What is Huntington’s Disease?

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Huntington’s Disease (HD) is a hereditary brain disorder that affects people of all races all over the world. It takes its name from Dr. George Huntington, a Long Island, NY physician who described what he called “hereditary chorea” in 1872. Chorea, from the Greek word fro dance, refers to the involuntary movements which are a common symptom of HD. In the United States, HD occurs in about 1 in 10,000 people. Currently about 30,000 people in the U.S. have HD and up to 200,000 are at risk.

In 1993, after a ten year search, scientists identified the gene that causes the disease. Since that breakthrough discovery, research has gained in momentum and much is now understood about HD and how it affects nerve cells in the brain. While researchers are actively looking for a treatment that can delay the onset or slow the progression of HD, medications are available that may help with some symptoms.

What is Huntington’s Disease?

HD is a “neurodegenerative disease,” which means that it causes the progressive death of nerve cells in the brain. Symptoms typically appear in mid-life, between the ages of 30 and 50, and progress for 10-25 years. However, the disease can also strike young children, adolescents and the elderly.

HD is a complicated disease that affects the body, the mind and the emotions. There are symptoms of HD that are easy to see, like chorea/involuntary movements, and there are those that are less visible, such as forgetfulness, impulsiveness or depression. Symptoms of HD vary widely from person to person, even within the same family. In addition, symptoms change over time as the disease progresses.

Symptoms appear gradually and people with HD can maintain their independence for years. As you will learn, HD affects all aspects of a person’s life and treating it requires a broad-based approach. Prolonging independence may call for a team of health care professionals that may include a primary care physician, neurologist, social worker, speech language pathologist,  nutritionist, occupational therapist and physical therapist, among others.

 

Inheritance

HD is a disease of families. Though everyone is born with the HD gene, the disease is caused by an abnormal copy of the gene that is passed from parent to child. It is not contagious in any way. Only a person who is born with the abnormal gene can ever get the illness or pass it on to their children. Every person who carries the abnormal copy of the gene will eventually develop symptoms, if they live long enough.

Every child born to an affected parent has a 50% chance of being born with the gene that causes the disease. Males and females have the same chance of inheriting the abnormal gene. Those who have not inherited the gene will not get eh disease and they cannot pass it on to their children. HD does not “skip generations.

 

Juvenile Huntington’s Disease (JHD)

In approximately 10% of cases, HD affects children or adolescents. The symptoms of JHD are somewhat different than adult onset HD and may include stiff or awkward walking, increased clumsiness or changes in speech. The ability to learn new information may decline and the child may lose skills they previously  had. JHD typically progresses more rapidly than adult onset HD.

 

Clinical Diagnosis

Although the abnormal gene is present from birth, a clinical diagnosis of HD indicates that symptoms have started. A diagnosis of HD can only be accomplished by a comprehensive neurological evaluation that is best performed by a specialist in HD or in neurological movement disorders. A genetic test may be used to help confirm or rule out a diagnosis, however, a positive test result indicating the presence of the HD gene, is not enough, by itself, to confirm a diagnosis of clinical HD.

For some, a diagnosis of HD can be a relief, providing an explanation for the changes in movements, thinking and emotions. Others find the news very upsetting. A state of “denial” is not uncommon when a diagnosis of HD is first made. Whatever the reaction, it is helpful to talk about the situation with an HD support group, a social worker, genetic counselor or therapist.

 

Stages of Huntington’s Disease

Although symptoms of HD vary from person to person, even within the same family, the progression of the disease can be roughly divided into three stages.

Early stage HD usually includes subtle changes in coordination, perhaps some involuntary movements (chorea), difficulty thinking through problems and often a depressed or irritable mood. Medications are often effective in treating depression or other emotional problems. The effects of the disease may make the person less able to work at their customary level and less functional in their regular activities at home.

In the middle stage, the movement disorder may become more of a problem. Medication fro chorea may be considered to provide relief from involuntary movements. Occupational and physical therapists may be needed to help maintain control of voluntary movements and to deal with changes in thinking and reasoning abilities. Diminished speech and difficulty swallowing may require help from a speech language pathologist. Ordinary activities will become harder to do.

In the late stage, the person with HD is totally dependent on others for their care. Choking becomes a major concern. Chorea may be severe or it may cease. At this stage, the person with HD can no longer walk and will be unable to speak. However, he or she is generally still able to comprehend language and retain an awareness of family and friends. When a person with HD dies, it is typically from complications of the disease, such as choking or infection and not from the disease itself.

In all stages o HD, weight loss can be an important complication that can correspond with worsening symptoms and should be countered by adjusting the diet and maintaining appetite.

 

Contact us today for more information on Huntington’s Disease or to schedule an appointment.

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