What is Huntington's disease?
Huntington's disease is an inherited disease of the brain that damages certain brain cells.
The disease damages some of the nerve cells in the brain, causing deterioration and gradual loss of function of these areas of the brain. This can affect movement, cognition (perception, awareness, thinking, judgement) and behaviour.
Early symptoms can include personality changes, mood swings and unusual behaviour, although these are often overlooked and attributed to something else.
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Huntington's disease was originally called Huntington's chorea, after the Greek word for dancing. This is because the associated involuntary movements of the condition can look like jerky dancing.
In the majority of cases, Huntington's disease is caused by an inherited faulty gene. However, in around 3% of cases there is no family history of the disease.
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Treating Huntington's disease
There is no cure for Huntington's disease and its progress cannot be reversed or slowed down.
As the condition progresses, it may put a strain on family and relationships. Treatments for Huntington's disease aim to help improve or maintain skills used in daily living that can deteriorate over time.
Medication can manage some of the symptoms, such as irritability or excessive movement. Therapies such as speech and language therapy and
Support is also available for families to help with decisions such as choosing a care home.
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Generally, the disease progresses and gets worse for around 10 to 20 years, until the person eventually dies. In the later stages of Huntington's disease, the person will be totally dependent and will need full nursing care.
Death is usually from a secondary cause, such as heart failure,
Who is affected?
Both men and women with a family history of Huntington's can inherit the disease. Symptoms usually start to appear during adulthood.
Juvenile (children's) Huntington's disease develops before the age of 20. Only 5-10% of people with Huntington's develop the condition at a very young age, and the pattern of features may be different.
It was previously thought that 4-6 people in a population of 100,000 were affected by Huntington's disease. However, UK research carried out in 2012 has found the actual figure for those affected by the condition to be about 12 people per 100,000.
It is thought the number of people who have the Huntington's gene and are not yet affected is twice that of those who have symptoms.
Symptoms of Huntington's disease
The symptoms of Huntington's disease can include psychiatric problems and difficulties with behaviour, feeding, communication and movement.
People can start to show the symptoms of Huntington's disease at almost any age, but most will develop problems between the ages of 35 and 55.
Generally, the disease progresses and gets worse for around 10 to 20 years until the person eventually dies. Symptoms vary between people and there is no typical pattern.
Early symptoms, such as personality changes, mood swings and unusual behaviour, are often overlooked at first and attributed to something else.
Some people with Huntington's may refuse to accept their illness or the seriousness of it.
Behavioural changes are often the first symptoms to appear in Huntington's disease and can be the most distressing. These symptoms often include:
- a lack of emotions and not recognising the needs of others in the family
- alternating periods of aggression, excitement, depression, apathy, antisocial behaviour and anger
- difficulty concentrating on more than one task, which causes irritability
- short-term memory lapses
- problems with orientation
A person with Huntington's may display a lack of drive, initiative and concentration that may make them appear lazy. This is not the case: it is just the way the disease affects their personality. Someone with Huntington's may also develop a lack of interest in hygiene and self-care.
Many people with Huntington's disease have
A few people may also develop problems such as obsessive behaviours and sometimes
Studies have shown that people with Huntington's disease are more likely to consider committing
Huntington's disease affects movement. Early symptoms include slight, uncontrollable movements of the face, and jerking, flicking or fidgety movements of the limbs and body. These move from one area of the body to another and can cause the person to lurch and stumble.
As the disease progresses, the uncontrollable movements are more frequent and extreme. This may change over time so that movements become slow and muscles more rigid.
People with Huntington's disease tend to lose weight despite having a good appetite. They can find eating tiring, frustrating and messy because the mouth and diaphragm muscles do not work properly, due to the loss of control.
Loss of co-ordination can lead to spilling or dropping food. Swallowing is a problem, so choking on food and drink, particularly thin drinks such as water, can be a common problem. You may be referred to a dietitian or a speech and language therapist if you find it difficult to swallow. In some cases, a feeding tube can be inserted. Read more about
Communication and cognition (perception, awareness, thinking and judgement) are affected by Huntington's disease.
People with Huntington's often have difficulty putting thoughts into words and they slur their speech. They can understand what is being said but may not be able to respond or communicate that they understand. Impaired breathing can make speech difficult.
People with Huntington's disease can have problems with sexual relationships. This is usually a loss of interest or, less commonly, making inappropriate sexual demands.
