Although drugs can partly alleviate some of the symptoms of the illness, such as psychosis and involuntary jerky movements of the face and body, there is no treatment.
Huntington's is a progressive genetic disease of the central nervous system caused by a degeneration of nerve cells in the brain. Hundreds of thousands of people around the world suffer from it. Symptoms usually appear between ages 35 and 40 and the disease is fatal within 10 to 15 years.
But French researchers have provided the first evidence that when healthy cells from the part of the brain damaged in Huntington's are extracted from a fetus and injected into the corresponding area of the brains of people with the illness, the grafts can survive and induce measurable improvements.
The findings are very preliminary because the transplants were tested on only five patients. Three of them improved, one improved at first then declined and the fifth continued to deteriorate throughout the study.
Also, they have only been followed for a year so far.
CBS News Correspondent Kimberly Dozier reports three of the five patients who received the brain cell injections improved to the point where they were able to resume riding bicycles. One of those three was able to mow his lawn and help his children with their homework; another was able to swim and play the guitar; and the third was able to play indoor games.
The pilot study, led by Dr. Marc Peschanski of the French Institute of Health and Medical Research, was published on the Web site of The Lancet medical journal.
"Although the findings by Peschanski and colleagues are promising, the clinical usefulness of cell replacement therapy for Huntington's disease remains unclear," said Dr. Olle Lindvall, a neuroscience professor at Lund University in Sweden.
"The ability of the graft to maintain a stable condition over a long time will be essential for its therapeutic value," said Lindvall, in a critique published by The Lancet.
In the study, the researchers used undeveloped brain tissue from aborted fetuses aged between 7 and 9 weeks. After tracking the patients for two years, the scientists injected the cells into first the right side of the brain, then into the left side a year later.
They all got drugs to suppress their immune system so that their bodies were less likely to reject the transplants.
One year after the second transplant the patients were given a battery of psychiatric and other brain tests and the results compared with those of 22 other Huntington's patients who had not received the transplants.
Brain scans showed increased or normal range motor function and cognitive activity in three of the five who had had the cell grafts. Oter tests indicated speech and articulation improved and that the evidence of dementia was less pronounced.
Researchers say the condition of all of the patients in the untreated comparison group steadily declined.
The researchers said it is unclear how the transplants might work, especially in the long run, but the aim is to replace lost nerve cells.
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