Brief overview
- Symptoms: Movement disorders, such as involuntary, jerky movements, falls, swallowing and speech disorders, personality and behavioral changes, depression, delusions, decline in intellectual abilities
- Course of the disease and prognosis: The disease progresses over a period of years. Those affected usually die from complications as a result of the disease.
- Causes and risk factors: A genetic defect leads to the formation of a defective protein that accumulates in the nerve cells and damages them. The development of the disease is not yet fully understood.
- Diagnosis: Family history, neurological examination, detection of the genetic mutation
- Prevention: There is no possibility of prevention. If you wish to have children, genetic testing of parents at increased risk can help to determine how likely they are to pass the disease on to their children. The test requires careful consideration in relation to the mental stress of the person affected.
What is Huntington’s disease?
Huntington’s disease (also known as Huntington’s disease) is a very rare hereditary disease of the brain. In studies on the incidence of Huntington’s disease, researchers assume that around seven to ten in 100,000 people are affected in Western Europe and North America.
Typical symptoms of Huntington’s disease are movement disorders and mental disorders, such as changes in character and a decline in intellectual abilities up to and including dementia.
The possibilities for influencing the course of Huntington’s disease are limited. Researchers have tested a large number of substances that are supposed to protect the nerve cells (neurons) and halt the progressive neuronal destruction. So far, none of these substances has been shown to have a significant effect on the course of the disease.
The main focus of therapy is therefore on alleviating the symptoms of Huntington’s disease.
There are self-help groups that help people with Huntington’s disease and their relatives.
Where the name “Huntington’s disease” comes from
The second part of the name, Huntington’s, goes back to the US doctor George Huntington, who was the first to describe the disease in 1872 and recognized that Huntington’s disease is inherited.
The terms used today for Huntington’s disease are Huntington’s disease or Huntington’s disease.
What are the symptoms of Huntington’s disease?
Huntington’s disease: early stages
Huntington’s disease often begins with non-specific symptoms. The first signs are, for example, mental abnormalities that progress further. Many patients are increasingly irritable, aggressive, depressed or disinhibited. Others experience a loss of spontaneity or increasing anxiety.
People with Huntington’s disease often manage to incorporate these exaggerated and unintentional movements into their movements at first. This gives the observer the impression of exaggerated gestures. In many cases, those affected do not even notice their movement disorders as such at first.
Huntington’s disease: later stages
If Huntington’s disease progresses further, the tongue and throat muscles are also affected. Speech appears choppy and sounds are emitted explosively. Swallowing disorders are also possible. There is then a risk of choking, food entering the airways and pneumonia developing as a result.
In the final stage of Huntington’s disease, patients are usually bedridden and completely dependent on the help of others.
Huntington’s disease – similar diseases
Symptoms similar to those of Huntington’s disease sometimes occur with other, non-hereditary causes. Examples include the consequences of infectious diseases or hormonal changes during pregnancy (chorea gravidarum). Medication and hormonal contraceptives such as the pill are less common triggers.
In contrast to Huntington’s disease, however, the course of these forms is not progressive. The movement disorders usually regress. Severe psychological symptoms are atypical in such cases.
What is the prognosis and life expectancy for Huntington’s disease?
Huntington’s disease cannot be cured. The life expectancy of Huntington’s disease depends, among other things, on the age at the onset of the disease. On average, sufferers live with the disease for around 15 to 20 years after diagnosis. However, as the course of the disease varies from person to person, life expectancy is higher or lower in individual cases.
How does Huntington’s disease progress?
The symptoms that those affected develop and how well they respond to the various medications varies greatly. Only specialists who deal with Huntington’s disease on a daily basis are sufficiently familiar with the many peculiarities of the disease.
It is advisable for Huntington’s patients to undergo regular examinations at one of the Huntington’s centers in Germany in order to adapt the individual therapy to the current course of the disease.
How is Huntington’s disease inherited?
