Gene for early aging found.

Scientists have identified a gene that, when mutated, causes a disease of premature aging. They believe the same gene may also play a role in such important age-related diseases as heart disease, cancer, and diabetes.

People born with Werner syndrome start the decline to old age in their twenties. First, they sport gray hair and wrinkles. Then, a raft of diseases starts to hit. Few people with the syndrome survive to age 50.

Molecular biologist Gerard D. Schellenberg of the University of Washington in Seattle and his colleagues located the Werner syndrome gene on chromosome 8.

In the April 12 Science, the researchers describe four different mutations of the gene that they found in Werner syndrome patients.

The protein that the gene codes for appears to be a helicase, an enzyme involved in DNA activity. "Here's a gene that affects the unwinding of DNA," says coauthor George M. Martin, also at the University of Washington. DNA consists of two twisted strands of genetic material. The researchers think the enzyme in question unwinds those strands, a process vital to DNA repair and replication. The team speculates that a defective gene might cause DNA damage that would lead, in turn, to cancer or other diseases.

For people with Werner syndrome, the discovery does not suggest an obvious treatment. Schellenberg explains that every cell in the body of a patient with the disorder is affected by the rogue gene. He says it is difficult to imagine repairing such systemwide defects with gene therapy.

Yet, says Martin, research may give scientists vital clues about the way the normal aging process works.