Huntington's disease

What is Huntington's disease?

Huntington's disease(HD) was first described in 1872 by an American doctor called George Huntington in 1872. It results from genetically programmed degeneration of brain cells, called neurons, in certain areas of the brain. This degeneration causes uncontrolled movements, loss of intellectual faculties, and emotional disturbance.

What is the cause of HD?

HD is a genetic disease, passed from parent to child through a mutation in the normal gene. Each child of an HD parent has a 50-50 chance of inheriting the HD gene. If a child does not inherit the HD gene, he or she will not develop the disease and cannot pass it to subsequent generations. A person who inherits the HD gene will sooner or later develop the disease. Whether one child inherits the gene has no bearing on whether others will or will not inherit the gene.

What are the symptoms?

The disease develops slowly and is sometimes difficult to recognise. Symptoms usually affect movement, personality, and mental function. Symptoms related to movement may include:

• clumsiness
  
• repeated, irregular movement of eyebrows and forehead
  
• facial grimaces
  
• rigid muscles
  
• loss of balance
  
• trouble walking
  
• uncontrolled jerking movements of arms, legs and trunk
  
• halting speech

Symptoms related to personality and mental function may include:

• having hallucinations (seeing or hearing things that aren't really there)
  
• having delusions (false beliefs or ideas)
  
• being suspicious without cause
  
• neglecting personal appearance (e.g.,failing to change clothes) and hygiene (failing to bathe or brush teeth)
  
• neglecting duties (such as not paying bills or going to work)
  
• being depressed
  
• being irritable
  
• behaving irresponsibly, impulsively, or violently (such as driving recklessly, getting drunk, or starting fights)
  
• losing the ability to remember, think logically, or exercise judgement
  
• becoming unaware of person, place, and time (you don't know who or where you are or what time, date, or day it is).

None of the symptoms are unique to HD, but jerky movements (chorea) along with dementia is suggestive of the disease. As time goes by the symptoms become worse. If symptoms begin when the person is younger, the disease may progress more rapidly.

How is it diagnosed?

A genetic test, coupled with a complete medical history and neurological and laboratory tests, help physicians diagnose HD. Presymptomic testing is available for individuals who are at risk of carrying the HD gene. In 1 at 3 percent of individuals with HD, no family history of HD can be found.

What is the treatment?

Physicians may prescribe medications to help control emotional and movement problems associated with HD. Most drugs used to treat the symptoms of HD have side effects such as fatigue, restlessness, or hyperexcitability. It is extremely important for people with HD to maintain physical fitness as much as possible, as individuals who exercise and keep active tend to do better than those who do not.

What is the future outlook?

At this time, there is no way to stop or reverse the course of HD. Now that the HD gene has been located, investigators are continuing to study the HD gene to understand how it causes disease in the human body.
What are the complications?

• loss of ability to care for self
  
• loss of ability to interact
  
• injuries to self or others
  
• increased risk of infections
  
• depression