What is Huntington´s Disease?
Huntington´s Disease (HD) is a hereditary, neurodegenerative illness that affects people of all races worldwide. The disease was named after Dr. George Huntington, a physician from Long Island that first published a description of “hereditary chorea” in 1872 in the article On Chorea and his due to his description, the disorder became known as Huntington´s Chorea. The term chorea is the Greek word for “dance”. Chorea refers to the involuntary movements, which is a common symptom of HD. Since Chorea is not the only symptom, the disorder has in later years been called Huntington´s Disease.
For a long time, little was known or published about HD but in the last 20 years, we have learnt a lot about the causes, effects, treatment, therapies and techniques for managing the symptoms of HD. After a ten-year research, scientists discovered the gene that causes HD, and important advances followed after the discovery of the gene. To date, there are no drugs to slow or stop the progression of Huntington disease; however, there are specific drugs available to reduce some of the symptoms.
HD is a brain disorder that has physical, cognitive and emotional symptoms. These symptoms are caused by the death/loss of brain cells in certain parts of the brain, specifically the basal ganglia and the cerebral cortex. The death/loss of this brain cells gradually starts affecting the cognitive ability (thinking, judgement and memory), physical ability (involuntary movements) and emotion control. These symptoms appear gradually, and the typical age of onset is between the ages of 35 to 55. It is important to note that HD can appear in youth (Juvenile HD) or older adults (late onset HD).
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-language pathologists (speech therapists) and nutritionists, can all play a useful role in maximizing abilities and prolonging independence.
Who gets HD?
Huntington´s disease is a hereditary genetic disorder meaning that each child of a parent that has been diagnosed with HD has a 50% chance of inheriting the disease and are said to be at-risk. Males and females have the same risk of inheriting the disease and HD occurs in all races. Carriers of the HD gene will eventually develop Huntington´s Disease unless they die of some other cause before the onset of symptoms.
HD occurs in approximately 1 in 10 000 people in most “western” countries. In other countries the prevalence may be much lower, although not much data about HD is available in African countries for example.
HD symptoms usually manifest cognitively, physically or emotionally. The symptoms vary widely from person to person, even within the same family. Which symptoms appear first vary greatly among patients. During the course of the disease, some symptoms appear to be more dominant or affect capability. For some, involuntary movements may be more dominant, even in the early stages of the disease, while for others these movements may be less evident and emotional/behavioural symptoms more evident. Below are the most common symptoms of HD.
Slight intellectual changes are often the first signs of cognitive disturbance. These can lead to the reduced ability of coping with new situations or perform routine tasks. Below are the most common cognitive HD symptoms;
- Difficulty organizing, prioritizing or focusing on tasks
- Lack of flexibility or the tendency to get stuck on a thought, behavior or action (perseveration)
- Lack of impulse control that can result in outbursts, acting without thinking and sexual promiscuity
- Lack of awareness of one’s own behaviours’ and abilities
- Slowness in processing thoughts or ”finding” words
- Difficulty in learning new information
Physical symptoms of HD can include involuntary movements (chorea) and the impairment of voluntary movements. The involuntary movements typically progress through the middle stages of HD but decline as rigidity increases in the later stages. Listed below are some of the symptoms;
- Involuntary jerking or writhing movements (chorea)
- Muscle problems, such as rigidity or muscle contracture (dystonia)
- Slow or abnormal eye movements
- Impaired gait, posture and balance
- Difficulty with the physical production of speech or swallowing
According to the Mayo Clinic, Impairments in voluntary movements — rather than the involuntary movements — may have a greater impact on a person’s ability to work, perform daily activities, communicate and remain independent. In addition to the above symptoms, weight loss is common in people with Huntington’s disease, especially as the disease progresses.
The most common emotional/psychiatric disorder associated with HD is depression. Some people can experience depression for months or even years before it is recognised as an early symptom of HD. Listed below are some of the other emotional symptoms;
- Feelings of irritability, sadness or apathy
- Social withdrawal
- Fatigue and loss of energy
- Frequent thoughts of death, dying or suicide
The Progression of HD
According to Dr. Ira Shoulson, the progress of HD can be divided into five stages that are flexible after diagnosis;
- Early Stage – the person is diagnosed as having HD and can function fully both at home and work.
- Early Intermediate Stage – the person remains employable but at a lower capacity. They are still able to manage their daily affairs despite some difficulties.
- Late Intermediate Stage – the person can no longer work and/or manage household responsibilities. They need considerable help or supervision to handle daily financial affairs. Other daily activities may be slightly difficult but usually only require minor help.
- Early Advanced Stage – the person is no longer independent in daily activities but is still able to live at home supported by their family or professionals.
- Advanced Stage – the person with HD requires complete support in daily activities and professional nursing care is usually needed.
People with HD usually die about 15 to 20 years after their symptoms first appear. The cause of death is not the disease itself but complications such as pneumonia, heart failure or infection developing from the body’s weakened condition.
HD & The Family
Due to HD´s impact on relatives/friends, HD is also a family disease. As the disease progresses, the family role of the patient gradually changes. The partner/spouse often assumes more and more tasks including housekeeping, decision-making and parenting duties because of the partners inability to fulfil their previous roles. The partner/spouse usually assume the role as primary care giver as well.
