Huntington's disease results from genetically programmed degeneration of brain cells, called neurons, in certain areas of the brain. This degeneration causes uncontrolled movements, loss of intellectual faculties and emotional disturbances.

Causes

Huntington's disease is a familial disease, passed from parent to child through a mutation in the normal gene. Each child of a Huntington's disease parent has a 50-50 chance of inheriting the Huntington's disease gene. If a child does not inherit the Huntington's disease gene, he or she will not develop the disease and cannot pass it to subsequent generations. A person who inherits the Huntington's disease gene will sooner or later develop the disease. Whether one child inherits the gene has no bearing on whether others will or will not inherit the gene.

In 1 to 3 percent of individuals with Huntington’s disease, no family history of it can be found.

Symptoms

It is impossible to predict when the symptoms of Huntington’s will develop. This can cause a great deal of anxiety for individuals who know their Huntington’s Disease gene status. For this reason, it is recommended that both symptomatic and non-symptomatic individuals with Huntington’s or at risk for Huntington’s consider routine visits to a movement disorder center. A specialist can review your condition and discuss any changes or potential treatments.

Some early symptoms of Huntington's disease are:

• Mood swings
• Depression
• Irritability
• Trouble driving
• Difficulty learning new things
• Difficulty remembering
• Difficulty making a decision

As the disease progresses, concentration on intellectual tasks becomes increasingly difficult and the patient may have difficulty feeding himself or herself and swallowing. The rate of disease progression and the age of onset vary from person to person.

Diagnosis

The diagnosis of most movement disorders are made based on the clinical exam and history. A neurological examination assesses motor and sensory skills, the functioning of one or more cranial nerves, hearing and speech, vision, coordination and balance, mental status and changes in mood or behavior, among other abilities. A movement disorder exam often focuses on additional features like tremor analysis, muscle tone, posture and balance.

However, in many cases, additional screening tests are useful to clarify the diagnosis. Laboratory screening tests of blood, urine or other substances are used to help diagnose disease, better understand the disease process and monitor levels of therapeutic drugs. Certain tests provide general information, while others are used to identify specific health concerns.

Genetic testing or counseling can help parents who have a family history of a neurological disease determine if they are carrying one of the known genes that cause the disorder or find out if their child is affected. Some movement disorders, especially those affecting young patients, have a known genetic component that can be tested in the blood.