What Is Huntington's Disease?
Huntington's Disease (known as HD) is a terminal genetic disorder that causes progressive degeneration of the nerve cells in the brain. As Huntington's Disease is a degenerative disorder, HD has a progressive course that impacts a person's functional abilities, often leading to uncontrolled movements, a steady loss of cognitive function as well as emotional or psychiatric disorders and an early death.
There is currently no cure for Huntington's Disease.
The typical age of onset for Huntington's Disease is in a person's 40's or 50's, however, this is only the average age of onset - symptoms may appear earlier or later.
If the symptoms of Huntington's Disease begin before age 20, the disease is called "Juvenile Huntington's Disease," which will be discussed in further detail below. For those who have Juvenile Huntington's Disease, the presentation of the disease may appear differently and the course of the disease progresses more rapidly.
While medications are available to manage the symptoms of Huntington's Disease, these treatments are unable to prevent the progression and decline of the physical, mental and behavioral functions.
What Causes Huntington's Disease?
Huntington's Disease is a genetic disorder, which means that a person with Huntington's Disease inherited a defect in a single gene. As an autosomal dominant disorder, Huntington's Disease only needs one copy of the defective gene to inherit the disease.
Read more about genetic disorders.
A parent with a defective Huntington's gene, can pass on the defective copy of the gene or the healthy copy of the gene. This means that every child of this parent has a 50% chance of developing Huntington's Disease.
In rare cases, people develop Huntington's disease without a family history of the disease. This may occur as a result of a genetic mutation during your father's sperm development.
What Are The Stages of Huntington's Disease?
While the symptoms of HD may vary wildly (even in families), the disease progression has three stages.
Early Stage Huntington's Disease:
In the early stages of Huntington's Disease, there are subtle changes in coordination as well as some involuntary movements, as well as difficulty with problem solving abilities. Often, the person is depressed. During Early Stage Huntington's Disease, a person may begin to lose the ability to be as functional at work and around the house.
Middle Stage Huntington's Disease:
In the Middle Stages of Huntington's Disease, a person will notice increased problems with movements. Medication may be used to reduce involuntary movements of Huntington's Chorea. Therapies, like occupational, speech, and physical therapies, may be used to help with strength training, dealing with new involuntary movements, and help with communication and eating. Activities of daily living may become more difficult.
Late Stage Huntington's Disease:
During the Late Stages of Huntington's Disease, the person who has Huntington's Disease is completely dependent upon others to care for him or her. Choking and falls become greater and greater concerns as the Huntington's Chorea becomes more (or less) severe. A person in Late Stage HD cannot walk or speak, but can still understand language and is aware of family and friends. Eventually, during the Last Stage of HD, the person will die from complications of Huntington's Disease.
What Are The Symptoms Of Huntington's Disease?
Huntington's Disease often causes a wide range of signs and symptoms. The presentation of signs and symptoms of Huntington's Disease vary wildly at first, but as the disease is progressive, some cognitive, movement, and psychiatric disorders may have more of an effect on a person with Huntington's Disease.
These symptoms are broken down by the part of the body affected by Huntington's.
Movement Disorders Associated With Huntington's Disease:
Movement disorders associated with Huntington's include both involuntary movements as well as impairments in voluntary movements. The impairments in voluntary movements can lead to greater problems with a person's ability to continue to work, perform activities of daily living as well as affect their ability to communicate and live independently:
- Huntington's Chorea - involuntary jerking or writhing movements
- Muscle rigidity
- Uncoordinated, slow fine movements
- Involuntary and sustained contracture of the muscles
- Impairment in gait, posture or balance
- Impaired ability to swallow
- Difficulties in speech
Cognitive Disorders Associated With Huntington's Disease:
- Unable to begin a task
- Unable to initiate a conversation
- Unable to properly plan, organize or prioritize tasks
- Perseveration - the repetition of a particular response (like a word, phrase, or gesture), despite the absence or cessation of a stimulus
- Diminished impulse control - leading to angry outbursts, acting without thinking through the consequences, or being sexually promiscuous
- Diminished awareness of their behaviors and abilities
- Inability to focus on a task for long periods of time
- Processes thoughts and finds words slowly
- Challenging to learn new information
Mental Illnesses Associated With Huntington's Disease:
Depression and Huntington's Disease: While depression is the most common mental illness associated with Huntington's Disease, it is not due to the grim diagnosis, instead, the depression in people who have Huntington's Disease is related to brain injury and changes in brain functions. Symptoms of depression include:
- Loss of interest in previously pleasurable activities
- Withdrawing socially from others
- Feeling sad and unhappy much of the time
- Changes in sleep patterns - insomnia or excessive sleeping
- Feeling worthless or guilty
- Reduced sexual appetite
- Struggles with concentration
Obsessive-Compulsive Disorder and Huntington's Disease - an anxiety disorder in which a person has intrusive thoughts and engages in repetitive behaviors as a way to reduce the anxiety he or she feels.
