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How a growing trove of genetic data is informing medical breakthroughs

Individualized medicine, in which treatments are customized based on a patient’s unique DNA, is a rising field. Along with an ever-expanding genetic database, it offers tantalizing promise for solving some of medicine's most daunting challenges. But individualized medicine also carries with it questions and risks -- both moral and medical. Science correspondent Miles O’Brien reports.

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  • Judy Woodruff:

    Earlier in the program, we mentioned the latest drop in cancer deaths.

    One of the many reasons for that is the rise of personalized medicine and an ever-expanding genetic database.

    Miles O'Brien looks at the larger hopes for that field and the serious questions and risks surrounding it as well.

    It's part of our ongoing coverage on the Leading Edge of science, technology and medicine.

  • Miles O’Brien:

    Like most of the 10 million people who have signed up for 23andMe, Jessica Algazi saw the do-it-yourself glimpse into her DNA as little more than a lark.

  • Jessica Algazi:

    I honestly had no idea what they were testing for. I just thought maybe we'd meet some cousins we don't know. Maybe we'd find some things out. But I literally didn't even look into it.

  • Miles O’Brien:

    But the results unexpectedly led her to the intersection of heredity and health, and a stunning prognosis.

  • Jessica Algazi:

    I saw right at the top of the page, something bad is there. I look at it, and I'm like, oh, God, this isn't good.

  • Miles O’Brien:

    The grim report? Her DNA includes a BRCA1 mutation; 72 percent of women who have it will develop breast cancer before age 80; 44 percent will get ovarian cancer.

    It was a devastating surprise.

  • Jessica Algazi:

    I had no family history of breast cancer, ovarian cancer, nothing to justify being sent for a BRCA test. And it wouldn't have been covered by insurance because I didn't have the right — I didn't have the family history, nothing. So, I kind of was somebody that fell through the cracks.

  • Miles O’Brien:

    A Hollywood entertainment lawyer, Jessica knew well the story of actress Angelina Jolie, who shocked many people by choosing to have a double mastectomy in 2013, after discovering she carries a mutated BRCA gene.

    So, Jessica faced a momentous decision enabled by technology that is moving fast from the laboratory to our lives. It's called precision or individualized medicine.

  • Keith Stewart:

    Individualized medicine, for us, is really understanding as much about each individual patient as we possibly can.

  • Miles O’Brien:

    Keith Stewart runs the Center for Individualized Medicine at the Mayo Clinic in Rochester, Minnesota.

    Is this a revolution?

  • Keith Stewart:

    I think it is. I think it's transformative. It's really a paradigm shift in how we think and manage cancer.

  • Miles O’Brien:

    Here at Mayo, they are helping find the genetic needles in the haystack that cause cancer and other genetic diseases.

    They built a huge biorepository for the National Institute of Health's All of Us initiative. The goal? Sequence the full genomes of one million Americans.

    When you get to the day where you have this repository of a million genomes, that's a very powerful tool for science, isn't it?

  • Keith Stewart:

    It's going to be an amazing tool for scientists and researchers for years, decades to come.

  • Miles O’Brien:

    It is an ambitious undertaking. Our genome consists of three billion distinct data points that are assigned the letters ATGC. By anonymizing and analyzing this rich trove of data, they hope to reveal the nuanced genetic interplay that is at the root of disease.

    The long-term promise? Inherited diseases like cancer detected while they can still be cured. But in the short term, genetic insight is already saving lives. It allows doctors to tailor medications to their patients, protecting them from adverse reactions and maximizing the efficacy of drugs aimed at fighting arthritis, high cholesterol, depression, HIV and more.

  • Richard Weinshilboum:

    Really, this is the camel's nose coming under the tent in terms of genomics being right at the bedside.

  • Miles O’Brien:

    Richard Weinshilboum is a professor of medicine and of pharmacology at Mayo and a pioneer in the field of pharmacogenomics, which is focused on the interplay between genes and drugs.

  • Richard Weinshilboum:

    Now we can scan across the whole genome, and we find all kinds of genes that play a role in variation in drug response that we would have never imagined.

