What is Huntington's disease?
Huntington's disease (HD) is a genetic disease (inherited from a parent) that affects the brain and causes unsteady and uncontrollable movements in the hands, feet, and face. These abnormal movements eventually affect such activities as walking, talking, and swallowing. Psychiatric and behavioral problems are also very common and may often be harder to manage than the involuntary movements themselves.
Who is at risk for Huntington's disease?
A person is at risk for HD if he or she inherits the abnormal HD gene from a parent. A child whose parent has the HD mutation has a 50% chance of inheriting the gene; anyone who inherits the gene will eventually develop HD symptoms, although the exact age is variable. In some cases, the onset of HD may be earlier than it was in the prior generation.
HD can affect people at any age. The term "juvenile" HD refers to development of the disease in a child. People who get HD as a child tend to have a more progressive illness, seizures, and more stiffness (less involuntary movements).
What is the cause of Huntington's disease?
Huntington's disease is caused by the destruction of nerve cells (neurons) located in the basal ganglia (an area deep inside the brain that is responsible for controlling body movement). The cortex (surface of the brain) may also be affected; this underlies intellectual functions such as thinking, decision-making, and memory.
What are the symptoms of Huntington's disease?
Huntington's disease affects a person both physically and mentally. One of the first physical symptoms are unintended muscle movements, called “chorea,” that appear abrupt and random. Chorea is derived from the Greek word for dance and is best described as slow, dance-like movements that may affect the limbs, torso, and face. The average age of onset is 40.
Physical problems may start out in small ways—for example, clumsiness, or losing balance—and then get worse over time. Chorea can make speaking, eating, and walking more difficult, and may also affect the person's ability to perform daily functions, such as driving. Subsequently, patients with HD are also at risk for falls. HD patients may sometimes develop “bradykinesia” or “akinesia,” where their movements and speech are slower and less animated, typically later in the disease.
The early behavioral signs of HD include increased irritability, mood swings, obsessional thinking, depression, and/or anger. Over time, patients with HD may develop problems with memory, multi-tasking, and attention. Sometimes, these mental changes precede physical signs for years.
HD is a progressive disease; this means that it gets worse over time, and coordination of everyday activities become harder and harder. Depending on the person's age, he or she may suffer with HD for up to 30 years. HD is not fatal, but people who have it most commonly die from infection, accidents, choking, or malnutrition.