What is Huntington’s Disease?

Huntington’s disease is a progressive neurodegenerative condition that leads to dysfunction and eventual death of brain cells, termed atrophy, triggered by an inherited mutation in the huntingtin (HTT) gene. This gene, crucial for brain development in both fetal stages and throughout life, undergoes mutations causing distinct motor and cognitive disturbances, usually noticeable in individuals aged 30 to 35. However, there are rare instances, around 5% – 10% of cases globally, where a more aggressive form known as Juvenile Huntington’s disease surfaces, even as early as 18 years old.

Those inheriting the mutated HTT gene may exhibit symptoms like agitation, irritability, and clumsiness arising from changes in the brain’s cortex (its outer layer) and basal nuclei. These parts of the brain are pivotal components of our brain’s feedback mechanism governing motor and emotional responses. Mutations in the HTT gene lead to abnormal levels of huntingtin’s protein, resulting in brain cell toxicity and disrupted functioning. This disruption may manifest as excessive movements alongside emotional and cognitive disturbances, shaping the spectrum of behaviours observed in Huntington’s disease.

Despite its hereditary nature, Huntington’s disease can occasionally appear without a family history due to spontaneous mutations, heightening the risk for future generations compared to the general population. There is a 50/50 chance of passing on the variant gene to offspring. However, advancements in gene-based therapies and personalised medicine offer hope for potential treatments beyond the current ‘symptomatic management’ approach. This opens doors to numerous therapies currently under investigation, promising a brighter future in the management of Huntington’s disease.

Symptom Watching

Living with the unknown is stressful for all of us and therefore it is a natural and understandable response to practice symptom watching. What does this mean? In real terms, we all do this when we are self-conscious or worried about our health. For individuals from a Huntington’s family, it is when you associate the majority of your actions and behaviours with the symptoms of Huntington’s disease regardless of your genetic status.

Please keep in mind, many of the symptoms of Huntington’s disease such as fumbling, moodiness or forgetfulness are also experienced by individuals in the general population that have no risk of Huntington’s disease. However, if this remains an issue of concern for you, please seek professional advice from someone you trust (i.e. your GP, psychologist, Huntington’s disease specialist, and/or Huntington’s Victoria).

Age of onset

Symptomatic Huntington’s disease predominantly occurs in young-middle aged adulthood. Juvenile Huntington’s disease (JHD) occurs when a child or adolescent under the age of 20 years develops the symptoms of Huntington’s disease.

Juvenile Huntington’s disease is a rare form of the disease, with prevalence estimates placing it at approximately 5-10% of all cases. In the majority of cases (but not all), the child with Juvenile Huntington’s disease has inherited the mutated gene from their father. The symptoms of Juvenile Huntington’s disease also differ slightly to that of the adult form of Huntington’s disease.

Whilst there is currently no cure or effective treatment of Huntington’s disease, there are practical steps you can take to either delay the age of onset or the severity of symptoms.

What is Huntington’s Disease?

Symptom Watching

Age of onset

If you would like to learn more about Huntington’s disease, please click the links below to find out more.

Huntington's Disease Timeline

Genetics

Genetic Testing

Symptoms