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the email, the podcast and the simultaneous truths of genetic testing

The email Nearly six months ago, a physician friend sent me an email.

She wrote to me on the subject of genetic testing after I told anyone who would listen about 23andMe, Health Diagnostic Labs, and quantified self trends.

I can get kinda gung-ho about this stuff.

Her email stopped me in my tracks I’ve been paralyzed by it, unable to respond.

I have to respond to the queasy feeling in my stomach about untempered enthusiasm about commercially available genetic testing. I know you sat through statistics, and remember that in a low-risk population, the likelihood of a false positive test greatly outweighs a true positive test. I want you to add to that the uncertainty about what a positive genetic test means: “penetrance” means sometimes you have the genetic abnormality, but never get the disease, “mosaicism” means that not all your cells are 100% identical genetically, and finally there is the plain old uncertainty about how the environment affects gene expression. No wonder the USPSTF doesn’t recommend any genetic screening for the general population.

…Personally, I see patients who spent the $100 to get their ultrasound screen (read by someone who may or may not be qualified to do so) when they can’t afford their copay for necessary care. I think there is an ethical issue in that. That’s not even considering the counseling needed to negotiate the quagmire of heritable diseases. A recent conversation with a 40 year-old who just discovered she was BRAC2 (breast and ovarian cancer) positive around when and how to tell her adolescent daughters and how it would affect their decisions around marriage and children, brought this home. What if she did NOT have a family history and her test was a false positive?

The traditional argument against screening marketed to consumers is the added cost burden to the system of proving that those false positives are actually negative. (The statistical chance of having all normal tests on a 12 test panel is very close to zero.) Remember the classic article that 50% of care is unneeded? Isn’t this part of that 50%?

OK, I know there is also a lot of promise in this, and if we don’t explore and think about it it will never be ready for prime time. However it still gives me a queasy feeling when it is popularized. I was wondering if you thought about any of the issues above before you decided to be tested?

Boom. That put the breaks on the hamster wheel in my head.

I mean, I did think about a lot of those issues, at least as they pertained to me personally. But still her questions gave me pause.

Those who know me personally will attest I’m rarely at a loss for banter. (A middle school teacher once remarked: “Dawson would argue with a brick wall if it would talk back.”)

It’s not that I couldn’t think of responses. For instance: Some people would rather know than not know. Or, everyone has a right to chose for themselves. When it comes to cost, some argue, early detection through advanced diagnostics leads to less expensive treatment.

But I stalled, perplexed…

The Podcast

And then I listened to the latest Freaknomics podcast. Do You Really Want to Know Your Future? You can download/subscribe at iTunes, or listen via the media player below.

The podcast opens with Nancy Wexler discussing her mother’s diagnosis of Huntington’s, a genetically inherited, fatal neurological disorder. Wexler’s father founded the Hereditary Disease Foundation —an organization dedicated to finding a cure —which Wexler now runs.

Wexler speaks openly about the invention of a genetic test for Huntington’s:

DUBNER: If there had been a test available then, a test like the one that you helped develop later, do you think your mom would have taken it at a young age?



WEXLER: Why should she have?

Later in the program, host Steven Dubner interviews Emily Oster, an economist trying to understand why some people simply don’t want to know what the future may hold:

OSTER: …I think what we come down to is the view that in fact largely the reason that people don’t want to get this test is because while they are untested they seem to be able to basically be able to basically pretend everything is fine and that that may be very valuable….I think what it tells us is that people care both about what they think will happen in the future and what actually happens. So you know, I enjoy going on a cruise, but I also value the time leading up to the cruise where I get to think about how great the cruise is going to be. I think often our normal, or standard economic models would basically say we only value the second thing, the only thing that’s beneficial of a cruise is the literal experience of being on the cruise. I think that what this says is in fact something that’s probably more comfortable for most non-economists, which is that there’s some value of, kind of, what you think is going to happen that that has like real benefits, or real costs for you.


The mantra

One of my favorite expressions is action conquers fear. We use it a lot in skiing. You can stand at the top of a mogul ridden black diamond and contemplate all the ways you'll fall and mangle your body. But the only way to settle the butterflies in your stomach is to make the first turn down the hill.

In the case of genetic testing, being able to take action on the results matters.

A friend and activist in BRCA testing and decision making suggests:

"...the key to all of this data is learning what's truly actionable. For something like BRCA, we have options. For Huntington's, we don't [yet]. But we need to build a model where we can find better preventative options for both diseases.  And I believe we can get there."

Knowing we can act on the results has a profound effect on the indifference curve (to borrow the economists' lingo), may impact our decision to test or not test. For instance, most of us don't shy away from taking our temperature to determine if we have a fever. We know how to treat a fever. But if we are contemplating something more serious and potentially life-changing, we may think differently about testing.

Each of us has to weigh the relative risk of knowing versus not knowing. 

The ah-ha

As simple, and even silly, as this may sound I found my ah-ha moment in the closing audio clips of the episode. It happened as I was walking out the door for an evening run.

Both things can co-exist: wanting to know and not wanting to know. And they can coexist in the same person.

The ah-ha is that there is no answer.

Whether we step through the looking glass or not, there will always be fear and rewards with both knowing and not knowing. They are simultaneous truths.

Will genetic testing bring some people peace? Yes. Might it incur unnecessary costs? Yes. Will knowing a propensity for a disease produce stress? Yes. Will not knowing have an effect? Yes.

I love the idea of two truths co-existing. Something can be reassuring and scary at the same time. Something cane be costly and cost-saving at the same time.

Absolutes, as it turns out, aren’t always absolute.

The podcast closes with recorded remarks from people who have a 50% chance of developing Huntington’s:

SHANA: My name is Shana Martin, I’m from Madison, Wisconsin, I’m 33 years old, I’m a world champion lumberjack athlete…I’m getting married in a few months, and we’re starting to explore having kids. And we chatted about it, I’m still quite firm that I don’t want to know.



>My name is Melinda Maher, I’m 25 years old and I’m living at risk for Huntington’s Disease…I hope to get a teaching job and I hope to move away from home and I hope to be able to move out and be on my own and have my own life and independence. And still right now I feel like if I were to test positive I would be afraid of that independence.

The Audio

The Prolog

 I asked my friend for permission to publish her email. She has again thrown down the gauntlet with more questions which challenge me to think deeper. But at the very least, we both agree that having these conversations is better than not having them.

What do you think, is it better to test, with the risks of knowing something you cannot un-know and may not be able to treat? Or, is it better to only test as needed?