End of life
In the later stages of Huntington's disease, the person will be totally dependent and need full nursing care.
Death is usually from a secondary cause, such as heart failure,
Causes of Huntington's disease
Huntington's disease is caused by a faulty gene that runs in families.
Genes and chromosomes
Genes are the instructions for making all humans. They are made up of DNA and packaged onto strands called chromosomes.
We have two copies of all our genes, so our chromosomes are in pairs.
Humans have 46 chromosomes (23 pairs). The faulty gene that causes Huntington's disease is found on chromosome number four.
The normal copy of the gene produces a protein called huntingtin, but the faulty gene is larger than normal and produces a larger form of huntingtin.
Cells in parts of the brain – specifically, the basal ganglia and parts of the cortex – are very sensitive to the effects of the abnormal huntingtin. This makes them function poorly and eventually die.
The brain normally sends messages through the basal ganglia. When this part of the brain is damaged, it causes problems with control of movement, behaviour and thinking.
It is still unclear exactly how abnormal huntingtin affects the brain cells and why some are more sensitive than others.
Chances of inheriting the disease
A parent with the Huntington's gene has one good copy of the gene and one faulty copy of the gene. Their child will inherit one of these genes. Therefore, there is a 50:50 chance that the child will get the faulty gene. If they get the faulty gene, they will develop Huntington's disease.
There is a 50:50 chance that the child with Huntington's disease will pass the faulty gene on to their future child. This pattern of inheritance is called "autosomal dominant".
In as many as 3% of cases, there is no family history of the disease. This could be due to adoption or because relatives with the disease died early from other causes. It could also be a new genetic mutation (a new error in a gene). For example, there may be a fault in the genetic material of the father's sperm.
Diagnosing Huntington's disease
If you have symptoms of Huntington's disease, your doctor will refer you to a clinician with specialist expertise in the condition if they feel your symptoms need further investigation.
Many areas have Huntington's disease management clinics with a range of specialists.
The specialist will ask about your symptoms, such as whether you have had recent emotional problems, to see if it is likely you have Huntington's disease and to rule out similar conditions.
They may also test a number of physical functions, such as your reflexes, eye movements, balance, walking, general movements and strength. All of these can be affected by Huntington's disease.
Confirming the diagnosis
If you are showing symptoms of Huntington's disease and it is known to run in your family, or if your doctor strongly suspects you have the disease, genetic testing can confirm the diagnosis.
It is important to realise the diagnosis is based on the doctor recognising a combination of a number of factors – neurological examination, family history and genetic testing. It is possible to have the gene change and still be healthy.
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Taking a genetic test
The children of someone with Huntington's disease can take a genetic test after the age of 18 to see if they have inherited the disease. If they have inherited the faulty gene, they will develop Huntington's but it is not possible to work out at what age.
You can ask your doctor or neurologist to arrange an appointment for you at a regional genetic clinic. You will have some counselling, then two blood samples will be taken. Your DNA is extracted from the blood sample and analysed to see if you have inherited the faulty gene.
You may have to wait two to four weeks for the test results.
Having a brain scan
In the early stages of Huntington's disease there may be no specific changes on the brain scan. A doctor may use a brain scan at any stage of the illness if there are concerns that there may be other problems in addition to Huntington's disease.
A brain scan may involve a
Getting tested in pregnancy
If you are pregnant and already known to have the Huntington's disease gene, it is possible to have a direct test on the pregnancy at 11 weeks. This needs careful consideration and can be discussed with a genetic counselling team.
If one half of a couple is at risk of Huntington's disease but does not want to find out if they have the disease, and the couple would like to have children free of risk, more complex indirect genetic testing is needed. This needs to be discussed with the genetic clinic. One option is preimplantation genetic diagnosis.
Preimplantation genetic diagnosis
Preimplantation genetic diagnosis can be used when one partner is known to have the faulty gene. This is a direct test.
It involves having
The procedure is also an option for couples where one partner has a 50% risk and does not want to be tested. An embryo that is not at 50% risk will be placed inside the woman.
Preimplantation genetic diagnosis is not a straightforward procedure, and raises a number of issues that need to be considered in detail.
Should I get tested?
Not everyone wants to know if they have inherited the disease. It is a personal choice.
Some people say they would rather not know because they want to enjoy their life and they may die of other causes before the disease develops.
Most people have approximately 40 years of a normal healthy life before the disease develops.
Less than one in five people at risk of Huntington's disease choose to have the genetic test.
