Huntington’s Disease – Characteristics And Symptoms

George Huntington first described Huntington’s disease in 1872 and referred to it as hereditary chorea. The term is derived from the Greek word “dance”, choreia. He used it to highlight distorted shapes, grimaces and uncontrolled movements that patients experience. This is why this disease is also known as “San Vitos dance” or “San Vitos evil”.

In any case, the current name is Huntington’s disease, and the disorder involves motor problems. It is part of incipient dementia.

Epidemiology

The prevalence of this disease is about 5-10 people per 100,000 people. The age a person can get it varies greatly, between 10 and 60 years. However, it is normal for it to manifest halfway through life, between the ages of 35 and 50. It can start in one of two ways:

• Subtype in children. Symptoms appear before the age of 20 in 3-10% of cases. It is a clinical picture characterized by slow movement, stiffness, important cognitive disorders and even epilepsy.
• Late or senile subtype. Changes after the age of 60 manifest themselves in 10-15% of cases. This condition occurs through maternal transmission and has a slower evolutionary course. It causes Korean symptoms, mainly with little cognitive functioning change.

The worsening is progressive after the first symptoms. Life expectancy in a patient is between 10 and 20 years.

The genetic cause of Huntington’s disease – a change in brain structure

The genetic change that causes Huntington’s disease occurs in the short arm of chromosome number 4. This mutation causes a series of changes in the structure of the striatum and in the cerebral cortex.

As the disease progresses, there is marked atrophy of the bilateral cudate nucleus and putamen, along with atrophy of the forehead and temporal lobe.

Similarly, there is a change in the transmission of the neurosystems, a lower density of dopamine receptors and loss of abundant glutamatergic afferents from the neocortex.

The striatum is found in the anterior brain and is the most important route for information into the basal ganglia. This participates in motor and non-motor functions. The changes caused in these structures, or the result of degeneration, are the causes of the characteristic symptomatic triad of HD.

The symptomatic triad of Huntington’s disease

Motor disorders

These are usually the most common symptoms of this disease. It begins with small tics and gradually increases the Korean movements that extend to the head, neck and extremities. They end up causing significant limitations in a person’s life.

For example, walking becomes increasingly unstable and people lose mobility completely.

It also affects speech, and communication becomes more difficult over time. In fact, the risk of suffocation increases due to ingestion. In addition, there are other changes such as stiffness, slowness and inability to initiate voluntary movements, especially complex movements. There is also dystonia and disturbances in the eye movements.

Cognitive disorders

During the first years of this disease, the most characteristic cognitive deficits affect memory and learning. The former is due to problems in information gathering rather than consolidation problems. However, they retain recognition.

Spatial and long-term memory disorders are common, although they do not show severe gradual deterioration.

There is a change in memory, which means that patients can forget how to perform learned and automated behaviors. It also affects their attention, and they have difficulty focusing and staying focused.

Others suffer from changes in verbal flow, decreased cognitive processing speed, visuospatial changes and impairment of executive functions.

Behavioral disorders

These may appear several years before the first symptoms. Thus, there are frequent personality changes, irritability, anxiety and inhibition in the prediagnostic phases.

35-75% of people who are diagnosed with this condition end up with other mental disorders. Some of them are depression, irritability, restlessness and anxiety, apathy and lack of initiative. There are also emotional changes such as aggression, fables and hallucinations, insomnia and suicidal thoughts.

Treatment and improvement of the quality of life of patients with Huntington’s disease

At present, no treatment can stop or reverse the course of Huntington’s disease. Treatment of symptoms is mainly to compensate for motor, cognitive, emotional and behavioral disorders. The goal is to increase a patient’s ability to function as much as possible and thus improve the quality of life.

Humans can address motor symptoms with medication and physiotherapy. They can also control behavioral and emotional changes through a combination of pharmacology and neuropsychological rehabilitation.

Genetic counseling is a great tool when it comes to addressing this disease. This is because it provides a presymptomatic diagnosis for people at risk for hereditary HD. In this way, they have the opportunity to start treatment early and prepare emotionally for this disease.