HD is associated with a genetic mutation that results in an expanded polyglutamine chain in the huntingtin protein. In HD, huntingtin becomes a misfolded protein, which can cause many problems for the nerve cell. Scientists have not yet found a straightforward way to explain how a single genetic mutation can lead to all the complex HD symptoms. In fact, it is thought that misfolded huntingtin damages the nerve cell in many different ways.
One proposed mechanism suggests that misfolded huntingtin damages an organelle in the nerve cell called the mitochondrion. Mitochondria are important because they help the cell produce energy and they also regulate the number of free radicals in the cell. When the mitochondria are not working correctly in HD, oxidative damage occurs in the cell because there are too many free radicals. This is thought to contribute to nerve cell death in HD. Therapies that reduce the amount of free radicals in the nerve cell might prevent some HD symptoms.
One potential treatment involves a molecule called coenzyme-Q10, which is naturally produced throughout the body. It plays a role in the electron transport chain and helps produce ATP, the cell’s major source of energy. For more on coenzyme-Q10 and the electron transport chain, click here. Coenzyme- Q10 also reduces oxidative damage by interacting directly with free radicals, inactivating them so they cannot damage the cell. In an HD patient, the level of coenzyme-Q10 in the brain is significantly lower than a person without HD. The nerve cell can no longer handle all of the free radicals, so it becomes damaged. Drug supplements might be used to raise the level of coenzyme-Q10 in the brain and prevent the damage caused by free radicals.
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Last Modified: 05/22/2009
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