Huntington's disease is a progressive, degenerative disease that causes certain nerve cells in your brain to waste away. As a result, you may experience uncontrolled movements, emotional disturbances and mental deterioration. Huntington's disease is an inherited disease. Signs and symptoms usually develop in middle age. Younger people with Huntington's disease often have a more severe case, and their symptoms may progress more quickly. Rarely, children may develop Huntington's disease. Medications are available to help manage the signs and symptoms of Huntington's disease, but treatments can't prevent the physical and mental decline associated with the condition.

Complications of Huntington’s disease

After onset of the disease, signs and symptoms continue until death. Though the signs and symptoms vary from person to person, vital functions, such as swallowing, eating, speaking and walking, usually degenerate over time. Depression is common in Huntington's disease, and some people are at risk of suicide. However, death generally occurs as a result of complications of the disease, such as a fall or an infection like pneumonia.

Causes of Huntington’s disease

• Huntington's disease is an inherited condition caused by a single abnormal gene. Doctors refer to the illness as an autosomal dominant disorder because only one copy of the defective gene, inherited from either parent, is necessary to produce the disease. If one parent has the single faulty gene, the chance that an offspring will have the defect is 50 percent. Because signs and symptoms typically first appear in middle age, some parents may not know they carry the gene until they've already had children and possibly passed on the trait.
• If your child doesn't inherit the faulty gene, he or she won't develop Huntington's disease and can't pass it on to the next generation. Everyone who has the gene eventually develops Huntington's disease, if he or she lives long enough.
• In 2006, researchers discovered that the protein expressed by the Huntington's gene interacts with another protein to disturb the way that cholesterol accumulates in the brain. Cholesterol is essential for healthy brain cells and the network among those brain cells — but the cholesterol needs to be in proper levels and in the proper locations. When the network of brain cells is disrupted, motor skills, cognitive skills and speech can be affected. If scientists can figure out a way to disrupt this interaction between the proteins, they may eventually be able to develop a targeted drug therapy.

Signs & Symptoms of Huntington’s disease

The signs and symptoms of Huntington's disease can vary significantly from person to person. Huntington's disease usually develops slowly, and the severity of signs and symptoms is related to the degree of nerve cell loss. Death occurs about 10 to 30 years after signs and symptoms first appear. The disease progression may occur faster in younger people.

Early signs and symptoms of Huntington's disease often include:

• Personality changes, such as irritability, anger, depression or a loss of interest
• Decreased cognitive abilities, such as difficulty making decisions, learning new information, answering questions and remembering important information
• Mild balance problems
• Clumsiness
• Involuntary facial movements, such as grimacing

Your family and friends may notice these changes before you become aware of them.

Later signs and symptoms of Huntington's disease can include:

• Sudden jerky, involuntary movements (chorea) throughout your body
• Severe problems with balance and coordination
• Jerky, rapid eye movements
• Hesitant, halting or slurred speech
• Swallowing problems
• Dementia

Young people who develop Huntington's disease may have signs and symptoms that mimic Parkinson's disease:

• Muscle rigidity
• Tremors
• Slow movements

Seizures may also occur in those with early-onset Huntington's disease.

Diagnosis of Huntington’s disease

During an initial evaluation, your doctor will:

• Perform a physical exam
• Ask about your medical history and your family medical history
• Ask about any recent emotional or intellectual changes

If your doctor suspects Huntington's disease, you'll likely:

• Undergo a psychiatric evaluation
• Meet with a genetic counselor to discuss the possibility of having a blood test to determine whether you have the defective gene. If you know that one of your parents had Huntington's, ask your doctor about genetic testing. Genetic testing is generally done in a setting where pre-test counseling and post-test support are available along with testing.

Your doctor may also suggest:

• Computerized tomography (CT)
• Magnetic resonance imaging (MRI)

These imaging tests can help your doctor identify any changes to your brain's structure and rule out other disorders.

