Huntington's disease

Huntington's disease is an inherited condition that damages certain nerve cells in the brain.

This brain damage gets progressively worse over time and can affect movement, cognition (perception, awareness, thinking, judgement) and behaviour.

Early features can include personality changes, mood swings, fidgety movements, irritability and altered behaviour, although these are often overlooked and attributed to something else.

Read more about the features of Huntington's disease

Huntington's disease was originally called Huntington's chorea ("chorea" is the Greek word for dancing). This is because the involuntary movements associated with the condition can look like jerky dancing. However, "disease" is now the preferred term, because the condition involves a lot more than just abnormal movements.

Huntington's disease is caused by an inherited faulty gene. However, in around 3% of cases, there's no family history of the condition, normally because the parents died at a young age.

Read more about the cause of Huntington's disease

Diagnosing Huntington's disease

If you have symptoms of Huntington's disease, your GP will refer you to a specialist clinician (usually a neurologist) if they feel your symptoms need further investigation.

The specialist will ask about your symptoms to assess how likely it is that you have Huntington's disease and to rule out similar conditions.

They may also test a number of physical functions, such as your eye movements, balance, control, movement and walking. Your speech and cognition may also be tested. All of these can be affected by Huntington's disease.

Genetic testing can be used to confirm the diagnosis.

Read more about how Huntington's disease is diagnosed

Treating Huntington's disease

There's no cure for Huntington's disease and its progress can't 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 improve any mood disturbance; this is done to maintain skills used in daily living that can deteriorate over time.

Medication can help manage some of the symptoms, such as irritability or excessive movement. Therapies such as speech and language therapy and occupational therapy can help with communication and day-to-day living.

Support is also available for the family of a person with Huntington's disease. This includes, for example, testing family members who don't have any of the condition's features (manifest) to see whether they carry the gene, or help with choosing a suitable care home in advanced cases.

Read more about how Huntington's disease is treated and living with Huntington's disease

Huntington's disease usually progresses and gets worse over a 10-25 year period from when it first appears, before the person eventually dies from it. During the condition's later stages, the person will be totally dependent and need full nursing care.

Death is usually from a secondary cause, such as heart failure, pneumonia or another infection.

Who's affected by Huntington's disease?

Both men and women with a family history of Huntington's disease can inherit the condition. 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 disease develop it 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 found the actual figure for those affected by the condition to be about 12 people per 100,000.  

It's thought that the number of people who have the Huntington's gene and are not yet affected is about twice that of those who have symptoms.

Current research

Research is underway to find disease-modifying medication and new treatments for the features of Huntington's disease.

Exciting progress has been made in identifying potential ways of slowing down or halting the condition by "switching off" the faulty gene that causes Huntington's disease.

Find out more by visiting the European Huntington's Disease Network

Information about you

If you have Huntington's disease, your clinical team will pass information about you on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).

This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.

Find out more about the register

The clinical features of Huntington's disease can include psychiatric problems and difficulties with behaviour, feeding, communication and abnormal movements.

People can start to show the features of Huntington's disease at almost any age, but most will develop problems between the ages of 35 and 55.

The condition usually progresses and gets worse for around 10-25 years, until the person eventually dies. Signs and symptoms may vary between individuals and there's no typical pattern.

Early features, such as personality changes, mood swings and unusual behaviour, are often overlooked at first and attributed to something else.

Some people with Huntington's disease may not recognise that they have any problems.

Behavioural changes

Behavioural changes are often the first features to appear in Huntington's disease and can be the most distressing. These changes 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 and handling complex situations
• irritability and impulsiveness

A person with Huntington's disease may appear to have a lack of drive, initiative and concentration, making them seem lazy. However, this isn't the case – it's just the way the condition affects the brain. As part of this, they may also develop a lack of interest in hygiene and self care.

Psychiatric problems

Many people with Huntington's disease have depression. This occurs as part of the condition, not just as a response to the diagnosis. Symptoms of depression include continuous low mood, low self-esteem, a lack of motivation or interest in things, and feelings of hopelessness.

A few people may also develop obsessive behaviours and schizophrenic-like problems, although this is relatively rare.

Studies have shown that people with Huntington's disease are more likely to consider suicide, particularly near the time of diagnosis when the condition is becoming apparent, and when they start to lose their independence.

Find out how to get help if you think someone you care for is suicidal

Movement problems

Huntington's disease affects movement. Early features 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.

These features are often first seen when the person is walking or resting (sitting in a chair or lying in bed).

As the condition progresses, the uncontrollable movements will become more frequent and extreme. However, over time this may change and in the advanced stages of the condition a person's movements may become slow and their muscles more rigid.

Feeding problems

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 throat muscles don't work properly, due to the loss of motor control. In some cases, this can lead to choking and recurrent chest infections.

Loss of coordination 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.

A referral to a dietitian or a speech and language therapist may be necessary if there are difficulties with swallowing. In some cases, a feeding tube can be inserted. 

