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 physician who published a description of what he called "hereditary chorea" in 1872. From the Greek word for "dance" is chorein. Chorea refers to the involuntary movements which are among the common symptoms of HD so therefore Huntington's Disease was at first called Huntington's Chorea. But, involuntary movements is only one symptom of three which is characteristic for this disease. It was in later years called Huntington's Disease.
Little was known or published about HD, until recently. In the last twenty years, much has been learned, the causes and effects of HD and treatment, therapies and techniques for managing the symptoms of the disease. In 1993, after a ten-year search, scientists have found the gene that causes HD, and important advances have developed from this very important discovery. Many scientists are actively envolved in the search for effective treatments to stop or reverse the effects of HD, and eventually to cure it altogether.
HD is a degenerative disease this is caused by the loss of cells in a part of the brain called the basal ganglia. This damage affects cognitive ability ofthe cells (thinking, judgment, memory), movement, and emotional control. Symptoms appear gradually, usually between the ages of 30 and 50. However, the disease can strike young children in the juvenile form as well as the elderly.
In most cases, people can maintain their independence for several years after the first symptoms of HD appear. A knowledgeable physician can prescribe treatment to minimize the impact of the symptoms. Allied health professionals, such as social workers, occupational and physical therapist, speech therapists and nutritionists, can all be helpful in maximizing the persons abilities and prolonging independence.
If you do not inherit the mutated gene you will not develop the disease, nor will their children; HD does not "skip a generation". Genetic testing is the only way to determine whether or not a person carries this gene for HD.
Symptoms of HD include: Depression, irritability, anxiety and apathy are often encountered. Some people can experience depression for a period of months or even years before it is recognised to be an early symptom of Huntington's. Behavioural changes may include aggressive outbursts, impulsiveness, mood swings and social withdrawal. Sexual needs are often not present or extremely big. Control of ones temper is difficult and the patient shows often a demanding behaviour. Often, existing personality traits will be overly exaggerated by HD, e.g. a person who had a tendency to be irritable will become more irritable. Schizophrenia and other serious psychiatric problems are not common but do occur.
Slight intellectual changes are often the first signs of cognitive disturbance. These may involve the inability to organise routine matters or to have a hard time coping with new situations. Short-term memory loss may occur while long-term memory stays intact. Work tasks become more difficult.
Physical symptoms may initially consist of "nervous" activity, fidgeting, twitching, or extreme restlessness. Handwriting may change and facial grimaces may appear. Day-to-day skills involving coordination and concentration, become more difficult.
These initial symptoms will gradually develop into involuntary movements of the head, torso and limbs, this will often lead to problems with walking and balance.
Speech and swallowing may become difficult. Movements will generally tend to increase during voluntary effort, stress or excitement can decrease.
Early in the disease, include slight changes in coordination, some involuntary movements, diffcult thinking through problems, and often, a depressed or irritable mood. At this stage, medications are often effective in treating depression and other emotional symptoms. When receiving news that HD is present, this is a good time to begin planning for your future. Financial plans should be made and legal documants drawn up.
In the middle stage, involuntary movements, this is where the word 'chorea' stems from, may become more pronounced. Staggering can sometimes be mistaken for drunkenness. Speech and swallowing will begin to be affected. Consult a speech therapist who will be able to offer suggestions and strategies for improving communication and swallowing abilities. Occupational and physical therapists can develop programs to help maintain the highest level of functioning and improve quality of life.
Thinking and reasoning skills will also diminish. At this stage it may become increasingly difficult to hold a job and to carry out household responsibilities. Here again, simple strategies may be employed to help decrease frustration, increase funtioning and prolong independence. Disorientation and short-term memory loss can be taken care of by labeling drawers, sticking to a daily routine and keeping a calendar for appointments and upcoming events.
People in the late stage HD may have severe 'chorea', but more often have become stiff. Choking on food is a major concern and weight loss. The late stage people are totally dependent on others for all of their care, they can no longer walk, and are no longer able to speak.
