Huntington's disease is a hereditary neurodegenerative disease that is caused by a mutation in the human huntingtin gene. It is characterized by uncontrollable dance-like movements (chorea) in the early stages of the disease and loss of voluntary movement (behavioral inflexibility) in the later stages.
Huntington's disease leads to massive cell death in the striatum, a part of the brain involved in voluntary motor movement, as well as to degenerative changes in the brain's cortex. Since many cells in the striatum use dopamine as a chemical signal for communication, changes in dopamine neurotransmission may hinder cell-to-cell communication in the brain, which leads to dysfunction and ultimately cell death.
In this article, researchers discuss the function of dopamine in the striatum as affected during Huntington's disease. Based on studies of human patients and genetically modified mice, they show that changes in dopamine function could contribute to some of the symptoms of Huntington's disease. Specifically, they propose that increases in dopamine levels may be involved in the initial onset of chorea whereas decreases in dopamine are part of the late-stage symptoms of this disease. According to the researchers, effective treatments for Huntington's disease should be tailored to these time-dependent changes in dopamine levels.