Huntington’s Disease

Huntington’s disease diagnosis

Huntington’s disease is a neurodegenerative disease that results in brain cell degeneration and death. The disease is named after George Huntington, an American doctor, who first detailed the disease in 1872.

Huntington’s disease was previously referred to as Huntington’s chorea – referencing the ‘dance like’ movements that are symptomatic of the condition.

Not all people with Huntington’s disease experience these symptoms, hence the shift to the term ‘Huntington’s disease’.

Cause of Huntington’s disease

In 1993 the Huntington’s disease gene was isolated. Huntington’s disease is caused by a genetic defect on chromosome 4. This defect causes a portion of DNA (called CAG) to replicate many more times than it is supposed to. Typically this portion of the DNA is repeated 10-28 times, however in Huntington’s disease, the repetition occurs between 36-120 times.

The Huntington’s disease gene may be passed from a parent to child. If a parent has Huntington’s disease, each child has an individual 50/50 (one in two) chance of inheriting the disease. Huntington’s disease does not present in one generation, skip the next and then reappear. However, it may appear to do so if a person dies before symptoms become apparent. If a person does not inherit the defective gene from the affected parent, they cannot pass it on to their own children. To understand more about the genetic and hereditary nature of Huntington’s disease, genetic counselling is advised. Genetic counselling is also advised if there is a family history of Huntington’s disease.

Two types of Huntington’s disease

There are two forms of Huntington’s disease.

The most common form of Huntington’s disease is adult onset. Symptoms usually present in mid 30’s and 40’s (mean onset age of 35-44 years).
A small number of cases begin in childhood or adolescence. This is termed Juvenile Huntington’s Disease. Juvenile Huntington’s Disease affects people under the age of 20. Symptoms of Juvenile Huntington’s Disease vary from adult onset symptoms, usually presenting with excessive rigidity and without the extent of involuntary movements associated with adult onset Huntington’s Disease.

Symptoms of Huntington’s disease

Early symptoms of the disease include:

Presentation of nervous like activity e.g. fidgeting and minor twitching
Excessive restlessness
Small changes in handwriting
Minor difficulty with activities of daily living (e.g. driving)
Clumsiness

Behaviour changes can precede motor or physical symptoms.

Behavioural symptoms may include:

Moodiness
Restlessness
Impulsiveness
Paranoia
Irritability
Behavioural disturbances
Hallucinations

Dementia (Cognitive) symptoms may include:

Disorientation
Confusion
Changes in judgement and personality
Memory loss (often short term)

Physical symptoms may include:

Spontaneous facial movements (e.g. grimace)
Sudden, jerking movements of the peripheral limbs (arms, legs) and other body parts
Slow uncontrolled motor movements
Unsteady gait

Other symptoms may include:

Increasing stress, anxiety and tension
Difficulty swallowing
Difficulties improving speech

As the disease progresses, the physical, cognitive and emotional symptoms become increasingly marked. Family and professional support is required to assist in meeting the demands of work and living activities. The level of support depends on the stage of the disease. Assistance with work, managing household affairs, financial affairs and activities of daily living may be required. In the advanced stages of the disease, people with Huntington’s disease can have significant difficulty completing activities of daily living. This may eventually require complete support in daily living activities. Professional nursing care is often required.

Is there a cure?

Despite advances in symptom management, there is no cure for Huntington’s disease. There is also no current way to stop the disease progression. The goal of treatment is to slow or minimise the impact of symptoms. This in turn supports a person with Huntington’s disease to maintain function for as long as possible. Treatment also aims to maximise comfort. There are medication options available, determined by and in consultation with the treating medical team. Life expectancy for a person with Huntington’s disease is approximately 15-20 years after the initial presentation of symptoms. Cause of death is not the disease in and of itself, rather complications that arise from it – this may include heart failure, pneumonia or infection.

How can a speech pathologist help?

Speech Pathologists are trained specialists in speech, language and swallowing. They provide interventions and support aimed at maintaining verbal speech for as long as possible or providing methods of communication when speech is no longer consistent or is difficult to understand. These methods of communication are called alternative augmentative communication (AAC). AAC ranges from basic picture selection boards, to iPad use, to advanced voice output devices. A speech pathologist works with a person with Huntington’s disease and their family to determine the most suitable method of communication. A speech pathologist is also trained to support a person with difficulties swallowing. For more information about difficulties with swallowing, please read our article about ‘Dysphagia’.

Stay tuned for our upcoming blog that outlines the specific communication and swallowing difficulties associated with Huntington’s disease.

Results focused speech therapy in Sydney

This article was written by our speech pathologist, Jenna Butterworth, who is a Speech Pathology Australia member.

If you have questions about a Huntington’s Disease or other difficulties with speech, contact your local doctor who will arrange for you to see a speech pathologist in Sydney. Contact us today!

Bibliography

American Speech and Hearing Association. (2013). Huntington’s disease. Accessed online on 23.07.2013 from here

Huntington’s Disease NSW. (2012). About Huntington’s disease. Accessed online on 23.07.2013 from here

Paulson, H.L & Albin, R.L. (2011). Neurobiology of Huntington’s Disease: Applications to Drug Discovery. Boca Raton: CRC Press. Accessed online on 23.07.2013 from here

Warby, S.C., Graham, R.K., Hayden, M.R. (1998) Gene Reviews: Huntington Disease. Accessed online on 23.07.2013 from here