Children and adolescents must face living with a mother or father who is ill and whose behaviour may be erratic. They may even be asked to participate in the parent’s care. For parents, telling children about HD can pose difficult questions. Should a child/children be told about HD? If so, at what age. When is a child old enough to cope with the idea of being at risk for HD?
There are no easy answers, particularly since children mature differently and each family situation is different. Generally, it is a good idea to be as open as possible without being alarmist, and to convey the facts bit by bit. This way, a child can develop a gradual awareness of HD rather than being suddenly overwhelmed by information.
For more information on how to break the news to children/adolescents´, please visit the Huntington Disease Youth Organization (HDYO), an organisation dedicated to helping young people and their parents to learn to live and cope with HD.
Juvenile Huntington´s Disease (JHD)
JHD is a less common, early-onset form of Huntington´s Disease that begins in childhood or adolescence. JHD is defined by the onset of symptoms before age 20 years and accounts for 5-10% of all HD cases. This can make dealing with the disease an isolating experience, and meeting with people in the same situation can help.
Most often, children with JHD inherit the HD gene from their fathers, although on occasion they can inherit it from their mothers. JHD has a rapid progression once symptoms begin to appear. Unfortunately, there is currently no cure for JHD, and treatment options are focused on support and on increasing the quality of life.
People with JHD often experience symptoms that are quite different from HD. It is less likely to have chorea (involuntary movements) that are typical with HD and more likely too experience muscle contractions and stiffness, meaning that it is slower and more difficult to make voluntary movements. Some may also experience changes in their mood such as feeling more frustrated or angry and finding it difficult to manage one’s behaviour. This can be the first symptoms of the disease, as well as a sudden drop in performance at school. It is important to note that these symptoms may relate to other causes, therefore making it very important to contact your regular physician.
Treatment Options For HD
Unfortunately, current treatment options can not alter the course of HD, but there are medicines available that are effective in treating some of the symptoms of emotional and physical symptoms of HD. It is important to note that drugs to treat some symptoms may result in side effects that worsen other symptoms of HD, thusly making it necessary to evolve and manage medication over the course of the disease. In some cases, people with HD do better when medication is kept to a minimum, but it is important to consult with a neurologist that is familiar with HD and have continuous communication with a regular physician.
There are also interventions that can help to adapt to the changes in his/her abilities for a certain amount of time. Some of the interventions include
- Psychotherapy ; a psychiatrist, psychologist or social worker can provide therapy in order to help manage the emotional symptoms of HD by developing coping strategies.
- Speech therapy ; HD can impair control of the muscles of mouth and throat that are essential for speech, eating and swallowing. Speech therapy can help in improving the ability to speak clearly and in addressing difficulties with the above-mentioned muscles.
- Physical therapy ; can help in enhancing strength, flexibility, balance and coordination in order to maintain mobility as long as possible.
- Occupational therapy ; can help in assisting HD patients and caregivers on the use of assistive devices that improve the functional ability.
Nutrition is important in everyone’s life, but takes on added significance in HD. People with HD require an unusually high number of calories to maintain their body weight.
Maintaining, or even gaining, weight can help reduce involuntary movements and other symptoms, particularly in the later stages of HD. Nutritional supplements can help and a nutritionist can offer other valuable suggestions. Please email firstname.lastname@example.org for a copy of “Huntington Disease Principles and practice of nutritional management By Jiří Klempíř and Alžbeta Mühlbäck”.
Often the best advice and emotional support one gets is from someone who “has been there”. The mutual support given, and the knowledge shared are the reasons that many find HD support groups to be an important part of their lives. Support groups are located in many countries.
Predictive Genetic Test
Since Huntington´s is a genetic Disease a DNA test can be carried out which will usually tell you whether or not you have the faulty gene that causes it. In a few cases, the test result is not clear making it difficult to give a definite answer. Below are somethings to think about if you are considering getting tested;
- It is important to know that only you can make the decision to get tested and usually one has to be over 18 years old before the test is performed. Parents, partners, friends or other family members may pressure/encourage you to get the test, but it is ultimately your decision alone.
- If you decide to get decide to take the test, in addition to the emotional impact on you and your family, you also need to consider the effect a positive result will have on other aspects of your life such as life insurance and future job opportunities since in some profession, a positive result may be an obstacle ( for example, joining the armed forces).
- When you first learn that you may be at risk, it is important not to rush into making a decision about getting tested, because once you have been given the result, you cannot change your mind.
- It is important to remember that you can withdraw from the testing process at any time.
- Going to a genetics clinic does not mean that you are obliged to take the test but it does give you the chance to talk over all the implications and any other concerns you may have. Each clinic follows an agreed counselling ‘protocol’; usually at least three sessions where you can talk over the implications of testing and any questions you may have, before you decide.
The testing procedure involves sessions with various professionals. It typically includes one session devoted to each of the following: genetic counselling, 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 his/her genetic status and is prepared to receive the results. The neurologic exam will determine if any early symptoms of HD are present. If the person is found to be symptomatic, he/she will be offered the option of discontinuing the testing procedure.
It is important to note that pre-symptomatic testing for HD cannot determine when the disease will begin or its course or severity. People who test positive for the gene may remain healthy for many years. HD can only be diagnosed by a neurological exam.