How Does Huntington's Dementia Differ From Alzheimer's?
Huntington’s disease (HD), also known as Huntington’s Chorea, is an inherited progressive form of dementia. The disease, first described by Dr. George Huntington in 1872, is a predominantly inherited one. Although Alzheimer’s disease (AD) can be inherited too it is not a single gene cause as in HD.
In Huntington’s disease the gene, a mutation of chromosome 4, was discovered in 1993. A so-called autosomal dominant disease, HD can be inherited from either the father or the mother. Any child, male or female, has a fifty percent chance of getting the disease themselves. Huntington’s does not skip generations. There are a few very rare, apparently spontaneous cases of Huntington’s that occurs with no familial links (three per cent of cases).
In Alzheimer’s disease there are two kinds of genes that are associated with a familial risk factor. The first is thought to be a “risk gene,” ApoE 4, the second, a “deterministic gene” is much rarer than risk genes and are only found in a few hundred extended families around the world. People with Down’s syndrome, affecting chromosome 21, are also are at greater risk of Alzheimer’s in their middle years.
Age of Onset
Symptoms of HD begin during the late 30s early 40s but can be seen, very rarely, in adolescence. Sadly, unless it is known that a family has Huntington’s, children can be born before symptoms appear in their mother or father. Alzheimer’s is generally a disease of older people. Early onset Alzheimer’s can affect people from late 30s, early 40s.
Symptoms of Huntington’s Disease
As with Alzheimer’s disease symptoms develop gradually over months or years. People with HD display increasingly uncontrollable movements and jerking of the limbs, trunk, and face, progressive psychiatric difficulties in 10 to 40 per cent of people. The first signs can be antisocial of the type that result from irritability and aggression. Initial contact may therefore be with the police. Later, psychiatric symptoms include depression, mania or psychosis.
Symptoms of dementia associated with HD begins with memory deficits, confusion, recognition difficulties, language disturbances, and changes in personality.
The onset and rate of progression of the disease tends to follow a pattern within each family.
Treatments for People with Huntington’s Dementia
As with Alzheimer’s disease, there is no cure for Huntington’s disease and dementia. Nutrition and diet are very important, as is social support and support for caregivers. There are medications than can help make some of the symptoms more tolerable. Medications include:
- Antipsychotic medications (such as olanzapine, haloperidol, chlorpromazine)
- antidepressants (such as Prozac, sertraline hydrochloride, nortriptyline)
- tranquillizers (such as benzodiazepines, paroxetine, venlafaxine, beta-blockers)
- mood stabilizers (such as lithium, valproate, carbamazepine)
Prognosis for People with Huntington’s Dementia
The disease progresses without remission over 10-20 years. Death for most people with Huntington’s disease is usually a result of infection, pneumonia, heart failure or choking. Constant nursing care is needed in the later stages of the disease.
Genetic Testing for Huntington’s disease
The HD gene was isolated in 1993 and a test is now available that can accurately determine whether a person carries the affected gene. The test is simple to do and involves giving a small amount of blood for analysis. The test cannot predict when symptoms of Huntington’s disease will begin. Because there is no cure some people choose not to take the test although it can help an adult decide whether or not to have children.
Famous person with Huntington’s disease:
Folk singer Woody Guthrie.
Links to How Alzheimer’s Differs From Other Types of Dementia
Christine Kennard wrote about Alzheimer’s for HealthCentral. She has many years of experience in private and public sector nursing care homes for people with dementia. She has worked in a variety of hospital, public and private health settings and specialized in community nursing. Christine is qualified in group analytic psychotherapy, is registered in general and mental health nursing and has a Masters degree.