What is Huntington's disease? Symptoms, causes and treatment

Huntington’s disease is a genetic disorder caused by a faulty gene on chromosome 4. A protein called Huntingtin usually helps nerve cells develop, but when it is faulty, it can damage them instead. This mainly occurs in the areas of the brain responsible for movement, learning, cognition, and emotions (basal ganglia and cerebral cortex). Huntington’s disease is primarily thought of as a condition of motor function — that is, it affects the person’s movement. But there can be damage to the brain, which can develop into dementia.

The first signs of Huntington’s disease are more commonly seen in the 30-50 year age group, but current research indicates that about 10% of cases can appear after the age of 60 years and 5-10% of cases under the age of 18 years (known as juvenile Huntington’s disease).

Symptoms of Huntington’s disease

There are a range of symptoms that someone with Huntington’s disease may exhibit, including:

• a reduction in reasoning, judgement, planning and decision-making abilities
• a change in emotional engagement
• poor impulse control
• attention problems
• difficulty learning new things
• slowed thinking
• reduced motivation
• reduced temper control
• reduced insight
• weight loss
• stiffness
• difficulty swallowing and speaking
• clumsiness and difficulty controlling their muscles

The person may also show signs of depression or anxiety.

Causes and risk factors of Huntington’s disease

Faulty gene on chromosome 4

A faulty gene on chromosome 4, the huntingtin gene (HTT), causes Huntington’s disease. If a person has a parent with the gene, they have a 50% chance of developing the disease.

Family history

The person with Huntington’s and their family may well have experienced the disease in other members and have fears about how this will progress and what help and support they may be able to receive. There may also be worries about any children within the family and whether or not they may eventually have Huntington’s too.

For more information, visit the Huntington’s Disease Association website.

How does Huntington’s disease develop?

As the disease progresses, people who have Huntington’s are increasingly likely to have involuntary movements, causing the characteristic signs (chorea) of Huntington’s disease. This can cause embarrassment, distress, discomfort and social isolation. As the disease progresses, it can also cause problems with swallowing, speech, balance and increase the risk of falls.

Research has indicated that in Huntington’s disease, the person’s cognitive processes are also affected and get progressively worse over the years, with some people going on to develop dementia in the later stages of Huntington’s.

Diagnosing Huntington’s disease

Someone who is experiencing symptoms of Huntington’s disease will be referred to a doctor who specialises in conditions that affect the brain (a neurologist) so that they can have further tests and treatment.

If there is a familial link, you can choose to have a genetic test to see if you have the altered gene; however, you’ll need to be over 18 to have the test, and it is your choice.

How common is Huntington’s disease?

An estimated 7,000 people are living with Huntington’s disease in the UK.

Treatment for Huntington’s disease

While there is no cure for Huntington’s disease, there are treatments to help manage the symptoms.

Managing symptoms

With Huntington’s disease, the interventions are focused on support and management of the changes; working with the person and their family to ensure they can live as well as possible with the condition. The physical effects of Huntington’s disease can be managed by:

• adapting the home environment so any trip hazards are removed and risks minimised
• a referral to speech and language therapy if there are speech or swallowing problems
• a referral to a physiotherapist if there are movement issues
• a referral to an occupational therapist for aids and adaptations that may help around the house

If the person with Huntington’s has significant cognitive issues, communication can be helped by:

• speaking slowly and clearly
• using short sentences and non-verbal communication alongside speech, eg, hand actions
• reducing distractions and noise
• giving extra time for communication – it may take longer to respond
• asking questions to narrow down the answer, give choices or use yes/no cards or picture cards – the person may have word finding difficulties as well as needing longer to respond
• using a mobile phone, tablet or electronic communication aid
• providing a routine and activities that the person enjoys and feels comfortable and relaxed with

Remember that comprehension can often be well preserved even if the person cannot speak.

The link between Huntington’s disease and dementia

Dementia can develop at any stage of Huntington’s disease. It affects people differently and is not the same as dementia caused by conditions like Alzheimer’s disease.

In Alzheimer’s disease, people often forget people, places or events. In Huntington’s disease, memory problems are more likely to involve forgetting how to do things—such as following steps in a task or making decisions—rather than losing personal memories.

People with Huntington’s disease-related dementia have a specific pattern of brain changes. These include thinning of the outer layer of the brain (the cortex) and a widespread loss of nerve cells across the brain. These changes can affect thinking, memory, and daily life in different ways.

How Huntington’s disease causes dementia

The progressive nature of Huntington’s disease can mean that dementia develops as the brain continues to be impacted, meaning the person will need more help in taking care of themselves, including bathing and swallowing.

Symptoms of dementia from Huntington’s disease

During the early stages of Huntington’s disease, some people will develop symptoms of dementia such as problems with perception and difficulty with thinking that they previously wouldn’t have. They may also find concentration and planning more difficult than they did before.

When to see a GP to get a dementia diagnosis

If you have any concerns about symptoms that you or someone in your life is experiencing, you should visit your GP to discuss them.