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Summaryvon Hippel-Lindau disease (VHL [MIM 193300]) is a heritable autosomal dominant multiple-neoplastic disorder with high penetrance. It is characterized by brain and spinal-cord hemangioblastomas, retinal angiomas, clear-cell renal carcinoma, neuroendocrine tumors and cysts of the pancreas, pheochromocytomas, endolymphatic-sac tumors, and papillary cystadenomas of the epididymis and broad ligament. Although most index cases have a positive family history of VHL, some do not and may represent de novo cases. Cases without a family history of VHL may or may not have a germline mutation in their VHL tumor-suppressor gene. We present two cases of VHL mosaicism. In each of two families, standard testing methods (Southern blot analysis and direct sequencing) identified the germline mutation in the VHL gene of the offspring, but not in their clinically affected parent. Additional methods of analysis of the affected parents' blood detected the VHL-gene mutation in a portion of their peripheral blood lymphocytes. In one case, detection of the deleted allele was by FISH, and, in the second case, the 3-bp deletion was detected by conformational sensitive gel electrophoresis and DNA sequencing of cloned genomic DNA. Mosaicism in VHL is important to search for and recognize when an individual without a family history of VHL has VHL. Patients diagnosed without family histories of the disease have been reported in as many as 23% of kindreds with VHL. Identification of individuals potentially mosaic for VHL will affect counseling of families, and these individuals should themselves be included in clinical screening programs for occult disease.

To evaluate the use of dual-phase three-dimensional magnetic resonance (MR) angiography in the preoperative staging of renal cancer.MR angiography was performed in 18 patients before performance of partial (n = 7), radical (n = 10), or laparoscopic (n = 1) nephrectomy to treat renal cancer. Dynamic, three-dimensional MR angiograms were obtained with gadoteridol enhancement, breath holding, and a three-dimensional spoiled gradient-echo sequence. Images were obtained at 15-second intervals to achieve opacification of arteries and veins. Source, maximum intensity projection, and multiplanar reconstruction images were evaluated. Imaging results were compared with surgical findings.Renal arterial phase MR angiograms depicted 30 of 31 (97%) surgically confirmed renal arteries, with one false-positive result (an artery that arose from an early-branching single main renal artery, interpreted as a separate accessory artery). Renal venous phase MR angiograms depicted all seven instances of renal vein involvement, including extension to the inferior vena cava in two patients. Collateral vessels around the tumor, including prominent gonadal veins in three patients, were demonstrated. Additional findings included adenopathy and adrenal and pulmonary metastases.Dual-phase MR angiography of the kidney may be a useful technique in depicting renal vessels before nephrectomy.

Von Hippel-Lindau (VHL) disease is a dominantly inherited familial cancer syndrome characterised by the development of retinal and central nervous system haemangioblastomas, renal cell carcinoma and phaeochromocytoma. The gene for VHL disease has been mapped to chromosome 3p25-p26 and presymptomatic diagnosis using linked DNA markers is available. We have previously mapped the VHL disease gene to a 4 cM interval between D3S1250 and D3S18. To increase access to presymptomatic diagnosis and to accelerate progress towards isolating the VHL disease gene we attempted to identify microsatellite DNA markers linked to the disease gene by genetic linkage analysis in 29 families. We found significant linkage between the VHL disease gene and dinucleotide (CA) repeat polymorphisms at D3S1038 (Zmax = 22.24 at theta = 0.01, CI 0.0001-0.06), D3S1110 (Zmax = 11.32 at theta = 0.07, CI 0.03-0.14) and D3S651 (Zmax = 7.73 at theta = 0.04, CI 0.008-0.13). We localised D3S1038 between D3S1250 and D3S601, and mapped D3S1110 and D3S651 centromeric to D3S1250. Multipoint linkage analysis mapped the VHL disease locus between D3S1038 and D3S18 with the maximum likelihood at D3S601. There was no evidence of locus heterogeneity. This study has (i) identified three microsatellite DNA markers in chromosome 3p25 linked to the VHL disease gene and (ii) narrowed the target region for the isolation of the VHL disease gene by positional cloning techniques. These findings will improve the management of families with VHL disease by improving the accuracy and availability of presymptomatic diagnosis using linked DNA markers, and will accelerate progress towards isolating the VHL disease gene.

In the setting of von Hippel-Lindau disease, accurate quantitation of kidney lesions is important for genetic research. Unfortunately, fully automated quantitation is difficult because the lesion boundaries are complex. Therefore, we developed a method to semi-automate the quantitation of these renal lesions. We studied helical CT scans of 10 kidneys from 8 patients with von Hippel-Lindau disease. The kidneys were segmented from surrounding structures using an interactive marker-controlled watershed algorithm. Renal lesions (cysts and solid tumors) were identified using thresholding and then characterized by size using mathematical morphology and granulometry. There were 50 cysts and 16 solid lesions. The mean (/spl plusmn/ sd) numbers of interior and exterior manually placed contours required to perform a complete watershed segmentation of the kidneys were 2.2 /spl plusmn/1.2 and 1.2 /spl plusmn/0.6, respectively. The mean difference between the watershed and manual methods of computing renal volume was 13 /spl plusmn/18 mL (5 /spl plusmn/2% of total renal volume) and is not clinically significant. There was no significant difference between volumes of renal lesions measured manually and using the semi-automated method (p > 0.3).

Hereditary papillary renal carcinoma (HPRC) is a recently recognized form of inherited kidney cancer characterized by a predisposition to develop multiple, bilateral papillary renal tumours. The pattern of inheritance of HPRC is consistent with autosomal dominant transmission with reduced penetrance. HPRC is histologically and genetically distinct from two other causes of inherited renal carcinoma, von Hippel-Lindau disease (VHL) and the chromosome translocation (3;8). Malignant papillary renal carcinomas are characterized by trisomy of chromosomes 7, 16 and 17, and in men, by loss of the Y chromosome. Inherited and sporadic clear cell renal carcinomas are characterized by inactivation of both copies of the VHL gene by mutation, and/or by hypermethylation. We found that the HPRC gene was located at chromosome 7q31.1-34 in a 27-centimorgan (cM) interval between D7S496 and D7S1837. We identified missense mutations located in the tyrosine kinase domain of the MET gene in the germline of affected members of HPRC families and in a subset of sporadic papillary renal carcinomas. Three mutations in the MET gene are located in codons that are homologous to those in c-kit and RET, proto-oncogenes that are targets of naturally-occurring mutations. The results suggest that missense mutations located in the MET proto-oncogene lead to constitutive activation of the MET protein and papillary renal carcinomas.

Mutational inactivation and allelic loss of the von Hippel-Lindau (VHL) gene appear to be causal events for the majority of spontaneous clear-cell renal carcinomas. We now show that hypermethylation of a normally unmethylated CpG island in the 5' region provides another potentially important mechanism for inactivation of the VHL gene in a significant portion of these cancers. This hypermethylation was found in 5 of 26 (19%) tumors examined. Four of these had lost one copy of VHL while one retained two heavily methylated alleles. Four of the tumors with VHL hypermethylation had no detectable mutations, whereas one had a missense mutation in addition to hypermethylation of the single retained allele. As would be predicted for the consequence of methylation in this 5' CpG island, none of the 5 tumors expressed the VHL gene. In contrast, normal kidney and all tumors examined with inactivating VHL gene mutations but no CpG island methylation had expression. In a renal cell culture line, treatment with 5-aza-2'-deoxycytidine resulted in reexpression of the VHL gene. These findings suggest that aberrant methylation of CpG islands may participate in the tumor-suppressor gene inactivations which initiate or cause progression of common human cancers.