The cause of Huntington’s disease is a genetic defect. As a result, nerve cells in certain areas of the brain die. The disease affects both men and women because the gene responsible is not inherited in a sex-linked manner. It is therefore not located on the sex chromosomes X and Y, but on the other chromosomes, the so-called autosomes. These autosomes are each present in two copies, one from the mother and one from the father.
Inheritance in Huntington’s disease
Inheritance of Huntington’s disease – errors on chromosome four
The molecular alphabet of genetic material (deoxyribonucleic acid, or DNA for short) consists of four nucleic acids: adenine, thymine, guanine and cytosine. New combinations of these four letters form the entire genetic information, which is stored in the form of thread-like structures known as chromosomes.
In Huntington’s disease, one gene on chromosome four is altered. This is the huntingtin gene (HTT gene). It was identified in 1993. The huntingtin protein, which is encoded by this gene, does not function properly. This ultimately leads to the symptoms of Huntington’s disease.
In around one to three percent of patients, no blood relative with Huntington’s disease can be found. This is either a completely new genetic change, a so-called new mutation, or a parent of the Huntington’s disease patient already had 30 to 35 repeats and the disease did not break out in them.
The more CAG repeats are counted on chromosome four, the earlier the onset of Huntington’s disease and the faster the disease progresses. The number of CAG repeats often increases in the next generation. If there are more than 36, the children develop Huntington’s disease.
How is Huntington’s disease diagnosed?
Determining nerve damage
To determine the extent of nerve damage, people with Huntington’s disease undergo neurological, neuropsychological and psychiatric examinations. These examinations are carried out either by experienced doctors or specially trained neuropsychologists. Imaging examinations such as computed tomography (CT) or magnetic resonance imaging (MRI) of the brain can be used to visualize the degeneration of individual areas of the brain that are particularly affected in Huntington’s disease. Electrophysiological diagnostics examine brain function and also provide important information in individual cases of Huntington’s disease.
Genetic test for Huntington’s disease
Genetic testing is not permitted for minors. Genetic testing for Huntington’s disease may also not be carried out at the request of third parties. This means, for example, that doctors, insurance companies, adoption agencies or employers are not allowed to carry out a genetic test if the (adult) person concerned does not want this themselves.
Genetic testing of the unborn child during pregnancy or of the embryo before artificial insemination is prohibited in Germany, as this is a disease that only breaks out after the age of 18. In Austria and Switzerland, however, such prenatal diagnostics or peri-implantation diagnostics are possible in principle.
What treatment is available for Huntington’s disease?
Huntington’s disease – medication
Huntington’s disease cannot be treated causally and cannot be cured. However, certain medications alleviate the symptoms.
For example, doctors use the active ingredients tiapride and tetrabenazine to combat the excessive and uncontrolled movements. These drugs counteract the body’s own messenger substance dopamine. Antidepressants from the group of selective serotonin reuptake inhibitors (SSRIs) or sulpiride are usually used for depressive moods.
There is no official treatment recommendation for the development of dementia in Huntington’s disease. In some studies, the active ingredient memantine slowed down the mental decline.
Occupational therapy can also be used to train activities of daily living. This enables people with Huntington’s disease to remain independent for longer. Psychotherapy helps many sufferers to cope better with the disease. Self-help groups are also a great support for many.
As many people with Huntington’s disease lose a lot of weight during the course of their illness, a high-calorie diet makes sense. In some cases, being slightly overweight improves the symptoms of Huntington’s disease.
Huntington’s disease – Research
Smaller studies showed slightly positive effects for CoEnzyme Q10 and creatine. However, larger-scale studies had to be discontinued as there was no prospect of efficacy. Coenzyme Q10 is a protein that occurs naturally in the body and protects cells from damage.
Another active substance tested for the treatment of Huntington’s disease, ethyl-icosapent, also failed to improve movement disorders according to studies.
Can Huntington’s disease be prevented?
As with all hereditary diseases, there is no prevention for Huntington’s disease. To prevent the disease from being passed on to a child, a genetic test provides information on whether a parent is a carrier of the genetic defect.
