Drugs Hint At Potential Reversal Of Autism
Scientific researchers can spend years in the lab on obscure topics, like how a sea slug remembers or how a fruit fly sees color. But every now and then, a basic scientist makes a discovery that changes human lives.
Mark Bear, who directs the Picower Institute for Learning and Memory at MIT, is one of those basic scientists. He's discovered a system in the brain that could change the lives of thousands of people with the genetic disorder known as Fragile X Syndrome.
Fragile X is a mutation on the X chromosome that can cause mental retardation and autism. Until now, there has been no treatment.
But Bear discovered that the mutation responsible for Fragile X appears to disrupt a system in the brain that regulates synapses — the connections between brain cells. He says the system works a bit like a car.
"You really need both the accelerator and the brake to properly function," Bear says. "In the case of Fragile X, it's like the brakes are missing. So even tapping the accelerator can have the car careening out of control."
Bear and other scientists have also identified several drugs that seem to correct the problem. The drugs don't replace the missing brakes in the brain. Instead, they limit acceleration by reducing the activity of a group of receptors on brain cells known as mGluR5 receptors.
The drugs have reversed most of the effects of Fragile X in mice. They are now being tried in humans. And at least one small study found that a single dose of a drug had an effect.
The implications for people with Fragile X are huge. If the drugs work, people with the disorder could see their IQs rise and their autism diminish.
"It's a dream come true to think that we have the prospect of having gone from really basic science discovery to a potential treatment," Bear says.
Bear's research was funded in part by a group called FRAXA. Katie Clapp and her husband, Michael Tranfaglia, started the group in the early 1990s as a way to help their son Andy, who has Fragile X Syndrome.
Clapp says she now has reason to hope that Andy, who is now 19, can get better.
"We're not expecting a miracle, or to make up for his 19 years of development," she says. "But if we can watch improvement happen, that's a dream."
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LINDA WERTHEIMER, host:
Scientific researchers can spend years in the lab on obscure topics like how a sea slug remembers or how a fruit fly sees color, and every now and then a basic scientist makes a discovery that changes human lives. NPR science correspondent John Hamilton tells a story of one these discoveries. It involves an inspired researcher, two determined parents, and a young man with a devastating genetic disorder called Fragile X.
JOHN HAMILTON: The young man is Andy Tranfaglia. He's 19 and lives in Newburyport, Massachusetts. Andy spends a lot of evenings racing a radio-controlled humvee around a cul-de-sac near his home.
Ms. KATIE CLAPP: This is probably his favorite thing to do, yeah, besides watch Sesame Street.
HAMILTON: He looks pretty happy.
Ms. CLAPP: Yeah, he really does like to do it.
HAMILTON: That's Andy's mom, Katie Clapp. She says Andy doesn't talk much. Fragile X has left him autistic and mentally retarded. It's also led to seizures so bad he's been taken by helicopter to a hospital in Boston. But Clapp says she's optimistic about Andy's future. That's because of a scientific discovery that she and her husband helped bring about. It all started in the early 1990s. Andy had just been diagnosed with Fragile X, and was going from doctor to doctor. At about the same time, a scientist named Mark Bear was in a research lab working on some pretty obscure brain science.
Dr. MARK BEAR (Director, Picower Institute for Learning and Memory): I am a basic scientist. I didn't know what Fragile X mental retardation was until just a few years ago, because my focus really is not on human disorders or correcting human disorders, but really my focus has always been on how does the brain work?
HAMILTON: Bear, who directs the Picower Institute for Learning and Memory at MIT, was concentrating on synapses, the connections between brain cells. He discovered that brain cells have a kind of switch. When it gets flipped on, the connections between cells get weaker, and the cells don't communicate as well. His research team knew that proteins must be flipping the switch, but they had no idea which proteins.
Dr. BEAR: And so that left us scratching our heads. What are the key proteins? This is where we bumped into Fragile X.
HAMILTON: Bear learned that the brains of people with Fragile X are missing a protein. He wondered if it might be one of the ones that controls the switch. And this question is what brought Bear into Andy Tranfaglia's life. Andy's mother, Katie Clapp, had seen the movie "Lorenzo's Oil" about two parents trying to find a cure for their dying son.
Ms. CLAPP: That was the moment when I went from thinking somebody's got to do something about this to, oh, geez, maybe I can do something about this.
HAMILTON: Clapp and her husband Mike Tranfaglia tried to get biotech companies involved. When that failed, they set up a foundation called FRAXA to raise money for research.