Read more about living with Huntington's disease

Communication problems

Communication and cognition (perception, awareness, thinking and judgement) are affected by Huntington's disease.

People with the condition often have difficulty putting thoughts into words and slur their speech. They can understand what's being said, but may not be able to respond or communicate that they understand. However, with time, a person with Huntington's disease will become less responsive, more withdrawn and communicate little.

Sexual problems

People with Huntington's disease can have problems with sexual relationships, particularly during the early stages of the condition. This is usually a loss of interest in sex 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 pneumonia or another infection.

You may find the palliative care section useful if you're caring for someone who's dying, or if you want to plan your end of life care in advance.

Juvenile Huntington's disease

Juvenile Huntington's disease is an uncommon form of the condition that can occur in people younger than 20 years old. Common signs include:

• a rapid decline in school performance
• changes in handwriting
• problems with movement, such as slowness, stiffness, tremor or muscle twitching (similar to the features of Parkinson's disease)
• seizures (fits)

Huntington's disease is caused by a faulty gene that runs in families.

Genes and chromosomes

Genes are the instructions for making all parts of the human body and brain. They're 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 contains an abnormal region of what are called CAG repeats. This area is larger than normal and produces a mutant 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 and cortex to control movement and thinking, as well as motivation. If this part of the brain is damaged, it causes problems with control of movement, behaviour and thinking.

It's still unclear exactly how abnormal huntingtin affects the brain cells and why some are more sensitive than others.

Inheriting Huntington's disease

A parent with the Huntington's disease gene has one good copy of the gene and one faulty copy. Their child will inherit one of these genes. Therefore, there's a 50:50 chance that the child will get the faulty gene and develop Huntington's disease.

However, it's very difficult to predict how old the child will be when they develop the condition if they inherit the abnormal gene, unless it contains a very long CAG repeat (>55).

There's also a 50:50 chance that the child with Huntington's disease will pass the faulty gene on to a child they may have in the future. This pattern of inheritance is called "autosomal dominant".

In around 3% of cases of Huntington's disease, there's no obvious family history of the condition. This could be due to adoption or because relatives with the condition died early from other causes. In rare cases, it's due to a new expansion in the gene.

If you have features of Huntington's disease, your GP will refer you to a clinician with specialist expertise in the condition if they feel further investigation is needed.

Many areas have Huntington's disease management clinics with a range of specialists, including a neurologist (a doctor who specialises in conditions that affect the brain and spinal cord).

The specialist will ask about your symptoms, such as whether you've had recent emotional problems, to see if it's likely you have Huntington's disease and to rule out similar conditions.

They may also examine you and test your thinking, eye movements, balance, walking, and whether you have any involuntary movements, such as chorea (fidgety or jerky movements).

Confirming the diagnosis

People with Huntington's disease often start to experience symptoms a number of years before the condition is actually diagnosed. This is particularly true in cases where someone is unaware that the condition runs in their family.

If you're showing features of Huntington's disease and it's known to run in your family, or if your doctor strongly suspects that you have the condition, genetic testing can be carried out to confirm the diagnosis.

It's important to realise that the diagnosis is based on the doctor recognising a combination of a number of factors – neurological examination, family history and genetic testing. It's possible to have the gene change and still be healthy. This is known as "premanifest Huntington's disease".

Genetic test

The children of someone with Huntington's disease can take a genetic test after the age of 18 to see whether they've inherited the faulty gene. If they've inherited the faulty gene, they'll develop Huntington's disease, but it's not possible to work out at what age.

You can ask your GP or neurologist to arrange an appointment for you at a regional genetic clinic. You'll receive some counselling and then blood samples will be taken. Your DNA will be extracted from the blood samples and analysed to see whether you have inherited the faulty gene.

You may have to wait two to four weeks for the test results.

Brain scan

In the early stages of Huntington's disease, there may not be any specific changes on the brain scan. A doctor may use a brain scan at any stage of the illness if they're concerned there may be other problems in addition to Huntington's disease.

A brain scan may involve having a computerised tomography (CT scan) or a magnetic resonance imaging (MRI) scan. An MRI scan is more detailed and is more sensitive at picking up changes in the brain. However, it's a more claustrophobic procedure.

Getting tested in pregnancy

If you're pregnant and already known to have the Huntington's disease gene, it's 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 doesn't want to find out whether they have the condition, 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 (see below).

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 in vitro fertilisation (IVF) treatment, then genetically testing the embryo in a laboratory to see if it has the faulty gene. The embryo will only be placed inside the woman if it doesn't have the faulty gene and there's no risk of the baby developing Huntington's disease.

Preimplantation genetic diagnosis isn't 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've inherited the faulty gene associated with Huntington's disease. It's 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 condition develops.

Most people have approximately 40 years of a normal healthy life before the condition develops.

Less than one in five people at risk of Huntington's disease choose to have the genetic test.

