However, the p.Arg82Leu mutation in the VHL gene described here among patients with familial bilateral pheochromocytoma, has never been reported previously in a germline configuration.
This may have relevance to the development of renal cell carcinoma (RCC), where mutations of the von Hippel-Lindau (VHL) gene are major risk factors for the development of familial and sporadic RCC.
Renal or kidney cancer accounts for about 3% of all cancer cases reported each year in the U.S. Molecular signatures that define the cancer, such as the loss of functional VHL, are found in both sporadic and familial cases of cancer.
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.
Specific mutations of the RET proto-oncogene cause familial predisposition to pheochromocytoma in multiple endocrine neoplasia type II, and mutations in the von Hippel-Lindau tumor suppressor gene cause familial disposition to pheochromocytoma in von Hippel-Lindau disease.
To assess the role of elongin B/C, Rbx1 and HIF-1alpha in RCC tumorigenesis we (a) mapped the genes to chromosomes 8q(cen) (elongin C), 16p13.3 (elongin B) and 22q11.2 (Rbx1) by FISH, monochromosomal somatic cell hybrid panel screening and in silico GenBank homology searching; (b) determined the genomic organisation of elongin C (by direct sequencing of PAC clones), Rbx1 and elongin B (by GenBank homology searching); and (c) performed mutation analysis of exons comprising the coding regions of elongins B, C and Rbx1 and the oxygen-dependent degradation domain of HIF-1alpha by SSCP screening and direct sequencing in 35 sporadic clear cell RCC samples without VHL gene inactivation and in 13 individuals with familial non-VHL clear cell RCC.
VHL gene mutation analysis also provides a basis for investigating the genetic basis of familial phaeochromocytoma and renal cell carcinoma, and apparently isolated retinal angiomas.
We analyzed nine specimens from eight cerebellar hemangioblastomas (three familial and five sporadic) and six blood samples from family members of two unrelated pedigrees for mutations of the VHL gene using single-strand conformation polymorphism analysis and direct sequencing.
Mutational analysis of the vhl gene in patients with familial phaeochromocytoma may permit specific diagnosis of von Hippel-Lindau disease, and is a good method for the identification of asymptomatic individuals at risk of von Hippel-Lindau disease.
The combined efforts of a number of investigators have led to the identification of the VHL gene, which appears to function as a tumor suppressor gene and is implicated in both sporadic and familial forms of RCC.