Newsweek: Genome Sequencing Begins To Payoff

Three years after scientists announced they had sequenced the human genome, new knowledge about how our genesaffect our health is transforming the way diseases are understood, diagnosed, treated-and even predicted, reports Newsweek senior writer Claudia Kalbin.

Newsweek's latest installment of its ongoing "Health for Life" series,"What's Next in Medicine" is in the December 11 issue, on newsstands Monday, December 4.

Today gene tests are available for more than 1,300 diseases, including cystic fibrosis and hemophilia. And now, as genetic screening gets cheaper and faster, researchers are hunting down the biological underpinnings of more-complex disorders that involve multiple genes-big,rampaging illnesses that strike millions of Americans every year. On the list: type 2 diabetes, Alzheimer's, heart disease and depression.

If the scientists are right, genetic tests for some of these diseases could beavailable by 2010. "We are on the leading edge of a genuine revolution,"says Dr. Francis Collins, head of the National Human Genome Research Institute.

The gene tests currently offered for certain diseases, like breast andcolon cancer, affect only a small percentage of total cases. But the impacton a single life can be huge. The key: being able to do something to ward off disease. "Genetic testing offers us profound insight," says Dr. Stephen Gruber, of the University of Michigan. "But it has to be balanced with ourability to care for these patients."

For example, the risk of breast and ovarian cancers in people with BRCA mutations can be reduced by frequent screening and radical surgery. Having healthy breasts or ovaries removed isn't easy, but the payoff--an end to constant anxiety and a pre-emptivestrike at disease--can be well worth it.

"Most women I've met who've had prophylactic surgery are glad they made the choice even if they're unhappy they were put in that position," says Sue Friedman, a breast-cancer survivor and head of FORCE, an advocacy and support group focused on hereditary cancers. "It's a double- edged sword."

The value of testing becomes especially murky -- and ethically complicated -- when there is no way to prevent or treat disease, as in the case of early-onset Alzheimer's, which often strikes before the age of 50,or Huntington's, Kalb reports.

Today, only about 5 percent of people whoare at risk for Huntington's, a devastating neurological disorder, take the test. Many are worried that genetic testing will put their health insurance or job security in jeopardy. Some people, however, can't live with uncertainty.

Stephanie Vogt knew Huntington's ran in her family -- her paternal grandfather and his three brothers all died from complications ofthe disease-and she wanted to find out where she stood. "As soon as I foundout there was a test, I just had to do it," she says.

In August 2000, after comprehensive genetic counseling, Stephanie, her sister, Victoria and their mother, Gayle Smith, learned her results: positive. "It was like a scene out of the Matrix, where everything freezes and starts again," says Stephanie.

On good days Stephanie feels empowered; on bad days she's frightened. "But most of the time," she says, "I'm comfortable with the fact that I have the knowledge."

Testing is just one piece of the genomic revolution. A major goal is to create new sophisticated therapies that home in on a disease's biological glitch, then fix the problem. Already, genes are helping to predict a patient's response to existing medications. A prime example in this field of pharmacogenetics, says Dr. Wylie Burke of the University of Washington, is a variant of the gene called TPMT, which can lead to life-threatening reactions to certain doses of chemotherapy. Knowing a patient's genotype,or genetic profile, may also help researchers uncover new preventative therapies for intractable diseases.

At Johns Hopkins University School of Medicine, Dr. Christopher Ross has tested several compounds shown to slow the progression of Huntington's in mice. Now he wants to test them in people who are positive for the Huntington's mutation but have not yetdeveloped symptoms--a novel approach to clinical drug trials, which almost always involve sick people seeking cures. "We're using genetics to move from treating the disease after it happens," he says, "to preventing the worst symptoms of the disease before it happens."