15 Jan Huntington’s Disease Management
What is Huntington’s Disease (HD)?
Huntington’s Disease (HD) is an inherited disease that causes progressive degeneration or dying off of the nerve cells in certain parts of the brain. HD is passed from parent to child through a gene mutation. The gene responsible for HD is the HD gene of chromosome 4. The most severe loss of nerve cells occurs in basal ganglia (inner brain) & cerebral cortex (outer surface of the brain). These two structures of the brain are responsible for controlling voluntary movement; as well as thinking, perception, memory & emotion. As disease progress, it may also affect the body metabolism leading to hormonal changes.
Genes are composed of chains of DNA molecules. The links in a DNA chain are called nucleotides which contain 4 bases: adenine, thymine, cytosine & guanine or abbreviated as A,T,C & G. Each gene has its unique combination of nucleotides or genetic codes to determine the gene’s function. Any changes in the genetic codes like mutation will cause variation in gene function.
The HD gene makes essential protein called Huntingtin; it is actively found in the brain. Its function is not known but is believed to support early nerve cells development.
The mutated HD gene consists of multiple repeated three-base sequence C-A-G or known as triplet CAG. People who have more than 36 CAG repeats & survive long enough are more likely to develop HD & their next generation are at risk.
As a general rule, the higher the number of repeats of CAG is associated with an earlier onset & faster disease progression.
When HD occurs without a family history, it is called sporadic HD. These cases occur when one parent has an intermediate range of CAG repeats or called premutation.
As HD is a hereditary disease, each child has a 50% of inheriting the HD mutation. If a child doesn’t inherit HD mutation, they will not develop the disease or pass it to their offspring. The majority of people with HD is adult onset, ages between 30-50. Some individuals develop symptoms of HD from 2- 20 years of age, known as Juvenile HD.
Symptoms of HD:
The rate of disease progression varies from person to person. Most people with HD may not develop symptoms until they are in their middle age. The duration of symptoms last between 15 to 20 years & sufferers usually die of disease complications such as pneumonia. In Juvenile HD, the most common signs include rapid decline in school performance &, or with movement problems. One of the typical motor symptoms is myoclonus; a rapid involuntary muscle twitches or jerks.
People with Huntington’s disease may begin with mood swings, cognitive function decline, personality & behaviour change long before they develop movement disorder. The typical movement is called “hereditary chorea’, describes as uncontrollable dance-like gesture. Some people may have walking, speaking & swallowing difficulties. Many individuals with Huntington’s suffer from depression as disease progress, & change in emotion & cognition can be devastating to themselves & for their families.
How is HD diagnosed?
A person with HD is being diagnosed by the Neurologist through a thorough assessment on their symptoms, family history & genetic testing.
|Number of CAG repeats||Outcome|
|<26||Normal range; individual will not develop Huntington’s Disease|
|27-35||Individual will not develop HD but the next generation is at risk|
|35-39||Some, but not all, individuals in this range will develop Huntington’s Disease; next generation is also at risk.|
|>40||Individual will develop Huntington’s Disease|
(Source from National institute of Neurological Disorder & Stroke)
What treatments are available for HD?
Up to present, Huntington’s Disease is not curable. There a number of medications like modulating neurotransmitters & anti-psychotic drugs are being used to help control emotion & movement problems of people associated with HD.
Clinical trials known as gene silencing therapy is underway for people in early onset of HD disease. This therapy may be able to lower the problematic protein in the spinal fluid. Research reports showed 60% reduction of identified toxin in some adult patients.
What kind of care to provide for people with Huntington’s Disease?
A holistic care approach with neurology, psychiatry, palliative care, allied health, social worker, counselling & nursing care are paramount in looking after people with HD.
Cognitive changes are often the first noticed in HD. Clinical neuropsychologists can conduct initial & on-going assessment for individuals with HD by evaluating their strength & weakness in cognitive level so as to give safety recommendations for them & their families. It is important for family members or carers not to isolate them because of their clumsiness, slurred speech & slow thinking process. To maintain regular routines in less distracted environment can reduce their aggressive behaviour.
It is very important for people with HD to maintain physical fitness in line with their physical strength. Exercises can help to improve their mood & mental well-being. It is advisable to wear supportive outfit & sturdy shoes without laces to avoid falling down.
Physiotherapist can conduct mobility assessment & exercise training so as to arrange suitable mobility equipment for individuals with HD. Our Support Coordinator at Integral Home Care can help you find you the most appropriate physiotherapist and follow-up on the progress and also be proactive in conducting the recommended exercises by following up with Support workers involved.
Occupational therapist can assess people’s body & cognitive functions in order to maximise individual’s residual abilities in order to live more independently through home modification, using special gadgets & assistive technologies. Integral Home Care can take the stress out by connecting you to available occupational health services and organise required appointments and facilitate required assessments.
It is necessary to maintain an optimal nutrition intake through the input of Dietetics. People with HD very often experience reduced appetite. On the other hand those with constant abnormal movement consume extra calories as many as 5000 calories a day.
Some may develop swallowing difficulties as time goes by & can easily go into aspiration pneumonia. Speech Pathologist can help individuals with HD to minimise choking risk by teaching them techniques while eating & adding thickener to their drinks. When swallowing becomes severe, some may take up the option for tube feeding. In addition, Speech Pathologist can assist individuals with speaking difficulties by adopting alternative forms of communication so as to minimise social isolation.
Your Integral Home Care (IHC) can provide support & care coordination for those people that are in need.
In Australia & many other countries in the world like USA, UK, Canada, Italy, Switzerland & Europe have set up Huntington’s Disease Foundations to support people with HD & their carers. Those organisations provide valuable information & education through newsletter, websites & other social media; activities include yearly conference, fund raising, carer retreats, youth groups, community & family support groups.
- Australian Huntington’s Disease Association NSW & ACT
- Huntington’s NSW
- Huntington’s Disease -Brian Foundation
- National Institute of Neurological Disorders and stroke
- Hereditary Disease Foundation
- Hereditary Disease Foundation
- Clinical Trial Website for the National Institutes of Health