ROBERT SIEGEL, HOST:
In East Africa, thousands of children have a rare form of epilepsy known as nodding syndrome. The cause of the condition has been a mystery. Now, NPR's Jon Hamilton reports that scientists may have solved that mystery.
JON HAMILTON, BYLINE: Several years ago, a government scientist named Avi Nath was dispatched to Uganda to investigate nodding syndrome. Nath is a researcher at the National Institute of Neurological Disorders and Stroke. And when he arrived in northern Uganda, he says it was all too easy to find affected children.
AVI NATH: These were kids, the young kids you would expect that they should be running around playing instead. If you go to these villages, they are just sitting there in groups.
HAMILTON: So villagers can keep an eye on them. Many have severe mental disabilities, often they stop growing and talking. And Nath says they have seizures that affect muscles in the head and neck.
NATH: So their head tends to fall forwards. And because that happens repeatedly as part of the seizure, it is termed nodding syndrome.
HAMILTON: Nath had one clue to work with. Nodding syndrome tends to occur in the same places as a parasitic infection known as river blindness. But the link was puzzling because although nodding syndrome is a brain disease, there was no evidence that the river blindness parasite gets into the brain. When Nath got back to his lab in the U.S., he was determined to solve the mystery. Tory Johnson is a researcher at Johns Hopkins who was working for Nath at the time.
TORY JOHNSON: He pulled all of the land together as a team and asked us to each investigate different components.
HAMILTON: Johnson's assignment was to see whether the body's own immune system might have a role, so she began screening blood samples from people with nodding syndrome.
JOHNSON: We looked at everything that was available.
HAMILTON: And eventually, she found something. Nath says he was in a meeting one day, when Johnson appeared suddenly.
NATH: I saw her waving at me from behind. I was like, OK, what happened?
HAMILTON: Johnson had discovered that in people with nodding syndrome, the immune system was targeting a protein found in certain cells. It looked like the body was attacking itself. The question was whether this attack included the brain. So Johnson started looking to see whether the targeted protein was in brain cells.
NATH: And lo and behold she found that, yes, it was not only present in brain, there was actually large amounts of it present in neurons. So the story really came together very nicely.
HAMILTON: The full story, the team's hypothesis, goes like this - when a person is infected with the river blindness parasite, their immune system begins sending antibodies to attack the invader. And these antibodies identify their enemy by looking for a specific protein in the parasite cells. Unfortunately, this protein looks a lot like a protein found in certain brain cells. So these brain cells become unintended casualties of the body's efforts to protect itself. Nath says the work, published in the journal "Science Translational Medicine," points at the importance of treating infected children.
NATH: Even if you can't treat the ones who already have nodding syndrome, you'll prevent new infections from taking place.
HAMILTON: A common drug can kill the parasite in its early stages. But the finding also raises the possibility that parasites might play a role in epilepsy here in the U.S. Children often get parasites like pinworms, and some people in the U.S. have a type of epilepsy that's caused by a malfunctioning immune system. Johnson now wants to know whether parasites or some other infection might be involved. Jon Hamilton, NPR News.
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