A novel treatment strategy encourages a patient's own cells to "eat" the malformed proteins that lead to these diseases.
Huntingdon's is one of several degenerative diseases marked by protein clumps in the brain. The symptoms include abnormal movements, psychiatric disturbances such as depression, and memory loss.
The disorder occurs when a rogue protein known as huntingtin builds up in brain neurons. Normally, cells dispose of, or recycle, waste material, including unwanted or defective proteins, through a process known as autophagy, or "self-eating".
Scientists found a way to induce autophagy in animals with Huntingdon's by giving them an antibiotic drug, rapamycin. Their findings were published in the journal Nature Chemical Biology.
Professor David Rubinsztein, of Cambridge University, who led the study, said: "We have shown that stimulating autophagy in the cells - in other words, encouraging the cells to eat the malformed huntingtin proteins - can be an effective way of preventing them from building up.
"This appears to stall the onset of Huntington's-like symptoms in fruit fly and mice, and we hope it will do the same in humans."
Rapamycin is used as an immunosuppressant for transplant patients. However, long-term use may produce serious side effects, such as kidney problems.
Working with US colleagues, Prof Rubinsztein has identified other molecules capable of triggering autophagy. Three in particular were able to induce autophagy in mammalian cells. They also enhanced the effect of rapamycin. "These compounds appear to be promising candidates for drug development," he said.