method for diagnosis. An appropriate surgical plan should be formulated based on the site, size and number of tumors, and the condition of the patient. Since VHL syndrome is an inheritable genetic disorder and relapse following surgery is common, pedigree analysis of the patient and lifelong follow-ups are essential. Additionally, physicians should pay attention to VHL syndrome in order to avoid missing diagnosis or misdiagnosis.

VHL mosaicism can be detected by clinical next-generation sequencing and is not restricted to patients with a mild phenotype

The identification of Von Hippel-Lindau (VHL) mosaic mutations by conventional Sanger sequencing requires a labour-intensive enrichment step, thus explaining that mosaicism occurrence is underestimated in patients. Nowadays, it is possible to detect mutation in cell sub-populations by next-generation sequencing (NGS). Here, we described a diagnosis strategy using NGS with high coverage in a series of eight patients who were negative for a VHL abnormality by Sanger sequencing and deletion search. In two patients, a mosaic mutation in VHL was detected by NGS. One patient with a 5.7% mutated allele frequency had a severe phenotype and an early disease onset. In conclusion, clinical NGS in an hospital molecular oncogenetics laboratory is an efficient tool to identify VHL mosaic mutation. Its use may improve patient monitoring and genetic counseling.