Presentation: Patient with a family history of Huntington disease
Huntington disease is an inherited, incurable neurological condition that typically features progressive motor dysfunction, cognitive decline and psychiatric symptoms.
At a glance:
- Huntington disease is an incurable, progressive neurological condition with an average age of onset of 40 years and a life expectancy of 15 to 20 years from diagnosis.
- Huntington disease is a fully penetrant, autosomal dominant condition. This means that the first-degree relatives of affected individuals have a 50% chance of being affected themselves.
- Genomic testing for Huntington disease can be either predictive (pre-symptomatic), diagnostic (in those with symptoms) or prenatal (or pre-implantation).
- Alert! The psychological health of an at-risk individual can be significantly affected even before the onset of motor symptoms.
Example clinical scenario
A 40-year-old woman consults you about her family history of Huntington disease. Her father was diagnosed with Huntington disease at the age of 45. Your patient feels well in herself but is concerned that she is at risk and would like to discuss genomic testing.
Identifying those at risk of a genetic condition
- Huntington disease is characterised by progressive motor dysfunction, cognitive decline and psychiatric conditions.
- Symptoms usually start between the ages of 30 and 50, but in the paediatric or juvenile form of Huntington disease, symptoms may be evident before the age of 20.
- Predictive genomic testing is available for at-risk individuals, although it is not routinely offered to children under the age of 18.
- The psychological health of an at-risk individual can be significantly affected even before the onset of motor symptoms. Critical times include when a parent is diagnosed and at the time of predictive testing.
What should you do next?
- At-risk individuals, including children, can be referred to local clinical genetics services for assessment, counselling and discussion of genomic testing. It is recognised that, in the absence of a specific treatment, most at-risk individuals choose not to go ahead with pre-symptomatic testing.
- Although predictive genomic testing is not routinely offered to children under the age of 18, a local clinical genetics service can provide appropriate counselling.
- If your patient presents in pregnancy, an urgent referral should be made to the clinical genetics service, as antenatal testing can be offered.
- Patients seeking reproductive options should also be referred to clinical genetics services as Huntington disease is currently on the list of approved conditions for pre-implantation genetic testing.
- Patients and at-risk individuals should be signposted to appropriate support groups, such as the Huntington’s Disease Association.
- Other social implications should be discussed, such as employment, driving and insurance.
- For information about how to arrange testing in Wales, Scotland or Northern Ireland, see our dedicated Knowledge Hub resource.
- Information about patient eligibility and test indications were correct at the time of writing. When requesting a test, please refer to the National Genomic Test Directory to confirm the right test for your patient.
Resources
For clinicians
- BMJ Best Practice: Huntington’s disease
- Huntington’s Disease Association: A guide for GPs and primary care teams (downloadable booklet)
- Patient Info: Huntington’s disease
For patients
- Huntington’s Disease Association
- Patient Info: Huntington’s disease