If you are considering genetic testing, it is strongly recommended you speak to a genetic counsellor first. Your doctor will be able to refer you.
Treatment for Huntington's disease
There is no cure for Huntington's disease. Its progress cannot be reversed or slowed down, although this is the goal of a number of research projects.
However, some symptoms can be managed with medication and therapies, which may be co-ordinated by specialist teams.
Therapies (such as speech and language therapy and
Regular exercise is also extremely important: people who keep active tend to feel much better physically and mentally than those who do not exercise. Co-ordination may be poor, but walking independently with the use of walking aids, if necessary, can make all the difference.
Medication for Huntington's disease
Medicines for Huntington's disease, which can be taken in liquid form, are described below.
Most of these drugs have side effects such as fatigue, restlessness and hyperexcitability. It may be hard to tell if these are symptoms of the disease or a result of the medication.
Antidepressants to treat depression
Antidepressants should be considered as they can improve mood swings and treat
- SSRI antidepressants, such as [fluoxetine] and [paroxetine]
- tricyclic antidepressants, such as [amitriptyline]
- other types of antidepressants, including mirtazapines, duloxetine and venlafaxine
Antidepressants may cause
Mood stabilisers to treat irritability or mood swings
Mood stabilisers, particularly carbamazepine, may be considered as a treatment for irritability.
The dose of carbamazepine needs to be slowly increased and any side effects monitored.
Carbamazepine cannot be used during pregnancy.
Medication to suppress involuntary movements
The medicines listed below suppress the involuntary movements – or chorea – seen in Huntington's disease.
- antipsychotic medication, such as risperidone, olanzapine and quetiapine
- tetrabenazine reduces the amount of the chemical dopamine reaching some of the nerve cells in the brain
- benzodiazepines, such as clonazepam and diazepam
Antipsychotic drugs may also help to control delusions (believing things that are untrue), hallucinations (seeing or hearing things that are unreal) and violent outbursts. But they may have severe side effects, such as:
- stiffness and rigidity
- tremor (shaking)
- slowness of movement
Because of these side effects, the lowest possible dose of antipsychotics will be prescribed.
Living with Huntington's disease
Help is available to assist people with Huntington's disease in their day-to-day living. This might include physiotherapy, occupational therapy or speech therapy.
Huntington's disease puts a great strain on relationships and is very stressful and upsetting for the family. It is distressing to see a family member's state of mind deteriorate so much that they may not be like their former self at all.
Daily routines such as getting dressed and eating meals can be frustrating and exhausting. The types of help listed below aim to ease the strain of the condition by improving skills that may deteriorate with Huntington's disease.
Help with communication
Speech and language therapy can improve communication skills, memory and teach alternative ways of communicating. It can also help with swallowing difficulties.
Communication aids can sometimes be helpful. These allow communication without the need for talking. For example, you can point to symbols on a chart to indicate your mood or whether you are hungry.
The family of the person with Huntington's disease will need to be patient and supportive. They can try alternative ways of communicating if speech is a problem.
Help with mealtimes
People with Huntington's disease need to have a high-calorie diet. A dietitian can help you work out an appropriate diet plan.
To help with eating and drinking, food should be easy to chew, swallow and digest. Food can be cut into small pieces or puréed to prevent choking. Feeding equipment is available, such as special straws and non-slip mats.
In the late stages of the disease, it may be necessary to use a tube that goes directly into the stomach for feeding. You may find it useful to read Swallowing Problems and Feeding Tubes in Huntington's Disease (PDF, 485kb).
If you do not want to be artificially fed in the later stages of the disease, you should make your wishes known to your family and doctor. You may want to consider making an advance decision (a living will) or a statement of wishes and preferences.
An occupational therapist (OT) can help you with day-to-day activities. Your home can be adapted by social services to make life easier for you, as you may be at risk of injuring yourself in a fall or accidentally starting a fire.
You may need to have your shower, bath, chairs and bed adapted. You may also need to think about wheelchair access.
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A physiotherapist can help you with mobility and balance by using a range of treatments, including manipulation, massage, exercise, electrotherapy and hydrotherapy. You may be referred to a physiotherapist through your doctor or through social services.
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Information on Huntington's disease
The Huntington's Disease Association (HDA) has a number of useful PDF factsheets that give advice on the following:
- communication skills – strategies you can use to make communication easier
- eating and swallowing difficulties
- seating, equipment and adaptations