Ever considered getting a peek inside your genes?
Today, it seems easy. Find a personalized gene-testing service — there are more than a dozen companies in the US alone — spit in one of the tubes the company sends you, pop it in the mail, and check out your results online.
But how much can the average person learn from one of these tests?
We chatted with Columbia University professor Dr. Robert Klitzman, a bioethicist and psychology professor and the author of the recent book "Am I My Genes?" to find out:
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They can't predict the future.
No evidence-based process for assessing personal genetic tests yet exists. Nevertheless, according to EGAPP, an CDC-backed initiative launched in 2004 to come up one such system, more than 1,000 genetics tests are available today.
So what can the average person find out from one of these tests? Not a whole lot, it turns out.
"For the vast majority of people who take personalized genetics tests, their results will have no predictive value," said Klitzman. In other words, while some rare diseases like Tay-Sachs or Huntington's have been linked with mutations on a few specific and identifiable genes, many illnesses and traits are much more complex. For most of these, scientists haven't come close to identifying all the genes the conditions might involve.
Some diseases are linked with just one or two specific genes.
Some diseases are directly caused by specific mutations.
Tay-Sachs, a fatal disorder that destroys the nervous system, for example, is caused by a mutation in a gene that's responsible for making a special protein that blocks that gene from doing its job.
People who inherit just one defective copy of this gene are healthy (their other healthy copy can do the work of the mutated one), but they can still pass on the defective gene to their children, raising their chances of developing the disease. To develop Tay-Sachs, you have to inherit two defective copies of the gene. So, if a genetic test tells you you're carrying the Tay-Sachs gene, it means you could pass it on to your kids.
Other diseases like Huntington's. can develop with only one copy of a faulty gene.
With other diseases, the connection is looser. For instance, having a gene "for" breast cancer does not mean you will get breast cancer.
Saying you have the gene "for" an illness typically means that one or both copies of a gene (you have two copies of each gene, one from each parent) has a mutation that's been linked with that illness. But having a mutated gene does not necessarily mean you'll develop that illness.
In 2013, Angelina Jolie wrote an article in the New York Times about her decision to have her breasts removed after she'd discovered she had a genetic mutation that dramatically raised her risk of developing breast cancer (she also had a family history of breast cancer). About 10% of all breast cancers in the US are linked to the mutation Jolie had. About 90% of all breast cancers are not.
In other words, having the mutation doesn't necessarily mean you'll get breast cancer, but it does mean that you're significantly more likely to get it — especially if you also have a family history of it. And not having the mutation doesn't mean you're risk-free. In other words, "you could have the mutation and not get it, or you could not have the mutation and get it," said Klitzman.
See the rest of the story at Business Insider