Nearly 7 million Americans currently live with Alzheimer's, and by 2060, experts say that number could be as high as 14 million.

Scientists are trying to find out why one man has been able to stave off Alzheimer's for nearly 25 years, despite having a rare genetic mutation that doctors say essentially guaranteed he developed the disease by his late 40s or early 50s.

Ali Rogan spoke with Pam Bellick, Health and Science Reporter for the New York Times.

Pam, welcome back to the program. Who is this one man? And why is he proven to be so essential to Alzheimer's research? So Doug

Whitney is a 76-year-old who lives near Seattle. And he comes from a family where a lot of members of the

family have inherited a rare genetic mutation. And the reason why Doug Whitney is so important is that he also

has the mutation, but he has not developed Alzheimer's. And he is about 25 years past the age

where it would have been expected for him to do so.

So scientists at Washington University School of Medicine and St. Louis who study people

with these rare mutations, they have been following him for 14 years, doing all kinds of

tests on him, trying to figure out what's his, you know, biological secret

sauce that is protecting him. And what have they found out so far? You mentioned they've

studying him. They've been running all kinds of tests. They've gone down some avenues. What has

become clear so far? The interesting thing about him is that Alzheimer's disease, not only the rare kind,

but the kind that, you know, is much more widespread, has sort of two proteins that are hallmarks

of the disease. One is called amyloid. That's the protein that clumps into plaques in

brains of people with Alzheimer's usually forms about 20 years before symptoms emerge. And the

second protein is called tau. And that's the thing that forms these kind of sticky tangles.

And that's much more connected to kind of symptoms of

cognitive decline. So what they've learned about Doug Whitney is that he has a whole lot of

amyloid in his brain. He has amyloid levels that should suggest that he would have Alzheimer's many years ago even. But he has very, very little

tau. So something in his biology has interrupted that progression from amyloid protein to

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