Dysfunction in brain structure may cause Huntington's disease

Scientists have identified a link between Huntington's disease and dysfunction in a section of brain structures that are critical for movement and impulse control.

Huntington's disease is characterised by the progressive loss of nerve cells in the brain and affects approximately one in 10,000 people. This fatal disorder is caused by a hereditary defect in a single gene.

According to the study, led by researchers at the Northwestern University in Illinois, the disease is caused by a dysfunction in the subthalamic nucleus -- a component of the basal ganglia which is a group of brain structures critical for movement and impulse control.

The findings may explain the causes of the debilitating symptoms such as as loss of motor and cognitive function, depression and personality changes that typically manifest in adulthood, as well as loss of brain tissue as the disease progresses.

For the study, the researchers used genetically engineered mice to carry the Huntington's disease gene. They discovered that the electrical activity of the subthalamic nucleus was lost. 

Impaired subthalamic activity was caused by anomalous receptor signalling, leading to defective energy metabolism and accumulation of damaging oxidants. 

In addition, the abnormalities in the subthalamic nucleus was found to occur earlier than in other brain regions and that subthalamic nucleus nerve cells progressively degenerate as the mice age, mirroring the human pathology of 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," said Mark Bevan, professor at Northwestern University. 

A better understanding of aberrant brain receptor signaling that leads to nerve cell dysfunction could reveal a target for therapy, the researchers said.

The study was published in the journal elife.