Genetic Testing Gets Personal

"Gene chips" that cost just a few hundred dollars can today detect hundreds of thousands of tiny molecular hiccups in a smidgeon of DNA collected from saliva or blood. Unlike better-known genes that single-handedly cause inherited diseases such as sickle cell anemia, most of these gene variants add in very small ways to a person's medical weaknesses or strengths.

Only about 100 such glitches have been convincingly linked to specific diseases or behavioral tendencies, but new connections are being discovered every month. Together they can start to paint a picture of a person's health prospects and behavioral predilections.

Meanwhile, the cost of spelling out an individual's entire genetic code, or genome, is also dropping precipitously, from several million dollars a few years ago to about $1 million last year and an anticipated $200,000 or so this year.

"Our goal and vision has been to make a total human genome affordable," said Christopher K. McLeod, chief executive of 454 Life Sciences in Branford, Conn., which makes some of the fastest and most powerful gene-sequencing machines under the corporate motto "Measuring Life One Genome at a Time."

By comparing an individual's genetic profile with databases of known correlations, companies can calculate that the person, for example, is 30 percent more likely than average to get colon cancer, 20 percent less likely to get cataracts, and 10 percent more likely to be impulsive or have anger-management issues.

Yet the probabilistic nature of those results is potentially problematic, said J. Craig Venter, the geneticist who broke scientific and cultural ground last year when his eponymous Rockville research institute spelled out his entire genetic code and posted the results on a publicly accessible database, revealing to the world that he has, among other things, genetic inclinations toward wet earwax.

It can be entertaining, Venter said, to learn one has a gene for soggy earwax. "But if you're on the receiving end of one of these tests and are told your probability of having a serious problem is 62 percent, what the hell does that mean?"

Results Can Mislead

And that is assuming the results are correct. As it turns out, many gene tests today search for DNA patterns that have been linked to a disease or trait in only one or two studies. Such findings are often overturned by later research.

Even if the findings hold up, there are countless other genes still unstudied that experts say will eventually be found to either augment or counterbalance the risks discovered to date. Until those factors -- harmful and protective -- are added to the gene chips, clients run the risk of being misled.

"This information can be quite profound," said R. Alta Charo, a professor of law and bioethics at the University of Wisconsin. "It can lead to a decision to have your breasts chopped off before you've been sick for a day or having your ovaries scooped out before you have children. These are dramatic decisions, but these products are going on the marketplace as though they were underarm deodorant."

Exacerbating the problem is that virtually no one is watching over the industry. The Food and Drug Administration does not regulate most gene-based tests, and there is no federal proficiency-testing system for companies offering them.

So while some of the new companies, including 23andMe, Knome and Navigenics of Redwood Shores, Calif., boast solid teams of renowned researchers and emphasize that the information they provide is not diagnostic, other outlets inhabit the scientific fringe.