Mr. MICHAEL TRANFAGLIA: The easy path was shut off to us, and so we really kind of got forced into the only way we could do this. And that's what we've done.
HAMILTON: Just as FRAXA got going, Mark Bear, the brain researcher, found himself looking for funding. He needed it to test his idea that the Fragile X protein was affecting connections between brain cells. Money for basic research can be pretty scarce, so when Bear heard about FRAXA, he applied for a grant, and got it. Bear says he doesn't usually have much contact with the places that fund his work, but FRAXA was different.
Dr. BEAR: I had a call from Mike Tranfaglia telling me how excited he was by my proposal, and how he'd love to come down and visit the lab, and hear about what's going on. And I'd never had that level of attention from anybody.
HAMILTON: The grant from FRAXA wasn't a lot, but it was enough to show that Bear's hunch might be right. And that led to money from other sources, including the National Institutes of Health. Bear says he began to suspect that the Fragile X protein was part of a system that regulates brain connections. He says the system works a bit like a car.
Dr. BEAR: You really need both the accelerator and the brake to properly function. And in the case of Fragile X, it's like the brakes are missing. So, even tapping the accelerator can have the car careening out of control. And a way to correct that is to take your foot off the gas.
HAMILTON: If someone could find a way to do that, it could help thousands of people like Andy Tranfaglia. Bear thought it was not only possible, it could be done with a drug.
Dr. BEAR: It was kind of a bold idea based on very little data.
HAMILTON: And that made him uncomfortable. The basic scientist in him wanted to do a lot more work in the lab before trying to sell other researchers on the idea. But Bear got a hard push from Andy's dad, Mike Tranfaglia.
Dr. BEAR: I think at the heart of every basic scientist, there's a person who really wants to make a difference.
HAMILTON: Bear took his idea to researchers who'd spent their careers studying Fragile X. He published in journals. He went to meetings. He also worked with a scientist to input the Fragile X gene into a mouse. The mouse model offered a way to see whether a drug might actually keep a Fragile X brain in check. Mice with this gene don't look or act very different from other mice. But Bear says they do have one unmistakable characteristic.
Dr. BEAR: So, you play a loud noise, about a hundred decibels sound, and the animals will start having seizures, and they'll die.
HAMILTON: Because their brains have no brake. Bear and other scientists had identified several drugs they thought might fix this problem, not by putting on the brakes, but by easing up on the gas pedal. Tranfaglia says the early results with Fragile X mice who got the drug were unequivocal. The mice didn't have seizures, and they didn't die.
Dr. BEAR: That affect was what really convinced us that we were definitely on the right track.
HAMILTON: And the drugs did more than prevent seizures. They appeared to reverse nearly all the effects of Fragile X, at least in mice. Right now, several of the drugs are being tested in people. Results from one small study suggested even a single dose can make a difference. Mark Bear says it's all been an experience he never expected.
Dr. BEAR: I will always be a basic scientist, because I have a love of the brain and a passion for understanding. But I would be lying if I told you that it didn't matter to me that my work had an impact on humanity. It's a dream come true to think that we have the prospect of having gone from really basic science discovery to a potential treatment.
HAMILTON: The implications for people like Andy are huge. If a drug actually works, the runaway car in his brain might slow down. Symptoms of autism could diminish. His IQ could increase. And that's why Katie Clapp remains hopeful.
Ms. CLAPP: Andy, why don't you come in and decide? What's that?
Mr. MICHAEL TRANFAGLIA: It's salami. I gave you salami, Andy.
Ms. CLAPP: Dad got you salami, Andy.
Mr. MICHAEL TRANFAGLIA: It's already opened.
Ms. CLAPP: See? And what are you going to have to drink? Orange juice?
Mr. ANDY TRANFAGLIA: Yeah.
Ms. CLAPP: Orange juice.
HAMILTON: Clapp says she knows that drugs for Fragile X may prove dangerous or ineffective.
Ms. CLAPP: We're not expecting a miracle, or to make up for his 19 years of development. But if we can watch improvement happen, that's a dream.
HAMILTON: It's a dream that could go far beyond the world of Fragile X. Researchers suspect that similar problems with brain connections may be part of what's going wrong in the brains of lots of children with autism and retardation. Mark Bear's lab has already started the basic research to find out if that's true. John Hamilton, NPR News.
WERTHEIMER: We recently profiled a young man with autism who is entering his first year of college. You can read that story and his advice for college-bound students with disabilities at npr.org. This is NPR News. Transcript provided by NPR, Copyright National Public Radio.