Although these abilities have been severely impaired the person with HD, it is also important to remember that the person is generally still aware of their environment, remains able to understand language, and is totally aware of loved ones and others. They may continue to enjoy your company, being part of your life, have a book read for them, this disease effects mostly motor function, not their awareness.
People do not die from Huntington's Disease, but from a complication of the disease, such as choking or infection. Death generally occurs about 15 to 20 years after onset.
Diagnosis of HD can only be done by a comprehensive examination which includs a series of neurological and psychological exams along with a detailed family history. MRI (Magnetic Resonance Imaging) or CT (Computerized Tomography) scans may be included in the exam but the results from these procedures are not enough to form a diagnosis.
A genetic test may be used to help confirm, or rule out, a diagnosis of HD. However, a positive test result that indicates the presence of the HD gene is not sufficient to confirm a diagnosis of HD.
It is best to see a neurologist familiar with HD, as the symptoms can mimic other disorders including Parkinson's Disease or alcoholism. A referral to knowledgeable help care workers can be provided by your local or national HD organisation.
The diagnosis of HD can be a relief or upsetting. It may explain for why their memory is not quite as sharp as it once was or why they are irritable or depressed.
Denial is also a possibility when first diagnosed with HD. Regardless of their initial reaction, it helps to discuss the situation with others, either in a support group, or with a social worker or with a counselor.
~ History of Huntington's Disease ~ The HD gene was found in 1993. A test was developed which enabled people to find out if they were carrying the mutated gene. Earlier tests were based on 'linkage analysis' which required blood samples from several family members. The new direct gene test is much more accurate and requires blood only from the individual taking the test.
By analyzing a person's DNA and counting the number of CAG's, it is possible to tell if that person will develop HD. The test cannot predict the age, but the juvenile form has normally more than 50 repeats up to more than 120.
The decision to have genetic testing is an intensely personal. Testing should never be forced upon any individual. There is a minimum age requirement usually 18 years.
Testing should only be done at testing centers where the health care workers are knowledgeable about HD.
The testing procedure involves the following: genetic counseling, a neurologic exam, a psychological interview, discussion of the results and follow-up. The genetic test itself is a blood test.
The purpose of the preliminary sessions is to ensure that the person understands the potential implications of their genetic status and is mentally prepared for the final the results. The neurologic exam determines if any early symptoms of HD are present. If the person is found to be symptomatic, they will be offered the option of stopping the testing procedure.
The presymptomatic testing for HD cannot tell when the disease will begin, the course or severity. HD can only be diagnosed by a neurological exam. People testing positive may remain healthy for many years.
Current treatments do not alter the course of HD, medications are used in treating common symptoms such as depression and anxiety. Involuntary movements can also be decreased by medication and some drugs have significant side effects, so it is important that all of these be explained by the physician before treatment begins. Some doctors may prescribe drug treatment when it is not absolutely necessary. In many cases, people with HD do better when medication is kept to a minimum. Drugs that are effective at one stage of the disease may not always be effective at the next.
It is preferred to locate a neurologist expert in HD. Not all neurologists are familiar with HD. Although a family physician is does not have much experience with HD, they should remain involved in your care and treatment. The person with HD and their family members play an important role in monitoring and can assess how effective any care and treatment has been.
Nutrition is important in everyone's life, but people with HD require an unusually high number of calories to maintain their body weight.
Maintaining, or gaining weight helps reduce involuntary movements and other symptoms, particularly in the later stages of HD. Nutritional supplements do help and a nutritionist can offer other valuable suggestions.
~Research~
There have been several breakthroughs in recent years, discovery of the HD gene in 1993. Certain brain proteins have been discovered which appear to interact with "huntington", the protein expressed by the HD gene. Research is also being done to determine how these substances combine to cause HD, and to find ways of stopping this interaction as a means of treatment. Huntington Study Group (HSG), was formed to conduct basic and clinical research with teams of doctors with expertise in treating HD. The group has begun to test new drugs which could lead to an effective treatment for HD.