Mania and Huntington's Disease - a particularly elevated mood leads to inflated self-esteem and impulsive behaviors.
Bipolar Disorder and Huntington's Disease - a mental illness in which a person has bouts of mania and depression.
Personality Changes With Huntington's Disease May Include:
As Huntington's Disease leads to degenerative brain damage, a person who has Huntington's Disease may exhibit changes in his or her personality that is not related to specific mental illnesses. These may include:
- Inappropriate sexual behaviors
- Lower sexual inhibitions
How Is Huntington's Disease Diagnosed?
The diagnosis of Huntington's Disease is primarily based upon a general exam, family history, neurological and psychiatric evaluations.
Neurological Examination: If Huntington's Disease is suspected, a general practitioner will write a referral to a neurologist for further testing. A neurologist will conduct simple tests to ascertain any motor symptoms. The neurologist will be looking at the following:
- Muscle strength
- Muscle tone
- Sensation of touch
- Mental Status
- Vision and movements of the eyes
Psychiatric Evaluation: If Huntington's is suspected, it's likely that the general practitioner will make a referral to a psychiatrist for a psychiatric examination. During this evaluation, a psychiatrist will evaluate the following:
- Emotional State
- Behavioral patterns
- Quality of judgement
- Ability to cope
- Any signs of distorted thinking
- Evidence of substance use and abuse
Brain Imagining Studies: The brain may be looked at in more detail to assess the function and structure of the brain. These tests may include:
- Brain Imaging Studies (MRI, CT Scan): these images of the brain may show structural changes at the sites in the brain commonly affected by Huntington's Disease. These images may not reflect change in brain structure or function if it is early in the disease process.
- EEG (Electroencephalogram): for people who have experienced seizures, an EEG may be ordered to record the electrical activity of the brain. Certain abnormal patterns may indicate problems that may contribute to seizures.
Genetic Counseling And Testing:
If all symptoms point to Huntington's Disease, it may be recommended that a person undergo a genetic test to ascertain whether or not the person is carrying the defective Huntington's Gene. The genetic test can confirm the diagnosis of HD, especially if no other family members have been diagnosed. This test, however, won't help with coming up with a plan of attack or treatment plan, but can provide a proper diagnosis. This test should only be performed after a person who may have Huntington's Disease meets with a genetic counselor.
Predictive Genetic Testing:
For those who have a family history of Huntington's Disease, a predictive genetic test may be given, even if the person in question does not display any signs of Huntington's Disease. This test will not help develop a treatment plan, nor can it properly predict when the onset of symptoms may begin, but many who have a relative with Huntington's cannot bear the wait to determine if the person, him or herself, will develop Huntington's Disease. This test is only done after a patient meets with a genetic counselor.
How Is Huntington's Disease Treated?
While there exists no cure currently for Huntington's Disease, treatment is aimed at increasing quality of life and minimizing the symptoms of this terminal disease. Treatment plans will change as the disease itself changes.
Treatment of Movement Disorders:
- Tetrabenazine (Xenazine) - the first drug marketed toward Huntington's Disease, this drug aims at reducing Huntington's Chorea - the systematic jerking and writing movements associated with Huntington's Disease. This drug, however, may trigger depression (already common in people with Huntington's Disease) or worsen existing depression.
- Anti-psychotic drugs may also treat Huntington's Chorea. However, typical antipsychotics may worsen the involuntary movements associated with Huntington's Disease.
- Anti-seizure drugs and anti-anxiety drugs may also be prescribed to aid in suppression of Huntington's Chorea, muscle dystonia, and muscle rigidity.
Treatment of Psychiatric Disorders:
Antidepressants may be used to treat the depression that Huntington's Disease causes.
Anti-psychotic drugs may be used to treat mood disorders, suppress any violent outbursts, or other psychotic features.
Mood-Stabilizers may be used to stabilize the moods of people with Huntington's Disease who develop bipolar disorder or other mood altering conditions.
Psychotherapy - a mental health professional can help a person who has Huntington's Disease deal with behavioral problems, help with coping strategies, work through end-of-life issues with the person and his or her family.
Physical Therapy - a physical therapist can help a person with Huntington's disease learn exercises that can help with strength, balance, coordination and flexibility, which can reduce the risks for falls.
Speech Therapy - Huntington's Disease can significantly impact control of the mouth and the muscles in the mouth and throat that are needed for eating, speaking and swallowing. A speech therapist can help with speech and work to develop other ways of communication as well as help with any difficulties eating or swallowing.
Occupational Therapy - an occupational therapist can teach a person who has Huntington's disease ways to use devices that can improve function. This may include:
- Handrails in the bathroom and hallways
- Utensils for those who have problems with fine motor abilities.
