Information leaflet for patients and families. Huntington Disease (HD)

Transcription

1 Information leaflet for patients and families Huntington Disease (HD)

2 Introduction Huntington disease, or Huntington Chorea, (HD) is a slowly progressive disorder of the brain in adults. HD is an inherited disorder caused by a change in one of our genes and most individuals have affected parent or relative. HD causes involuntary muscle movements, memory problems and mood changes usually from mid-adult life. The signs of HD begin gradually and progress very slowly. Early symptoms of HD The age at which symptoms develop can vary from one person to another. The onset of the condition is usually between the ages of 35 and 55 but may be earlier or later. Even within the same family the age of onset can vary from one person to another. Early symptoms include stumbling, clumsiness and slight, uncontrollable muscular movements. Lack of concentration, short term memory lapses, depression, mood changes, irritability, aggression and antisocial behaviour can all be early symptoms of HD. The onset of symptoms can be subtle and they may be present for some time before a diagnosis of HD is made. How HD progresses Later in the illness people may experience many different symptoms including involuntary movements, weight loss and difficulty with speech and swallowing. The emotional changes can lead to stubbornness, frustration, mood swings

3 and depression. Some people experience changes in the way that they think, called cognitive changes. These can lead to a loss of initiative, drive and multi-tasking or organisational skills which can result in the person appearing to be lazy. Sometimes these cognitive and personality changes cause more difficulties, both for the person with HD and their carers, than the physical deterioration. Some changes are part of the disease process but may be made worse by other factors such as depression. In the later stages of the illness full nursing care will be needed. Secondary illnesses such as pneumonia are often the actual cause of death. What treatment and help is available? Management and support for affected individuals and their families is coordinated through our specialist multi-disciplinary HD service. This service is run jointly by the Genetics and Neuropsychiatry teams and include allied professionals such as an occupational therapist, speech therapist and dietitian. Useful treatments may include medication to treat symptoms such as mood swings and depression, speech therapy, anxiety management, dietary advice and assistance with home adaptations. Although a cure is not yet available for HD there is significant drive towards identification of effective future treatments. You may wish to consider becoming involved in one of our active research projects towards treatments or a cure for HD.

4 What causes HD? Genes are the units of information which tell the cells of our bodies how to work. HD is caused by a change in a gene called HTT. Within this gene three letters of the genetic code repeat themselves. In people with HD the number of times that these letters are repeated is increased. This is called an expansion. The HTT gene produces a protein which is not usually harmful. A repeat expansion leads to production of an altered protein which damages nerve cells. How is HD inherited? In each of our cells we have two copies of the gene which causes HD, one copy inherited from each of our parents. The HD gene change is dominant. This means that if someone (male or female) inherits a changed copy they will develop symptoms of HD at some point in their lifetime. Each of their children will have a 1 in 2 (50%) chance of inheriting the changed copy of the HD gene. This is shown in the diagram below.

5 Is a genetic test available for HD? A blood sample can show if an expansion in the HD gene is present. This genetic test confirms that symptoms of HD will occur but not when symptoms will occur, how they might be affected or how they will progress. There are many issues to consider before having a HD test. Those who wish to consider testing are offered a series of appointments to discuss the implications of the test and the result. Genetic testing is a very personal decision which can only be made by the individual themselves. Genetic testing is not usually offered to people under the age of 18 years. Tests during pregnancy can be offered to gene carriers who want to find out if the pregnancy is affected. These tests are complex and a Genetic Counsellor or Clinical Geneticist can provide more information. These tests are ideally discussed before beginning a pregnancy but if this is not possible, they should be discussed as early in the pregnancy as possible. Information and support is also available from the Huntington Disease Association at: Huntington s Disease Association Suite 24, Liverpool Science Park Innovation Centre Mount Pleasant Liverpool L3 5TF Telephone: info@hda.org.uk Website:

6 For information or advice please contact your local Genetic Counsellor. Alternatively please contact the HD team: Chris Platt, Genetic Counsellor Dr Mary O Driscoll, Consultant Geneticist Dr Nicola Cooper, Consultant Geneticist Telephone: genetics.info@nhs.net Birmingham Women s and Children s NHS Foundation Trust Mindelsohn Way, Edgbaston Birmingham B15 2TG Author: Clinical genetics Unit Reviewed date: June 2017 Next review: June 2020 Ref No: GG8