EVANSTON, Ill., Dec. 21 (UPI) -- Scientists at Northwestern University have identified a link between Huntington's disease and dysfunction of the subthalamic nucleus, a component of the basal ganglia responsible for movement and impulse control.
The study findings may explain the causes of the debilitating symptoms and loss of brain tissue as the disease progresses.
Huntington's disease affects roughly 1 in 10,000 people and is a hereditary gene mutation that results in the progressive loss of nerve cells in the brain.
Even though patients are born with Huntington's disease, they typically don't experience symptoms until adulthood. These symptoms include loss of motor and cognitive function, depression and personality changes. The symptoms intensify and lead to death from complications associated with the disease.
"Although the genetic basis of the disease is well established, why the mutation leads to expression of symptoms and loss of brain tissue remains poorly understood," Mark Bevan, senior author and professor of physiology at Northwestern University Feinberg School of Medicine, said in a press release.
For the study, researchers used mice genetically engineered to carry the Huntington's disease gene. Scientists found that the electrical activity of the subthalamic nucleus was lost in the mice along with impaired subthalamic activity caused by anomalous receptor signaling, leading to defective energy metabolism and accumulation of damaging oxidants.
"While research into Huntington's disease has focused on other parts of the basal ganglia, the subthalamic nucleus has been largely overlooked," Bevan said. "This is surprising because patients with Huntington's disease have fewer nerve cells in the subthalamic nucleus. People who have suffered damage to the subthalamic nucleus exhibit excessive movement and impulsive behavior, similar to patients with Huntington's disease."
The study found abnormalities in the subthalamic nucleus occurred earlier than in other regions in the brain, and that subthalamic nucleus nerve cells progressively degenerated as the mice aged like they do in patients with Huntington's disease.
"Our findings suggest early problems in the subthalamic nucleus not only contribute to the symptoms of Huntington's disease, but are also likely to impair the processing capacity and health of other brain structures, more traditionally associated with the disease," Bevan said.
The study was published in the journal eLife.