Scientists have discovered the first new human disease caused by a "prion" in more than 50 years. Prions are strange, deformed proteins that can act like viruses and bacteria.
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Scientists have discovered a mutant protein that can spread through the brain like a virus, causing a rare and terrible disease. NPR health correspondent Rob Stein reports that the findings could be an important advance for many brain disorders, including Parkinson's and Alzheimer's.
ROB STEIN, BYLINE: Fifty years ago, scientists made a stunning discovery. Bizarre, deformed proteins called prions could spread sort of like viruses and bacteria and cause awful brain diseases. Thankfully, these diseases are pretty rare and hard to get, like kuru, which cannibals in Papua New Guinea got from eating human brains and mad cow disease, which people can get from eating infected cow brains. But Kurt Giles says scientists thought there could be more of these diseases.
KURT GILES: There's been, the past 10 years now, but really, more so maybe the past five years, the understanding that many neurodegenerative diseases may be prion diseases.
STEIN: Diseases like Alzheimer's and Parkinson's, so Giles and his colleagues at the University of California, San Francisco took a look at a disease called multiple-system atrophy or MSA.
GILES: Initially, it looks like Parkinson's disease. People have the tremors and the loads of problems of Parkinson's disease.
STEIN: But MSA destroys the brain even faster than Parkinson's. Giles and his colleagues suspected MSA might be caused by a misshapen version of a protein called alpha-synuclein. So they created mice that have the human form of that protein in their brains and injected the mice with alpha-synuclein from the brains of 14 people who had died from MSA.
GILES: And in every case, the mice died about four months later of the disease.
STEIN: Under a microscope, their brains looked exactly like the brains of people who died from MSA. And tissue taken from the brains of the dead mice could do the same thing to the brains of other mice.
GILES: So that really shows that this is a transmissible disease and that the protein involved in it is acting as a prion.
STEIN: That has all kinds of implications. For starters, Giles says it raises the disturbing possibility that MSA could spread from one person to another by surgical instruments that have been used on the brains of MSA patients.
GILES: Protein sticks very tightly to the stainless steel. And when you clean it afterwards, you could potentially still have misfolded clumps of protein on the surgical instruments that, if you then do surgery on a second person, could potentially induce that in the other person.
STEIN: And the new research, which is being published in the proceedings of the National Academy of Sciences, could be really important for other reasons.
CORINNE LASMEZAS: The fact that these proteins behave like prions - it has tremendous implications.
STEIN: Corinne Lasmezas is a neuroscientist at the Scripps Research Institute in Florida. If a prion can cause MSA, Lasmezas says that's a big boost for the idea that prions could cause other much more common diseases like Alzheimer's, Parkinson's and Lou Gehrig's disease.
LASMEZAS: It's one more stone in our garden of knowledge now about what these toxic proteins are doing. And we know that this is where we have to intervene in order to be able to treat these diseases.
STEIN: Scientists are already trying to find drugs that block these mutant proteins in the hopes of finally finding something that could treat people suffering from MSA, Alzheimer's, Parkinson's and other terrible brain diseases. Rob Stein, NPR News. Transcript provided by NPR, Copyright NPR.