Genetic discrimination: a prejudice is born.

She is unusually tall, with an expansive reach and long, reed-thin fingers and toes-traits marking a condition so distinctive that ancient physicians named it arachnodactyly, after the Greek word for spider. But it was her honesty, not her skeletal disorder, that nearly cost the woman her job.

She was fired the day after she told her employer, a law firm, that she had the genetic anomaly now known as Marfan syndrome. She got her job back only after she threatened to haul her employer into court.

This story is true. And although the woman's name has been withheld to protect her from further discrimination, she is not alone. A study in the Oct. 25 Science indicates that nearly one-fourth of members of support groups for a variety of genetic disorders report that they have experienced discrimination.

"I'm inclined to believe that although the numbers may vary in other studies, this is a problem our society needs to deal with," says E. Virginia Lapham of Georgetown University in Washington, D.C., an author of the report.

The study, funded by the government's Human Genome Project in Bethesda, Md., is the most extensive attempt so far to document genetic discrimination.

Although just 3 percent of children are born with rare genetic anomalies like Marfan syndrome, researchers say the pool of potential victims of discrimina- tion will expand each time science pinpoints a gene, or group of genes, that raises a person's risk of developing such illnesses as heart disease or breast cancer.

Measuring the true extent of the problem may prove challenging, however, because of widespread fears about the misuse of genetic information should it fall into the hands of insurers or employers.

To locate people who might be willing to cooperate in such a study, Lapham and her colleagues contacted more than 100 support groups, with a combined total of 585,000 members, and asked for volunteers. Ultimately, only 332 people from 44 states and the District of Columbia agreed to participate. Each person was asked, among other things, whether he or she or a family member had had problems with health insurance, life insurance, or employment.

The researchers found that 25 percent of the volunteers believed that genetic information had been used to deny them or members of their families life insurance; 22 percent believed the information had been similarly misused by health insurers; and 13 percent believed the information had led to job dis- crimination.

The study confirms what many researchers have long suspected, says Kathy L.

Hudson, policy coordinator for the Human Genome Project. "People believe genetic information has been used to discriminate against them." This concern already presents an obstacle to genetic research, she adds. "One of the prin- cipal reasons people give for not participating in studies is the fear that this information will get out and be used against them." Richard Coorsh of the Health Insurance Association of America (HIAA) in Washington, D.C., notes that the study reflects perceived-not necessarily actual-discrimination. "Percep- tions are difficult to quantify," he says. "It's difficult to know any more about this without checking the particulars of each case." He says that as far as he knows, no member of HIAA plans to require that applicants take genetic tests.

Martha Volner of the Alliance of Genetic Support Groups in Chevy Chase, Md., which collaborated on the study, says insurers don't need genetic test results in order to discriminate. "They can require you to submit 5 years of medical records, they can ask what your family members have died of-there are many ways to get that information without directly posing the question of genetic disorders."