WebMD Medical News
Daniel J. DeNoon
Laura J. Martin, MD
May 13, 2010 -- Walgreens has postponed its plans to sell an over-the-counter genetic test due to FDA concerns that "consumers are putting themselves at risk if they use a test not approved" by the federal agency.
The test, offered by Pathway Genomics, already is offered online. So are similar tests from other companies. None have FDA approval, but the FDA has not previously intervened.
"FDA believes we have regulatory authority over these laboratory-developed tests, but we recognize we have not always used this authority," FDA spokeswoman Erica Jefferson tells WebMD.
Now Pathway's planned retail sale of the test has attracted FDA attention. The agency has sent an enforcement letter to Pathway, asking the company to tell it why it does not think it needs FDA approval to sell the test.
"We don't have any record of this test being submitted for approval or clearance, so we will look at claims being made," Jefferson says. "It is a process where we consider a number of different options. We want to make sure information given to consumers is accurate and that any product is going to do what it says."
The Pathway test does not sequence a person's entire genome, but instead looks for the most common single-letter genetic code variations (single nucleotide polymorphisms or SNPs) linked to disease risk, medical conditions, and sensitivity to certain drugs.
According to the Pathway web site, the tests report some of the genetic risks for 61 medical conditions and sensitivity or predisposition to adverse events for eight drugs.
The test kit will sell for between $20 and $30 at 7,500 Walgreens stores across the U.S., with the notable exception of New York, which has a law blocking sale of the test. But the kit isn't the whole cost. Pathway will offer kit buyers Drug Response results for $79, "Pre-Pregnancy Planning" results for $179, "Health Conditions" for $179, or a combination of all results for $249.
The kit contains a small saliva collection tube and a postage-paid envelope for customers to send in their samples for testing at Pathway's lab. Customers then go online to a password-protected site to see the results.
Genetic counseling is available at a price. It will cost $40 for a call of up to 20 minutes, and $99 for an hour of counseling, although Pathway will not charge for counseling calls it makes to customers to warn them of particularly troubling test results.
Only adults will get their full test results. If a parent sends in a child's saliva for testing, Pathway will report only those risks that affect childhood health. When the child reaches age 18, he or she can then ask Pathway for the full report.
Geneticists tell WebMD that the Pathway test is probably very accurate, as far as it goes.
"They are not sequencing the genes, just the SNPs," Jeffery Vance, MD, PhD, chairman of genetics at the University of Miami Miller School of Medicine, tells WebMD.
This means that while the test accurately identifies the most common variations on a gene linked to disease, it may miss rarer or yet-unknown variations that have the same effect.
"They could test for the six common SNPs that are most common ones that cause a disease, but a lot of other ones on the same gene could also go bad," Vance says. "So absence of information like that does not give you clean bill of health."
Even so, the test will accurately identify a large number of health-related risk factors. That's both good and bad, says Robert Marion, MD, director of genetics and developmental medicine at Montefiore Children's Hospital and Albert Einstein College of Medicine, Bronx, N.Y.
The good news, Marion says, is the availability of genetic tests means we are entering a new age of personalized medicine.
"We will be able to take a sample of DNA from a newborn or fetus or adult and analyze all 20,000 genes and come up with the profile of this person's lifetime disease susceptibility," Marion tells WebMD. "So people with susceptibility to diabetes, for example, will know they should be at a good weight, have a good diet, and pay attention to blood glucose levels earlier in life than they might otherwise have done."
The bad news, Marion says, is that it's extremely difficult to interpret the information that comes back from genetic testing.
"It opens up a Pandora's box," Marion says. "For a lot of other things they are testing for, we are not at a point yet where we can understand the results in a way that will be helpful to most families."
Vance uses even stronger language.
"They are giving people information without knowledge," he says. "The question is not whether a person has a risk gene but how much risk is involved. The average risk gene for a common disease is probably one and a half times the normal risk. So if it takes 100 pounds of risk to get the disease, these may be 1-pound risks."
And as every expert who spoke to WebMD is quick to note, genetic risk is not destiny. There is robust interplay between a person's genes, a person's lifestyle, a person's environment, and a person's experience. Genes, particularly SNPs, are only part of this complex equation.
"A lot of people who have a genetic risk for a disease never get the disease," Vance says. "And a lot of people who get a disease never had that genetic risk."
Vance and Marion both strongly agree that genetic counseling should not be an add-on option to genetic testing. Genetic counseling, they say, is the whole point of genetic testing.
Who might need such counseling? Virtually everyone who gets genetic testing.
"With the number of susceptibility genes out there, everybody is going to find he or she is susceptible to one condition or another. Virtually 100% of the population is going to have a positive result," Marion says.
SOURCES:Erica Jefferson, spokeswoman, FDA.FDA enforcement letter to Pathway Genomics, dated May 10; posted May 13.Jeffery Vance, MD, professor and chair of genetics, University of Miami Miller School of Medicine.Robert Marion, MD, director of genetics and developmental medicine, department of pediatrics, Montefiore Children's Hospital and Albert Einstein College of Medicine, Bronx, N.Y.News release, Pathway Genomics.Pathway Genomics web site.
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