    Where the world is going to go, I think, is preemptively to have that kind of genetic information parked in your electronic health record.

  • Miles O’Brien:

    Direct-to-consumer genetic testing services, like 23andMe, are pushing this trend. It's as simple as spitting into a tube, sealing it up and shipping it off.

    A few weeks later, the results confirmed a lot of what I knew. The big surprise? I have an unusually high number of Neanderthal genes. It explains so much.

    But most important, the test uncovered no genetic diseases.

    Emily Drabant Conley is 23andMe's vice president of business development.

  • Emily Drabant Conley:

    I think a good way to think about this is, we're a great screening tool. We're looking at lots of different — over 90 different health conditions. And you're getting all that information.

    And then some of those things may require additional follow-up with a doctor.

  • Miles O’Brien:

    At first, 23andMe offered health reports without any federal regulation. But it is now an FDA-approved tool for assessing the risks for 13 diseases.

    But it's important to understand its limits. Our DNA has three billion pairs of letters, and 23andMe only reads 600,000 of them, or 0.02 percent. It's like reading a book, but only every 5,000th letter.

    But DNA is 99.9 percent identical in every human, so nearly all of the letters in this book are the same for everyone. The letters that vary from person to person are called single-nucleotide polymorphisms, or SNPs. So 23andMe focuses on a subset of SNPs. It is more practical and much cheaper than reading the whole genome.

  • Emily Drabant Conley:

    The things that we are looking at in DNA are the things that we know change between people, they differ, and that's why we have chosen them.

  • Miles O’Brien:

    But, buyer beware. And consider the story of Matt Fender. In 2013, he bought a 23andMe kit. But he didn't settle for the standard genetic report from the company.

    He uploaded his raw DNA data to a third-party Web site that compares the genetic report to hundreds of scientific papers. The report delivered a grim prognosis, that he had a mutated gene that carries a very high risk of Alzheimer's disease.

  • Matt Fender:

    And in that moment, I was like, yes, like, I can totally see this really grim future where, in a couple of decades, at most, I'm going to be like late-stage Alzheimer's. And I was just in shock.

  • Miles O’Brien:

    Almost overnight, he changed his lifestyle. He started running regularly and eating healthier foods.

    But after retesting, he learned it was a false positive five weeks later. He doesn't carry that particular mutation. He claims 23andMe made the mistake. While the company doesn't deny a SNP was misread, it warns downloading the raw data and using third parties carries additional risk.

  • Emily Drabant Conley:

    Some of those third parties have done a disservice, potentially, by not always having accurate information or interpretations. We can't control what they say.

    I sort of feel it's up to consumers. Like, if you want to take your data file somewhere and have it interpreted, you need to know the risks of that. We're not going to be paternalistic and say, you can't do it. But people need to be careful.

  • Miles O’Brien:

    This is what Jessica Algazi did. And once her doctors confirmed the 23andMe report, she made the decision to have a prophylactic double mastectomy and removal of her ovaries and fallopian tubes. She has no regrets.

  • Jessica Algazi:

    If you don't have the surgery, that means every single time you're going in for mammograms and ultrasounds, and you're just going to be freaking out that much more every single time. So, for me, it was a no-brainer.

  • Miles O’Brien:

    So what began as a fun way to learn about heritage and traits became something deadly serious.

  • Jessica Algazi:

    They quite possibly saved my life.

  • Miles O’Brien:

    At the Mayo Clinic, they hope stories of pre-disease detection and prevention like Jessica's will become routine.

  • Keith Stewart:

    I think, if people are involved in their health, they understand more about it, and it's part of their health record, I think that can't be bad.

  • Miles O’Brien:

    As more people sign up, and the biorepository fills up, the collective DNA database is growing fast.

    It might sound like a scary Big Brother overreach, but proponents insist all this data will remain anonymized, and the risks to privacy come with a huge potential reward.

    Researchers are convinced patterns are likely to emerge, making medicine more precise, predictive and preventative.

    For the "PBS NewsHour," I'm Miles O'Brien in Rochester, Minnesota.

  • Judy Woodruff:

    Fascinating reporting.

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