美国国家公共电台 NPR Prion Test For Rare, Fatal Brain Disease Helps Families Cope（在线收听）

RACHEL MARTIN, HOST:

Scientists have developed a better test for a very rare brain disease. And as NPR's Rae Ellen Bichell reports, this test could lead to new ways to diagnose more common diseases like Parkinson's and Alzheimer's.

RAE ELLEN BICHELL, BYLINE: Last spring, Kay Schwister started feeling strange. Her head hurt, and she felt dizzy all the time. She was 53 years old. And aging, she thought, just didn't feel very good. But her husband Tim says over the next few weeks, she just got worse.

TIM SCHWISTER: She was so nauseous and so dizzy that she stopped driving and actually stopped working.

BICHELL: Tim says by the time Kay was admitted to the hospital, she was talking in a strange way.

SCHWISTER: And she would end at a very high note as you were talking to her. And you knew right away that something certainly wasn't right.

BICHELL: Doctors drew blood and spinal fluid and tested it for all sorts of things, like multiple sclerosis and carbon monoxide poisoning. The tests all came back negative.

Tim and his two sons, one in college and one in high school, spent a lot of time at the hospital with Kay.

SCHWISTER: Not knowing what we were dealing with was probably one of the hardest things to ever go through in life. We really, truly wanted to know if there was something that we could do for her.

BICHELL: Weeks went by. Kay couldn't walk or talk anymore, but doctors still didn't know what was wrong. Then, Tim says, they ordered a brand new test for a rare condition, Creutzfeldt-Jakob disease, or CJD. It came back positive.

CJD is really rare, literally 1 in a million. It's fatal, and there's no treatment. The disease was shrinking Kay's brain and riddling it with holes.

SCHWISTER: It's almost as if it starts to turn certain portions of your brain off.

BICHELL: CJD is one of a number of diseases that happen when normal proteins in the brain get folded the wrong way, forming clumps that kill off neurons. Now that they had a diagnosis, the Schwisters knew Kay didn't have long. Tim says family and friends flew in from all over the country to visit her in the hospital.

SCHWISTER: No, she didn't come home.

BICHELL: Kay died a few weeks later.

The reason a test for CJD exists at all is because of people like Byron Caughey. He's a biochemist at Rocky Mountain Laboratories in Montana, who helped develop the method, which involves a spinal tap and takes about four days. But why bother coming up with a test if there's nothing anyone can do about CJD?

BYRON CAUGHEY: Well, there's a couple of reasons why that's important. One is to provide accurate information to the patient, their family and the doctors so that they know what's ahead of them.

BICHELL: Caughey says another is to help researchers study possible treatments. And then there's this.

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFED REPORTER: New this morning - a North Carolina hospital says surgical tools may have exposed 18 patients to a rare and deadly brain disease.

BICHELL: CJD can be passed between patients during certain surgeries, although the last report of that happening was in 1976. But the possibility can put hospitals on edge, says Caughey, because these misfolded proteins survive normal sterilization.

CAUGHEY: It's already a small risk, but it'd be nice to reduce it to zero since it's fatal and there's no treatment and it's really devastating to all concerned.

BICHELL: Alison Green, a biochemist at the University of Edinburgh in the U.K., sees another possibility for this test - as a template for many others. She says while CJD may be extremely rare, there are much more common diseases that also involve proteins misfolding.

ALISON GREEN: Such as Alzheimer's disease, Parkinson's disease, Lewy body dementia and some forms of motor neuron disease as well.

BICHELL: The test for CJD specifically detects proteins called prions. But Alison Green is modifying it to detect other proteins, like alpha-synuclein, which is associated with Parkinson's disease. In a small study, Green's modified test successfully detected Parkinson's in 19 people. She's now redoing the study on a larger scale. And she's applied for funding to work on a test that might someday spot Alzheimer's early on.

GREEN: So yes, the idea is to introduce it for Alzheimer's disease and other protein-misfolding disorders as we go along.

BICHELL: Ultimately, Green says she'd like to have a whole bank of tests so that patients with any kind of undiagnosed dementia can get answers.

GREEN: If you have early onset dementia, do you really want to, maybe, spend the last few years of your life working? Or do you want to take early retirement? They may be able to actually make decisions about their life.

BICHELL: Green and Caughey hope that in the future, their tests will give people the chance to make those decisions.

Rae Ellen Bichell, NPR News.