Huntington Disease
Huntington disease
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Huntington disease is a disorder in which nerve cells in certain parts of the brain waste away, or degenerate. The disease is passed down through families.
Causes
Huntington disease is caused by a genetic defect on chromosome 4. The defect causes a part of DNA, called a CAG repeat, to occur many more times than it is supposed to. Normally, this section of DNA is repeated 10 to 28 times. But in persons with Huntington disease, it is repeated 36 to 120 times.
As the gene is passed down through families, the number of repeats tend to get larger. The larger the number of repeats, the higher your chance of developing symptoms at an earlier age. Therefore, as the disease is passed along in families, symptoms develop at younger and younger ages.
There are two forms of Huntington disease.
Adult-onset Huntington disease is the most common. Persons with this form usually develop symptoms in their mid 30s and 40s.
Early-onset Huntington disease affects a small number of cases and begins in childhood or the teens.
If one of your parents has Huntington disease, you have a 50% chance of getting the gene. If you get the gene from both your parents, you will develop the disease at some point in your life. You will also pass it on to your children. If you do not get the gene from your parents, you cannot pass the gene on to your children.
Symptoms
Behavior changes may occur before movement problems, and can include:
Behavioral disturbances
Hallucinations
Irritability
Moodiness
Restlessness or fidgeting
Paranoia
Psychosis
Abnormal and unusual movements include:
Facial movements, including grimaces
Head turning to shift eye position
Quick, sudden, sometimes wild jerking movements of the arms, legs, face, and other body parts
Slow, uncontrolled movements
Unsteady gait
Dementia that slowly gets worse, including:
Disorientation or confusion
Email this page to a friendShare on facebookShare on twitterBookmark & SharePrinter-friendly version
Huntington disease is a disorder in which nerve cells in certain parts of the brain waste away, or degenerate. The disease is passed down through families.
Causes
Huntington disease is caused by a genetic defect on chromosome 4. The defect causes a part of DNA, called a CAG repeat, to occur many more times than it is supposed to. Normally, this section of DNA is repeated 10 to 28 times. But in persons with Huntington disease, it is repeated 36 to 120 times.
As the gene is passed down through families, the number of repeats tend to get larger. The larger the number of repeats, the higher your chance of developing symptoms at an earlier age. Therefore, as the disease is passed along in families, symptoms develop at younger and younger ages.
There are two forms of Huntington disease.
Adult-onset Huntington disease is the most common. Persons with this form usually develop symptoms in their mid 30s and 40s.
Early-onset Huntington disease affects a small number of cases and begins in childhood or the teens.
If one of your parents has Huntington disease, you have a 50% chance of getting the gene. If you get the gene from both your parents, you will develop the disease at some point in your life. You will also pass it on to your children. If you do not get the gene from your parents, you cannot pass the gene on to your children.
Symptoms
Behavior changes may occur before movement problems, and can include:
Behavioral disturbances
Hallucinations
Irritability
Moodiness
Restlessness or fidgeting
Paranoia
Psychosis
Abnormal and unusual movements include:
Facial movements, including grimaces
Head turning to shift eye position
Quick, sudden, sometimes wild jerking movements of the arms, legs, face, and other body parts
Slow, uncontrolled movements
Unsteady gait
Dementia that slowly gets worse, including:
Disorientation or confusion