Testing for HD

In 1993 a gene test (predictive test) became available to allow a person at risk to find out if they carry the faulty HD gene and therefore at some point in their life develop symptoms. Making a decision to undergo predictive testing is often the most challenging decision a person at risk will need to make.

According to international guidelines, if you are 18 years of age or older and have a blood relative who has been diagnosed with HD, you are eligible for the predictive test. This test is performed through local genetic services. If you are under 18 years of age and have questions about testing please seek advice from your local HD association.

What is predictive testing?

Predictive testing is performed by extracting your DNA from a blood sample to identify whether you are carrying the faulty Huntingtin gene. The testing usually consists of genetic and psychosocial counselling, a neurological examination and a blood test. The time between the initial blood test and receiving your results is generally 6 to 8 weeks. The test for HD cannot determine when symptoms will begin or how severe symptoms are likely to be.

It’s a personal choice

There is no right or wrong decision whether to undergo pre-symptomatic testing for HD, it is a personal choice and should be carefully considered:

  • Genetic counselling is a supportive discussion-based process to help you consider all relevant factors before making an informed decision (i.e. around future career and family planning, insurance, etc.)
  • Other counselling support may be helpful to explore the outcomes and make sure you’re emotionally ready to make the decision

What to expect

The testing process usually includes the following steps:

  • An initial appointment with a genetic counsellor during which you may discuss the history of HD in your family, the genetics of HD, the reason that you’re seeking testing, and potential impacts of a positive result
  • A second appointment, which may include a neurological examination and a blood test if you decide to go ahead
  • Another appointment once your test results are ready
  • Follow up counselling and support is also provided and recommended

Please note: It is ideal if you attend these appointments with a support person (i.e. spouse, sibling or friend etc). If you wish to have our support through this process, a Huntington’s Victoria representative can attend these appointments with you.

Diagnosis

Receiving a diagnosis of HD is far more complicated than a visit to your GP. In order to receive a diagnosis, you will need to obtain a referral from your GP to see a HD specialist. Consultation(s) with a specialist is covered by Medicare. The initial consultation may include:

  • Discussion of family history
  • Your current knowledge of HD
  • Discussion of symptoms you believe to be exhibiting
  • Neurological/cognitive examination (body movement, reflexes, memory etc.)
  • Assessment of mental and emotional state

After the above assessments, the specialist will inform you of whether or not they believe you are exhibiting symptoms of HD. The specialist will require a blood test to confirm that your symptoms are associated with HD. They may also request that you have a MRI scan to see any physical changes in the brain.