Huntington’s Disease Discovery in Mice is Breakthrough
Scientists have made a new discovery concerning Huntington’s disease, one that is “hugely exciting” according to one of the researchers, Asa Petersen, associate professor of neuroscience at Lund University. For the first time, scientists have prevented very early symptoms of Huntington’s in mice, a breakthrough that could lead to better ways to treat and manage the disease.
Why we need a cure for Huntington’s disease
Huntington’s disease is an inherited condition in which the cells in the part of the brain (basal ganglia) that controls cognitive skills, movement, and emotion are destroyed. The blame for this destruction falls on a mutated gene on chromosome 4.
When the gene is normal, it has a coding area with the DNA sequence “CAG” repeated from 10 to 26 times. In people who have Huntington’s disease, however, the CAG sequence is repeated about 40 or more times, which disrupts the function of the gene’s protein product, called huntingtin.
For reasons unknown, the brain cells of people with Huntington’s accumulate bunches of protein that kill brain cells. If either parent has a mutated Huntington’s gene, there’s a 50 percent chance their children will have the disease.
More than 15,000 Americans have Huntington’s disease, and at least ten times that number have a 50 percent risk of developing the disease. No cure has yet been found, and currently available treatments can provide only some relief of symptoms.
The Huntington’s disease discovery
Lund University researchers found that when they deactivated the mutated huntingtin protein in the brains of mice, they were able to prevent very early symptoms of the disease, which are depression and anxiety. As the disease progresses, symptoms can include problems with memory and other cognitive functions, uncontrolled movements in the fingers, face, feet, or trunk (chorea), slurred speech, and difficulty with walking and swallowing.
Petersen explained the importance of the discovery, especially the finding that depression and anxiety occur very early in the disease and come from the hypothalamus region of the brain. Scientists can now identify which specific nerve cells in the hypothalamus are involved, and “this gives us better opportunities to develop more accurate treatments that can attack the mutated huntingtin where it does the most damage.”
More about Huntington’s disease
Huntington’s disease can occur at any age, but it usually first appears between ages 35 and 44. When symptoms do first appear before age 20, they typically progress more rapidly than they do in older individuals.
The first and so far only drug approved by the Food and Drug Administration for chorea associated with Huntington’s is tetrabenazine (Xenazine; August 2008). The drug does not address any other symptoms of the disease.
Other treatments for Huntington’s disease include antipsychotics drugs such as haloperidol and clonazepam, but these medications have serious side effects including rigidity, sedation, and stiffness. Drugs such as fluoxetine, nortriptyline, and sertraline are often prescribed for depression, while tranquilizers may help with anxiety.
After onset of the disease, the average lifespan of patients is 10 to 20 years, but this period is generally shorter if the disease begins at an early age. Given all that is known about Huntington’s disease thus far, the latest discovery is most welcome and will hopefully lead to effective treatments for this devastating disease.
Huntington’s Disease Society of America