What is Huntington’s Disease?

Huntington’s disease (HD) is a neurological illness caused by an expanded gene in your DNA. The faulty HD gene causes cells in parts of your brain to gradually malfunction and die. As brain cells die, you will experience changes with your movement, thinking and emotions.

What Are The Symptoms?

Symptoms vary from person to person and at different stages of the illness. Even people in the same family may be affected differently. You may start to notice subtle changes in the way you move, how you think and how you feel. Over time motor changes may include clumsiness, poor balance and jerky movements. Later, you may experience difficulties with maintaining your weight, speaking and swallowing. Changes to thinking skills may include difficulty with understanding and retaining information, concentration and decision making. You may also experience mood changes such as depression, anxiety, compulsive thoughts and irritability.

Huntington's Disease symptoms can begin at any age but usually first appear between the ages of 30 and 50 years. About 5-10% of people have symptoms before age 20 (Juvenile HD) and 10% have onset after age 60 (late onset). The disease usually progresses slowly over a period of 10 – 25 years resulting in gradual physical, cognitive and emotional changes.

Living with Huntington’s disease can be very challenging so it is important to get the right information and support as soon as possible.  There are different support options available to help you to manage your symptoms and to live as well as possible. Your family may also need support and information.

What is Juvenile Huntington’s Disease?

Juvenile Huntington’s disease (JHD) is a rare form of the illness where you develop symptoms before the age of 21. Less than 10% of people with Huntington's disease will have Juvenile-onset.

Symptoms of Juvenile Huntington’s are similar to those of the adult disease but there are some key differences. Children and young people affected by Huntington’s are less likely to experience involuntary movements, known as chorea, that often characterise the adult illness, and more likely to be affected by muscle contractions and stiffness. Epilepsy is also more common. Mood changes and a drop in school performance (which can be caused by other factors in a child'd life) can often be the first noticeable signs of Juvenile Huntington's.

• It may become harder to concentrate, learn new things, follow instructions and remember things.
• It may take you longer to respond to questions and perform tasks.
• You may start to feel more frustrated, impatient, irritable or angry than usual.
• You may start to experience stiffness in your limbs. Your movements may slow down and you might find that you start to stumble or walk unevenly.
• It is important to remember that these symptoms may relate to other causes and are not always due to Huntington’s disease.

The Huntington's Disease Youth Organization is an international non-profit supporting, educating, and empowering young people impacted by Huntington's Disease (HD). See their information and resources on early onset / Juvenile HD here

Who Gets Huntington’s Disease?

Huntington's Disease is hereditary.  Each child conceived naturally (see family planning in At Risk section ) to a parent who carries the HD gene has a 50% chance of inheriting or not inheriting the illness. If you inherit the HD gene you will develop the illness at some stage in your life and your children will have a 50% risk. If you do not inherit the gene you will not develop symptoms nor can you pass the illness to your children.

Is there always a family history?

Some people develop Huntington’s disease without ever knowing they were at risk. This may be explained by a parent’s misdiagnosis, the early death of a parent before symptoms appeared, adoption or mistaken paternity. On rare occasions it can be caused by the random expansion of a normal parental gene.