Perhaps pre-knowledge of the relentless disease is just too much to bear, they posit. Or equally possible, the experts add, people may be reluctant to get the testing done because of insurance concerns.

In a recent study of people at risk for a genetic disease, 63 percent said they wouldn't have genetic testing if the results would be available to insurance companies. The fear is very real.

"Insurance issues potentially pose a real deterrent," said Dr. Jeffrey Botkin, a Salt Lake pediatrician and bioethics expert. "If a company knows what it's doing, it could figure it out. But it's not clear to me to what extent they're sophisticated enough to get family histories."

There's enough evidence of insurance discrimination that the issue has been addressed by a Task Force on Genetic Information and Insurance, created by the Working Group on the Ethical, Legal and Social Implications of Human Genome Research.

Among other things, the group noted, "One of the ironies of the current crisis in health-care coverage is that developing more accurate biomedical data could make things worse rather than better for those most in need.

"Knowledge useful in predicting the individual's likelihood of developing a particular disease opens the door to both the welcome preventive strategies and the unwelcome possibility of genetic discrimination."

It said information about past, present or future health status, including genetic information, shouldn't be used to deny health-care coverage or service and asked insurance companies to consider a moratorium on use of genetic tests in underwriting.

Several states have taken a proactive stance against genetic discrimination, including California, Maryland, New Hampshire, Ohio, Wisconsin and Minnesota, barring discrimination by insurers against people who have a genetic predisposition to a disease. Others are considering it. Utah's Legislature has twice declined to pass a proposed genetic privacy act.

The good news for people with a positive genetic test, according to Robert Perry of the Perry Group is most insurance policies don't ask about genetic testing. And if they don't ask, you don't have to tell them.

But that only deals with genetic discrimination in cases of a future illness. That's very different than having a diagnosis of an active disease.

So people who have Huntington's in their families exchange information on insurance. There are numerous Web pages explaining how important it is to have insurance before you get a diagnosis of Huntington's or similarly devastating — and expensive — diseases.