What is Huntington’s disease (HD)?
Huntington’s disease (HD) is a devastating, genetically caused brain disorder that causes brain cells to die and systematically robs people of their ability to walk, talk, eat, and think. Eventually, the person with HD becomes totally dependent upon others for his or her care.
Huntington's disease profoundly affects the lives of entire families – emotionally, socially and economically. HD affects both sexes and all ethnic groups and typically strikes begins in the prime of life, between the ages of 30 and 50, although onset may occur as early as the age of 2. Children of a parent with HD have a 50-50 chance of inheriting the condition. HD does not skip generations.
Children who develop HD rarely live to adulthood. People with the disease-causing genetic defect do not have a mere tendency or possibility to develop HD. HD has full penetrance, meaning that they will definitely become ill.The final result for everybody with HD is death. There is no effective treatment or cure.
Named for Dr. George Huntington, who first described this hereditary disorder in 1872, HD is now recognized as one of the more common genetic disorders. More than a quarter of a million Americans have HD or are "at risk" of inheriting the disease from an affected parent. HD affects as many people as hemophilia, cystic fibrosis or muscular dystrophy.
Early symptoms of Huntington's Disease may affect cognitive ability or mobility and include depression, mood swings, forgetfulness, clumsiness, involuntary twitching and lack of coordination. As the disease progresses, concentration and short-term memory diminish and involuntary movements of the head, trunk and limbs increase. Walking, speaking and swallowing abilities deteriorate. Eventually the person is unable to care for him or herself. Death follows from complications such as choking, infection or heart failure.
In 1993, the HD gene was isolated and a direct genetic test developed that can accurately determine whether a person carries the HD gene. The test cannot predict when symptoms will begin. However, in the absence of a cure, most at-risk elect not to take the test.
Since the discovery of the gene, scientific research has accelerated and much has been added to our understanding of HD and its effects upon different individuals. By continuing to increase investment in both clinical and basic HD research each year, breakthroughs in treatment – and a cure – can be forthcoming.
Symptoms usually evolve slowly and vary from person to person, even within the same family. Some individuals may be affected first cognitively: depression, anxiety, irritability, aggressive outbursts, mood swings, forgetfulness, impaired judgment, social withdrawal, and problems with short-term memory, organization, coping, and concentration.
Others suffer first with motor skill impairment: involuntary movements known as chorea and dystonia, unsteady gait, fidgety behavior, lack of coordination, and difficulties with speech, swallowing, balance, and walking. Eventually, every person afflicted by HD requires full-time care.
Most patients are affected both in their motor and cognitive skills. The average lifespan after onset of HD is 10-20 years. The younger the age of onset, the more rapid the progression of the disease. Most people with HD do not die as a direct result of HD but rather from medical problems that arise (infections, choking and pneumonia) from the effects of HD on the body.
Those affected by HD often face discrimination both on the job and from their health insurance carrier. Individuals who suffer from the movement disorder associated with HD are often accused of being intoxicated because of slurred speech or an uneven gait. For those in which the first stage of the disease may show itself either mentally or emotionally, these "hidden" disabilities can be difficult for people to understand. Those with HD are often blamed for behaviors they cannot control.
This is a process where blood is taken and analyzed to determine if the gene for HD is present. The result of this genetic testing enables those who are at risk to learn whether they carry the gene or not. Anyone considering genetic testing for HD is advised to work with a genetic testing center that follows testing guidelines that include both pre-and post- test counseling. Only those over the age of 18 may be testing for HD unless they are exhibiting symptoms of the disorder.
Frequently Asked Questions about HD