Genotype-phenotype correlation in von Hippel-Lindau syndrome.

The von Hippel-Lindau (VHL) syndrome (OMIM 193300) is an autosomal dominant disorder caused by deletions or mutations in a tumor suppressor gene on human chromosome 3p25. It is characterized clinically by vascular tumors including benign hemangioblastomas of the cerebellum, spine, brain stem and retina. Clear-cell renal cell carcinoma is a frequent cause of death, occurring in up to 70% of patients with VHL. Pheochromocytomas occur in association with specific alleles (usually mutations as opposed to deletions), therefore a family history of pheochromocytoma in association with VHL is an indication for thorough surveillance for pheochromocytoma in affected family members. The VHL gene coding sequence contains three exons. Two isoforms of mRNA exist, reflecting the presence or absence of exon 2. Tumors arise following the loss or inactivation of the wild-type allele in a cell. In initial studies approximately 20% of patients had large germline mutations detectable by Southern blot analysis, 27% had missense mutations and 27% had nonsense or frameshift mutations. Advances in mutation analysis now allow for a 100% mutation detection rate in families with definite VHL. Families may be characterized by the presence [type 2 (7-20% of families)] or absence (type 1) of pheochromocytomas. Most type 2 families are affected by missense mutations, whereas most type 1 families have deletions or premature termination mutations. The prognosis for the lifetime risk of pheochromocytoma can be estimated by determination of the underlying mutation even if there is no family history of VHL.