Huntington’s Disease (HD) is a life-limiting genetic neurodegenerative condition that leads to progressive physical, cognitive and emotional symptoms. HD symptoms vary over the course of the condition and between individuals within the same family. Most people with HD develop the symptoms in their forties and fifties, although there may be subtle changes much earlier. About 5-10% of patients have onset of symptoms before age 20 (Juvenile Huntington's Disease) and 10% have onset after age 60.
Symptoms may include involuntary movements, speech and swallowing impairments, weight loss, continence issues, loss of initiative and mental flexibility, loss of organisational skills, changes in motivation, reduced self-awareness, impulsivity, depression, anxiety, obsessive-compulsive type behaviours and apathy.
HD is caused by an expansion in the IT-15, or huntingtin gene, on chromosome 4. Each child of a parent with the HD gene has a 50% chance of developing the disease.
A diagnostic test is used to confirm the diagnosis of HD in a person showing symptoms of the disease. The test is carried out to confirm a clinical likelihood that a person already has HD.
A predictive test for HD is available to a healthy person over 18 years, who has no symptoms, but who has a family history of HD. Not everyone at risk of HD wishes to pursue a predictive genetic HD test, and having the test remains an individual choice.
Genetic counselling and information on pre-symptomatic genetic testing is available from the Genetic Centre - Tel: (01) 409 6739, Website: www.genetics.ie
Treatment and Care
There is no cure for HD at present but symptoms can be managed with timely multidisciplinary support including: neurology, genetic services, neuropsychiatry, neuropsychology, neuro-rehabilitative therapies (physiotherapy, speech & language, dietetics, occupational therapy) and specialist care. Much can be done to improve the quality of life of a person with HD and their family members.
Maintaining a healthy body weight is essential because people who are under weight lose muscle mass and therefore feel weaker, become more apathetic or depressed and are more prone to catching infections. Exercise, social and psychological support can help manage a persons physical and mental well-being. Medication should be reviewed regularly to ensure it remains effective in treating symptoms over the course of the illness. For more information see the HD Handbooks on the Information page.
Standards of Care
The European Huntington’s Disease Network (EHDN) have formed a number of working groups to encourage new collaborative work in the care of HD with the aim of developing evidence based guidelines for best practice. The standard of Care working group comprises over one hundred clinicians and allied health professionals from various disciplines, from Europe and the USA. All contributed their wealth of expertise and knowledge gained through working with HD patients and their families.
A special edition issue of the Journal of Neurodegenerative Disease Management focuses on Standards of Care for the clinical management of HD. Please follow the link for open access to this series of articles which is kindly supported by CHDI Foundation: A standard of care for Huntington’s disease.
Prevalence of HD
Professor Patrick Morrison conducted a survey in Northern Ireland in 2001 which estimated the prevalence of 10-16 people per 100,000 (Lancet Neurology). His analysis of more recent data suggests a prevalence of 14-16 per 100,000. Based on the Republic of Ireland population of 4,670,976 (July 2011) this would indicate approximately 700 people with HD and a further 3000 at risk.
How does the disease get its name?
The disease is named after Dr. George Huntington, an American physician, who was the first to publish a precise description of the symptoms and course of the disease in an article written in 1872.