Huntington’s disease overview
Huntington’s disease is an inherited disorder in which the brain slowly degenerates.^1,2 Over a number of years, a person with Huntington’s disease will experience uncontrolled movements, emotional disturbance and mental deterioration.^1,2 Ultimately, people with Huntington’s disease become completely dependent on a caregiver.³ This places a huge burden on the caregiver, who is usually a family member.

Huntington’s disease is a genetic disorder. If one parent has the disease, their child has a 50% chance of inheriting the defective Huntington’s disease gene.^1,2 Everyone who has this defective gene will develop symptoms of the disease.³

Symptoms
The signs and symptoms of Huntington’s disease most often appear in middle age, though this varies from person to person.^1,2 As the disease emerges, the patient will exhibit changes in behaviour and personality, including depression, irritability and anxiety.² As the disease progresses, severe memory problems can occur.²

‘Chorea’ is the most common symptom of Huntington’s disease, and is often the initial concern that brings a patient to a doctor.² Chorea consists of jerky, involuntary movements of the upper and lower extremities, face or body. The word chorea comes from the Greek word for ‘dance’, since people with chorea often writhe, twist and turn in a constant uncontrollable dance-like motion.

Statistics
According to the World Health Organisation, for every 100,000 people in western countries, 5–7 will have Huntington’s disease.³

Huntington’s disease is a genetic disorder that can affect men and women of all ethnic groups.³ The disease occurs throughout the world; however, there are geographic clusters where it is unusually common.⁴

There are no accurate estimates of the number of new cases each year.⁴

Seeking diagnosis and care
A doctor should be consulted if a person experiences changes in their movements, emotional state or mental ability. While a family doctor may be able to diagnose Huntington’s disease, most people will see a neurologist to confirm the diagnosis and to get help in managing their various symptoms. Huntington’s disease is typically diagnosed after a thorough neurological examination, including brain imaging or genetic testing, and a review of family history.

There is a genetic test for Huntington’s disease, which can be used to confirm a diagnosis, and also identify future risk in people who have Huntington’s disease in their family.^1,2 It is recommended that the genetic test is accompanied by counselling, since a positive diagnosis can be emotionally devastating.^1,2

Medication is available to treat the symptoms of Huntington’s disease. However, there is currently no cure, and the average life expectancy following diagnosis is 15–20 years.¹

It is essential that people with Huntington’s disease receive professional advice regarding their treatment.

References
1. MayoClinic.com. Huntington’s disease. May 2011. www.mayoclinic.com/print/huntingtonsdisease/DS00401/DSECTION=all&METHOD=print. Accessed 07/09/11.

2. American Psychiatric Association (APA). Diagnostic and Statistical Manual of Mental Disorders. Fourth Edition. Text Revision. DSM-IV-TR™. © 2000 American Psychiatric Association.

3. World Health Organisation (WHO). Genes and human disease: Huntington’s disease. www.who.int/genomics/public/geneticdiseases/en/index2.html#HD. Accessed 07/09/11.

4. Revilla FJ, Grutzendler J, Larsh TR. Huntington disease. Medscape Reference 2011. emedicine.medscape.com/article/1150165-overview#showall. Accessed 07/09/11.