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A Defective Side to Genetic Testing

Critics say the process has its shortcomings. But the tests can predict disorders that are deadly.

July 26, 1999|RICK WEISS | WASHINGTON POST

WASHINGTON — Most women would have been thrilled to have received the report Nancy Seeger got last September from Oncormed, a genetic testing company then based in Gaithersburg, Md. Seeger's mother and maternal aunt both had died of breast cancer, but the company's test of Seeger's blood indicated that she had not inherited any of the common genetic mutations that would predispose her to the disease.

The problem was that Oncormed had come to a different conclusion eight months earlier, when Seeger's doctor first sent her blood to the company. At that time, Oncormed had told Seeger she harbored a mutation that could place her at a greatly increased risk of breast and ovarian cancer. As a result, and after consulting with her doctor, Seeger quickly underwent surgery to remove her ovaries.

Now the company was writing to say the first result had been a mistake.

"I was shocked, of course; then I was relieved, then I was horrified," said Seeger, who lives in Evanston, Ill. "Everybody had believed that this information was so true, and I'd had this surgery based on it, and I'd lived for the past eight months with this horror and anxiety and all the trauma of how to tell the kids. I felt like I'd been forced to confront my own death prematurely."

Seeger is one of a growing number of people in this country learning the hard way that the rapidly expanding field of genetic testing is not everything its gleaming molecular image would suggest.

Genetic tests--in particular those that can predict a person's medical future--are technically more difficult to perform and trickier to interpret than conventional medical tests. And they can have a far more profound impact on people's lives, exacting intense psychological tolls, disrupting family relationships and unfairly jeopardizing employment and insurability.

Yet genetic tests are subject to virtually none of the formal oversight required of standard medical tests. The Food and Drug Administration, which approves the safety and effectiveness of other blood tests, has opted not to regulate genetic tests such as the one Seeger took, saying it lacks the resources. And the primary piece of federal legislation that ensures a certain level of expertise and quality control at the nation's 170,000 medical laboratories does not have provisions for genetic tests.

That means that commercial biotechnology companies and other laboratories, which already are offering more than 400 genetic tests to a largely uneducated public, are free to decide how accurate their tests need to be before marketing them and what they will say in their advertisements to doctors and others.

As a result, some people are paying hundreds or even thousands of dollars apiece for tests that either give wrong answers or are medically useless because they are still experimental.

"Many of these tests are in the quasi-research category," said Edward R.B. McCabe, physician in chief of Mattel Children's Hospital at UCLA, "but everybody wants to charge for them."

McCabe is chairman of a new advisory committee to Health and Human Services Secretary Donna E. Shalala that is to decide by the end of the year how to ensure the quality of genetic testing in this country. The committee faces the enormous challenge of devising a system that will protect people such as Seeger without stifling the nascent genetic testing industry, which could bring many medical benefits in the new millennium.

Detecting Disease

Unlike conventional medical tests, which help doctors diagnose diseases by looking for biochemical or cellular abnormalities, genetic tests probe for tiny alterations in crucial genes. The information they provide can predict, with varying degrees of reliability, a healthy adult's odds of succumbing to a deadly disorder later in life, in some cases providing an opportunity to prevent the disease. The tests also can detect genetic traits in embryos or fetuses and thus can influence a woman's decision on whether to end her pregnancy.

Most genetic tests probably are being conducted skillfully and ethically, but there is evidence of shortcomings in how labs perform the tests and how doctors interpret their results, committee members said at their first meeting earlier this month. One recent study, for example, found that 15% of 245 genetic testing laboratories surveyed scored lower than 70% on a quality-assurance scale, "suggestive of substandard laboratory practice."

Meanwhile, the field is growing exponentially. Some 4,000 genes already have been linked to hereditary medical problems, and new tests are emerging every week. Yet nobody knows exactly how many are on the market or how many people are taking them--much less how many are providing wrong or misleading results.

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