- Devices for bathing and dressing
What is The Prognosis For Huntington's Disease?
There is currently no known cure for Huntington's Disease - nothing has been identified that can properly stop or reverse the progressive course of the disease. However, the HD has been located, which means that research is being done to ascertain how the HD gene causes diseases in the body.
Huntington's Disease is currently a terminal illness. Treatment may be aimed at reducing symptoms, but not stopping or reversing the damage that HD causes the brain.
Complications of Huntington's Disease:
Huntington's Disease is a progressive, degenerative disease, which means that after the onset of initial symptoms, a person who has Huntington's Disease loses functional abilities over a period of time.
The rate of progression and duration for Huntington's varies wildly: from onset to death usually takes 10-30 years.
The major depression that many people with Huntington's Disease experience may increase risks for suicide. Research into Huntington's Disease and suicide suggests that the greatest risk for suicide in those who have major depression and Huntington's Disease occurs before the diagnosis as well as in the middle stages of the disease - when the person can see him or herself losing independence.
Over time, a person who has Huntington's Disease will require help with all activities of daily living and care. During the late stage of Huntington's disease, she or he will be bedbound and unable to communicate. The person, even in the late stages of the disease, will still understand what is going on around him or her.
Most common causes of death for those who have Huntington's Disease are:
- Infections like pneumonia
- Complications from being unable to swallow
- Fall-related Injuries
Coping With A Diagnosis of Huntington's Disease:
There is no easy way to learn that you, or someone you love, has a terminal illness. The emotional reaction of coping with a terminal illness like Huntington's can range from shock to anger to depression to anger and back again. Here are some strategies for coping with a terminal diagnosis:
Locate and use any support services in the area. This can include non-profit agencies as well as the governmental agencies.
Plan for the end-of-life care. Huntington's is not only terminal, it's a progressive disease, so arrangements for a live-in facility and defining end of life preferences should be discussed and determined before the person with Huntington's Disease enters the later stages of the disease.
Put together a living will to specifically define end of life wishes - this can include care preferences (hospice versus skilled nursing facility), end of life interventions as well as DNR orders.
Put together an advance directive - this can spell out and identify several people who can make medical or financial decisions in the event that the person with the terminal illness can no longer communicate.
Find - and use - local support services, such as a support group. Not only can a support group provide you with others in your situation to talk to, a support group can also identify resources available to you in your community.
Take all signs of suicide or suicidal ideation seriously.
Expect that the grief over this diagnosis will be a lasting one, especially for friends and family who watch someone they love lose all ability to care for him or herself.
Don't be afraid, if you are the caregiver, of taking a break and using respite care so that you do not burn out. Caregiver burnout can be avoided if you make time for yourself.
Enjoy the time you do have with the person who has Huntington's Disease and help him or her create some amazing memories.
Read more about terminal illness.
Read more about caregiving.
What Is Juvenile Huntington's Disease?
Less than ten percent of those who have Huntington's Disease will develop symptoms before the age of twenty. As Juvenile Huntington's Disease is uncommon and differs from the adult-onset version of Huntington's Disease, the way in which HD presents can provide unique challenges to the affected person, his or her family, and other medical professionals involved in his or her care.
Juvenile-Onset Huntington's Disease results in death within 15 years from first symptoms.
Symptoms of Juvenile Huntington's Disease:
Both the onset and progression of Huntington's Disease in those under twenty may be different than what adults experience. Early signs of Juvenile Huntington's Disease include:
- Behavioral issues and problems
- Rapid and significant drop in scholastic performance
- Loss of formerly-known psychical or academic skills
- Slight involuntary movements
- Changes in fine motor skills - such as handwriting ability
- Contracted and rigid muscles that can affect movement
If Juvenile-Onset Huntington's Disease is suspected, visit here to find a local center for Huntington's Disease (Huntington's Disease Society of America).
Additional Huntington's Disease Resources:
Huntington's Disease Society of America - national voluntary health organization that provides support, research materials and education to the public about Huntington's Disease.
University of Utah Genetics Center - great resource about genetics and the role genes play in Huntington's Disease.
Hereditary Disease Foundation - aims to cure genetic illness by supporting basic biomedical research. The HDF was started by Dr. Milton Wexler in 1968 when his wife was diagnosed with Huntington's disease (HD). The Foundation uses a variety of strategies - workshops, grants, fellowships, and targeted research contracts - to solve the mysteries of genetic disease and develop new treatments and cures.
International Huntington's Association - a federation of national voluntary health agencies that share common concern for individuals with Huntington's Disease (HD) and their families. Each agency promotes lay and professional education; individual and family support; psycho-social, clinical and biomedical research; and ethical and legal considerations related to Huntington's Disease in its respective country.