Scientists at the Harvard-affiliated Massachussets General Hospital (MGH) announced this week that they have pinpointed the gene that causes a form of kidney cancer.

Locating the gene that causes Von Hippel Lindau (VHL) disease--a rare form of kidney cancer--is the first step to understanding the causes of kidney cancer in general, said Bernd R. Seizinger the researcher who headed the international project. About 10 thousand Americans die from kidney cancer each year.

Seizinger and his team analyzed blood samples from more than 200 people from nine families affected with VHL to find the gene that causes the rare inherited disorder whose victims may get tumors in their central nervous system and kidneys.

Ordinarily, this gene--and other tumor suppressing genes like it--"act as guardian genes," preventing tumor growth, Seizinger said. When something happens to disturb the function of these genes--such as a mutation--they produces defective proteins and tumors may result.

These tumors often cause blindness and paralysis.

Discovering the location of the gene that causes VHL will have "major implications very soon," Seizinger said. Scientists are now working on a prenatal diagnostic test for VHL, which should be ready within one year, he said.

This test will allow women carrying affected fetuses to make informed decisions about whether to have an abortion, the researcher said.

Because VHL victims usually do not show symptoms of the disorder until they are 20 to 50 years old, scientists are also developing a test that will detect the disease in children. Such a test would allow doctors to find and operate on tumors at an early stage, perhaps preventing blindness or paralysis, Seizinger said.

Seizinger said he hopes in the future to isolate the protein product of the VHL gene and understand exactly how the gene and its products suppress tumor growth. Then "you might be able to design drugs that interfere with the defective molecules," and stop the growth of tumors.

Scientists someday might also be able to design a permanent cure for VHL, the researcher said. The cure might involve the creation of a special virus that VHL sufferers would be infected with. The virus, known as a "shuttle vector," would insert correctly functioning copies of the gene into a person's chromosomes, Seizinger said.