DNA tests can reveal ancestry or disease risk, but do not provide certainty about your future

DENVER - What if you could find out your personal risk of getting Alzheimer's or specific drugs you may have a reaction to? Would you have your DNA tested?

The business of personalized health care is booming. For example, 23andMe offers a health and ancestry analysis, GenePartner claims to use DNA to help identify a potential romantic partner and YouScript promises advice on the prescriptions that will work best for each customer.

Not many 19-year-olds ask their parents for genetic testing, but Dana Hall is fascinated by her family history.

"I opened up my box and I was so excited," Hall said. "I was really excited to find out about my ancestry, heritage."

So, she spat into the test tube and shipped it back to be tested by 23andMe.

"There are some ethical issues, but that's not to say that Americans won't go for something that's $99," said Dr. Matthew Taylor, of the Adult Medical Genetics Program at CU's School of Medicine.

Taylor says the science behind genetics testing is robust, but the problem can come when people interpret the results.

Many genetic diseases are heavily influenced by outside factors like environment and lifestyle. He says that without that context, the results could create unnecessary worry or a false sense of security.

"There are people in the genetics field who are worried that this is genetic testing, and it's done without a physician, and it's done without a genetic counselor," said Taylor.

The tests, including the one offered by 23 and Me, compare an individual's risk compared to others across the population.

"It would be nice to know if you take this drug you are going to get sick, but it really tells you if you take this drug, you might have a slightly higher chance of getting sick than somebody else who takes the drug," Taylor said.  "If you want to know what’s going to happen next, this is not that test. That’s the crystal ball test, and that doesn’t exist."

In their blog, 23andMe points to examples of people who have benefitted from the tests, such as a runner who was diagnosed with a rare disease after he got his results.

And as that company continues to grow, they hope to compile a database that will help track disease patterns, find cures and create personal healthcare road maps.

When Hall got her test back, there were a few surprises.

Her ancestry came back as mostly northern European, but without a Y chromosome the results only reflected her mother's Danish ancestry. Her father's side of the family was not included.

"Reading through, I was so nervous just because I didn't want to find out something that could change the course of the rest of my life, even though it's just a genetics test," Hall said.

After working up the courage to read her health risks, Hall found the report indicated she had almost double the average risk for Alzheimer's disease.

"I look at it as a tool that I can use to help my own choices and lifestyle, but I'm not going to take it as something that's 100 percent true," she said.

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