A simple dye has suggested a way to stop an abnormal process in the brain which leads to a devastating disease.

Huntington's chorea is a genetic condition in which cells incorrectly construct a particular protein, Huntingtin.

Over time, the abnormal proteins clump together and appear to poison cells in certain regions of the brain, particularly those connected with muscle control.

Scientists have shown in the laboratory that the dye molecule can impede this aggregation process and may therefore open up a novel avenue to tackle the disease.

Sticking point

The most noticeable symptom of Huntington's is uncontrollable twitching, worsening over time.

People who inherit the faulty gene responsible are fated to develop the disease - normally between 30 and 50 years of age.

However, scientists at Harvard Medical School in Boston, US, may have found a promising way to tackle the protein lumps.

For years, sections of brain from Huntington's patients taken for scientific examination have been stained with a dye called Congo red.

This is very good at picking out areas of protein aggregation so researchers can measure their extent.

Need for refinement

However, experiments on brain cells in culture found that the dye not only stuck to the protein clumps, it seemed to slow down their formation.

Brain cells treated with the dye were less likely to die than those left untreated.

In addition, mice bred with the faulty gene showed less neuronal dysfunction when infused with the dye.

Even though Congo red is a specialist cell-marking dye which travels well through tissues, it will have to be altered before it can be considered as a treatment for Huntington's.

Bile attempt

Professor Junying Yuan, from Harvard, told BBC News Online: "Obviously we can't use Congo red in humans as a treatment, because the dye cannot get past the blood-brain barrier.

"Companies are now working to produce a smaller version which can do this."

She said that medicines made from the dye could have broader applications than just Huntington's. Congo red is also good at marking the protein clumps that characterise Alzheimer's disease, and the abnormal protein prions found in CJD.

This is not the first treatment under examination as a possible therapy for Huntington's.

A chemical extracted from bile has been found to have a neuroprotective effect in a number of illnesses.

Other scientists have been experimenting with transplants of foetal brain cells as a way to perhaps repair some of the damage caused in regions of the brain hardest hit by Huntington's.

The latest research is published in the journal Nature.