Why Huntington`s disease symptoms take so long to appear
Washington: A new Canadian study has discovered a protective pathway in the brain that could help explain why Huntington`s disease (HS) symptoms take so long to appear.
HD is hereditary condition that causes severe physical and mental deterioration, psychiatric problems and eventually, death.
The symptoms of Huntington`s disease are caused by cell death in specific regions of the brain. Patients who have HD are born with a mutated version of the protein Huntington (Htt), which is believed to cause these toxic effects. While researchers know HD results from this single, mutated protein, no one is sure what it does, why it does not cause symptoms until later in life, or why it kills a specific set of brain cells, even though Htt is found in every single cell in the human body.
Stephen Ferguson and Fabiola Ribeiro of Robarts Research Institute at The University of Western Ontario used a genetically-modified mouse model of HD to look at the effects of mutated Htt on the brain.
Ferguson, director of the Molecular Brain Research Group at Robarts, said: "We found there was some kind of compensation going on early in the life of these mice that was helping to protect them from the development of the disease.
"As they age, they lose this compensation and the associated protective effects, which could explain the late onset of the disease."
Ferguson added that metabotropic glutamate receptors (mGluRs), which are responsible for communication between brain cells, play an important role in these protective effects. By interacting with the mutant Htt protein, mGluRs change the way the brain signals in the early stages of HD in an attempt to offset the disease, and save the brain from cell death. As a result, mGluRs could offer a drug target for HD treatment.
Since HD is a dominant genetic disease, every child with an affected parent has a 50 per cent chance of inheriting the fatal condition.
The study has appeared in The Journal of Neuroscience.
First Published: Wednesday, February 24, 2010, 00:00
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