Tag Archives: genetics

Genetic testing: Walgreens says it will, and then it won’t

Walgreens genetic test kitOn Monday, news broke that Walgreens was about to announce a genetic test kit, available in stores starting on Friday. The kits would allow consumers to test for such things as how you respond to statins or blood-thinners; whether you carry genes for Tay-Sachs disease or cystic fibrosis; whether you have an increased risk for coronary artery disease, Alzheimer’s, MS, colon, lung or prostate cancer; and your chances of becoming obese, developing psoriasis, or going blind. There are three separate tests, individually priced, so you don’t have to confront the bad news all at once.

On Tuesday, when the announcement became official, commentators speculated on how the FDA would react. A spokesman for Pathway Genomics, the developer of the test partnering with Walgreens, said: “FDA clearance is not necessary to sell the … Kit in retail.” He also confirmed that the product had not been submitted for FDA approval.

Meanwhile, FDA officials, contacted for their comments, were saying that any test that “could lead to a consumer making a decision on whether they are going to terminate a pregnancy — we consider that a very important decision to be made on a test that has not been looked at by the FDA.”

The FDA requires products that make health claims to be reviewed. Walgreens/Pathway argued that the test provides consumers with “information about their personal genetic makeup and traits,” hoping that would be sufficient to avoid the FDA’s purview.

On Wednesday the FDA made public a letter to Pathway “suggesting” that the kit did need regulatory approval. The FDA was on top of this all along. The letter was actually written on Monday.

Late Wednesday, Walgreens announced it would postpone sales of the kit.

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Health Culture Daily Dose #16

Here are some things I’ve come across recently. Categories include: Aging/End of Life/Death, Doctors, Influenza, Genetics, and Health Care Reform.

AGING, END OF LIFE, AND DEATH

End-of-Life Care: Where Ethics Meet Economics (The New York Times – Uwe Reinhardt)
Health spending in the United States has doubled every 10 years during the last four decades. Americans sooner or later will have to confront the hard questions about access to expensive treatments, perhaps after a rational national conversation, if such can still be had in America.
Health Care’s Generation Gap (The New York Times – Richard Dooling)
Money spent on exorbitant intensive-care medicine for dying, elderly people should be redirected to preventive care for children and mothers.

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Health Culture Daily Dose #9

In today’s Dose:

Health care reform
(Robert Reich on the public option)

Health news
(Migraines, Nipple piercing and breast feeding)

Obesity politics
(TB and the thrifty gene)

Medical journalism
(Drug company ties to journalists)

Health care reform

  • As you may have noticed by now, I’m a fan of Robert Reich. He has an opinion column in the Wall Street Journal that pulls together much of what he’s been saying in his blog posts on health care, such as his insistence on the importance of a public health insurance option.

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Are you a supertaster: DNA testing

Got Taste?

In the last two posts I’ve discussed counting the taste bud containers (papillae) on your tongue or using a bitter test strip to determine taste sensitivity. There’s one more option: genetic testing. A DNA analysis will reveal whether you’ve inherited the dominant gene for bitter taste sensitivity from both parents. If you have, there’s a high probability you’ll experience food and drink with the taste buds of a supertaster.

An analysis of your genes will not only tell you about inherited traits, like bitter taste perception and earwax type, but about your ancestry and your risk for certain diseases. Do-it-yourself genetic testing is now available on the Internet. You simply send a test tube full of saliva to a lab and the results are sent directly to you, the customer. There’s controversy in the medical profession about whether this is an advisable practice. Is it wise to absorb confusing and potentially disturbing medical information on your own or should a physician/genetics counselor spoon feed you the results?

What your genes tell you (for a price)

Test tube for genetic testing

Image source: Newsweek

Currently there are three high-profile, do-it-yourself DNA-testing companies: deCODEme, Navigenics, and 23andMe.

deCODEme will calculate your “genetic risk” for bitter taste perception, but only as part of their complete scan. Price: $985.

Navigenics position themselves above the fray of the merely curious. They pride themselves on testing only for conditions that are actionable, for example, can you delay onset of a disease or benefit from early detection. They also limit testing to conditions where quality research shows a definitive link between genetic findings and disease. An additional constraint is that the condition must be “medically relevant.” You could make a case that bitter taste perception, which influences what we eat, is relevant to heart disease and diabetes, but the quality research is scarce. The price tag for Navigenics’ premium genetic test, the Health Compass, is $2499.

23andMe is a Silicon Valley start-up that’s received a lot of good publicity, like being the number one 2008 Invention of the Year in Time Magazine. For $399 the company will read 500,000+ locations in your genome and return the data to your computer. They provide research information on 100+ diseases, conditions, and traits. One of those traits is bitter taste perception.
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The genetics of supertasting

Got Taste?

After almost 80 years of study, the genetics of taste sensitivity is still not completely understood. Just when one theory seems to account for all the facts, an exception to the rule pops up. Studying human beings may be a science, but it’s not always an exact one.

Most supertasters have a gene that appears to control their sensitivity to bitter tastes. I say “appears” because other genes also influence sensitivity to bitterness. So far geneticists have discovered 35 bitter receptor genes. According to a company that offers to test your genes, up to 20% of the variation in bitter taste sensitivity may be due to these other genes. A more academic source puts that number as high as 50%. Geneticists debate whether sensitivity to bitterness is even related to overall taste sensitivity. Experimental psychologists like Linda Bartoshuk continue to study supertasters, but many geneticists no longer use the term.

One question that interests both geneticists and those who study evolution is this: Why have nontasters survived? In the days before supermarkets, nontasters presumably couldn’t tell if what they were about to eat would be deadly. Over millions of years you’d expect natural selection to favor the dominant gene for bitter taste sensitivity. But roughly 25 percent of the population have two recessive genes for this trait and are classified as nontasters. Interestingly enough, it turns out that 25 percent of chimpanzees are also nontasters.
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