If you're considering genetic testing, it's strongly recommended that you speak to a genetic counsellor first. Your GP can refer you.

There's no cure for Huntington's disease. Its progress can't be reversed or slowed down, although this is the goal of many research projects.

Some of the features of Huntington's disease can be managed with medication and therapies, which may be coordinated by specialist teams.

Therapies, such as speech and language therapy and occupational therapy, can help with communication and day-to-day living.

Regular exercise is also very important. People who are active tend to feel much better physically and mentally than those who don't exercise. Someone with Huntington's disease may have poor coordination, but walking independently, with the use of walking aids if necessary, can make all the difference.

Read more about managing lifestyle issues, such as feeding and communication

Medication for Huntington's disease

Medicines for Huntington's disease, which can be taken in liquid form in many cases if needed, are described below.

Most of these medications have side effects, such as extreme tiredness. However, it may sometimes be difficult to tell whether these are symptoms of the condition or a result of the medication.

Antidepressants to treat depression

Antidepressants can help improve mood swings and treat depression. They include:

• SSRI antidepressants – such as fluoxetine, citalopram and paroxetine
• tricyclic antidepressants – such as amitriptyline
• other types of antidepressants – including mirtazapine, duloxetine and venlafaxine

Side effects of antidepressants may include:

• constipation
• sweating
• shaking or trembling
• difficulty sleeping (insomnia)

Mood stabilisers to treat irritability or mood swings

Mood stabilisers, particularly carbamazepine, may be considered as a treatment for irritability. Olanzapine can also help, along with sodium valproate and lamotrigine.

The dose of carbamazepine needs to be slowly increased and any side effects monitored. Carbamazepine can't be used during pregnancy.

Medication to suppress involuntary movements

The medications listed below suppress the involuntary movements – or chorea – seen in Huntington's disease. In the UK, antipsychotic medicines are usually preferred.

• antipsychotic medication – such as olanzapine, sulpiride, risperidone and quetiapine
• tetrabenazine – reduces the amount of dopamine reaching some of the nerve cells in the brain
• benzodiazepines – such as clonazepam and diazepam

Antipsychotic medication may also help control delusions and violent outbursts. However, they may have severe side effects, such as:

• stiffness and rigidity
• sedation
• tremor (shaking)
• moving slowly

Due to the possibility of experiencing these side effects, the lowest possible dose of antipsychotics are normally prescribed in the first instance.

Help is available to assist people with Huntington's disease in their day-to-day living. This might include physiotherapy, occupational therapy and speech therapy.

Huntington's disease puts a great deal of strain on relationships, and is very stressful and upsetting for the family. It's 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 outlined below aim to ease the strain of the condition by improving skills that may deteriorate.

Help with communication

Speech and language therapy can improve communication skills, memory and teach alternative ways of communicating. It can also help with swallowing problems.

Communication aids can sometimes be helpful, as they allow communication without the need for talking. For example, you can point to symbols on a chart to indicate your mood or whether you're hungry.

The family of someone 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. It can be cut into small pieces or puréed to prevent choking. Feeding equipment is also available, such as special straws and non-slip mats.

At some point, it may be necessary to use a feeding tube that goes directly into the stomach. If a person with Huntington's disease doesn't want to be artificially fed during the later stages of the condition, they should make their wishes known to their family and doctor. They may want to consider making an advance decision (a living will) or a statement of wishes and preferences.

Occupational therapy

An occupational therapist (OT) can help with day-to-day activities. Your home can be adapted by social services to make life easier for a person with Huntington's disease, as they may be at risk of injury from a fall or accidentally starting a fire.

Your shower, bath, chairs and bed may need to be adapted. You may also need to think about wheelchair access.

Read more about occupational therapy and how it can help

Physiotherapy

A physiotherapist can help 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 GP or social services.

Electronic assistive technology

The Royal Hospital for Neuro-disability provides an electronic assistive technology (EAT) service. It's made up of a team of healthcare professionals who provide EAT equipment for patients and residents within the hospital, as well as for people with disabilities living in the community or at other hospitals or units.

Equipment includes:

• communication aids
• computers and software
• switches and other access devices
• powered wheelchair controls
• environmental controls

Information about Huntington's disease

It's worth finding out what benefits you may be entitled to if you have Huntington’s disease, or if you're looking after someone with it. You can do this by contacting the Citizens Advice Bureau (CAB). 

Read more about benefits if you need care, and carers’ benefits

Driving

A person diagnosed with Huntington's disease who's started to experience clinical features should inform the Driver and Vehicle Licensing Agency (DVLA) because it will affect their ability to drive.

The DVLA will write to your doctor, with your permission, to ask for their opinion about your condition. Based on that information, a decision will be made about whether you can still drive and for how long before another assessment is needed.

There's no need to tell the DVLA if you're carrying the faulty gene but haven't yet developed the features of the condition.