Treatments of Huntington’s disease

No satisfactory treatment is available to stop or reverse Huntington's disease. Some approaches can control signs and symptoms, but Huntington's disease eventually causes physical and mental disability. As the disease progresses, long-term nursing home care may be necessary.

Medications

Tetrabenazine (Xenazine) is the first medication to be specifically approved by the Food and Drug Administration for the treatment of the signs or symptoms of Huntington's. It helps reduce the jerky, involuntary movements of Huntington's disease by increasing the amount of dopamine available in the brain. Possible side effects include insomnia, drowsiness, nausea and restlessness. This medication isn't recommended for use in anyone with depression, especially anyone with suicidal thoughts. Tranquilizers such as clonazepam (Klonopin) and antipsychotic drugs such as haloperidol and clozapine (Clozaril) can help control movements, violent outbursts and hallucinations. While these medications can be helpful, a common side effect is sedation, and in some cases, these medications may cause additional stiffness and rigidity. Various medications, including fluoxetine (Prozac, Sarafem), sertraline (Zoloft) and nortriptyline (Pamelor), can help control depression and the obsessive-compulsive rituals that some people with Huntington's disease develop. Medications such as lithium (Eskalith, Lithobid) can help control extreme emotions and mood swings. Side effects from many of the drugs used to treat the symptoms of Huntington's disease may include hyperexcitability, fatigue and restlessness.

Speech therapy

Huntington's disease can impair your speech, affecting your ability to express complex thoughts. You may find that speech therapy helps. Remind friends, family members and caregivers that if you don't speak, it doesn't necessarily mean that you don't understand what's going on. Ask people to continue talking to you and keep your environment as normal as possible.

Physical and occupational therapy

Physical therapy can help keep muscles stronger and more flexible, which helps maintain balance and may lessen the risk of falling. Occupational therapy can help make your home safer and give you strategies for coping with memory and concentration problems. Later in the disease, occupational therapy can assist you with eating, dressing and hygiene challenges.

Experimental treatments and new research

Scientists are working to try to come up with new treatments to slow the course of Huntington's disease. One area of research is the combination of certain cancer and AIDS drugs. This combination has halted the progress of Huntington's in fruit flies. The use of stem cells is another avenue for research. Transplanted in the brain, stem cells might help reduce some of the damage that's been done to the neurons in the brain. Animal studies have shown promising results, but much more research must occur. In October 2008, researchers began recruiting for a randomized, placebo-controlled clinical trial of a new drug currently known as ACR16. This medication stabilizes levels of dopamine, which may improve motor, cognitive and psychiatric functioning.

Prevention of Huntington’s disease

• If you have a family history of Huntington's disease, you may want to consider genetic counseling before starting a family. A blood test can determine the presence of the faulty gene, even before you show signs or symptoms. If one parent carries the defective gene, his or her child has a 50 percent chance of developing Huntington's disease.
• If you're at risk of passing the genetic defect that causes Huntington's disease to your children, you may wish to consider adoption or certain forms of assisted reproduction. One possibility is in vitro fertilization with pre-implantation screening. In this procedure, embryos are screened for the Huntington's disease gene mutation, and those that don't have the mutation are then implanted in the woman's uterus.

When to seek Medical Advice

• See your doctor if you notice changes in your movements, emotional control or mental ability. These signs and symptoms can be the result of many conditions, so they don't necessarily mean you have Huntington's disease.
• If you have a family history of Huntington's disease, you may want to talk with your doctor about genetic testing that can tell you whether or not you carry the defective gene. Deciding whether to be tested for the gene is a personal decision. For some people, the uncertainty of whether they carry the faulty gene is stressful and distracting. For others, the knowledge that they will develop the condition is burdensome. If you're uncertain whether testing is right for you, consider contacting a genetic counselor who can help you understand the implications of a positive or negative test result, walk you through the testing process, and help you weigh the pros and cons. Ask your doctor for help locating a genetic counselor.