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, judgment) 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.
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.
Causes and Symptoms
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 Huntington, 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 Huntington.
Cells in parts of the brain – specifically, the basal ganglia and parts of the cortex – are very sensitive to the effects of the abnormal Huntington. 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 Huntington 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.
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 recognize that they have any problems.
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 recognizing 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.
The Huntington's Disease Association has more information about the behavioural problems associated with the condition.
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.
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.
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.
The Huntington's Disease Association has more information about the eating and swallowing difficulties associated with the condition.
Communication and cognition (perception, awareness, thinking and judgment) 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.
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.
The Huntington's Disease Association has more information about sexual problems associated with the condition.
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 end of life care guide 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)
Our support and care
George Springall Homecare provides dedicated and experienced staff to help you maintain your quality of life and support you and your family through the difficult times. We create a specialized care plan that focuses on meeting all your needs. We support you set up realistic goals you wish to achieve and we are there to help when ever you need through out your journey to achieving your goals. This might include:
helping with personal care and getting you ready for the day or for a good night sleep
catheter care and continence management to maintain your dignity and comfort
prompting or administering your medication to manage your symptoms
assisting with nutrition and hydration to keep you healthy
assisting with routine household chores and shopping so your home life is as you would like it to be
emotional or social support to keep you connected to the people who are important to you
support with rehabilitation to get back to a normal life and independence
Further information and support is available from the Huntington's Disease Association.
Contact us to discuss a care package and support service for you.