HUNTINGTON'S DISEASE DIAGNOSIS, TREATMENT AND CAUSES

Huntington’s disease is a rare genetic disorder caused by a mutation in the gene for a protein called huntingtin. The mutation causes progressive destruction of brain cells, primarily in a region called the basal ganglia. As a result, patients have difficulties controlling their movements, their emotions and behavior, and have trouble thinking. The disease worsens over time, with patients eventually losing the ability to walk, speak, or care for themselves and, thus, they become completely dependent on others.

Huntington's disease is inherited in an autosomal dominant pattern and thus anyone who inherits the faulty gene eventually gets the disease. A parent with the faulty gene has a 50% chance of passing the disease to his or her children.

Huntington’s disease affects both men and women equally. The onset and progression of the disease vary from one person to another. The most common form of the disease occurs in middle-aged people and progresses slowly over the course of 15 to 20 years, with a gradual loss of mental abilities and control of body movements. It can also occur in children, with symptoms usually beginning in the teen years.

In 2000, there were 30,000 cases of Huntington's disease in the US, according to Stanford University's Huntington's Outreach Project for Education, suggesting a prevalence rate of 100 cases per million people.

Huntington's disease is a complex neuropsychiatric disease that produces three main types of symptoms: difficulty controlling movement, difficulty with emotion and behavior, and difficulty thinking.

The most common movement problem is chorea, which are large, jerky, dance-like movements. Other problems can include slowed movements, sustained twisting movements, small twitch-like movements in the limbs, and difficulties speaking and swallowing.

Problems with thinking can include difficulty paying attention, problems with mental planning and flexibility, inability to successfully perform mental tasks (eg, balancing a checkbook), and memory loss. These problems can appear before the first signs of motor impairment emerge.

There can be emotional and behavioral changes that are particularly challenging for the patient and family members as well. These can include anxiety, depression, lack of motivation, impulsivity, emotional outbursts, and mood swings. In the first year after diagnosis, there is a higher incidence of depression and suicidal thoughts. As many as 40% of people with the condition may experience depressive symptoms. Speaking with a doctor is important if you or your loved one has this condition. Depressive or suicidal thoughts should be monitored closely.

People with Huntington’s disease become increasingly impaired over the course of the illness. In the later stages of the disease, patients lose the ability to walk or speak. They frequently lose a significant amount of weight and can have difficulty sleeping. They usually become completely dependent on others for activities of daily living, such as dressing, grooming, and feeding.

Ultimately, the most common causes of death associated with this disease are pneumonia, aspiration of food or impaired swallowing, heart disease, and infections.

Diagnosis requires a complete neurological examination, including motor, sensory, neuropsychological, and psychiatric assessments. If results of this examination suggest that a patient has the disease, brain imaging, such as MRI, may be ordered. A genetic test is usually required to provide a definite diagnosis. Patients should meet with a genetic counselor before the gene test is ordered so they can make an informed decision about whether or not they want the test.

Genetic tests can also determine whether a person carries the faulty gene before they have symptoms if they have a parent with Huntington’s disease. The decision to get tested can be very difficult and is a personal one; there is no right or wrong decision. At-risk individuals should consider the many implications that genetic testing may have when deciding whether or not to get tested.

There is no cure for Huntington's disease, and there are no treatments known to slow or reverse its process. Medications used to treat patients with Huntington’s disease are targeted to specific symptoms.

Dopamine blockers and drugs such as amantadine and tetrabenazine can be used to help control involuntary movements and some of the abnormal behaviors associated with this disease. Antidepressants and antipsychotic drugs are used to help with emotional and behavioral problems. Depression and suicide are common among those diagnosed with this condition. It is important for caregivers to watch symptoms closely and seek medical help immediately when issues or questions come up.

A nutritionist can provide advice and support if weight loss becomes problematic.