Getting to Know Your Genome

Posted on by Paul Turek, MD

Did you see Angelina Jolie’s heartfelt letter to the public about her decision to have her breasts removed? It was based on a genetic blood test. Sobering. That, my friends is the power of medical genetics in action. Accurate. Predictive. Life saving. But is all genetic testing that good?

Genetics Rocks

It is unfathomable to me how the DNA of mice and men— 92% identical in content–can give rise to two such entirely different creatures. And who is not blown away at how quickly the Human Genomic Project mapped all of the genes on our chromosomes. And, I’m not pulling your leg when I say that pretty soon our individual genomes will be downloadable to a memory stick. Your very being, wrapped like a lollypop.

The Genetic Fog

Ah but all of this is just reams and reams of information, like a million unreadable books. Given the choice, I would grab a small but pithy dose of real-live knowledge to hoards of undecipherable data when deciding health issues. And into this misty scientific jungle in which we now find ourselves, enters the wild beast that is “direct-to-consumer (DTC)” genetic testing.
You may already know my considered opinion on the subject of DTC genetic testing. Kind of like the soda machine in the hallway at work, a host of genetic tests spanning hundreds of diseases is now available over the internet at the touch of a button. DTC genetic testing typically involves scraping a few cells from inside your cheek and mailing them to a laboratory. Testing may suggest that you are at increased risk for a disorder in the future, such as Alzheimer’s disease, for which there is currently no cure. This may help you plan your life, or make you anxious or depressed. Some genetic tests for cancers (colon, ovary, breast and maybe prostate) are reasonably good right now. But are you ready to schedule that colonoscopy or have your breasts removed like Angelina Jolie if testing suggests an increased cancer risk?

Get Your Testing Here

Here is a breakdown of the 3 kinds of DTC genetic tests on the market today:
Health-related tests are those seek to identify changes in all or parts of the genome to assess the risk of developing certain diseases. Here is the skinny on these tests:

  • Current tests only provide, at best, a partial picture of disease risk as many pieces of the genetic puzzle are still missing.
  • How genetics interacts with lifestyle and environmental factors to shape disease is unclear.
  • Genetic tests can falsely reassure people with unknown risk factors, or needlessly alarm people without critical risk. Talk about casting a shadow over the rest of your life.

Nutrigenetic tests claim to use information about your genetic makeup to create customized diet plans that optimize health. Points to keep in mind include:

  • These tests may be misleading or even harmful because most claims are not scientifically proven.
  • Unproven and ambiguous predictions are not meaningful or truthful for consumers. What does it really mean when they say, “you are at increased risk of ____” when in fact we are all at risk to some degree? Pretty useless for the price you paid.
  • Supplements recommended based on testing are often far more expensive than common vitamins.

Non-medical tests claim to scan your genome for variations and relate them to relatively obtuse attributes such as physical traits, ancestry, or even personality. Given the complex relationship between genetics and the environment, the validity of these tests is, in a word, terrible.
I love genetics, don’t get me wrong. But honestly, my opinion about most DTC genetic tests is that it’s too early to take them personally.