Cause

Huntington's disease: a genetic disorder

Huntington’s disease is caused by a gene defect located in the Huntingtin gene chromosome 4. The defective gene causes the slow, progressive death of nerve cells in the brain. These changes are responsible for the various symptoms of the hereditary, autosomal dominant disease. Autosomal dominant means that only one parent needs to possess the abnormal gene in order for the child to have a 50% risk of inheriting the defective gene. Whoever possesses the defective gene will become sick sooner or later.

Symptoms

Duration

The disease most often appears in adults between the ages of 40 and 50. However, Huntington’s disease can also appear in children as young as 1 or in adults as old as 80. The latter form of Huntington’s is, however, very rare. Huntington’s manifests itself through motor dysfunction and through emotional changes that can vary extensively.   

Chorea and other motor dysfunctions

Typical motor dysfunctions consist of jerky, involuntary movements of the arms (e.g. finger and hands), the legs, the torso and the face (chorea: Greek for dance). At the beginning, family members and friends often fail to see the symptoms for what they really are, instead they interpret the sick person’s staggering and slurring as drunkenness.

Aside from the considerable motor dysfunctions, one will also notice swallowing and speaking impairments in later phases. Difficulty in swallowing can lead to life-threatening situations.

Emotional and psychiatric problems

Early symptoms of Huntington’s usually include irritability, loss of motivation and a change in the emotional state. Another obvious symptom is the diminishment of mental faculties to the point of dementia. Vegetative symptoms such as a lack of appetite and sleep can also occur.

Patients with Huntington's disease also go through emotional changes. They can become emotionally closed, moody and aggressive. Some patients start having delusions and develop a psychosis as their disease progresses.

Depression can be a symptom of the disease or it can be a reaction to the realization that one has the disease.

Diagnosis

A number of tests need to be carried out in order to diagnose Huntington’s disease, particularly during the early stages of the disease.

The first step is to obtain a comprehensive overview of the family background

By taking the typical symptoms into account, an experienced neurologist/psychiatrist can usually suspect Huntington’s disease if a family member from the patient is known to have had it.

The neurological examination

A diagnosis can be made without the need for additional testing through clinical findings and an anamnesis. In most cases however, imaging techniques such as computer tomography and MRIs are used to make a final diagnosis.

Neuropsychological test

Neuropsychological tests that test factors like mental performance can be used to judge the severity of the disease. However they tend to be unspecific.

Genetic testing

Since 1993, Huntington’s disease can be accurately diagnosed using a gene test that only needs a small blood sample from the patient. Even healthy persons, who are at risk as a result of having a family member with Huntington’s disease, can be tested to see whether or not they have inherited the gene.

Any individual who is considering genetic diagnosis should first seek professional support.

Everyday life

It is important for both the patient and family members, friends and colleagues at work to take the time to develop strategies on how to handle future conflicts as soon as possible.

Social support is essential for the patient and the family. It is in the best interest of the Huntington’s disease patient to remain in their working environment for as long as possible. During the later stages of the disease, efforts should be made to establish a structured, daily routine.

It is also very important that the Huntington’s disease patient has the correct diet. These patients have an increased metabolic rate. Any weight loss should be avoided. Indeed, being slightly overweight actually has a positive influence on the prognosis.

Self-help groups can provide assistance for patients and family members to cope with daily life.